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 Error *local_err = NULL; 125 QCryptoBlockOpenOptions *crypto_opts = NULL; 126 unsigned int cflags = 0; 127 QDict *encryptopts = NULL; 128 const char *encryptfmt; 129 130 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 131 encryptfmt = qdict_get_try_str(encryptopts, "format"); 132 133 bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file, 134 false, errp); 135 if (!bs->file) { 136 ret = -EINVAL; 137 goto fail; 138 } 139 140 ret = bdrv_pread(bs->file, 0, &header, sizeof(header)); 141 if (ret < 0) { 142 goto fail; 143 } 144 header.magic = be32_to_cpu(header.magic); 145 header.version = be32_to_cpu(header.version); 146 header.backing_file_offset = be64_to_cpu(header.backing_file_offset); 147 header.backing_file_size = be32_to_cpu(header.backing_file_size); 148 header.mtime = be32_to_cpu(header.mtime); 149 header.size = be64_to_cpu(header.size); 150 header.crypt_method = be32_to_cpu(header.crypt_method); 151 header.l1_table_offset = be64_to_cpu(header.l1_table_offset); 152 153 if (header.magic != QCOW_MAGIC) { 154 error_setg(errp, "Image not in qcow format"); 155 ret = -EINVAL; 156 goto fail; 157 } 158 if (header.version != QCOW_VERSION) { 159 error_setg(errp, "Unsupported qcow version %" PRIu32, header.version); 160 ret = -ENOTSUP; 161 goto fail; 162 } 163 164 if (header.size <= 1) { 165 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 166 ret = -EINVAL; 167 goto fail; 168 } 169 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 170 error_setg(errp, "Cluster size must be between 512 and 64k"); 171 ret = -EINVAL; 172 goto fail; 173 } 174 175 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 176 * so bytes = num_entries << 3. */ 177 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 178 error_setg(errp, "L2 table size must be between 512 and 64k"); 179 ret = -EINVAL; 180 goto fail; 181 } 182 183 s->crypt_method_header = header.crypt_method; 184 if (s->crypt_method_header) { 185 if (bdrv_uses_whitelist() && 186 s->crypt_method_header == QCOW_CRYPT_AES) { 187 error_setg(errp, 188 "Use of AES-CBC encrypted qcow images is no longer " 189 "supported in system emulators"); 190 error_append_hint(errp, 191 "You can use 'qemu-img convert' to convert your " 192 "image to an alternative supported format, such " 193 "as unencrypted qcow, or raw with the LUKS " 194 "format instead.\n"); 195 ret = -ENOSYS; 196 goto fail; 197 } 198 if (s->crypt_method_header == QCOW_CRYPT_AES) { 199 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 200 error_setg(errp, 201 "Header reported 'aes' encryption format but " 202 "options specify '%s'", encryptfmt); 203 ret = -EINVAL; 204 goto fail; 205 } 206 qdict_put_str(encryptopts, "format", "qcow"); 207 crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 208 if (!crypto_opts) { 209 ret = -EINVAL; 210 goto fail; 211 } 212 213 if (flags & BDRV_O_NO_IO) { 214 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 215 } 216 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.", 217 NULL, NULL, cflags, 1, errp); 218 if (!s->crypto) { 219 ret = -EINVAL; 220 goto fail; 221 } 222 } else { 223 error_setg(errp, "invalid encryption method in qcow header"); 224 ret = -EINVAL; 225 goto fail; 226 } 227 bs->encrypted = true; 228 } else { 229 if (encryptfmt) { 230 error_setg(errp, "No encryption in image header, but options " 231 "specified format '%s'", encryptfmt); 232 ret = -EINVAL; 233 goto fail; 234 } 235 } 236 s->cluster_bits = header.cluster_bits; 237 s->cluster_size = 1 << s->cluster_bits; 238 s->l2_bits = header.l2_bits; 239 s->l2_size = 1 << s->l2_bits; 240 bs->total_sectors = header.size / 512; 241 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 242 243 /* read the level 1 table */ 244 shift = s->cluster_bits + s->l2_bits; 245 if (header.size > UINT64_MAX - (1LL << shift)) { 246 error_setg(errp, "Image too large"); 247 ret = -EINVAL; 248 goto fail; 249 } else { 250 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 251 if (l1_size > INT_MAX / sizeof(uint64_t)) { 252 error_setg(errp, "Image too large"); 253 ret = -EINVAL; 254 goto fail; 255 } 256 s->l1_size = l1_size; 257 } 258 259 s->l1_table_offset = header.l1_table_offset; 260 s->l1_table = g_try_new(uint64_t, s->l1_size); 261 if (s->l1_table == NULL) { 262 error_setg(errp, "Could not allocate memory for L1 table"); 263 ret = -ENOMEM; 264 goto fail; 265 } 266 267 ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, 268 s->l1_size * sizeof(uint64_t)); 269 if (ret < 0) { 270 goto fail; 271 } 272 273 for(i = 0;i < s->l1_size; i++) { 274 s->l1_table[i] = be64_to_cpu(s->l1_table[i]); 275 } 276 277 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 278 s->l2_cache = 279 qemu_try_blockalign(bs->file->bs, 280 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 281 if (s->l2_cache == NULL) { 282 error_setg(errp, "Could not allocate L2 table cache"); 283 ret = -ENOMEM; 284 goto fail; 285 } 286 s->cluster_cache = g_malloc(s->cluster_size); 287 s->cluster_data = g_malloc(s->cluster_size); 288 s->cluster_cache_offset = -1; 289 290 /* read the backing file name */ 291 if (header.backing_file_offset != 0) { 292 len = header.backing_file_size; 293 if (len > 1023 || len >= sizeof(bs->backing_file)) { 294 error_setg(errp, "Backing file name too long"); 295 ret = -EINVAL; 296 goto fail; 297 } 298 ret = bdrv_pread(bs->file, header.backing_file_offset, 299 bs->auto_backing_file, len); 300 if (ret < 0) { 301 goto fail; 302 } 303 bs->auto_backing_file[len] = '\0'; 304 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 305 bs->auto_backing_file); 306 } 307 308 /* Disable migration when qcow images are used */ 309 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 310 "does not support live migration", 311 bdrv_get_device_or_node_name(bs)); 312 ret = migrate_add_blocker(s->migration_blocker, &local_err); 313 if (local_err) { 314 error_propagate(errp, local_err); 315 error_free(s->migration_blocker); 316 goto fail; 317 } 318 319 qobject_unref(encryptopts); 320 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 321 qemu_co_mutex_init(&s->lock); 322 return 0; 323 324 fail: 325 g_free(s->l1_table); 326 qemu_vfree(s->l2_cache); 327 g_free(s->cluster_cache); 328 g_free(s->cluster_data); 329 qcrypto_block_free(s->crypto); 330 qobject_unref(encryptopts); 331 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 332 return ret; 333 } 334 335 336 /* We have nothing to do for QCOW reopen, stubs just return 337 * success */ 338 static int qcow_reopen_prepare(BDRVReopenState *state, 339 BlockReopenQueue *queue, Error **errp) 340 { 341 return 0; 342 } 343 344 345 /* 'allocate' is: 346 * 347 * 0 to not allocate. 348 * 349 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start' 350 * to 'n_end' within the cluster) 351 * 352 * 2 to allocate a compressed cluster of size 353 * 'compressed_size'. 'compressed_size' must be > 0 and < 354 * cluster_size 355 * 356 * return 0 if not allocated, 1 if *result is assigned, and negative 357 * errno on failure. 