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