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