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 <zlib.h> 32 #include "qapi/qmp/qerror.h" 33 #include "crypto/cipher.h" 34 #include "migration/migration.h" 35 36 /**************************************************************/ 37 /* QEMU COW block driver with compression and encryption support */ 38 39 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 40 #define QCOW_VERSION 1 41 42 #define QCOW_CRYPT_NONE 0 43 #define QCOW_CRYPT_AES 1 44 45 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 46 47 typedef struct QCowHeader { 48 uint32_t magic; 49 uint32_t version; 50 uint64_t backing_file_offset; 51 uint32_t backing_file_size; 52 uint32_t mtime; 53 uint64_t size; /* in bytes */ 54 uint8_t cluster_bits; 55 uint8_t l2_bits; 56 uint16_t padding; 57 uint32_t crypt_method; 58 uint64_t l1_table_offset; 59 } QEMU_PACKED QCowHeader; 60 61 #define L2_CACHE_SIZE 16 62 63 typedef struct BDRVQcowState { 64 int cluster_bits; 65 int cluster_size; 66 int cluster_sectors; 67 int l2_bits; 68 int l2_size; 69 unsigned int l1_size; 70 uint64_t cluster_offset_mask; 71 uint64_t l1_table_offset; 72 uint64_t *l1_table; 73 uint64_t *l2_cache; 74 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 75 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 76 uint8_t *cluster_cache; 77 uint8_t *cluster_data; 78 uint64_t cluster_cache_offset; 79 QCryptoCipher *cipher; /* NULL if no key yet */ 80 uint32_t crypt_method_header; 81 CoMutex lock; 82 Error *migration_blocker; 83 } BDRVQcowState; 84 85 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 86 87 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 88 { 89 const QCowHeader *cow_header = (const void *)buf; 90 91 if (buf_size >= sizeof(QCowHeader) && 92 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 93 be32_to_cpu(cow_header->version) == QCOW_VERSION) 94 return 100; 95 else 96 return 0; 97 } 98 99 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 100 Error **errp) 101 { 102 BDRVQcowState *s = bs->opaque; 103 unsigned int len, i, shift; 104 int ret; 105 QCowHeader header; 106 107 ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header)); 108 if (ret < 0) { 109 goto fail; 110 } 111 be32_to_cpus(&header.magic); 112 be32_to_cpus(&header.version); 113 be64_to_cpus(&header.backing_file_offset); 114 be32_to_cpus(&header.backing_file_size); 115 be32_to_cpus(&header.mtime); 116 be64_to_cpus(&header.size); 117 be32_to_cpus(&header.crypt_method); 118 be64_to_cpus(&header.l1_table_offset); 119 120 if (header.magic != QCOW_MAGIC) { 121 error_setg(errp, "Image not in qcow format"); 122 ret = -EINVAL; 123 goto fail; 124 } 125 if (header.version != QCOW_VERSION) { 126 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version); 127 ret = -ENOTSUP; 128 goto fail; 129 } 130 131 if (header.size <= 1) { 132 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 133 ret = -EINVAL; 134 goto fail; 135 } 136 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 137 error_setg(errp, "Cluster size must be between 512 and 64k"); 138 ret = -EINVAL; 139 goto fail; 140 } 141 142 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 143 * so bytes = num_entries << 3. */ 144 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 145 error_setg(errp, "L2 table size must be between 512 and 64k"); 146 ret = -EINVAL; 147 goto fail; 148 } 149 150 if (header.crypt_method > QCOW_CRYPT_AES) { 151 error_setg(errp, "invalid encryption method in qcow header"); 152 ret = -EINVAL; 153 goto fail; 154 } 155 if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) { 156 error_setg(errp, "AES cipher not available"); 157 ret = -EINVAL; 158 goto fail; 159 } 160 s->crypt_method_header = header.crypt_method; 161 if (s->crypt_method_header) { 162 if (bdrv_uses_whitelist() && 163 s->crypt_method_header == QCOW_CRYPT_AES) { 164 error_report("qcow built-in AES encryption is deprecated"); 165 error_printf("Support for it will be removed in a future release.