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 "qemu/module.h" 28 #include <zlib.h> 29 #include "qapi/qmp/qerror.h" 30 #include "crypto/cipher.h" 31 #include "migration/migration.h" 32 33 /**************************************************************/ 34 /* QEMU COW block driver with compression and encryption support */ 35 36 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 37 #define QCOW_VERSION 1 38 39 #define QCOW_CRYPT_NONE 0 40 #define QCOW_CRYPT_AES 1 41 42 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 43 44 typedef struct QCowHeader { 45 uint32_t magic; 46 uint32_t version; 47 uint64_t backing_file_offset; 48 uint32_t backing_file_size; 49 uint32_t mtime; 50 uint64_t size; /* in bytes */ 51 uint8_t cluster_bits; 52 uint8_t l2_bits; 53 uint16_t padding; 54 uint32_t crypt_method; 55 uint64_t l1_table_offset; 56 } QEMU_PACKED QCowHeader; 57 58 #define L2_CACHE_SIZE 16 59 60 typedef struct BDRVQcowState { 61 int cluster_bits; 62 int cluster_size; 63 int cluster_sectors; 64 int l2_bits; 65 int l2_size; 66 unsigned int l1_size; 67 uint64_t cluster_offset_mask; 68 uint64_t l1_table_offset; 69 uint64_t *l1_table; 70 uint64_t *l2_cache; 71 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 72 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 73 uint8_t *cluster_cache; 74 uint8_t *cluster_data; 75 uint64_t cluster_cache_offset; 76 QCryptoCipher *cipher; /* NULL if no key yet */ 77 uint32_t crypt_method_header; 78 CoMutex lock; 79 Error *migration_blocker; 80 } BDRVQcowState; 81 82 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 83 84 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 85 { 86 const QCowHeader *cow_header = (const void *)buf; 87 88 if (buf_size >= sizeof(QCowHeader) && 89 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 90 be32_to_cpu(cow_header->version) == QCOW_VERSION) 91 return 100; 92 else 93 return 0; 94 } 95 96 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 97 Error **errp) 98 { 99 BDRVQcowState *s = bs->opaque; 100 unsigned int len, i, shift; 101 int ret; 102 QCowHeader header; 103 104 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header)); 105 if (ret < 0) { 106 goto fail; 107 } 108 be32_to_cpus(&header.magic); 109 be32_to_cpus(&header.version); 110 be64_to_cpus(&header.backing_file_offset); 111 be32_to_cpus(&header.backing_file_size); 112 be32_to_cpus(&header.mtime); 113 be64_to_cpus(&header.size); 114 be32_to_cpus(&header.crypt_method); 115 be64_to_cpus(&header.l1_table_offset); 116 117 if (header.magic != QCOW_MAGIC) { 118 error_setg(errp, "Image not in qcow format"); 119 ret = -EINVAL; 120 goto fail; 121 } 122 if (header.version != QCOW_VERSION) { 123 char version[64]; 124 snprintf(version, sizeof(version), "QCOW version %" PRIu32, 125 header.version); 126 error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE, 127 bdrv_get_device_or_node_name(bs), "qcow", 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 bs->encrypted = 1; 164 } 165 s->cluster_bits = header.cluster_bits; 166 s->cluster_size = 1 << s->cluster_bits; 167 s->cluster_sectors = 1 << (s->cluster_bits - 9); 168 s->l2_bits = header.l2_bits; 169 s->l2_size = 1 << s->l2_bits; 170 bs->total_sectors = header.size / 512; 171 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 172 173 /* read the level 1 table */ 174 shift = s->cluster_bits + s->l2_bits; 175 if (header.size > UINT64_MAX - (1LL << shift)) { 176 error_setg(errp, "Image