358 */ 359 static int get_cluster_offset(BlockDriverState *bs, 360 uint64_t offset, int allocate, 361 int compressed_size, 362 int n_start, int n_end, uint64_t *result) 363 { 364 BDRVQcowState *s = bs->opaque; 365 int min_index, i, j, l1_index, l2_index, ret; 366 int64_t l2_offset; 367 uint64_t *l2_table, cluster_offset, tmp; 368 uint32_t min_count; 369 int new_l2_table; 370 371 *result = 0; 372 l1_index = offset >> (s->l2_bits + s->cluster_bits); 373 l2_offset = s->l1_table[l1_index]; 374 new_l2_table = 0; 375 if (!l2_offset) { 376 if (!allocate) 377 return 0; 378 /* allocate a new l2 entry */ 379 l2_offset = bdrv_getlength(bs->file->bs); 380 if (l2_offset < 0) { 381 return l2_offset; 382 } 383 /* round to cluster size */ 384 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); 385 /* update the L1 entry */ 386 s->l1_table[l1_index] = l2_offset; 387 tmp = cpu_to_be64(l2_offset); 388 BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE); 389 ret = bdrv_pwrite_sync(bs->file, 390 s->l1_table_offset + l1_index * sizeof(tmp), 391 &tmp, sizeof(tmp)); 392 if (ret < 0) { 393 return ret; 394 } 395 new_l2_table = 1; 396 } 397 for(i = 0; i < L2_CACHE_SIZE; i++) { 398 if (l2_offset == s->l2_cache_offsets[i]) { 399 /* increment the hit count */ 400 if (++s->l2_cache_counts[i] == 0xffffffff) { 401 for(j = 0; j < L2_CACHE_SIZE; j++) { 402 s->l2_cache_counts[j] >>= 1; 403 } 404 } 405 l2_table = s->l2_cache + (i << s->l2_bits); 406 goto found; 407 } 408 } 409 /* not found: load a new entry in the least used one */ 410 min_index = 0; 411 min_count = 0xffffffff; 412 for(i = 0; i < L2_CACHE_SIZE; i++) { 413 if (s->l2_cache_counts[i] < min_count) { 414 min_count = s->l2_cache_counts[i]; 415 min_index = i; 416 } 417 } 418 l2_table = s->l2_cache + (min_index << s->l2_bits); 419 BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD); 420 if (new_l2_table) { 421 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 422 ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 423 s->l2_size * sizeof(uint64_t)); 424 if (ret < 0) { 425 return ret; 426 } 427 } else { 428 ret = bdrv_pread(bs->file, l2_offset, l2_table, 429 s->l2_size * sizeof(uint64_t)); 430 if (ret < 0) { 431 return ret; 432 } 433 } 434 s->l2_cache_offsets[min_index] = l2_offset; 435 s->l2_cache_counts[min_index] = 1; 436 found: 437 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 438 cluster_offset = be64_to_cpu(l2_table[l2_index]); 439 if (!cluster_offset || 440 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 441 if (!allocate) 442 return 0; 443 BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); 444 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE)); 445 /* allocate a new cluster */ 446 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 447 (n_end - n_start) < s->cluster_size) { 448 /* if the cluster is already compressed, we must 449 decompress it in the case it is not completely 450 overwritten */ 451 if (decompress_cluster(bs, cluster_offset) < 0) { 452 return -EIO; 453 } 454 cluster_offset = bdrv_getlength(bs->file->bs); 455 if ((int64_t) cluster_offset < 0) { 456 return cluster_offset; 457 } 458 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 459 /* write the cluster content */ 460 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 461 ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, 462 s->cluster_size); 463 if (ret < 0) { 464 return ret; 465 } 466 } else { 467 cluster_offset = bdrv_getlength(bs->file->bs); 468 if ((int64_t) cluster_offset < 0) { 469 return cluster_offset; 470 } 471 if (allocate == 1) { 472 /* round to cluster size */ 473 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 474 if (cluster_offset + s->cluster_size > INT64_MAX) { 475 return -E2BIG; 476 } 477 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size, 478 PREALLOC_MODE_OFF, NULL); 479 if (ret < 0) { 480 return ret; 481 } 482 /* if encrypted, we must initialize the cluster 483 content which won't be written */ 484 if (bs->encrypted && 485 (n_end - n_start) < s->cluster_size) { 486 uint64_t start_offset; 487 assert(s->crypto); 488 start_offset = offset & ~(s->cluster_size - 1); 489 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) { 490 if (i < n_start || i >= n_end) { 491 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE); 492 if (qcrypto_block_encrypt(s->crypto, 493 start_offset + i, 494 s->cluster_data, 495 BDRV_SECTOR_SIZE, 496 NULL) < 0) { 497 return -EIO; 498 } 499 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 500 ret = bdrv_pwrite(bs->file, 501 cluster_offset + i, 502 s->cluster_data, 503 BDRV_SECTOR_SIZE); 504 if (ret < 0) { 505 return ret; 506 } 507 } 508 } 509 } 510 } else if (allocate == 2) { 511 cluster_offset |= QCOW_OFLAG_COMPRESSED | 512 (uint64_t)compressed_size << (63 - s->cluster_bits); 513 } 514 } 515 /* update L2 table */ 516 tmp = cpu_to_be64(cluster_offset); 517 l2_table[l2_index] = tmp; 518 if (allocate == 2) { 519 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); 520 } else { 521 BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); 522 } 523 ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 524 &tmp, sizeof(tmp)); 525 if (ret < 0) { 526 return ret; 527 } 528 } 529 *result = cluster_offset; 530 return 1; 531 } 532 533 static int coroutine_fn qcow_co_block_status(BlockDriverState *bs, 534 bool want_zero, 535 int64_t offset, int64_t bytes, 536 int64_t *pnum, int64_t *map, 537 BlockDriverState **file) 538 { 539 BDRVQcowState *s = bs->opaque; 540 int index_in_cluster, ret; 541 int64_t n; 542 uint64_t cluster_offset; 543 544 qemu_co_mutex_lock(&s->lock); 545 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 546 qemu_co_mutex_unlock(&s->lock); 547 if (ret < 0) { 548 return ret; 549 } 550 index_in_cluster = offset & (s->cluster_size - 1); 551 n = s->cluster_size - index_in_cluster; 552 if (n > bytes) { 553 n = bytes; 554 } 555 *pnum = n; 556 if (!cluster_offset) { 557 return 0; 558 } 559 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) { 560 return BDRV_BLOCK_DATA; 561 } 562 *map = cluster_offset | index_in_cluster; 563 *file = bs->file->bs; 564 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; 565 } 566 567 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 568 const uint8_t *buf, int buf_size) 569 { 570 z_stream strm1, *strm = &strm1; 571 int ret, out_len; 572 573 memset(strm, 0, sizeof(*strm)); 574 575 strm->next_in = (uint8_t *)buf; 576 strm->avail_in = buf_size; 577 strm->next_out = out_buf; 578 strm->avail_out = out_buf_size; 579 580 ret = inflateInit2(strm, -12); 581 if (ret != Z_OK) 582 return -1; 583 ret = inflate(strm, Z_FINISH); 584 out_len = strm->next_out - out_buf; 585 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 586 out_len != out_buf_size) { 587 inflateEnd(strm); 588 return -1; 589 } 590 inflateEnd(strm); 591 return 0; 592 } 593 594 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 595 { 596 BDRVQcowState *s = bs->opaque; 597 int ret, csize; 598 uint64_t coffset; 599 600 coffset = cluster_offset & s->cluster_offset_mask; 601 if (s->cluster_cache_offset != coffset) { 602 csize = cluster_offset >> (63 - s->cluster_bits); 603 csize &= (s->cluster_size - 1); 604 BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 605 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 606 if (ret != csize) 607 return -1; 608 if (decompress_buffer(s->cluster_cache, s->cluster_size, 609 s->cluster_data, csize) < 0) { 610 return -1; 611 } 612 s->cluster_cache_offset = coffset; 613 } 614 return 0; 615 } 616 617 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp) 618 { 619 /* At least encrypted images require 512-byte alignment. Apply the 620 * limit universally, rather than just on encrypted images, as 621 * it's easier to let the block layer handle rounding than to 622 * audit this code further. */ 623 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 624 } 625 626 static coroutine_fn int qcow_co_preadv(BlockDriverState *bs, uint64_t offset, 627 uint64_t bytes, QEMUIOVector *qiov, 628 int flags) 629 { 630 BDRVQcowState *s = bs->opaque; 631 int offset_in_cluster; 632 int