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 25 #include "qemu/osdep.h" 26 #include "qapi/error.h" 27 #include "qemu/error-report.h" 28 #include "block/block_int.h" 29 #include "block/qdict.h" 30 #include "sysemu/block-backend.h" 31 #include "qemu/module.h" 32 #include "qemu/option.h" 33 #include "qemu/bswap.h" 34 #include "qemu/cutils.h" 35 #include "qemu/memalign.h" 36 #include <zlib.h> 37 #include "qapi/qmp/qdict.h" 38 #include "qapi/qmp/qstring.h" 39 #include "qapi/qobject-input-visitor.h" 40 #include "qapi/qapi-visit-block-core.h" 41 #include "crypto/block.h" 42 #include "migration/blocker.h" 43 #include "crypto.h" 44 45 /**************************************************************/ 46 /* QEMU COW block driver with compression and encryption support */ 47 48 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 49 #define QCOW_VERSION 1 50 51 #define QCOW_CRYPT_NONE 0 52 #define QCOW_CRYPT_AES 1 53 54 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 55 56 typedef struct QCowHeader { 57 uint32_t magic; 58 uint32_t version; 59 uint64_t backing_file_offset; 60 uint32_t backing_file_size; 61 uint32_t mtime; 62 uint64_t size; /* in bytes */ 63 uint8_t cluster_bits; 64 uint8_t l2_bits; 65 uint16_t padding; 66 uint32_t crypt_method; 67 uint64_t l1_table_offset; 68 } QEMU_PACKED QCowHeader; 69 70 #define L2_CACHE_SIZE 16 71 72 typedef struct BDRVQcowState { 73 int cluster_bits; 74 int cluster_size; 75 int l2_bits; 76 int l2_size; 77 unsigned int l1_size; 78 uint64_t cluster_offset_mask; 79 uint64_t l1_table_offset; 80 uint64_t *l1_table; 81 uint64_t *l2_cache; 82 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 83 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 84 uint8_t *cluster_cache; 85 uint8_t *cluster_data; 86 uint64_t cluster_cache_offset; 87 QCryptoBlock *crypto; /* Disk encryption format driver */ 88 uint32_t crypt_method_header; 89 CoMutex lock; 90 Error *migration_blocker; 91 } BDRVQcowState; 92 93 static QemuOptsList qcow_create_opts; 94 95 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 96 97 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 98 { 99 const QCowHeader *cow_header = (const void *)buf; 100 101 if (buf_size >= sizeof(QCowHeader) && 102 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 103 be32_to_cpu(cow_header->version) == QCOW_VERSION) 104 return 100; 105 else 106 return 0; 107 } 108 109 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 110 Error **errp) 111 { 112 BDRVQcowState *s = bs->opaque; 113 unsigned int len, i, shift; 114 int ret; 115 QCowHeader header; 116 QCryptoBlockOpenOptions *crypto_opts = NULL; 117 unsigned int cflags = 0; 118 QDict *encryptopts = NULL; 119 const char *encryptfmt; 120 121 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 122 encryptfmt = qdict_get_try_str(encryptopts, "format"); 123 124 ret = bdrv_open_file_child(NULL, options, "file", bs, errp); 125 if (ret < 0) { 126 goto fail; 127 } 128 129 ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0); 130 if (ret < 0) { 131 goto fail; 132 } 133 header.magic = be32_to_cpu(header.magic); 134 header.version = be32_to_cpu(header.version); 135 header.backing_file_offset = be64_to_cpu(header.backing_file_offset); 136 header.backing_file_size = be32_to_cpu(header.backing_file_size); 137 header.mtime = be32_to_cpu(header.mtime); 138 header.size = be64_to_cpu(header.size); 139 header.crypt_method = be32_to_cpu(header.crypt_method); 140 header.l1_table_offset = be64_to_cpu(header.l1_table_offset); 141 142 if (header.magic != QCOW_MAGIC) { 143 error_setg(errp, "Image not in qcow format"); 144 ret = -EINVAL; 145 goto fail; 146 } 147 if (header.version != QCOW_VERSION) { 148 error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32, 149 QCOW_VERSION, header.version); 150 if (header.version == 2 || header.version == 3) { 151 error_append_hint(errp, "Try the 'qcow2' driver instead.