too large"); 177 ret = -EINVAL; 178 goto fail; 179 } else { 180 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 181 if (l1_size > INT_MAX / sizeof(uint64_t)) { 182 error_setg(errp, "Image too large"); 183 ret = -EINVAL; 184 goto fail; 185 } 186 s->l1_size = l1_size; 187 } 188 189 s->l1_table_offset = header.l1_table_offset; 190 s->l1_table = g_try_new(uint64_t, s->l1_size); 191 if (s->l1_table == NULL) { 192 error_setg(errp, "Could not allocate memory for L1 table"); 193 ret = -ENOMEM; 194 goto fail; 195 } 196 197 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table, 198 s->l1_size * sizeof(uint64_t)); 199 if (ret < 0) { 200 goto fail; 201 } 202 203 for(i = 0;i < s->l1_size; i++) { 204 be64_to_cpus(&s->l1_table[i]); 205 } 206 207 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 208 s->l2_cache = 209 qemu_try_blockalign(bs->file->bs, 210 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 211 if (s->l2_cache == NULL) { 212 error_setg(errp, "Could not allocate L2 table cache"); 213 ret = -ENOMEM; 214 goto fail; 215 } 216 s->cluster_cache = g_malloc(s->cluster_size); 217 s->cluster_data = g_malloc(s->cluster_size); 218 s->cluster_cache_offset = -1; 219 220 /* read the backing file name */ 221 if (header.backing_file_offset != 0) { 222 len = header.backing_file_size; 223 if (len > 1023 || len >= sizeof(bs->backing_file)) { 224 error_setg(errp, "Backing file name too long"); 225 ret = -EINVAL; 226 goto fail; 227 } 228 ret = bdrv_pread(bs->file->bs, header.backing_file_offset, 229 bs->backing_file, len); 230 if (ret < 0) { 231 goto fail; 232 } 233 bs->backing_file[len] = '\0'; 234 } 235 236 /* Disable migration when qcow images are used */ 237 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 238 "does not support live migration", 239 bdrv_get_device_or_node_name(bs)); 240 migrate_add_blocker(s->migration_blocker); 241 242 qemu_co_mutex_init(&s->lock); 243 return 0; 244 245 fail: 246 g_free(s->l1_table); 247 qemu_vfree(s->l2_cache); 248 g_free(s->cluster_cache); 249 g_free(s->cluster_data); 250 return ret; 251 } 252 253 254 /* We have nothing to do for QCOW reopen, stubs just return 255 * success */ 256 static int qcow_reopen_prepare(BDRVReopenState *state, 257 BlockReopenQueue *queue, Error **errp) 258 { 259 return 0; 260 } 261 262 static int qcow_set_key(BlockDriverState *bs, const char *key) 263 { 264 BDRVQcowState *s = bs->opaque; 265 uint8_t keybuf[16]; 266 int len, i; 267 Error *err; 268 269 memset(keybuf, 0, 16); 270 len = strlen(key); 271 if (len > 16) 272 len = 16; 273 /* XXX: we could compress the chars to 7 bits to increase 274 entropy */ 275 for(i = 0;i < len;i++) { 276 keybuf[i] = key[i]; 277 } 278 assert(bs->encrypted); 279 280 qcrypto_cipher_free(s->cipher); 281 s->cipher = qcrypto_cipher_new( 282 QCRYPTO_CIPHER_ALG_AES_128, 283 QCRYPTO_CIPHER_MODE_CBC, 284 keybuf, G_N_ELEMENTS(keybuf), 285 &err); 286 287 if (!s->cipher) { 288 /* XXX would be nice if errors in this method could 289 * be properly propagate to the caller. Would need 290 * the bdrv_set_key() API signature to be fixed. */ 291 error_free(err); 292 return -1; 293 } 294 return 0; 295 } 296 297 /* The crypt function is compatible with the linux cryptoloop 298 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 299 supported */ 300 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 301 uint8_t *out_buf, const uint8_t *in_buf, 302 int nb_sectors, bool enc, Error **errp) 303 { 304 union { 305 uint64_t ll[2]; 306 uint8_t b[16]; 307 } ivec; 308 int i; 309 int ret; 310 311 for(i = 0; i < nb_sectors; i++) { 312 ivec.ll[0] = cpu_to_le64(sector_num); 313 ivec.ll[1] = 0; 314 if (qcrypto_cipher_setiv(s->cipher, 315 ivec.b, G_N_ELEMENTS(ivec.b), 316 errp) < 0) { 317 return -1; 318 } 319 if (enc) { 320 ret = qcrypto_cipher_encrypt(s->cipher, 321 in_buf, 322 out_buf, 323 512, 324 errp); 325 } else { 326 ret = qcrypto_cipher_decrypt(s->cipher, 327 in_buf, 328 out_buf, 329 512, 330 errp); 331 } 332 if (ret < 0) { 333 return -1; 334 } 335 sector_num++; 336 in_buf += 512; 337 out_buf += 512; 338 } 339 return 0; 340 } 341 342 /* 'allocate' is: 343 * 344 * 0 to not allocate. 345 * 346 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 347 * 'n_end') 348 * 349 * 2 to allocate a compressed cluster of size 350 * 'compressed_size'. 'compressed_size' must be > 0 and < 351 * cluster_size 352 * 353 * return 0 if not allocated. 354 */ 355 static uint64_t get_cluster_offset(BlockDriverState *bs, 356 uint64_t offset, int allocate, 357 int compressed_size, 358 int n_start, int n_end) 359 { 360 BDRVQcowState *s = bs->opaque; 361 int min_index, i, j, l1_index, l2_index; 362 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 363 uint32_t min_count; 364 int new_l2_table; 365 366 l1_index = offset >> (s->l2_bits + s->cluster_bits); 367 l2_offset = s->l1_table[l1_index]; 368 new_l2_table = 0; 369 if (!l2_offset) { 370 if (!allocate) 371 return 0; 372 /* allocate a new l2 entry */ 373 l2_offset = bdrv_getlength(bs->file->bs); 374 /* round to cluster size */ 375 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 376 /* update the L1 entry */ 377 s->l1_table[l1_index] = l2_offset; 378 tmp = cpu_to_be64(l2_offset); 379 if (bdrv_pwrite_sync(bs->file->bs, 380 s->l1_table_offset + l1_index * sizeof(tmp), 381 &tmp, sizeof(tmp)) < 0) 382 return 0; 383 new_l2_table = 1; 384 } 385 for(i = 0; i < L2_CACHE_SIZE; i++) { 386 if (l2_offset == s->l2_cache_offsets[i]) { 387 /* increment the hit count */ 388 if (++s->l2_cache_counts[i] == 0xffffffff) { 389 for(j = 0; j < L2_CACHE_SIZE; j++) { 390 s->l2_cache_counts[j] >>= 1; 391 } 392 } 393 l2_table = s->l2_cache + (i << s->l2_bits); 394 goto found; 395 } 396 } 397 /* not found: load a new entry in the least used one */ 398 min_index = 0; 399 min_count = 0xffffffff; 400 for(i = 0; i < L2_CACHE_SIZE; i++) { 401 if (s->l2_cache_counts[i] < min_count) { 402 min_count = s->l2_cache_counts[i]; 403 min_index = i; 404 } 405 } 406 l2_table = s->l2_cache + (min_index << s->l2_bits); 407 if (new_l2_table) { 408 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 409 if (bdrv_pwrite_sync(bs->file->bs, l2_offset, l2_table, 410 s->l2_size * sizeof(uint64_t)) < 0) 411 return 0; 412 } else { 413 if (bdrv_pread(bs->file->bs, l2_offset, l2_table, 414 s->l2_size * sizeof(uint64_t)) != 415 s->l2_size * sizeof(uint64_t)) 416 return 0; 417 } 418 s->l2_cache_offsets[min_index] = l2_offset; 419 s->l2_cache_counts[min_index] = 1; 420 found: 421 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 422 cluster_offset = be64_to_cpu(l2_table[l2_index]); 423 if (!cluster_offset || 424 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 425 if (!allocate) 426 return 0; 427 /* allocate a new cluster */ 428 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 429 (n_end - n_start) < s->cluster_sectors) { 430 /* if the cluster is already compressed, we must 431 decompress it in the