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