\n"); 152 } 153 154 ret = -ENOTSUP; 155 goto fail; 156 } 157 158 if (header.size <= 1) { 159 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 160 ret = -EINVAL; 161 goto fail; 162 } 163 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 164 error_setg(errp, "Cluster size must be between 512 and 64k"); 165 ret = -EINVAL; 166 goto fail; 167 } 168 169 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 170 * so bytes = num_entries << 3. */ 171 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 172 error_setg(errp, "L2 table size must be between 512 and 64k"); 173 ret = -EINVAL; 174 goto fail; 175 } 176 177 s->crypt_method_header = header.crypt_method; 178 if (s->crypt_method_header) { 179 if (bdrv_uses_whitelist() && 180 s->crypt_method_header == QCOW_CRYPT_AES) { 181 error_setg(errp, 182 "Use of AES-CBC encrypted qcow images is no longer " 183 "supported in system emulators"); 184 error_append_hint(errp, 185 "You can use 'qemu-img convert' to convert your " 186 "image to an alternative supported format, such " 187 "as unencrypted qcow, or raw with the LUKS " 188 "format instead.\n"); 189 ret = -ENOSYS; 190 goto fail; 191 } 192 if (s->crypt_method_header == QCOW_CRYPT_AES) { 193 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 194 error_setg(errp, 195 "Header reported 'aes' encryption format but " 196 "options specify '%s'", encryptfmt); 197 ret = -EINVAL; 198 goto fail; 199 } 200 qdict_put_str(encryptopts, "format", "qcow"); 201 crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 202 if (!crypto_opts) { 203 ret = -EINVAL; 204 goto fail; 205 } 206 207 if (flags & BDRV_O_NO_IO) { 208 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 209 } 210 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.", 211 NULL, NULL, cflags, 1, errp); 212 if (!s->crypto) { 213 ret = -EINVAL; 214 goto fail; 215 } 216 } else { 217 error_setg(errp, "invalid encryption method in qcow header"); 218 ret = -EINVAL; 219 goto fail; 220 } 221 bs->encrypted = true; 222 } else { 223 if (encryptfmt) { 224 error_setg(errp, "No encryption in image header, but options " 225 "specified format '%s'", encryptfmt); 226 ret = -EINVAL; 227 goto fail; 228 } 229 } 230 s->cluster_bits = header.cluster_bits; 231 s->cluster_size = 1 << s->cluster_bits; 232 s->l2_bits = header.l2_bits; 233 s->l2_size = 1 << s->l2_bits; 234 bs->total_sectors = header.size / 512; 235 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 236 237 /* read the level 1 table */ 238 shift = s->cluster_bits + s->l2_bits; 239 if (header.size > UINT64_MAX - (1LL << shift)) { 240 error_setg(errp, "Image too large"); 241 ret = -EINVAL; 242 goto fail; 243 } else { 244 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 245 if (l1_size > INT_MAX / sizeof(uint64_t)) { 246 error_setg(errp, "Image too large"); 247 ret = -EINVAL; 248 goto fail; 249 } 250 s->l1_size = l1_size; 251 } 252 253 s->l1_table_offset = header.l1_table_offset; 254 s->l1_table = g_try_new(uint64_t, s->l1_size); 255 if (s->l1_table == NULL) { 256 error_setg(errp, "Could not allocate memory for L1 table"); 257 ret = -ENOMEM; 258 goto fail; 259 } 260 261 ret = bdrv_pread(bs->file, s->l1_table_offset, 262 s->l1_size * sizeof(uint64_t), s->l1_table, 0); 263 if (ret < 0) { 264 goto fail; 265 } 266 267 for(i = 0;i < s->l1_size; i++) { 268 s->l1_table[i] = be64_to_cpu(s->l1_table[i]); 269 } 270 271 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 272 s->l2_cache = 273 qemu_try_blockalign(bs->file->bs, 274 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 275 if (s->l2_cache == NULL) { 276 error_setg(errp, "Could not allocate L2 table cache"); 277 ret = -ENOMEM; 278 goto fail; 279 } 280 s->cluster_cache = g_malloc(s->cluster_size); 281 s->cluster_data = g_malloc(s->cluster_size); 282 s->cluster_cache_offset = -1; 283 284 /* read the backing file name */ 285 if (header.backing_file_offset != 0) { 286 len = header.backing_file_size; 287 if (len > 1023 || len >= sizeof(bs->backing_file)) { 288 error_setg(errp, "Backing file name too long"); 289 ret = -EINVAL; 290 goto fail; 291 } 292 ret = bdrv_pread(bs->file, header.backing_file_offset, len, 293 bs->auto_backing_file, 0); 294 if (ret < 0) { 295 goto fail; 296 } 297 bs->auto_backing_file[len] = '\0'; 298 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 299 bs->auto_backing_file); 300 } 301 302 /* Disable migration when qcow images are used */ 303 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 304 "does not support live migration", 