ret = 0, n; 633 uint64_t cluster_offset; 634 QEMUIOVector hd_qiov; 635 uint8_t *buf; 636 void *orig_buf; 637 638 assert(!flags); 639 if (qiov->niov > 1) { 640 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 641 if (buf == NULL) { 642 return -ENOMEM; 643 } 644 } else { 645 orig_buf = NULL; 646 buf = (uint8_t *)qiov->iov->iov_base; 647 } 648 649 qemu_co_mutex_lock(&s->lock); 650 651 while (bytes != 0) { 652 /* prepare next request */ 653 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 654 if (ret < 0) { 655 break; 656 } 657 offset_in_cluster = offset & (s->cluster_size - 1); 658 n = s->cluster_size - offset_in_cluster; 659 if (n > bytes) { 660 n = bytes; 661 } 662 663 if (!cluster_offset) { 664 if (bs->backing) { 665 /* read from the base image */ 666 qemu_iovec_init_buf(&hd_qiov, buf, n); 667 qemu_co_mutex_unlock(&s->lock); 668 /* qcow2 emits this on bs->file instead of bs->backing */ 669 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 670 ret = bdrv_co_preadv(bs->backing, offset, n, &hd_qiov, 0); 671 qemu_co_mutex_lock(&s->lock); 672 if (ret < 0) { 673 break; 674 } 675 } else { 676 /* Note: in this case, no need to wait */ 677 memset(buf, 0, n); 678 } 679 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 680 /* add AIO support for compressed blocks ? */ 681 if (decompress_cluster(bs, cluster_offset) < 0) { 682 ret = -EIO; 683 break; 684 } 685 memcpy(buf, s->cluster_cache + offset_in_cluster, n); 686 } else { 687 if ((cluster_offset & 511) != 0) { 688 ret = -EIO; 689 break; 690 } 691 qemu_iovec_init_buf(&hd_qiov, buf, n); 692 qemu_co_mutex_unlock(&s->lock); 693 BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); 694 ret = bdrv_co_preadv(bs->file, cluster_offset + offset_in_cluster, 695 n, &hd_qiov, 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 QEMUIOVector hd_qiov; 735 uint8_t *buf; 736 void *orig_buf; 737 738 assert(!flags); 739 s->cluster_cache_offset = -1; /* disable compressed cache */ 740 741 /* We must always copy the iov when encrypting, so we 742 * don't modify the original data buffer during encryption */ 743 if (bs->encrypted || qiov->niov > 1) { 744 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 745 if (buf == NULL) { 746 return -ENOMEM; 747 } 748 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 749 } else { 750 orig_buf = NULL; 751 buf = (uint8_t *)qiov->iov->iov_base; 752 } 753 754 qemu_co_mutex_lock(&s->lock); 755 756 while (bytes != 0) { 757 offset_in_cluster = offset & (s->cluster_size - 1); 758 n = s->cluster_size - offset_in_cluster; 759 if (n > bytes) { 760 n = bytes; 761 } 762 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster, 763 offset_in_cluster + n, &cluster_offset); 764 if (ret < 0) { 765 break; 766 } 767 if (!cluster_offset || (cluster_offset & 511) != 0) { 768 ret = -EIO; 769 break; 770 } 771 if (bs->encrypted) { 772 assert(s->crypto); 773 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) { 774 ret = -EIO; 775 break; 776 } 777 } 778 779 qemu_iovec_init_buf(&hd_qiov, buf, n); 780 qemu_co_mutex_unlock(&s->lock); 781 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO); 782 ret = bdrv_co_pwritev(bs->file, cluster_offset + offset_in_cluster, 783 n, &hd_qiov, 0); 784 qemu_co_mutex_lock(&s->lock); 785 if (ret < 0) { 786 break; 787 } 788 ret = 0; 789 790 bytes -= n; 791 offset += n; 792 buf += n; 793 } 794 qemu_co_mutex_unlock(&s->lock); 795 796 qemu_vfree(orig_buf); 797 798 return ret; 799 } 800 801 static void qcow_close(BlockDriverState *bs) 802 { 803 BDRVQcowState *s = bs->opaque; 804 805 qcrypto_block_free(s->crypto); 806 s->crypto = NULL; 807 g_free(s->l1_table); 808 qemu_vfree(s->l2_cache); 809 g_free(s->cluster_cache); 810 g_free(s->cluster_data); 811 812 migrate_del_blocker(s->migration_blocker); 813 