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 "qemu-common.h" 26 #include "block/block_int.h" 27 #include "sysemu/block-backend.h" 28 #include "qemu/module.h" 29 #include <zlib.h> 30 #include "qapi/qmp/qerror.h" 31 #include "crypto/cipher.h" 32 #include "migration/migration.h" 33 34 /**************************************************************/ 35 /* QEMU COW block driver with compression and encryption support */ 36 37 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 38 #define QCOW_VERSION 1 39 40 #define QCOW_CRYPT_NONE 0 41 #define QCOW_CRYPT_AES 1 42 43 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 44 45 typedef struct QCowHeader { 46 uint32_t magic; 47 uint32_t version; 48 uint64_t backing_file_offset; 49 uint32_t backing_file_size; 50 uint32_t mtime; 51 uint64_t size; /* in bytes */ 52 uint8_t cluster_bits; 53 uint8_t l2_bits; 54 uint16_t padding; 55 uint32_t crypt_method; 56 uint64_t l1_table_offset; 57 } QEMU_PACKED QCowHeader; 58 59 #define L2_CACHE_SIZE 16 60 61 typedef struct BDRVQcowState { 62 int cluster_bits; 63 int cluster_size; 64 int cluster_sectors; 65 int l2_bits; 66 int l2_size; 67 unsigned int l1_size; 68 uint64_t cluster_offset_mask; 69 uint64_t l1_table_offset; 70 uint64_t *l1_table; 71 uint64_t *l2_cache; 72 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 73 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 74 uint8_t *cluster_cache; 75 uint8_t *cluster_data; 76 uint64_t cluster_cache_offset; 77 QCryptoCipher *cipher; /* NULL if no key yet */ 78 uint32_t crypt_method_header; 79 CoMutex lock; 80 Error *migration_blocker; 81 } BDRVQcowState; 82 83 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 84 85 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 86 { 87 const QCowHeader *cow_header = (const void *)buf; 88 89 if (buf_size >= sizeof(QCowHeader) && 90 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 91 be32_to_cpu(cow_header->version) == QCOW_VERSION) 92 return 100; 93 else 94 return 0; 95 } 96 97 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 98 Error **errp) 99 { 100 BDRVQcowState *s = bs->opaque; 101 unsigned int len, i, shift; 102 int ret; 103 QCowHeader header; 104 105 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header)); 106 if (ret < 0) { 107 goto fail; 108 } 109 be32_to_cpus(&header.magic); 110 be32_to_cpus(&header.version); 111 be64_to_cpus(&header.backing_file_offset); 112 be32_to_cpus(&header.backing_file_size); 113 be32_to_cpus(&header.mtime); 114 be64_to_cpus(&header.size); 115 be32_to_cpus(&header.crypt_method); 116 be64_to_cpus(&header.l1_table_offset); 117 118 if (header.magic != QCOW_MAGIC) { 119 error_setg(errp, "Image not in qcow format"); 120 ret = -EINVAL; 121 goto fail; 122 } 123 if (header.version != QCOW_VERSION) { 124 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version); 125 ret = -ENOTSUP; 126 goto fail; 127 } 128 129 if (header.size <= 1) { 130 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 131 ret = -EINVAL; 132 goto fail; 133 } 134 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 135 error_setg(errp, "Cluster size must be between 512 and 64k"); 136 ret = -EINVAL; 137 goto fail; 138 } 139 140 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 141 * so bytes = num_entries << 3. */ 142 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 143 error_setg(errp, "L2 table size must be between 512 and 64k"); 144 ret = -EINVAL; 145 goto fail; 146 } 147 148 if (header.crypt_method > QCOW_CRYPT_AES) { 149 error_setg(errp, "invalid encryption method in qcow header"); 150 ret = -EINVAL; 151 goto fail; 152 } 153 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 154 error_setg(errp, "AES cipher not available"); 155 ret = -EINVAL; 156 goto fail; 157 } 158 s->crypt_method_header = header.crypt_method; 159 if (s->crypt_method_header) { 160 bs->encrypted = 1; 161 } 162 s->cluster_bits = header.cluster_bits; 163 s->cluster_size = 1 << s->cluster_bits; 164 s->cluster_sectors = 1 << (s->cluster_bits - 9); 165 s->l2_bits = header.l2_bits; 166 s->l2_size = 1 << s->l2_bits; 167 bs->total_sectors = header.size / 512; 168 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 169 170 /* read the level 1 table */ 171 shift = s->cluster_bits + s->l2_bits; 172 if (header.size > UINT64_MAX - (1LL << shift)) { 173 error_setg(errp, "Image too large"); 174 ret = -EINVAL; 175 goto fail; 176 } else { 177 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 178 if (l1_size > INT_MAX / sizeof(uint64_t)) { 179 error_setg(errp, "Image too large"); 180 ret = -EINVAL; 181 goto fail; 182 } 183 s->l1_size = l1_size; 184 } 185 186 s->l1_table_offset = header.l1_table_offset; 187 s->l1_table = g_try_new(uint64_t, s->l1_size); 188 if (s->l1_table == NULL) { 189 error_setg(errp, "Could not allocate memory for L1 table"); 190 ret = -ENOMEM; 191 goto fail; 192 } 193 194 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table, 195 s->l1_size * sizeof(uint64_t)); 196 if (ret < 0) { 197 goto fail; 198 } 199 200 for(i = 0;i < s->l1_size; i++) { 201 be64_to_cpus(&s->l1_table[i]); 202 } 203 204 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 205 s->l2_cache = 206 qemu_try_blockalign(bs->file->bs, 207 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 208 if (s->l2_cache == NULL) { 209 error_setg(errp, "Could not allocate L2 table cache"); 210 ret = -ENOMEM; 211 goto fail; 212 } 213 s->cluster_cache = g_malloc(s->cluster_size); 214 s->cluster_data = g_malloc(s->cluster_size); 215 s->cluster_cache_offset = -1; 216 217 /* read the backing file name */ 218 if (header.backing_file_offset != 0) { 219 len = header.backing_file_size; 220 if (len > 1023 || len >= sizeof(bs->backing_file)) { 221 error_setg(errp, "Backing file name too long"); 222 ret = -EINVAL; 223 goto fail; 224 } 225 ret = bdrv_pread(bs->file->bs, header.backing_file_offset, 226 bs->backing_file, len); 227 if (ret < 0) { 228 goto fail; 229 } 230 bs->backing_file[len] = '\0'; 231 } 232 233 /* Disable migration when qcow images are used */ 234 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 235 "does not support live migration", 236 bdrv_get_device_or_node_name(bs)); 237 migrate_add_blocker(s->migration_blocker); 238 239 qemu_co_mutex_init(&s->lock); 240 return 0; 241 242 fail: 243 g_free(s->l1_table); 244 qemu_vfree(s->l2_cache); 245 g_free(s->cluster_cache); 246 g_free(s->cluster_data); 247 return ret; 248 } 249 250 251 /* We have nothing to do for QCOW reopen, stubs just return 252 * success */ 253 static int qcow_reopen_prepare(BDRVReopenState *state, 254 BlockReopenQueue *queue, Error **errp) 255 { 256 return 0; 257 } 258 259 static int qcow_set_key(BlockDriverState *bs, const char *key) 260 { 261 BDRVQcowState *s = bs->opaque; 262 uint8_t keybuf[16]; 263 int len, i; 264 Error *err; 265 266 memset(keybuf, 0, 16); 267 len = strlen(key); 268 if (len > 16) 269 len = 16; 270 /* XXX: we could compress the chars