305 bdrv_get_device_or_node_name(bs)); 306 ret = migrate_add_blocker(s->migration_blocker, errp); 307 if (ret < 0) { 308 error_free(s->migration_blocker); 309 goto fail; 310 } 311 312 qobject_unref(encryptopts); 313 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 314 qemu_co_mutex_init(&s->lock); 315 return 0; 316 317 fail: 318 g_free(s->l1_table); 319 qemu_vfree(s->l2_cache); 320 g_free(s->cluster_cache); 321 g_free(s->cluster_data); 322 qcrypto_block_free(s->crypto); 323 qobject_unref(encryptopts); 324 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 325 return ret; 326 } 327 328 329 /* We have nothing to do for QCOW reopen, stubs just return 330 * success */ 331 static int qcow_reopen_prepare(BDRVReopenState *state, 332 BlockReopenQueue *queue, Error **errp) 333 { 334 return 0; 335 } 336 337 338 /* 'allocate' is: 339 * 340 * 0 to not allocate. 341 * 342 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start' 343 * to 'n_end' within the cluster) 344 * 345 * 2 to allocate a compressed cluster of size 346 * 'compressed_size'. 'compressed_size' must be > 0 and < 347 * cluster_size 348 * 349 * return 0 if not allocated, 1 if *result is assigned, and negative 350 * errno on failure. 351 */ 352 static int get_cluster_offset(BlockDriverState *bs, 353 uint64_t offset, int allocate, 354 int compressed_size, 355 int n_start, int n_end, uint64_t *result) 356 { 357 BDRVQcowState *s = bs->opaque; 358 int min_index, i, j, l1_index, l2_index, ret; 359 int64_t l2_offset; 360 uint64_t *l2_table, cluster_offset, tmp; 361 uint32_t min_count; 362 int new_l2_table; 363 364 *result = 0; 365 l1_index = offset >> (s->l2_bits + s->cluster_bits); 366 l2_offset = s->l1_table[l1_index]; 367 new_l2_table = 0; 368 if (!l2_offset) { 369 if (!allocate) 370 return 0; 371 /* allocate a new l2 entry */ 372 l2_offset = bdrv_getlength(bs->file->bs); 373 if (l2_offset < 0) { 374 return l2_offset; 375 } 376 /* round to cluster size */ 377 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); 378 /* update the L1 entry */ 379 s->l1_table[l1_index] = l2_offset; 380 tmp = cpu_to_be64(l2_offset); 381 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 382 ret = bdrv_pwrite_sync(bs->file, 383 s->l1_table_offset + l1_index * sizeof(tmp), 384 sizeof(tmp), &tmp, 0); 385 if (ret < 0) { 386 return ret; 387 } 388 new_l2_table = 1; 389 } 390 for(i = 0; i < L2_CACHE_SIZE; i++) { 391 if (l2_offset == s->l2_cache_offsets[i]) { 392 /* increment the hit count */ 393 if (++s->l2_cache_counts[i] == 0xffffffff) { 394 for(j = 0; j < L2_CACHE_SIZE; j++) { 395 s->l2_cache_counts[j] >>= 1; 396 } 397 } 398 l2_table = s->l2_cache + (i << s->l2_bits); 399 goto found; 400 } 401 } 402 /* not found: load a new entry in the least used one */ 403 min_index = 0; 404 min_count = 0xffffffff; 405 for(i = 0; i < L2_CACHE_SIZE; i++) { 406 if (s->l2_cache_counts[i] < min_count) { 407 min_count = s->l2_cache_counts[i]; 408 min_index = i; 409 } 410 } 411 l2_table = s->l2_cache + (min_index << s->l2_bits); 412 BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); 413 if (new_l2_table) { 414 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 415 ret = bdrv_pwrite_sync(bs->file, l2_offset, 416 s->l2_size * sizeof(uint64_t), l2_table, 0); 417 if (ret < 0) { 418 return ret; 419 } 420 } else { 421 ret = bdrv_pread(bs->file, l2_offset, s->l2_size * sizeof(uint64_t), 422 l2_table, 0); 423 if (ret < 0) { 424 return ret; 425 } 426 } 427 s->l2_cache_offsets[min_index] = l2_offset; 428 s->l2_cache_counts[min_index] = 1; 429 found: 430 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 431 cluster_offset = be64_to_cpu(l2_table[l2_index]); 432 if (!cluster_offset || 433 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 434 if (!allocate) 435 return 0; 436 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); 437 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE)); 438 /* allocate a new cluster */ 439 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 440 (n_end - n_start) < s->cluster_size) { 441 /* if the cluster is already compressed, we must 442 decompress it in the case it is not completely 443 overwritten */ 444 if (decompress_cluster(bs, cluster_offset) < 