\n" 166 "You can use 'qemu-img convert' to switch to an\n" 167 "unencrypted qcow image, or a LUKS raw image.\n"); 168 } 169 170 bs->encrypted = 1; 171 } 172 s->cluster_bits = header.cluster_bits; 173 s->cluster_size = 1 << s->cluster_bits; 174 s->cluster_sectors = 1 << (s->cluster_bits - 9); 175 s->l2_bits = header.l2_bits; 176 s->l2_size = 1 << s->l2_bits; 177 bs->total_sectors = header.size / 512; 178 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 179 180 /* read the level 1 table */ 181 shift = s->cluster_bits + s->l2_bits; 182 if (header.size > UINT64_MAX - (1LL << shift)) { 183 error_setg(errp, "Image too large"); 184 ret = -EINVAL; 185 goto fail; 186 } else { 187 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 188 if (l1_size > INT_MAX / sizeof(uint64_t)) { 189 error_setg(errp, "Image too large"); 190 ret = -EINVAL; 191 goto fail; 192 } 193 s->l1_size = l1_size; 194 } 195 196 s->l1_table_offset = header.l1_table_offset; 197 s->l1_table = g_try_new(uint64_t, s->l1_size); 198 if (s->l1_table == NULL) { 199 error_setg(errp, "Could not allocate memory for L1 table"); 200 ret = -ENOMEM; 201 goto fail; 202 } 203 204 ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table, 205 s->l1_size * sizeof(uint64_t)); 206 if (ret < 0) { 207 goto fail; 208 } 209 210 for(i = 0;i < s->l1_size; i++) { 211 be64_to_cpus(&s->l1_table[i]); 212 } 213 214 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 215 s->l2_cache = 216 qemu_try_blockalign(bs->file->bs, 217 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 218 if (s->l2_cache == NULL) { 219 error_setg(errp, "Could not allocate L2 table cache"); 220 ret = -ENOMEM; 221 goto fail; 222 } 223 s->cluster_cache = g_malloc(s->cluster_size); 224 s->cluster_data = g_malloc(s->cluster_size); 225 s->cluster_cache_offset = -1; 226 227 /* read the backing file name */ 228 if (header.backing_file_offset != 0) { 229 len = header.backing_file_size; 230 if (len > 1023 || len >= sizeof(bs->backing_file)) { 231 error_setg(errp, "Backing file name too long"); 232 ret = -EINVAL; 233 goto fail; 234 } 235 ret = bdrv_pread(bs->file->bs, header.backing_file_offset, 236 bs->backing_file, len); 237 if (ret < 0) { 238 goto fail; 239 } 240 bs->backing_file[len] = '\0'; 241 } 242 243 /* Disable migration when qcow images are used */ 244 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 245 "does not support live migration", 246 bdrv_get_device_or_node_name(bs)); 247 migrate_add_blocker(s->migration_blocker); 248 249 qemu_co_mutex_init(&s->lock); 250 return 0; 251 252 fail: 253 g_free(s->l1_table); 254 qemu_vfree(s->l2_cache); 255 g_free(s->cluster_cache); 256 g_free(s->cluster_data); 257 return ret; 258 } 259 260 261 /* We have nothing to do for QCOW reopen, stubs just return 262 * success */ 263 static int qcow_reopen_prepare(BDRVReopenState *state, 264 BlockReopenQueue *queue, Error **errp) 265 { 266 return 0; 267 } 268 269 static int qcow_set_key(BlockDriverState *bs, const char *key) 270 { 271 BDRVQcowState *s = bs->opaque; 272 uint8_t keybuf[16]; 273 int len, i; 274 Error *err; 275 276 memset(keybuf, 0, 16); 277 len = strlen(key); 278 if (len > 16) 279 len = 16; 280 /* XXX: we could compress the chars to 7 bits to increase 281 entropy */ 282 for(i = 0;i < len;i++) { 283 keybuf[i] = key[i]; 284 } 285 