to 7 bits to increase 271 entropy */ 272 for(i = 0;i < len;i++) { 273 keybuf[i] = key[i]; 274 } 275 assert(bs->encrypted); 276 277 qcrypto_cipher_free(s->cipher); 278 s->cipher = qcrypto_cipher_new( 279 QCRYPTO_CIPHER_ALG_AES_128, 280 QCRYPTO_CIPHER_MODE_CBC, 281 keybuf, G_N_ELEMENTS(keybuf), 282 &err); 283 284 if (!s->cipher) { 285 /* XXX would be nice if errors in this method could 286 * be properly propagate to the caller. Would need 287 * the bdrv_set_key() API signature to be fixed. */ 288 error_free(err); 289 return -1; 290 } 291 return 0; 292 } 293 294 /* The crypt function is compatible with the linux cryptoloop 295 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 296 supported */ 297 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 298 uint8_t *out_buf, const uint8_t *in_buf, 299 int nb_sectors, bool enc, Error **errp) 300 { 301 union { 302 uint64_t ll[2]; 303 uint8_t b[16]; 304 } ivec; 305 int i; 306 int ret; 307 308 for(i = 0; i < nb_sectors; i++) { 309 ivec.ll[0] = cpu_to_le64(sector_num); 310 ivec.ll[1] = 0; 311 if (qcrypto_cipher_setiv(s->cipher, 312 ivec.b, G_N_ELEMENTS(ivec.b), 313 errp) < 0) { 314 return -1; 315 } 316 if (enc) { 317 ret = qcrypto_cipher_encrypt(s->cipher, 318 in_buf, 319 out_buf, 320 512, 321 errp); 322 } else { 323 ret = qcrypto_cipher_decrypt(s->cipher, 324 in_buf, 325 out_buf, 326 512, 327 errp); 328 } 329 if (ret < 0) { 330 return -1; 331 } 332 sector_num++; 333 in_buf += 512; 334 out_buf += 512; 335 } 336 return 0; 337 } 338 339 /* 'allocate' is: 340 * 341 * 0 to not allocate. 342 * 343 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 344 * 'n_end') 345 * 346 * 2 to allocate a compressed cluster of size 347 * 'compressed_size'. 'compressed_size' must be > 0 and < 348 * cluster_size 349 * 350 * return 0 if not allocated. 351 */ 352 static uint64_t get_cluster_offset(BlockDriverState *bs, 353 uint64_t offset, int allocate, 354 int compressed_size, 355 int n_start, int n_end) 356 { 357 BDRVQcowState *s = bs->opaque; 358 int min_index, i, j, l1_index, l2_index; 359 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 360 uint32_t min_count; 361 int new_l2_table; 362 363 l1_index = offset >> (s->l2_bits + s->cluster_bits); 364 l2_offset = s->l1_table[l1_index]; 365 new_l2_table = 0; 366 if (!l2_offset) { 367 if (!allocate) 368 return 0; 369 /* allocate a new l2 entry */ 370 l2_offset = bdrv_getlength(bs->file->bs); 371 /* round to cluster size */ 372 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 373 /* update the L1 entry */ 374 s->l1_table[l1_index] = l2_offset; 375 tmp = cpu_to_be64(l2_offset); 376 if (bdrv_pwrite_sync(bs->file->bs, 377 s->l1_table_offset + l1_index * sizeof(tmp), 378 &tmp, sizeof(tmp)) < 0) 379 return 0; 380 new_l2_table = 1; 381 } 382 for(i = 0; i < L2_CACHE_SIZE; i++) { 383 if (l2_offset == s->l2_cache_offsets[i]) { 384 /* increment the hit count */ 385 if (++s->l2_cache_counts[i] == 0xffffffff) { 386 for(j = 0; j < L2_CACHE_SIZE; j++) { 387 s->l2_cache_counts[j] >>= 1; 388 } 389 } 390 l2_table = s->l2_cache + (i << s->l2_bits); 391 goto found; 392 } 393 } 394 /* not found: load a new entry in the least used one */ 395 min_index = 0; 396 min_count = 0xffffffff; 397 for(i = 0; i < L2_CACHE_SIZE; i++) { 398 if (s->l2_cache_counts[i] < min_count) { 399 min_count = s->l2_cache_counts[i]; 400 min_index = i; 401 } 402 } 403 l2_table = s->l2_cache + (min_index << s->l2_bits); 404 if (new_l2_table) { 405 