0) { 445 return -EIO; 446 } 447 cluster_offset = bdrv_getlength(bs->file->bs); 448 if ((int64_t) cluster_offset < 0) { 449 return cluster_offset; 450 } 451 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 452 /* write the cluster content */ 453 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 454 ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_size, 455 s->cluster_cache, 0); 456 if (ret < 0) { 457 return ret; 458 } 459 } else { 460 cluster_offset = bdrv_getlength(bs->file->bs); 461 if ((int64_t) cluster_offset < 0) { 462 return cluster_offset; 463 } 464 if (allocate == 1) { 465 /* round to cluster size */ 466 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 467 if (cluster_offset + s->cluster_size > INT64_MAX) { 468 return -E2BIG; 469 } 470 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size, 471 false, PREALLOC_MODE_OFF, 0, NULL); 472 if (ret < 0) { 473 return ret; 474 } 475 /* if encrypted, we must initialize the cluster 476 content which won't be written */ 477 if (bs->encrypted && 478 (n_end - n_start) < s->cluster_size) { 479 uint64_t start_offset; 480 assert(s->crypto); 481 start_offset = offset & ~(s->cluster_size - 1); 482 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) { 483 if (i < n_start || i >= n_end) { 484 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE); 485 if (qcrypto_block_encrypt(s->crypto, 486 start_offset + i, 487 s->cluster_data, 488 BDRV_SECTOR_SIZE, 489 NULL) < 0) { 490 return -EIO; 491 } 492 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 493 ret = bdrv_pwrite(bs->file, cluster_offset + i, 494 BDRV_SECTOR_SIZE, 495 s->cluster_data, 0); 496 if (ret < 0) { 497 return ret; 498 } 499 } 500 } 501 } 502 } else if (allocate == 2) { 503 cluster_offset |= QCOW_OFLAG_COMPRESSED | 504 (uint64_t)compressed_size << (63 - s->cluster_bits); 505 } 506 } 507 /* update L2 table */ 508 tmp = cpu_to_be64(cluster_offset); 509 l2_table[l2_index] = tmp; 510 if (allocate == 2) { 511 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); 512 } else { 513 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); 514 } 515 ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 516 sizeof(tmp), &tmp, 0); 517 if (ret < 0) { 518 return ret; 519 } 520 } 521 *result = cluster_offset; 522 return 1; 523 } 524 525 static int coroutine_fn qcow_co_block_status(BlockDriverState *bs, 526 bool want_zero, 527 int64_t offset, int64_t bytes, 528 int64_t *pnum, int64_t *map, 529 BlockDriverState **file) 530 { 531 BDRVQcowState *s = bs->opaque; 532 int index_in_cluster, ret; 533 int64_t n; 534 uint64_t cluster_offset; 535 536 qemu_co_mutex_lock(&s->lock); 537 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 538 qemu_co_mutex_unlock(&s->lock); 539 if (ret < 0) { 540 return ret; 541 } 542 index_in_cluster = offset & (s->cluster_size - 1); 543 n = s->cluster_size - index_in_cluster; 544 if (n > bytes) { 545 n = bytes; 546 } 547 *pnum = n; 548 if (!cluster_offset) { 549 return 0; 550 } 551 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) { 552 return BDRV_BLOCK_DATA; 553 } 554 *map = cluster_offset | index_in_cluster; 555 *file = bs->file->bs; 556 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; 557 } 558 559 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 560 const uint8_t *buf, int buf_size) 561 { 562 z_stream strm1, *strm = &strm1; 563 int ret, out_len; 564 565 memset(strm, 0, sizeof(*strm)); 566 567 strm->next_in = (uint8_t *)buf; 568 strm->avail_in = buf_size; 569 strm->next_out = out_buf; 570 strm->avail_out = out_buf_size; 571 572 ret = inflateInit2(strm, -12); 573 if (ret != Z_OK) 574 return -1; 575 ret = inflate(strm, Z_FINISH); 576 out_len = strm->next_out - out_buf; 577 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 578 out_len != out_buf_size) { 579 inflateEnd(strm); 580 return -1; 581 } 582 inflateEnd(strm); 583 return 0; 584 } 585 586 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 587 { 588 BDRVQcowState *s = bs->opaque; 589 int ret, csize; 590 uint64_t coffset; 591 592 coffset = cluster_offset & s->cluster_offset_mask; 593 if (s->cluster_cache_offset != coffset) { 594 csize = cluster_offset >> (63 - s->cluster_bits); 595 csize &= (s->cluster_size - 1); 596 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 597 ret = bdrv_pread(bs->file, coffset, csize, s->cluster_data, 0); 598 if (ret < 0) 599 return -1; 600 if (decompress_buffer(s->cluster_cache, s->cluster_size, 601 s->cluster_data, csize) < 0) { 602 return -1; 603 } 604 s->cluster_cache_offset = coffset; 605 } 606 return 0; 607 } 608 609 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp) 610 { 611 /* At least encrypted images require 512-byte alignment. Apply the 612 * limit universally, rather than just on encrypted images, as 613 * it's easier to let the block layer handle rounding than to 614 * audit this code further. */ 615 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 616 } 617 618 static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, int64_t offset, 619 int64_t bytes, QEMUIOVector *qiov, 620 BdrvRequestFlags flags) 621 { 622 BDRVQcowState *s = bs->opaque; 623 int offset_in_cluster; 624 int ret = 0, n; 625 uint64_t cluster_offset; 626 uint8_t *buf; 627 void *orig_buf; 628 629 assert(!flags); 630 if (qiov->niov > 1) { 631 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 632 if (buf == NULL) { 633 return -ENOMEM; 634 } 635 } else { 636 orig_buf = NULL; 637 buf = (uint8_t *)qiov->iov->iov_base; 638 } 639 640 qemu_co_mutex_lock(&s->lock); 641 642 while (bytes != 0) { 643 /* prepare next request */ 644 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 645 if (ret < 0) { 646 break; 647 } 648 offset_in_cluster = offset & (s->cluster_size - 1); 649 n = s->cluster_size - offset_in_cluster; 650 if (n > bytes) { 651 n = bytes; 652 } 653 654 if (!cluster_offset) { 655 if (bs->backing) { 656 /* read from the base image */ 657 qemu_co_mutex_unlock(&s->lock); 658 /* qcow2 emits this on bs->file instead of bs->backing */ 659 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 660 ret = bdrv_co_pread(bs->backing, offset, n, buf, 0); 661 qemu_co_mutex_lock(&s->lock); 662 if (ret < 0) { 663 break; 664 } 665 } else { 666 /* Note: in this case, no need to wait */ 667 memset(buf, 0, n); 668 } 669 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 670 /* add AIO support for compressed blocks ? */ 671 if (decompress_cluster(bs, cluster_offset) < 0) { 672 ret = -EIO; 673 break; 674 } 675 memcpy(buf, s->cluster_cache + offset_in_cluster, n); 676 } else { 677 if ((cluster_offset & 511) != 0) { 678 ret = -EIO; 679 break; 680 } 681 qemu_co_mutex_unlock(&s->lock); 682 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 683 ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster, 684 n, buf, 0); 685 qemu_co_mutex_lock(&s->lock); 686 if (ret < 0) { 687 break; 688 } 689 if (bs->encrypted) { 690 assert(s->crypto); 691 if (qcrypto_block_decrypt(s->crypto, 692 offset, buf, n, NULL) < 0) { 693 ret = -EIO; 694 break; 695 } 696 } 697 } 698 ret = 0; 699 700 bytes -= n; 701 offset += n; 702 buf += n; 703 } 704 705 qemu_co_mutex_unlock(&s->lock); 706 707 if (qiov->niov > 1) { 708 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 709 qemu_vfree(orig_buf); 710 } 711 712 return ret; 713 } 714 715 static coroutine_fn int qcow_co_pwritev(BlockDriverState *bs, int64_t offset, 716 int64_t bytes, QEMUIOVector *qiov, 717 BdrvRequestFlags flags) 718 { 719 BDRVQcowState *s = bs->opaque; 720 int offset_in_cluster; 721 uint64_t cluster_offset; 722 int ret = 0, n; 723 uint8_t *buf; 724 void *orig_buf; 725 726 assert(!flags); 727 s->cluster_cache_offset = -1; /* disable compressed cache */ 728 729 /* We must always copy the iov when encrypting, so we 730 * don't modify the original data buffer during encryption */ 731 if (bs->encrypted || qiov->niov > 1) { 732 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 733 if (buf == NULL) { 734 return -ENOMEM; 735 } 736 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 737 } else { 738 orig_buf = NULL; 739 buf = (uint8_t *)qiov->iov->iov_base; 740 } 741 742 qemu_co_mutex_lock(&s->lock); 743 744 while (bytes != 0) { 745 offset_in_cluster = offset & (s->cluster_size - 1); 746 n = s->cluster_size - offset_in_cluster; 747 if (n > bytes) { 748 n = bytes; 749 } 750 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster, 751 offset_in_cluster + n, &cluster_offset); 