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