error_free(s->migration_blocker); 814 } 815 816 static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts, 817 Error **errp) 818 { 819 BlockdevCreateOptionsQcow *qcow_opts; 820 int header_size, backing_filename_len, l1_size, shift, i; 821 QCowHeader header; 822 uint8_t *tmp; 823 int64_t total_size = 0; 824 int ret; 825 BlockDriverState *bs; 826 BlockBackend *qcow_blk; 827 QCryptoBlock *crypto = NULL; 828 829 assert(opts->driver == BLOCKDEV_DRIVER_QCOW); 830 qcow_opts = &opts->u.qcow; 831 832 /* Sanity checks */ 833 total_size = qcow_opts->size; 834 if (total_size == 0) { 835 error_setg(errp, "Image size is too small, cannot be zero length"); 836 return -EINVAL; 837 } 838 839 if (qcow_opts->has_encrypt && 840 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW) 841 { 842 error_setg(errp, "Unsupported encryption format"); 843 return -EINVAL; 844 } 845 846 /* Create BlockBackend to write to the image */ 847 bs = bdrv_open_blockdev_ref(qcow_opts->file, errp); 848 if (bs == NULL) { 849 return -EIO; 850 } 851 852 qcow_blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL); 853 ret = blk_insert_bs(qcow_blk, bs, errp); 854 if (ret < 0) { 855 goto exit; 856 } 857 blk_set_allow_write_beyond_eof(qcow_blk, true); 858 859 /* Create image format */ 860 ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp); 861 if (ret < 0) { 862 goto exit; 863 } 864 865 memset(&header, 0, sizeof(header)); 866 header.magic = cpu_to_be32(QCOW_MAGIC); 867 header.version = cpu_to_be32(QCOW_VERSION); 868 header.size = cpu_to_be64(total_size); 869 header_size = sizeof(header); 870 backing_filename_len = 0; 871 if (qcow_opts->has_backing_file) { 872 if (strcmp(qcow_opts->backing_file, "fat:")) { 873 header.backing_file_offset = cpu_to_be64(header_size); 874 backing_filename_len = strlen(qcow_opts->backing_file); 875 header.backing_file_size = cpu_to_be32(backing_filename_len); 876 header_size += backing_filename_len; 877 } else { 878 /* special backing file for vvfat */ 879 qcow_opts->has_backing_file = false; 880 } 881 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 882 unmodified sectors */ 883 header.l2_bits = 12; /* 32 KB L2 tables */ 884 } else { 885 header.cluster_bits = 12; /* 4 KB clusters */ 886 header.l2_bits = 9; /* 4 KB L2 tables */ 887 } 888 header_size = (header_size + 7) & ~7; 889 shift = header.cluster_bits + header.l2_bits; 890 l1_size = (total_size + (1LL << shift) - 1) >> shift; 891 892 header.l1_table_offset = cpu_to_be64(header_size); 893 894 if (qcow_opts->has_encrypt) { 895 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 896 897 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.", 898 NULL, NULL, NULL, errp); 899 if (!crypto) { 900 ret = -EINVAL; 901 goto exit; 902 } 903 } else { 904 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 905 } 906 907 /* write all the data */ 908 ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0); 909 if (ret != sizeof(header)) { 910 goto exit; 911 } 912 913 if (qcow_opts->has_backing_file) { 914 ret = blk_pwrite(qcow_blk, sizeof(header), 915 qcow_opts->backing_file, backing_filename_len, 0); 916 if (ret != backing_filename_len) { 917 goto exit; 918 } 919 } 920 921 tmp = g_malloc0(BDRV_SECTOR_SIZE); 922 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 923 i++) { 924 ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 925 tmp, BDRV_SECTOR_SIZE, 0); 926 if (ret != BDRV_SECTOR_SIZE) { 927 g_free(tmp); 928 goto exit; 929 } 930 } 931 932 g_free(tmp); 933 ret = 0; 934 exit: 935 blk_unref(qcow_blk); 936 bdrv_unref(bs); 937 qcrypto_block_free(crypto); 938 return ret; 939 } 940 941 static int coroutine_fn qcow_co_create_opts(const char *filename, 942 QemuOpts *opts, Error **errp) 943 { 944 BlockdevCreateOptions *create_options = NULL; 945 BlockDriverState *bs = NULL; 946 