752 if (ret < 0) { 753 break; 754 } 755 if (!cluster_offset || (cluster_offset & 511) != 0) { 756 ret = -EIO; 757 break; 758 } 759 if (bs->encrypted) { 760 assert(s->crypto); 761 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) { 762 ret = -EIO; 763 break; 764 } 765 } 766 767 qemu_co_mutex_unlock(&s->lock); 768 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 769 ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster, 770 n, buf, 0); 771 qemu_co_mutex_lock(&s->lock); 772 if (ret < 0) { 773 break; 774 } 775 ret = 0; 776 777 bytes -= n; 778 offset += n; 779 buf += n; 780 } 781 qemu_co_mutex_unlock(&s->lock); 782 783 qemu_vfree(orig_buf); 784 785 return ret; 786 } 787 788 static void qcow_close(BlockDriverState *bs) 789 { 790 BDRVQcowState *s = bs->opaque; 791 792 qcrypto_block_free(s->crypto); 793 s->crypto = NULL; 794 g_free(s->l1_table); 795 qemu_vfree(s->l2_cache); 796 g_free(s->cluster_cache); 797 g_free(s->cluster_data); 798 799 migrate_del_blocker(s->migration_blocker); 800 error_free(s->migration_blocker); 801 } 802 803 static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts, 804 Error **errp) 805 { 806 BlockdevCreateOptionsQcow *qcow_opts; 807 int header_size, backing_filename_len, l1_size, shift, i; 808 QCowHeader header; 809 uint8_t *tmp; 810 int64_t total_size = 0; 811 int ret; 812 BlockDriverState *bs; 813 BlockBackend *qcow_blk; 814 QCryptoBlock *crypto = NULL; 815 816 assert(opts->driver == BLOCKDEV_DRIVER_QCOW); 817 qcow_opts = &opts->u.qcow; 818 819 /* Sanity checks */ 820 total_size = qcow_opts->size; 821 if (total_size == 0) { 822 error_setg(errp, "Image size is too small, cannot be zero length"); 823 return -EINVAL; 824 } 825 826 if (qcow_opts->has_encrypt && 827 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW) 828 { 829 error_setg(errp, "Unsupported encryption format"); 830 return -EINVAL; 831 } 832 833 /* Create BlockBackend to write to the image */ 834 bs = bdrv_open_blockdev_ref(qcow_opts->file, errp); 835 if (bs == NULL) { 836 return -EIO; 837 } 838 839 qcow_blk = blk_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, 840 BLK_PERM_ALL, errp); 841 if (!qcow_blk) { 842 ret = -EPERM; 843 goto exit; 844 } 845 blk_set_allow_write_beyond_eof(qcow_blk, true); 846 847 /* Create image format */ 848 memset(&header, 0, sizeof(header)); 849 header.magic = cpu_to_be32(QCOW_MAGIC); 850 header.version = cpu_to_be32(QCOW_VERSION); 851 header.size = cpu_to_be64(total_size); 852 header_size = sizeof(header); 853 backing_filename_len = 0; 854 if (qcow_opts->has_backing_file) { 855 if (strcmp(qcow_opts->backing_file, "fat:")) { 856 header.backing_file_offset = cpu_to_be64(header_size); 857 backing_filename_len = strlen(qcow_opts->backing_file); 858 header.backing_file_size = cpu_to_be32(backing_filename_len); 859 header_size += backing_filename_len; 860 } else { 861 /* special backing file for vvfat */ 862 qcow_opts->has_backing_file = false; 863 } 864 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 865 unmodified sectors */ 866 header.l2_bits = 12; /* 32 KB L2 tables */ 867 } else { 868 header.cluster_bits = 12; /* 4 KB clusters */ 869 header.l2_bits = 9; /* 4 KB L2 tables */ 870 } 871 header_size = (header_size + 7) & ~7; 872 shift = header.cluster_bits + header.l2_bits; 873 l1_size = (total_size + (1LL << shift) - 1) >> shift; 874 875 header.l1_table_offset = cpu_to_be64(header_size); 876 877 if (qcow_opts->has_encrypt) { 878 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 879 880 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.", 881 NULL, NULL, NULL, errp); 882 if (!crypto) { 883 ret = -EINVAL; 884 goto exit; 885 } 886 } else { 887 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 888 } 889 890 /* write all the data */ 891 ret = blk_pwrite(qcow_blk, 0, sizeof(header), &header, 0); 892 if (ret < 0) { 893 goto exit; 894 } 895 896 if (qcow_opts->has_backing_file) { 897 ret = blk_pwrite(qcow_blk, sizeof(header), backing_filename_len, 898 qcow_opts->backing_file, 0); 899 if (ret < 0) { 900 goto exit; 901 } 902 } 903 904 tmp = g_malloc0(BDRV_SECTOR_SIZE); 905 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 906 i++) { 907 