case it is not completely 432 overwritten */ 433 if (decompress_cluster(bs, cluster_offset) < 0) 434 return 0; 435 cluster_offset = bdrv_getlength(bs->file->bs); 436 cluster_offset = (cluster_offset + s->cluster_size - 1) & 437 ~(s->cluster_size - 1); 438 /* write the cluster content */ 439 if (bdrv_pwrite(bs->file->bs, cluster_offset, s->cluster_cache, 440 s->cluster_size) != 441 s->cluster_size) 442 return -1; 443 } else { 444 cluster_offset = bdrv_getlength(bs->file->bs); 445 if (allocate == 1) { 446 /* round to cluster size */ 447 cluster_offset = (cluster_offset + s->cluster_size - 1) & 448 ~(s->cluster_size - 1); 449 bdrv_truncate(bs->file->bs, cluster_offset + s->cluster_size); 450 /* if encrypted, we must initialize the cluster 451 content which won't be written */ 452 if (bs->encrypted && 453 (n_end - n_start) < s->cluster_sectors) { 454 uint64_t start_sect; 455 assert(s->cipher); 456 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 457 memset(s->cluster_data + 512, 0x00, 512); 458 for(i = 0; i < s->cluster_sectors; i++) { 459 if (i < n_start || i >= n_end) { 460 Error *err = NULL; 461 if (encrypt_sectors(s, start_sect + i, 462 s->cluster_data, 463 s->cluster_data + 512, 1, 464 true, &err) < 0) { 465 error_free(err); 466 errno = EIO; 467 return -1; 468 } 469 if (bdrv_pwrite(bs->file->bs, 470 cluster_offset + i * 512, 471 s->cluster_data, 512) != 512) 472 return -1; 473 } 474 } 475 } 476 } else if (allocate == 2) { 477 cluster_offset |= QCOW_OFLAG_COMPRESSED | 478 (uint64_t)compressed_size << (63 - s->cluster_bits); 479 } 480 } 481 /* update L2 table */ 482 tmp = cpu_to_be64(cluster_offset); 483 l2_table[l2_index] = tmp; 484 if (bdrv_pwrite_sync(bs->file->bs, l2_offset + l2_index * sizeof(tmp), 485 &tmp, sizeof(tmp)) < 0) 486 return 0; 487 } 488 return cluster_offset; 489 } 490 491 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 492 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 493 { 494 BDRVQcowState *s = bs->opaque; 495 int index_in_cluster, n; 496 uint64_t cluster_offset; 497 498 qemu_co_mutex_lock(&s->lock); 499 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 500 qemu_co_mutex_unlock(&s->lock); 501 index_in_cluster = sector_num & (s->cluster_sectors - 1); 502 n = s->cluster_sectors - index_in_cluster; 503 if (n > nb_sectors) 504 n = nb_sectors; 505 *pnum = n; 506 if (!cluster_offset) { 507 return 0; 508 } 509 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) { 510 return BDRV_BLOCK_DATA; 511 } 512 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 513 *file = bs->file->bs; 514 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 515 } 516 517 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 518 const uint8_t *buf, int buf_size) 519 { 520 z_stream strm1, *strm = &strm1; 521 int ret, out_len; 522 523 memset(strm, 0, sizeof(*strm)); 524 525 strm->next_in = (uint8_t *)buf; 526 strm->avail_in = buf_size; 527 strm->next_out = out_buf; 528 strm->avail_out = out_buf_size; 529 530 ret = inflateInit2(strm, -12); 531 if (ret != Z_OK) 532 return -1; 533 ret = inflate(strm, Z_FINISH); 534 out_len = strm->next_out - out_buf; 535 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 536 out_len != out_buf_size) { 537 inflateEnd(strm); 538 return -1; 539 } 540 inflateEnd(strm); 541 return 0; 542 } 543 544 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 545 { 546 BDRVQcowState *s = bs->opaque; 547 int ret, csize; 548 uint64_t coffset; 549 