QDict *qdict; 947 Visitor *v; 948 const char *val; 949 Error *local_err = NULL; 950 int ret; 951 952 static const QDictRenames opt_renames[] = { 953 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 954 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 955 { NULL, NULL }, 956 }; 957 958 /* Parse options and convert legacy syntax */ 959 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true); 960 961 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 962 if (val && !strcmp(val, "on")) { 963 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 964 } else if (val && !strcmp(val, "off")) { 965 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 966 } 967 968 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 969 if (val && !strcmp(val, "aes")) { 970 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 971 } 972 973 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 974 ret = -EINVAL; 975 goto fail; 976 } 977 978 /* Create and open the file (protocol layer) */ 979 ret = bdrv_create_file(filename, opts, &local_err); 980 if (ret < 0) { 981 error_propagate(errp, local_err); 982 goto fail; 983 } 984 985 bs = bdrv_open(filename, NULL, NULL, 986 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 987 if (bs == NULL) { 988 ret = -EIO; 989 goto fail; 990 } 991 992 /* Now get the QAPI type BlockdevCreateOptions */ 993 qdict_put_str(qdict, "driver", "qcow"); 994 qdict_put_str(qdict, "file", bs->node_name); 995 996 v = qobject_input_visitor_new_flat_confused(qdict, errp); 997 if (!v) { 998 ret = -EINVAL; 999 goto fail; 1000 } 1001 1002 visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err); 1003 visit_free(v); 1004 1005 if (local_err) { 1006 error_propagate(errp, local_err); 1007 ret = -EINVAL; 1008 goto fail; 1009 } 1010 1011 /* Silently round up size */ 1012 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW); 1013 create_options->u.qcow.size = 1014 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE); 1015 1016 /* Create the qcow image (format layer) */ 1017 ret = qcow_co_create(create_options, errp); 1018 if (ret < 0) { 1019 goto fail; 1020 } 1021 1022 ret = 0; 1023 fail: 1024 qobject_unref(qdict); 1025 bdrv_unref(bs); 1026 qapi_free_BlockdevCreateOptions(create_options); 1027 return ret; 1028 } 1029 1030 static int qcow_make_empty(BlockDriverState *bs) 1031 { 1032 BDRVQcowState *s = bs->opaque; 1033 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 1034 int ret; 1035 1036 memset(s->l1_table, 0, l1_length); 1037 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 1038 l1_length) < 0) 1039 return -1; 1040 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, 1041 PREALLOC_MODE_OFF, NULL); 1042 if (ret < 0) 1043 return ret; 1044 1045 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 1046 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 1047 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 1048 1049 return 0; 1050 } 1051 1052 /* XXX: put compressed sectors first, then all the cluster aligned 1053 tables to avoid losing bytes in alignment */ 1054 static coroutine_fn int 1055 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset, 1056 uint64_t bytes, QEMUIOVector *qiov) 1057 { 1058 BDRVQcowState *s = bs->opaque; 1059 QEMUIOVector hd_qiov; 1060 z_stream strm; 1061 int ret, out_len; 1062 uint8_t *buf, *out_buf; 1063 uint64_t cluster_offset; 1064 1065 buf = qemu_blockalign(bs, s->cluster_size); 1066 if (bytes != s->cluster_size) { 1067 if (bytes > s->cluster_size || 1068 offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS) 1069 { 1070 qemu_vfree(buf); 1071 return -EINVAL; 1072 } 1073 /* Zero-pad last write if image size is not cluster aligned */ 1074 memset(buf + bytes, 0, s->cluster_size - bytes); 1075 } 1076 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 