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 908 BDRV_SECTOR_SIZE, tmp, 0); 909 if (ret < 0) { 910 g_free(tmp); 911 goto exit; 912 } 913 } 914 915 g_free(tmp); 916 ret = 0; 917 exit: 918 blk_unref(qcow_blk); 919 bdrv_unref(bs); 920 qcrypto_block_free(crypto); 921 return ret; 922 } 923 924 static int coroutine_fn qcow_co_create_opts(BlockDriver *drv, 925 const char *filename, 926 QemuOpts *opts, Error **errp) 927 { 928 BlockdevCreateOptions *create_options = NULL; 929 BlockDriverState *bs = NULL; 930 QDict *qdict = NULL; 931 Visitor *v; 932 const char *val; 933 int ret; 934 char *backing_fmt; 935 936 static const QDictRenames opt_renames[] = { 937 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 938 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 939 { NULL, NULL }, 940 }; 941 942 /* 943 * We can't actually store a backing format, but can check that 944 * the user's request made sense. 945 */ 946 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 947 if (backing_fmt && !bdrv_find_format(backing_fmt)) { 948 error_setg(errp, "unrecognized backing format '%s'", backing_fmt); 949 ret = -EINVAL; 950 goto fail; 951 } 952 953 /* Parse options and convert legacy syntax */ 954 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true); 955 956 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 957 if (val && !strcmp(val, "on")) { 958 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 959 } else if (val && !strcmp(val, "off")) { 960 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 961 } 962 963 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 964 if (val && !strcmp(val, "aes")) { 965 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 966 } 967 968 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 969 ret = -EINVAL; 970 goto fail; 971 } 972 973 /* Create and open the file (protocol layer) */ 974 ret = bdrv_create_file(filename, opts, errp); 975 if (ret < 0) { 976 goto fail; 977 } 978 979 bs = bdrv_open(filename, NULL, NULL, 980 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 981 if (bs == NULL) { 982 ret = -EIO; 983 goto fail; 984 } 985 986 /* Now get the QAPI type BlockdevCreateOptions */ 987 qdict_put_str(qdict, "driver", "qcow"); 988 qdict_put_str(qdict, "file", bs->node_name); 989 990 v = qobject_input_visitor_new_flat_confused(qdict, errp); 991 if (!v) { 992 ret = -EINVAL; 993 goto fail; 994 } 995 996 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp); 997 visit_free(v); 998 if (!create_options) { 999 ret = -EINVAL; 1000 goto fail; 1001 } 1002 1003 /* Silently round up size */ 1004 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW); 1005 create_options->u.qcow.size = 1006 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE); 1007 1008 /* Create the qcow image (format layer) */ 1009 ret = qcow_co_create(create_options, errp); 1010 if (ret < 0) { 1011 goto fail; 1012 } 1013 1014 ret = 0; 1015 fail: 1016 g_free(backing_fmt); 1017 qobject_unref(qdict); 1018 bdrv_unref(bs); 1019 qapi_free_BlockdevCreateOptions(create_options); 1020 return ret; 1021 } 1022 1023 static int qcow_make_empty(BlockDriverState *bs) 1024 { 1025 BDRVQcowState *s = bs->opaque; 1026 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 1027 int ret; 1028 1029 memset(s->l1_table, 0, l1_length); 1030 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, l1_length, s->l1_table, 1031 0) < 0) 1032 return -1; 1033 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false, 1034 PREALLOC_MODE_OFF, 0, NULL); 1035 if (ret < 0) 1036 return ret; 1037 1038 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 1039 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 1040 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 1041 1042 return 0; 1043 } 1044 1045 /* XXX: put compressed sectors first, then all the cluster aligned 1046 tables to avoid losing bytes in alignment */ 1047 static coroutine_fn int 1048 qcow_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes, 1049 QEMUIOVector *qiov) 1050 { 1051 BDRVQcowState *s = bs->opaque; 1052 z_stream strm; 1053 int ret, out_len; 1054 uint8_t *buf, *out_buf; 1055 uint64_t cluster_offset; 1056 1057 buf = qemu_blockalign(bs, s->cluster_size); 1058 if (bytes != s->cluster_size) { 