assert(bs->encrypted); 286 287 qcrypto_cipher_free(s->cipher); 288 s->cipher = qcrypto_cipher_new( 289 QCRYPTO_CIPHER_ALG_AES_128, 290 QCRYPTO_CIPHER_MODE_CBC, 291 keybuf, G_N_ELEMENTS(keybuf), 292 &err); 293 294 if (!s->cipher) { 295 /* XXX would be nice if errors in this method could 296 * be properly propagate to the caller. Would need 297 * the bdrv_set_key() API signature to be fixed. */ 298 error_free(err); 299 return -1; 300 } 301 return 0; 302 } 303 304 /* The crypt function is compatible with the linux cryptoloop 305 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 306 supported */ 307 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 308 uint8_t *out_buf, const uint8_t *in_buf, 309 int nb_sectors, bool enc, Error **errp) 310 { 311 union { 312 uint64_t ll[2]; 313 uint8_t b[16]; 314 } ivec; 315 int i; 316 int ret; 317 318 for(i = 0; i < nb_sectors; i++) { 319 ivec.ll[0] = cpu_to_le64(sector_num); 320 ivec.ll[1] = 0; 321 if (qcrypto_cipher_setiv(s->cipher, 322 ivec.b, G_N_ELEMENTS(ivec.b), 323 errp) < 0) { 324 return -1; 325 } 326 if (enc) { 327 ret = qcrypto_cipher_encrypt(s->cipher, 328 in_buf, 329 out_buf, 330 512, 331 errp); 332 } else { 333 ret = qcrypto_cipher_decrypt(s->cipher, 334 in_buf, 335 out_buf, 336 512, 337 errp); 338 } 339 if (ret < 0) { 340 return -1; 341 } 342 sector_num++; 343 in_buf += 512; 344 out_buf += 512; 345 } 346 return 0; 347 } 348 349 /* 'allocate' is: 350 * 351 * 0 to not allocate. 352 * 353 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 354 * 'n_end') 355 * 356 * 2 to allocate a compressed cluster of size 357 * 'compressed_size'. 'compressed_size' must be > 0 and < 358 * cluster_size 359 * 360 * return 0 if not allocated. 361 */ 362 static uint64_t get_cluster_offset(BlockDriverState *bs, 363 uint64_t offset, int allocate, 364 int compressed_size, 365 int n_start, int n_end) 366 { 367 BDRVQcowState *s = bs->opaque; 368 int min_index, i, j, l1_index, l2_index; 369 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 370 uint32_t min_count; 371 int new_l2_table; 372 373 l1_index = offset >> (s->l2_bits + s->cluster_bits); 374 l2_offset = s->l1_table[l1_index]; 375 new_l2_table = 0; 376 if (!l2_offset) { 377 if (!allocate) 378 return 0; 379 /* allocate a new l2 entry */ 380 l2_offset = bdrv_getlength(bs->file->bs); 381 /* round to cluster size */ 382 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 383 /* update the L1 entry */ 384 s->l1_table[l1_index] = l2_offset; 385 tmp = cpu_to_be64(l2_offset); 386 if (bdrv_pwrite_sync(bs->file->bs, 387 s->l1_table_offset + l1_index * sizeof(tmp), 388 &tmp, sizeof(tmp)) < 0) 389 return 0; 390 new_l2_table = 1; 391 } 392 for(i = 0; i < L2_CACHE_SIZE; i++) { 393 if (l2_offset == s->l2_cache_offsets[i]) { 394 /* increment the hit count */ 395 if (++s->l2_cache_counts[i] == 0xffffffff) { 396 for(j = 0; j < L2_CACHE_SIZE; j++) { 397 s->l2_cache_counts[j] >>= 1; 398 } 399 } 400 l2_table = s->l2_cache + (i << s->l2_bits); 401 goto found; 402 } 403 } 404 /* not found: load a new entry in the least used one */ 405 min_index = 0; 406 min_count = 0xffffffff; 407 for(i = 0; i < L2_CACHE_SIZE; i++) { 408 if (s->l2_cache_counts[i] < min_count) { 409 min_count = s->l2_cache_counts[i]; 410 min_index = i; 411 } 412 } 413 l2_table = s->l2_cache + (min_index << s->l2_bits); 414 if (new_l2_table) { 415 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 416 if (bdrv_pwrite_sync(bs->file->bs, l2_offset, l2_table, 417 s->l2_size * sizeof(uint64_t)) < 0) 418 return 0; 419 } else { 420 if (bdrv_pread(bs->file->bs, l2_offset, l2_table, 421 s->l2_size * sizeof(uint64_t)) != 422 s->l2_size * sizeof(uint64_t)) 423 return 0; 424 } 425 s->l2_cache_offsets[min_index] = l2_offset; 426 s->l2_cache_counts[min_index] = 1; 427 found: 428 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 429 cluster_offset = be64_to_cpu(l2_table[l2_index]); 430 if (!cluster_offset || 431 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 432 if (!allocate) 433 return 0; 434 /* allocate a new cluster */ 435 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 436 (n_end - n_start) < s->cluster_sectors) { 437 /* if the cluster is already compressed, we must 438 decompress it in the case it is not completely 439 overwritten */ 440 if (decompress_cluster(bs, cluster_offset) < 0) 441 return 0; 442 cluster_offset = bdrv_getlength(bs->file->bs); 443 cluster_offset = (cluster_offset + s->cluster_size - 1) & 444 ~(s->cluster_size - 1); 445 /* write the cluster content */ 446 if (bdrv_pwrite(bs->file->bs, cluster_offset, s->cluster_cache, 447 s->cluster_size) != 448 s->cluster_size) 449 return -1; 450 } else { 451 cluster_offset = bdrv_getlength(bs->file->bs); 452 if (allocate == 1) { 453 /* round to cluster size */ 454 cluster_offset = (cluster_offset + s->cluster_size - 1) & 455 ~(s->cluster_size - 1); 456 bdrv_truncate(bs->file->bs, cluster_offset + s->cluster_size); 457 /* if encrypted, we must initialize the cluster 458 content which won't be written */ 459 if (bs->encrypted && 460 (n_end - n_start) < s->cluster_sectors) { 461 uint64_t start_sect; 462 assert(s->cipher); 463 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 464 memset(s->cluster_data + 512, 0x00, 512); 465 for(i = 0; i < s->cluster_sectors; i++) { 466 if (i < n_start || i >= n_end) { 467 Error *err = NULL; 468 if (encrypt_sectors(s, start_sect + i, 469 s->cluster_data, 470 s->cluster_data + 512, 1, 471 true, &err) < 0) { 472 error_free(err); 473 errno = EIO; 474 return -1; 475 } 476 if (bdrv_pwrite(bs->file->bs, 477 cluster_offset + i * 512, 478 s->cluster_data, 512) != 512) 479 return -1; 480 } 481 } 482 } 483 } else if (allocate == 2) { 484 cluster_offset |= QCOW_OFLAG_COMPRESSED | 485 (uint64_t)compressed_size << (63 - s->cluster_bits); 486 } 487 } 488 /* update L2 table */ 489 tmp = cpu_to_be64(cluster_offset); 490 l2_table[l2_index] = tmp; 491 if (bdrv_pwrite_sync(bs->file->bs, l2_offset + l2_index * sizeof(tmp), 492 &tmp, sizeof(tmp)) < 0) 493 return 0; 494 } 495 return cluster_offset; 496 } 497 498 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs, 499 int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file) 500 { 501 BDRVQcowState *s = bs->opaque; 502 int index_in_cluster, n; 503 uint64_t cluster_offset; 504 505 qemu_co_mutex_lock(&s->lock); 506 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 507 qemu_co_mutex_unlock(&s->lock); 508 index_in_cluster = sector_num & (s->cluster_sectors - 1); 509 n = s->cluster_sectors - index_in_cluster; 510 if (n > nb_sectors) 511 n = nb_sectors; 512 *pnum = n; 513 if (!cluster_offset) { 514 return 0; 515 } 516 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) { 517 return BDRV_BLOCK_DATA; 518 } 519 cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS); 520 *file = bs->file->bs; 521 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset; 522 } 523 524 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 525 const uint8_t *buf, int buf_size) 526 { 527 z_stream strm1, *strm = &strm1; 528 int ret, out_len; 529 530 memset(strm, 0, sizeof(*strm)); 531 532 strm->next_in = (uint8_t *)buf; 533 strm->avail_in = buf_size; 534 strm->next_out = out_buf; 535 strm->avail_out = out_buf_size; 536 537 ret = inflateInit2(strm, -12); 538 if (ret != Z_OK) 539 return -1; 540 ret = inflate(strm, Z_FINISH); 541 out_len = strm->next_out - out_buf; 542 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 543 out_len != out_buf_size) { 544 inflateEnd(strm); 545 return -1; 546 } 547 inflateEnd(strm); 548 return 0; 549 } 550 551 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 552 { 553 BDRVQcowState *s = bs->opaque; 554 int ret, csize; 555 uint64_t coffset; 556 557 coffset = cluster_offset & s->cluster_offset_mask; 558 if (s->cluster_cache_offset != coffset) { 559 csize = cluster_offset >> (63 - s->cluster_bits); 560 csize &= (s->cluster_size - 1); 561 ret = bdrv_pread(bs->file->bs, coffset, s->cluster_data, csize); 562 if (ret != csize) 563 return -1; 564 if (decompress_buffer(s->cluster_cache, s->cluster_size, 565 s->cluster_data, csize) < 0) { 566 return -1; 567 } 568 s->cluster_cache_offset = coffset; 569 } 570 return 0; 571 } 572 573 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 574 int nb_sectors, QEMUIOVector *qiov) 575 { 576 BDRVQcowState *s = bs->opaque; 577 int index_in_cluster; 578 int ret = 0, n; 579 uint64_t cluster_offset; 580 struct iovec hd_iov; 581 QEMUIOVector hd_qiov; 582 uint8_t *buf; 583 void *orig_buf; 584 Error *err = NULL; 585 586 if (qiov->niov > 1) { 587 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 588 if (buf == NULL) { 589 return -ENOMEM; 590 } 591 } else { 592 orig_buf = NULL; 593 buf = (uint8_t *)qiov->iov->iov_base; 594 } 595 596 qemu_co_mutex_lock(&s->lock); 597 598 while (nb_sectors != 0) { 599 /* prepare next request */ 600 cluster_offset = get_cluster_offset(bs, sector_num << 9, 601 0, 0, 0, 0); 602 index_in_cluster = sector_num & (s->cluster_sectors - 1); 603 n = s->cluster_sectors - index_in_cluster; 604 if (n > nb_sectors) { 605 n = nb_sectors; 606 } 607 608 if (!cluster_offset) { 609 if (bs->backing) { 610 /* read from the base image */ 611 hd_iov.iov_base = (void *)buf; 612 hd_iov.iov_len = n * 512; 613 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 614 qemu_co_mutex_unlock(&s->lock); 615 ret = bdrv_co_readv(bs->backing->bs, sector_num, 616 n, &hd_qiov); 617 qemu_co_mutex_lock(&s->lock); 618 if (ret < 0) { 619 goto fail; 620 } 621 } else { 622 /* Note: in this case, no need to wait */ 623 memset(buf, 0, 512 * n); 624 } 625 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 626 /* add AIO support for compressed blocks ? */ 627 if (decompress_cluster(bs, cluster_offset) < 0) { 628 goto fail; 629 } 630 memcpy(buf, 631 s->cluster_cache + index_in_cluster * 512, 512 * n); 632 } else { 633 if ((cluster_offset & 511) != 0) { 634 goto fail; 635 } 636 hd_iov.iov_base = (void *)buf; 637 hd_iov.iov_len = n * 512; 638 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 639 qemu_co_mutex_unlock(&s->lock); 640 ret = bdrv_co_readv(bs->file->bs, 641 (cluster_offset >> 9) + index_in_cluster, 642 n, &hd_qiov); 643 qemu_co_mutex_lock(&s->lock); 644 if (ret < 0) { 645 break; 646 } 647 if (bs->encrypted) { 648 assert(s->cipher); 649 if (encrypt_sectors(s, sector_num, buf, buf, 650 n, false, &err) < 0) { 651 goto fail; 652 } 653 } 654 } 655 ret = 0; 656 657 nb_sectors -= n; 658 sector_num += n; 659 buf += n * 512; 660 } 661 662 done: 663 qemu_co_mutex_unlock(&s->lock); 664 665 if (qiov->niov > 1) { 666 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 667 qemu_vfree(orig_buf); 668 } 669 670 return ret; 671 672 fail: 673 error_free(err); 674 ret = -EIO; 675 goto done; 676 } 677 678 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 679 int nb_sectors, QEMUIOVector *qiov) 680 { 681 BDRVQcowState *s = bs->opaque; 682 int index_in_cluster; 