1077 1078 out_buf = g_malloc(s->cluster_size); 1079 1080 /* best compression, small window, no zlib header */ 1081 memset(&strm, 0, sizeof(strm)); 1082 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 1083 Z_DEFLATED, -12, 1084 9, Z_DEFAULT_STRATEGY); 1085 if (ret != 0) { 1086 ret = -EINVAL; 1087 goto fail; 1088 } 1089 1090 strm.avail_in = s->cluster_size; 1091 strm.next_in = (uint8_t *)buf; 1092 strm.avail_out = s->cluster_size; 1093 strm.next_out = out_buf; 1094 1095 ret = deflate(&strm, Z_FINISH); 1096 if (ret != Z_STREAM_END && ret != Z_OK) { 1097 deflateEnd(&strm); 1098 ret = -EINVAL; 1099 goto fail; 1100 } 1101 out_len = strm.next_out - out_buf; 1102 1103 deflateEnd(&strm); 1104 1105 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 1106 /* could not compress: write normal cluster */ 1107 ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0); 1108 if (ret < 0) { 1109 goto fail; 1110 } 1111 goto success; 1112 } 1113 qemu_co_mutex_lock(&s->lock); 1114 ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset); 1115 qemu_co_mutex_unlock(&s->lock); 1116 if (ret < 0) { 1117 goto fail; 1118 } 1119 if (cluster_offset == 0) { 1120 ret = -EIO; 1121 goto fail; 1122 } 1123 cluster_offset &= s->cluster_offset_mask; 1124 1125 qemu_iovec_init_buf(&hd_qiov, out_buf, out_len); 1126 BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED); 1127 ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0); 1128 if (ret < 0) { 1129 goto fail; 1130 } 1131 success: 1132 ret = 0; 1133 fail: 1134 qemu_vfree(buf); 1135 g_free(out_buf); 1136 return ret; 1137 } 1138 1139 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1140 { 1141 BDRVQcowState *s = bs->opaque; 1142 bdi->cluster_size = s->cluster_size; 1143 return 0; 1144 } 1145 1146 static QemuOptsList qcow_create_opts = { 1147 .name = "qcow-create-opts", 1148 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1149 .desc = { 1150 { 1151 .name = BLOCK_OPT_SIZE, 1152 .type = QEMU_OPT_SIZE, 1153 .help = "Virtual disk size" 1154 }, 1155 { 1156 .name = BLOCK_OPT_BACKING_FILE, 1157 .type = QEMU_OPT_STRING, 1158 .help = "File name of a base image" 1159 }, 1160 { 1161 .name = BLOCK_OPT_ENCRYPT, 1162 .type = QEMU_OPT_BOOL, 1163 .help = "Encrypt the image with format 'aes'. (Deprecated " 1164 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 1165 }, 1166 { 1167 .name = BLOCK_OPT_ENCRYPT_FORMAT, 1168 .type = QEMU_OPT_STRING, 1169 .help = "Encrypt the image, format choices: 'aes'", 1170 }, 1171 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 1172 { /* end of list */ } 1173 } 1174 }; 1175 1176 static const char *const qcow_strong_runtime_opts[] = { 1177 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, 1178 1179 NULL 1180 }; 1181 1182 static BlockDriver bdrv_qcow = { 1183 .format_name = "qcow", 1184 .instance_size = sizeof(BDRVQcowState), 1185 .bdrv_probe = qcow_probe, 1186 .bdrv_open = qcow_open, 1187 .bdrv_close = qcow_close, 1188 .bdrv_child_perm = bdrv_format_default_perms, 1189 .bdrv_reopen_prepare = qcow_reopen_prepare, 1190 .bdrv_co_create = qcow_co_create, 1191 .bdrv_co_create_opts = qcow_co_create_opts, 1192 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1193 .supports_backing = true, 1194 .bdrv_refresh_limits = qcow_refresh_limits, 1195 1196 .bdrv_co_preadv = qcow_co_preadv, 1197 .bdrv_co_pwritev = qcow_co_pwritev, 1198 .bdrv_co_block_status = qcow_co_block_status, 1199 1200 .bdrv_make_empty = qcow_make_empty, 1201 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1202 .bdrv_get_info = qcow_get_info, 1203 1204 .create_opts = &qcow_create_opts, 1205 .strong_runtime_opts = qcow_strong_runtime_opts, 1206 }; 1207 1208 static void bdrv_qcow_init(void) 1209 { 1210 bdrv_register(&bdrv_qcow); 1211 } 1212 1213 block_init(bdrv_qcow_init); 1214