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 406 if (bdrv_pwrite_sync(bs->file->bs, l2_offset, l2_table, 407 s->l2_size * sizeof(uint64_t)) < 0) 408 return 0; 409 } else { 410 if (bdrv_pread(bs->file->bs, l2_offset, l2_table, 411 s->l2_size * sizeof(uint64_t)) != 412 s->l2_size * sizeof(uint64_t)) 413 return 0; 414 } 415 s->l2_cache_offsets[min_index] = l2_offset; 416 s->l2_cache_counts[min_index] = 1; 417 found: 418 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 419 cluster_offset = be64_to_cpu(l2_table[l2_index]); 420 if (!cluster_offset || 421 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 422 if (!allocate) 423 return 0; 424 /* allocate a new cluster */ 425 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 426 (n_end - n_start) < s->cluster_sectors) { 427 /* if the cluster is already compressed, we must 428 decompress it in the case it is not completely 429 overwritten */ 430 if (decompress_cluster(bs, cluster_offset) < 0) 431 return 0; 432 cluster_offset = bdrv_getlength(bs->file->bs); 433 cluster_offset = (cluster_offset + s->cluster_size - 1) & 434 ~(s->cluster_size - 1); 435 /* write the cluster content */ 436 if (bdrv_pwrite(bs->file->bs, cluster_offset, s->cluster_cache, 437 s->cluster_size) != 438 s->cluster_size) 439 return -1; 440 } else { 441 cluster_offset = bdrv_getlength(bs->file->bs); 442 if (allocate == 1) { 443 /* round to cluster size */ 444 cluster_offset = (cluster_offset + s->cluster_size - 1) & 445 ~(s->cluster_size - 1); 446 bdrv_truncate(bs->file->bs, cluster_offset + s->cluster_size); 447 /* if encrypted, we must initialize the cluster 448 content which won't be written */ 449 if (bs->encrypted && 450 (n_end - n_start) < s->cluster_sectors) { 451 uint64_t start_sect; 452 assert(s->cipher); 453 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 454 memset(s->cluster_data + 512, 0x00, 512); 455 for(i = 0; i < s->cluster_sectors; i++) { 456 if (i < n_start || i >= n_end) { 457 Error *err = NULL; 458 if (encrypt_sectors(s, start_sect + i, 459 s->cluster_data, 460 s->cluster_data + 512, 1, 461 true, &err) < 0) { 462 error_free(err); 463 errno = EIO; 464 return -1; 465 } 466 if (bdrv_pwrite(bs->file->bs, 467 cluster_offset + i * 512, 468 s->cluster_data, 512) != 512) 469 return -1; 470 } 471 } 472 } 473 } else if (allocate == 2) { 474 cluster_offset |= QCOW_OFLAG_COMPRESSED | 475 (uint64_t)compressed_size << (63 - s->cluster_bits); 476 } 477 } 478 /* update L2 table */ 479 tmp = cpu_to_be64(cluster_offset); 480 l2_table[l2_index] = tmp; 481 if (bdrv_pwrite_sync(bs->file->bs, l2_offset + l2_index * sizeof(tmp), 482 &tmp, sizeof(tmp)) < 0) 483 return 0; 484 } 485 return cluster_offset; 486 } 487 488 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 489 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 490 { 491 BDRVQcowState *s = bs->opaque; 492 int index_in_cluster, n; 493 uint64_t cluster_offset; 494 495 qemu_co_mutex_lock(&s->lock); 496 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 497 qemu_co_mutex_unlock(&s->lock); 498 index_in_cluster = sector_num & (s->cluster_sectors - 1); 499 n = s->cluster_sectors - index_in_cluster; 500 if (n > nb_sectors) 501 n = nb_sectors; 502 *pnum = n; 503 if (!cluster_offset) { 504 return 0; 505 } 506 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) { 507 return BDRV_BLOCK_DATA; 508 } 509 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 510 *file = bs->file->bs; 511 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 