1059 if (bytes > s->cluster_size || 1060 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 1061 { 1062 qemu_vfree(buf); 1063 return -EINVAL; 1064 } 1065 /* Zero-pad last write if image size is not cluster aligned */ 1066 memset(buf + bytes, 0, s->cluster_size - bytes); 1067 } 1068 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 1069 1070 out_buf = g_malloc(s->cluster_size); 1071 1072 /* best compression, small window, no zlib header */ 1073 memset(&strm, 0, sizeof(strm)); 1074 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 1075 Z_DEFLATED, -12, 1076 9, Z_DEFAULT_STRATEGY); 1077 if (ret != 0) { 1078 ret = -EINVAL; 1079 goto fail; 1080 } 1081 1082 strm.avail_in = s->cluster_size; 1083 strm.next_in = (uint8_t *)buf; 1084 strm.avail_out = s->cluster_size; 1085 strm.next_out = out_buf; 1086 1087 ret = deflate(&strm, Z_FINISH); 1088 if (ret != Z_STREAM_END && ret != Z_OK) { 1089 deflateEnd(&strm); 1090 ret = -EINVAL; 1091 goto fail; 1092 } 1093 out_len = strm.next_out - out_buf; 1094 1095 deflateEnd(&strm); 1096 1097 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 1098 /* could not compress: write normal cluster */ 1099 ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0); 1100 if (ret < 0) { 1101 goto fail; 1102 } 1103 goto success; 1104 } 1105 qemu_co_mutex_lock(&s->lock); 1106 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset); 1107 qemu_co_mutex_unlock(&s->lock); 1108 if (ret < 0) { 1109 goto fail; 1110 } 1111 if (cluster_offset == 0) { 1112 ret = -EIO; 1113 goto fail; 1114 } 1115 cluster_offset &= s->cluster_offset_mask; 1116 1117 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 1118 ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0); 1119 if (ret < 0) { 1120 goto fail; 1121 } 1122 success: 1123 ret = 0; 1124 fail: 1125 qemu_vfree(buf); 1126 g_free(out_buf); 1127 return ret; 1128 } 1129 1130 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1131 { 1132 BDRVQcowState *s = bs->opaque; 1133 bdi->cluster_size = s->cluster_size; 1134 return 0; 1135 } 1136 1137 static QemuOptsList qcow_create_opts = { 1138 .name = "qcow-create-opts", 1139 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1140 .desc = { 1141 { 1142 .name = BLOCK_OPT_SIZE, 1143 .type = QEMU_OPT_SIZE, 1144 .help = "Virtual disk size" 1145 }, 1146 { 1147 .name = BLOCK_OPT_BACKING_FILE, 1148 .type = QEMU_OPT_STRING, 1149 .help = "File name of a base image" 1150 }, 1151 { 1152 .name = BLOCK_OPT_BACKING_FMT, 1153 .type = QEMU_OPT_STRING, 1154 .help = "Format of the backing image", 1155 }, 1156 { 1157 .name = BLOCK_OPT_ENCRYPT, 1158 .type = QEMU_OPT_BOOL, 1159 .help = "Encrypt the image with format 'aes'. (Deprecated " 1160 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 1161 }, 1162 { 1163 .name = BLOCK_OPT_ENCRYPT_FORMAT, 1164 .type = QEMU_OPT_STRING, 1165 .help = "Encrypt the image, format choices: 'aes'", 1166 }, 1167 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 1168 { /* end of list */ } 1169 } 1170 }; 1171 1172 static const char *const qcow_strong_runtime_opts[] = { 1173 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, 1174 1175 NULL 1176 }; 1177 1178 static BlockDriver bdrv_qcow = { 1179 .format_name = "qcow", 1180 .instance_size = sizeof(BDRVQcowState), 1181 .bdrv_probe = qcow_probe, 1182 .bdrv_open = qcow_open, 1183 .bdrv_close = qcow_close, 1184 .bdrv_child_perm = bdrv_default_perms, 1185 .bdrv_reopen_prepare = qcow_reopen_prepare, 1186 .bdrv_co_create = qcow_co_create, 1187 .bdrv_co_create_opts = qcow_co_create_opts, 1188 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1189 .is_format = true, 1190 .supports_backing = true, 1191 .bdrv_refresh_limits = qcow_refresh_limits, 1192 1193 .bdrv_co_preadv = qcow_co_preadv, 1194 .bdrv_co_pwritev = qcow_co_pwritev, 1195 .bdrv_co_block_status = qcow_co_block_status, 1196 1197 .bdrv_make_empty = qcow_make_empty, 1198 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1199 .bdrv_get_info = qcow_get_info, 1200 1201 .create_opts = &qcow_create_opts, 1202 .strong_runtime_opts = qcow_strong_runtime_opts, 1203 }; 1204 1205 static void bdrv_qcow_init(void) 1206 { 1207 bdrv_register(&bdrv_qcow); 1208 } 1209 1210 block_init(bdrv_qcow_init); 1211