683 uint64_t cluster_offset; 684 const uint8_t *src_buf; 685 int ret = 0, n; 686 uint8_t *cluster_data = NULL; 687 struct iovec hd_iov; 688 QEMUIOVector hd_qiov; 689 uint8_t *buf; 690 void *orig_buf; 691 692 s->cluster_cache_offset = -1; /* disable compressed cache */ 693 694 if (qiov->niov > 1) { 695 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 696 if (buf == NULL) { 697 return -ENOMEM; 698 } 699 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 700 } else { 701 orig_buf = NULL; 702 buf = (uint8_t *)qiov->iov->iov_base; 703 } 704 705 qemu_co_mutex_lock(&s->lock); 706 707 while (nb_sectors != 0) { 708 709 index_in_cluster = sector_num & (s->cluster_sectors - 1); 710 n = s->cluster_sectors - index_in_cluster; 711 if (n > nb_sectors) { 712 n = nb_sectors; 713 } 714 cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0, 715 index_in_cluster, 716 index_in_cluster + n); 717 if (!cluster_offset || (cluster_offset & 511) != 0) { 718 ret = -EIO; 719 break; 720 } 721 if (bs->encrypted) { 722 Error *err = NULL; 723 assert(s->cipher); 724 if (!cluster_data) { 725 cluster_data = g_malloc0(s->cluster_size); 726 } 727 if (encrypt_sectors(s, sector_num, cluster_data, buf, 728 n, true, &err) < 0) { 729 error_free(err); 730 ret = -EIO; 731 break; 732 } 733 src_buf = cluster_data; 734 } else { 735 src_buf = buf; 736 } 737 738 hd_iov.iov_base = (void *)src_buf; 739 hd_iov.iov_len = n * 512; 740 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1); 741 qemu_co_mutex_unlock(&s->lock); 742 ret = bdrv_co_writev(bs->file->bs, 743 (cluster_offset >> 9) + index_in_cluster, 744 n, &hd_qiov); 745 qemu_co_mutex_lock(&s->lock); 746 if (ret < 0) { 747 break; 748 } 749 ret = 0; 750 751 nb_sectors -= n; 752 sector_num += n; 753 buf += n * 512; 754 } 755 qemu_co_mutex_unlock(&s->lock); 756 757 if (qiov->niov > 1) { 758 qemu_vfree(orig_buf); 759 } 760 g_free(cluster_data); 761 762 return ret; 763 } 764 765 static void qcow_close(BlockDriverState *bs) 766 { 767 BDRVQcowState *s = bs->opaque; 768 769 qcrypto_cipher_free(s->cipher); 770 s->cipher = NULL; 771 g_free(s->l1_table); 772 qemu_vfree(s->l2_cache); 773 g_free(s->cluster_cache); 774 g_free(s->cluster_data); 775 776 migrate_del_blocker(s->migration_blocker); 777 error_free(s->migration_blocker); 778 } 779 780 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp) 781 { 782 int header_size, backing_filename_len, l1_size, shift, i; 783 QCowHeader header; 784 uint8_t *tmp; 785 int64_t total_size = 0; 786 char *backing_file = NULL; 787 int flags = 0; 788 Error *local_err = NULL; 789 int ret; 790 BlockBackend *qcow_blk; 791 792 /* Read out options */ 793 total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0), 794 BDRV_SECTOR_SIZE); 795 backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE); 796 if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) { 797 flags |= BLOCK_FLAG_ENCRYPT; 798 } 799 800 ret = bdrv_create_file(filename, opts, &local_err); 801 if (ret < 0) { 802 error_propagate(errp, local_err); 803 goto cleanup; 804 } 805 806 qcow_blk = blk_new_open(filename, NULL, NULL, 807 BDRV_O_RDWR | BDRV_O_CACHE_WB | BDRV_O_PROTOCOL, 808 &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)); 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); 865 if (ret != backing_filename_len) { 866 goto exit; 867 } 868 } 869 870 tmp = g_malloc0(BDRV_SECTOR_SIZE); 871 for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/ 872 BDRV_SECTOR_SIZE); i++) { 873 ret = blk_pwrite(qcow_blk, header_size + 874 BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE); 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