512 } 513 514 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 515 const uint8_t *buf, int buf_size) 516 { 517 z_stream strm1, *strm = &strm1; 518 int ret, out_len; 519 520 memset(strm, 0, sizeof(*strm)); 521 522 strm->next_in = (uint8_t *)buf; 523 strm->avail_in = buf_size; 524 strm->next_out = out_buf; 525 strm->avail_out = out_buf_size; 526 527 ret = inflateInit2(strm, -12); 528 if (ret != Z_OK) 529 return -1; 530 ret = inflate(strm, Z_FINISH); 531 out_len = strm->next_out - out_buf; 532 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 533 out_len != out_buf_size) { 534 inflateEnd(strm); 535 return -1; 536 } 537 inflateEnd(strm); 538 return 0; 539 } 540 541 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 542 { 543 BDRVQcowState *s = bs->opaque; 544 int ret, csize; 545 uint64_t coffset; 546 547 coffset = cluster_offset & s->cluster_offset_mask; 548 if (s->cluster_cache_offset != coffset) { 549 csize = cluster_offset >> (63 - s->cluster_bits); 550 csize &= (s->cluster_size - 1); 551 ret = bdrv_pread(bs->file->bs, coffset, s->cluster_data, csize); 552 if (ret != csize) 553 return -1; 554 if (decompress_buffer(s->cluster_cache, s->cluster_size, 555 s->cluster_data, csize) < 0) { 556 return -1; 557 } 558 s->cluster_cache_offset = coffset; 559 } 560 return 0; 561 } 562 563 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 564 int nb_sectors, QEMUIOVector *qiov) 565 { 566 BDRVQcowState *s = bs->opaque; 567 int index_in_cluster; 568 int ret = 0, n; 569 uint64_t cluster_offset; 570 struct iovec hd_iov; 571 QEMUIOVector hd_qiov; 572 uint8_t *buf; 573 void *orig_buf; 574 Error *err = NULL; 575 576 if (qiov->niov > 1) { 577 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 578 if (buf == NULL) { 579 return -ENOMEM; 580 } 581 } else { 582 orig_buf = NULL; 583 buf = (uint8_t *)qiov->iov->iov_base; 584 } 585 586 qemu_co_mutex_lock(&s->lock); 587 588 while (nb_sectors != 0) { 589 /* prepare next request */ 590 cluster_offset = get_cluster_offset(bs, sector_num << 9, 591 0, 0, 0, 0); 592 index_in_cluster = sector_num & (s->cluster_sectors - 1); 593 n = s->cluster_sectors - index_in_cluster; 594 if (n > nb_sectors) { 595 n = nb_sectors; 596 } 597 598 if (!cluster_offset) { 599 if (bs->backing) { 600 /* read from the base image */ 601 hd_iov.iov_base = (void *)buf; 602 hd_iov.iov_len = n * 512; 603 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 604 qemu_co_mutex_unlock(&s->lock); 605 ret = bdrv_co_readv(bs->backing->bs, sector_num, 606 n, &hd_qiov); 607 qemu_co_mutex_lock(&s->lock); 608 if (ret < 0) { 609 goto fail; 610 } 611 } else { 612 /* Note: in this case, no need to wait */ 613 memset(buf, 0, 512 * n); 614 } 615 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 616 /* add AIO support for compressed blocks ? */ 617 if (decompress_cluster(bs, cluster_offset) < 0) { 618 goto fail; 619 } 620 memcpy(buf, 621 s->cluster_cache + index_in_cluster * 512, 512 * n); 622 } else { 623 if ((cluster_offset & 511) != 0) { 624 goto fail; 625 } 626 hd_iov.iov_base = (void *)buf; 627 hd_iov.iov_len = n * 512; 628 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 629 qemu_co_mutex_unlock(&s->lock); 630 ret = bdrv_co_readv(bs->file->bs, 631 (cluster_offset >> 9) + index_in_cluster, 632 n, &hd_qiov); 633 qemu_co_mutex_lock(&s->lock); 634 if (ret < 0) { 635 break; 636 } 637 if (bs->encrypted) { 638 assert(s->cipher); 639 if (encrypt_sectors(s, sector_num, buf, buf, 