550 coffset = cluster_offset & s->cluster_offset_mask; 551 if (s->cluster_cache_offset != coffset) { 552 csize = cluster_offset >> (63 - s->cluster_bits); 553 csize &= (s->cluster_size - 1); 554 ret = bdrv_pread(bs->file->bs, coffset, s->cluster_data, csize); 555 if (ret != csize) 556 return -1; 557 if (decompress_buffer(s->cluster_cache, s->cluster_size, 558 s->cluster_data, csize) < 0) { 559 return -1; 560 } 561 s->cluster_cache_offset = coffset; 562 } 563 return 0; 564 } 565 566 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 567 int nb_sectors, QEMUIOVector *qiov) 568 { 569 BDRVQcowState *s = bs->opaque; 570 int index_in_cluster; 571 int ret = 0, n; 572 uint64_t cluster_offset; 573 struct iovec hd_iov; 574 QEMUIOVector hd_qiov; 575 uint8_t *buf; 576 void *orig_buf; 577 Error *err = NULL; 578 579 if (qiov->niov > 1) { 580 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 581 if (buf == NULL) { 582 return -ENOMEM; 583 } 584 } else { 585 orig_buf = NULL; 586 buf = (uint8_t *)qiov->iov->iov_base; 587 } 588 589 qemu_co_mutex_lock(&s->lock); 590 591 while (nb_sectors != 0) { 592 /* prepare next request */ 593 cluster_offset = get_cluster_offset(bs, sector_num << 9, 594 0, 0, 0, 0); 595 index_in_cluster = sector_num & (s->cluster_sectors - 1); 596 n = s->cluster_sectors - index_in_cluster; 597 if (n > nb_sectors) { 598 n = nb_sectors; 599 } 600 601 if (!cluster_offset) { 602 if (bs->backing) { 603 /* read from the base image */ 604 hd_iov.iov_base = (void *)buf; 605 hd_iov.iov_len = n * 512; 606 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 607 qemu_co_mutex_unlock(&s->lock); 608 ret = bdrv_co_readv(bs->backing->bs, sector_num, 609 n, &hd_qiov); 610 qemu_co_mutex_lock(&s->lock); 611 if (ret < 0) { 612 goto fail; 613 } 614 } else { 615 /* Note: in this case, no need to wait */ 616 memset(buf, 0, 512 * n); 617 } 618 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 619 /* add AIO support for compressed blocks ? */ 620 if (decompress_cluster(bs, cluster_offset) < 0) { 621 goto fail; 622 } 623 memcpy(buf, 624 s->cluster_cache + index_in_cluster * 512, 512 * n); 625 } else { 626 if ((cluster_offset & 511) != 0) { 627 goto fail; 628 } 629 hd_iov.iov_base = (void *)buf; 630 hd_iov.iov_len = n * 512; 631 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 632 qemu_co_mutex_unlock(&s->lock); 633 ret = bdrv_co_readv(bs->file->bs, 634 (cluster_offset >> 9) + index_in_cluster, 635 n, &hd_qiov); 636 qemu_co_mutex_lock(&s->lock); 637 if (ret < 0) { 638 break; 639 } 640 if (bs->encrypted) { 641 assert(s->cipher); 642 if (encrypt_sectors(s, sector_num, buf, buf, 643 n, false, &err) < 0) { 644 goto fail; 645 } 646 } 647 } 648 ret = 0; 649 650 nb_sectors -= n; 651 sector_num += n; 652 buf += n * 512; 653 } 654 655 done: 656 qemu_co_mutex_unlock(&s->lock); 657 658 if (qiov->niov > 1) { 659 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 660 qemu_vfree(orig_buf); 661 } 662 663 return ret; 664 665 fail: 666 error_free(err); 667 ret = -EIO; 668 goto done; 669 } 670 671 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 672 int nb_sectors, QEMUIOVector *qiov) 673 { 674 BDRVQcowState *s = bs->opaque; 675 int index_in_cluster; 676 uint64_t cluster_offset; 677 const uint8_t *src_buf; 678 int ret = 0, n; 679 uint8_t *cluster_data = NULL; 680 struct iovec hd_iov; 681 QEMUIOVector hd_qiov; 682 uint8_t *buf; 683 void *orig_buf; 684 685 s->cluster_cache_offset = -1; /* disable compressed cache */ 686 687 if (qiov->niov > 1) { 688 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 689 if (buf == NULL) { 690 return -ENOMEM; 691 } 692 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 693 } else { 694 orig_buf = NULL; 695 buf = (uint8_t *)qiov->iov->iov_base; 696 } 697 698 qemu_co_mutex_lock(&s->lock); 699 700 while (nb_sectors != 0) { 701 702 index_in_cluster = sector_num & (s->cluster_sectors - 1); 703 n = s->cluster_sectors - index_in_cluster; 704 if (n > nb_sectors) { 705 n = nb_sectors; 706 } 707 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 708 index_in_cluster, 709 index_in_cluster + n); 710 if (!cluster_offset || (cluster_offset & 511) != 0) { 711 ret = -EIO; 712 break; 713 } 714 if (bs->encrypted) { 715 Error *err = NULL; 716 assert(s->cipher); 717 if (!cluster_data) { 718 cluster_data = g_malloc0(s->cluster_size); 719 } 720 if (encrypt_sectors(s, sector_num, cluster_data, buf, 721 n, true, &err) < 0) { 722 error_free(err); 723 ret = -EIO; 724 break; 725 } 726 src_buf = cluster_data; 727 } else { 728 src_buf = buf; 729 } 730 731 hd_iov.iov_base = (void *)src_buf; 732 hd_iov.iov_len = n * 512; 733 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 734 qemu_co_mutex_unlock(&s->lock); 735 ret = bdrv_co_writev(bs->file->bs, 736 (cluster_offset >> 9) + index_in_cluster, 737 n, &hd_qiov); 738 qemu_co_mutex_lock(&s->lock); 739 if (ret < 0) { 740 break; 741 } 742 ret = 0; 743 744 nb_sectors -= n; 745 sector_num += n; 746 buf += n * 512; 747 } 748 qemu_co_mutex_unlock(&s->lock); 749 750 if (qiov->niov > 1) { 751 qemu_vfree(orig_buf); 752 } 753 g_free(cluster_data); 754 755 return ret; 756 } 757 758 static void qcow_close(BlockDriverState *bs) 759 { 760 BDRVQcowState *s = bs->opaque; 761 762 qcrypto_cipher_free(s->cipher); 763 s->cipher = NULL; 764 g_free(s->l1_table); 765 qemu_vfree(s->l2_cache); 766 g_free(s->cluster_cache); 767 g_free(s->cluster_data); 768 769 migrate_del_blocker(s->migration_blocker); 770 error_free(s->migration_blocker); 771 } 772 773 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 774 { 775 int header_size, backing_filename_len, l1_size, shift, i; 776 QCowHeader header; 777 uint8_t *tmp; 778 int64_t total_size = 0; 779 char *backing_file = NULL; 780 int flags = 0; 781 Error *local_err = NULL; 782 int ret; 783 BlockDriverState *qcow_bs; 784 785 /* Read out options */ 786 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 787 BDRV_SECTOR_SIZE); 788 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 789 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 790 flags |= BLOCK_FLAG_ENCRYPT; 791 } 792 793 ret = bdrv_create_file(filename, opts, &local_err); 794 if (ret < 0) { 795 error_propagate(errp, local_err); 796 goto cleanup; 797 } 798 799 qcow_bs = NULL; 800 ret = bdrv_open(&qcow_bs, filename, NULL, NULL, 801 BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err); 802 if (ret < 0) { 803 error_propagate(errp, local_err); 804 goto cleanup; 805 } 806 807 ret = bdrv_truncate(qcow_bs, 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 = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header)); 848 if (ret != sizeof(header)) { 849 goto exit; 850 } 851 852 if (backing_file) { 853 ret = bdrv_pwrite(qcow_bs, 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 = bdrv_pwrite(qcow_bs, 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 bdrv_unref(qcow_bs); 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