640 n, false, &err) < 0) { 641 goto fail; 642 } 643 } 644 } 645 ret = 0; 646 647 nb_sectors -= n; 648 sector_num += n; 649 buf += n * 512; 650 } 651 652 done: 653 qemu_co_mutex_unlock(&s->lock); 654 655 if (qiov->niov > 1) { 656 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 657 qemu_vfree(orig_buf); 658 } 659 660 return ret; 661 662 fail: 663 error_free(err); 664 ret = -EIO; 665 goto done; 666 } 667 668 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 669 int nb_sectors, QEMUIOVector *qiov) 670 { 671 BDRVQcowState *s = bs->opaque; 672 int index_in_cluster; 673 uint64_t cluster_offset; 674 const uint8_t *src_buf; 675 int ret = 0, n; 676 uint8_t *cluster_data = NULL; 677 struct iovec hd_iov; 678 QEMUIOVector hd_qiov; 679 uint8_t *buf; 680 void *orig_buf; 681 682 s->cluster_cache_offset = -1; /* disable compressed cache */ 683 684 if (qiov->niov > 1) { 685 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 686 if (buf == NULL) { 687 return -ENOMEM; 688 } 689 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 690 } else { 691 orig_buf = NULL; 692 buf = (uint8_t *)qiov->iov->iov_base; 693 } 694 695 qemu_co_mutex_lock(&s->lock); 696 697 while (nb_sectors != 0) { 698 699 index_in_cluster = sector_num & (s->cluster_sectors - 1); 700 n = s->cluster_sectors - index_in_cluster; 701 if (n > nb_sectors) { 702 n = nb_sectors; 703 } 704 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 705 index_in_cluster, 706 index_in_cluster + n); 707 if (!cluster_offset || (cluster_offset & 511) != 0) { 708 ret = -EIO; 709 break; 710 } 711 if (bs->encrypted) { 712 Error *err = NULL; 713 assert(s->cipher); 714 if (!cluster_data) { 715 cluster_data = g_malloc0(s->cluster_size); 716 } 717 if (encrypt_sectors(s, sector_num, cluster_data, buf, 718 n, true, &err) < 0) { 719 error_free(err); 720 ret = -EIO; 721 break; 722 } 723 src_buf = cluster_data; 724 } else { 725 src_buf = buf; 726 } 727 728 hd_iov.iov_base = (void *)src_buf; 729 hd_iov.iov_len = n * 512; 730 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 731 qemu_co_mutex_unlock(&s->lock); 732 ret = bdrv_co_writev(bs->file->bs, 733 (cluster_offset >> 9) + index_in_cluster, 734 n, &hd_qiov); 735 qemu_co_mutex_lock(&s->lock); 736 if (ret < 0) { 737 break; 738 } 739 ret = 0; 740 741 nb_sectors -= n; 742 sector_num += n; 743 buf += n * 512; 744 } 745 qemu_co_mutex_unlock(&s->lock); 746 747 if (qiov->niov > 1) { 748 qemu_vfree(orig_buf); 749 } 750 g_free(cluster_data); 751 752 return ret; 753 } 754 755 static void qcow_close(BlockDriverState *bs) 756 { 757 BDRVQcowState *s = bs->opaque; 758 759 qcrypto_cipher_free(s->cipher); 760 s->cipher = NULL; 761 g_free(s->l1_table); 762 qemu_vfree(s->l2_cache); 763 g_free(s->cluster_cache); 764 g_free(s->cluster_data); 765 766 migrate_del_blocker(s->migration_blocker); 767 error_free(s->migration_blocker); 768 } 769 770 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 771 { 772 int header_size, backing_filename_len, l1_size, shift, i; 773 QCowHeader header; 774 uint8_t *tmp; 775 int64_t total_size = 0; 776 char *backing_file = NULL; 777 int flags = 0; 778 Error *local_err = NULL; 779 int ret; 780 BlockBackend *qcow_blk; 781 782 /* Read out options */ 783 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 784 BDRV_SECTOR_SIZE); 785 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 786 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 787 flags |= BLOCK_FLAG_ENCRYPT; 788 } 789 790 ret = bdrv_create_file(filename, opts, &local_err); 791 if (ret < 0) { 792 error_propagate(errp, local_err); 793 goto cleanup; 794 } 795 796 qcow_blk = blk_new_open(filename, NULL, NULL, 797 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, 798 &local_err); 799 if (qcow_blk == NULL) { 800 error_propagate(errp, local_err); 801 ret = -EIO; 802 goto cleanup; 803 } 804 805 blk_set_allow_write_beyond_eof(qcow_blk, true); 806 807 ret = blk_truncate(qcow_blk, 0); 808 if (ret < 0) { 809 goto exit; 810 } 811 812 memset(&header, 0, sizeof(header)); 813 header.magic = cpu_to_be32(QCOW_MAGIC); 814 header.version = cpu_to_be32(QCOW_VERSION); 815 header.size = cpu_to_be64(total_size); 816 header_size = sizeof(header); 817 backing_filename_len = 0; 818 if (backing_file) { 819 if (strcmp(backing_file, "fat:")) { 820 header.backing_file_offset = cpu_to_be64(header_size); 821 backing_filename_len = strlen(backing_file); 822 header.backing_file_size = cpu_to_be32(backing_filename_len); 823 header_size += backing_filename_len; 824 } else { 825 /* special backing file for vvfat */ 826 backing_file = NULL; 827 } 828 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 829 unmodified sectors */ 830 header.l2_bits = 12; /* 32 KB L2 tables */ 831 } else { 832 header.cluster_bits = 12; /* 4 KB clusters */ 833 header.l2_bits = 9; /* 4 KB L2 tables */ 834 } 835 header_size = (header_size + 7) & ~7; 836 shift = header.cluster_bits + header.l2_bits; 837 l1_size = (total_size + (1LL << shift) - 1) >> shift; 838 839 header.l1_table_offset = cpu_to_be64(header_size); 840 if (flags & BLOCK_FLAG_ENCRYPT) { 841 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 842 } else { 843 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 844 } 845 846 /* write all the data */ 847 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header)); 848 if (ret != sizeof(header)) { 849 goto exit; 850 } 851 852 if (backing_file) { 853 ret = blk_pwrite(qcow_blk, sizeof(header), 854 backing_file, backing_filename_len); 855 if (ret != backing_filename_len) { 856 goto exit; 857 } 858 } 859 860 tmp = g_malloc0(BDRV_SECTOR_SIZE); 861 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 862 BDRV_SECTOR_SIZE); i++) { 863 ret = blk_pwrite(qcow_blk, header_size + 864 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 865 if (ret != BDRV_SECTOR_SIZE) { 866 g_free(tmp); 867 goto exit; 868 } 869 } 870 871 g_free(tmp); 872 ret = 0; 873 exit: 874 blk_unref(qcow_blk); 875 cleanup: 876 g_free(backing_file); 877 return ret; 878 } 879 880 static int qcow_make_empty(BlockDriverState *bs) 881 { 882 BDRVQcowState *s = bs->opaque; 883 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 884 int ret; 885 886 memset(s->l1_table, 0, l1_length); 887 if (bdrv_pwrite_sync(bs->file->bs, s->l1_table_offset, s->l1_table, 888 l1_length) < 0) 889 return -1; 890 ret = bdrv_truncate(bs->file->bs, s->l1_table_offset + l1_length); 891 if (ret < 0) 892 return ret; 893 894 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 895 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 896 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 897 898 return 0; 899 } 900 901 /* XXX: put compressed sectors first, then all the cluster aligned 902 tables to avoid losing bytes in alignment */ 903 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 904 const uint8_t *buf, int nb_sectors) 905 { 906 BDRVQcowState *s = bs->opaque; 907 z_stream strm; 908 int ret, out_len; 909 uint8_t *out_buf; 910 uint64_t cluster_offset; 911 912 if (nb_sectors != s->cluster_sectors) { 913 ret = -EINVAL; 914 915 /* Zero-pad last write if image size is not cluster aligned */ 916 if (sector_num + nb_sectors == bs->total_sectors && 917 nb_sectors < s->cluster_sectors) { 918 uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size); 919 memset(pad_buf, 0, s->cluster_size); 920 memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE); 921 ret = qcow_write_compressed(bs, sector_num, 922 pad_buf, s->cluster_sectors); 923 qemu_vfree(pad_buf); 924 } 925 return ret; 926 } 927 928 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 929 930 /* best compression, small window, no zlib header */ 931 memset(&strm, 0, sizeof(strm)); 932 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 933 Z_DEFLATED, -12, 934 9, Z_DEFAULT_STRATEGY); 935 if (ret != 0) { 936 ret = -EINVAL; 937 goto fail; 938 } 939 940 strm.avail_in = s->cluster_size; 941 strm.next_in = (uint8_t *)buf; 942 strm.avail_out = s->cluster_size; 943 strm.next_out = out_buf; 944 945 ret = deflate(&strm, Z_FINISH); 946 if (ret != Z_STREAM_END && ret != Z_OK) { 947 deflateEnd(&strm); 948 ret = -EINVAL; 949 goto fail; 950 } 951 out_len = strm.next_out - out_buf; 952 953 deflateEnd(&strm); 954 955 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 956 /* could not compress: write normal cluster */ 957 ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors); 958 if (ret < 0) { 959 goto fail; 960 } 961 } else { 962 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 963 out_len, 0, 0); 964 if (cluster_offset == 0) { 965 ret = -EIO; 966 goto fail; 967 } 968 969 cluster_offset &= s->cluster_offset_mask; 970 ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len); 971 if (ret < 0) { 972 goto fail; 973 } 974 } 975 976 ret = 0; 977 fail: 978 g_free(out_buf); 979 return ret; 980 } 981 982 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 983 { 984 BDRVQcowState *s = bs->opaque; 985 bdi->cluster_size = s->cluster_size; 986 return 0; 987 } 988 989 static QemuOptsList qcow_create_opts = { 990 .name = "qcow-create-opts", 991 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 992 .desc = { 993 { 994 .name = BLOCK_OPT_SIZE, 995 .type = QEMU_OPT_SIZE, 996 .help = "Virtual disk size" 997 }, 998 { 999 .name = BLOCK_OPT_BACKING_FILE, 1000 .type = QEMU_OPT_STRING, 1001 .help = "File name of a base image" 1002 }, 1003 { 1004 .name = BLOCK_OPT_ENCRYPT, 1005 .type = QEMU_OPT_BOOL, 1006 .help = "Encrypt the image", 1007 .def_value_str = "off" 1008 }, 1009 { /* end of list */ } 1010 } 1011 }; 1012 1013 static BlockDriver bdrv_qcow = { 1014 .format_name = "qcow", 1015 .instance_size = sizeof(BDRVQcowState), 1016 .bdrv_probe = qcow_probe, 1017 .bdrv_open = qcow_open, 1018 .bdrv_close = qcow_close, 1019 .bdrv_reopen_prepare = qcow_reopen_prepare, 1020 .bdrv_create = qcow_create, 1021 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1022 .supports_backing = true, 1023 1024 .bdrv_co_readv = qcow_co_readv, 1025 .bdrv_co_writev = qcow_co_writev, 1026 .bdrv_co_get_block_status = qcow_co_get_block_status, 1027 1028 .bdrv_set_key = qcow_set_key, 1029 .bdrv_make_empty = qcow_make_empty, 1030 .bdrv_write_compressed = qcow_write_compressed, 1031 .bdrv_get_info = qcow_get_info, 1032 1033 .create_opts = &qcow_create_opts, 1034 }; 1035 1036 static void bdrv_qcow_init(void) 1037 { 1038 bdrv_register(&bdrv_qcow); 1039 } 1040 1041 block_init(bdrv_qcow_init); 1042