1 /* 2 * Block driver for the QCOW format 3 * 4 * Copyright (c) 2004-2006 Fabrice Bellard 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a copy 7 * of this software and associated documentation files (the "Software"), to deal 8 * in the Software without restriction, including without limitation the rights 9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 * copies of the Software, and to permit persons to whom the Software is 11 * furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN 22 * THE SOFTWARE. 23 */ 24 25 #include "qemu/osdep.h" 26 #include "qapi/error.h" 27 #include "qemu/error-report.h" 28 #include "block/block_int.h" 29 #include "block/qdict.h" 30 #include "sysemu/block-backend.h" 31 #include "qemu/module.h" 32 #include "qemu/option.h" 33 #include "qemu/bswap.h" 34 #include "qemu/cutils.h" 35 #include "qemu/memalign.h" 36 #include <zlib.h> 37 #include "qapi/qmp/qdict.h" 38 #include "qapi/qmp/qstring.h" 39 #include "qapi/qobject-input-visitor.h" 40 #include "qapi/qapi-visit-block-core.h" 41 #include "crypto/block.h" 42 #include "migration/blocker.h" 43 #include "crypto.h" 44 45 /**************************************************************/ 46 /* QEMU COW block driver with compression and encryption support */ 47 48 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 49 #define QCOW_VERSION 1 50 51 #define QCOW_CRYPT_NONE 0 52 #define QCOW_CRYPT_AES 1 53 54 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 55 56 typedef struct QCowHeader { 57 uint32_t magic; 58 uint32_t version; 59 uint64_t backing_file_offset; 60 uint32_t backing_file_size; 61 uint32_t mtime; 62 uint64_t size; /* in bytes */ 63 uint8_t cluster_bits; 64 uint8_t l2_bits; 65 uint16_t padding; 66 uint32_t crypt_method; 67 uint64_t l1_table_offset; 68 } QEMU_PACKED QCowHeader; 69 70 #define L2_CACHE_SIZE 16 71 72 typedef struct BDRVQcowState { 73 int cluster_bits; 74 int cluster_size; 75 int l2_bits; 76 int l2_size; 77 unsigned int l1_size; 78 uint64_t cluster_offset_mask; 79 uint64_t l1_table_offset; 80 uint64_t *l1_table; 81 uint64_t *l2_cache; 82 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 83 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 84 uint8_t *cluster_cache; 85 uint8_t *cluster_data; 86 uint64_t cluster_cache_offset; 87 QCryptoBlock *crypto; /* Disk encryption format driver */ 88 uint32_t crypt_method_header; 89 CoMutex lock; 90 Error *migration_blocker; 91 } BDRVQcowState; 92 93 static QemuOptsList qcow_create_opts; 94 95 static int coroutine_fn GRAPH_RDLOCK 96 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 97 98 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 99 { 100 const QCowHeader *cow_header = (const void *)buf; 101 102 if (buf_size >= sizeof(QCowHeader) && 103 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 104 be32_to_cpu(cow_header->version) == QCOW_VERSION) 105 return 100; 106 else 107 return 0; 108 } 109 110 static int qcow_open(BlockDriverState *bs, QDict *options, int flags, 111 Error **errp) 112 { 113 BDRVQcowState *s = bs->opaque; 114 unsigned int len, i, shift; 115 int ret; 116 QCowHeader header; 117 QCryptoBlockOpenOptions *crypto_opts = NULL; 118 unsigned int cflags = 0; 119 QDict *encryptopts = NULL; 120 const char *encryptfmt; 121 122 qdict_extract_subqdict(options, &encryptopts, "encrypt."); 123 encryptfmt = qdict_get_try_str(encryptopts, "format"); 124 125 ret = bdrv_open_file_child(NULL, options, "file", bs, errp); 126 if (ret < 0) { 127 goto fail; 128 } 129 130 ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0); 131 if (ret < 0) { 132 goto fail; 133 } 134 header.magic = be32_to_cpu(header.magic); 135 header.version = be32_to_cpu(header.version); 136 header.backing_file_offset = be64_to_cpu(header.backing_file_offset); 137 header.backing_file_size = be32_to_cpu(header.backing_file_size); 138 header.mtime = be32_to_cpu(header.mtime); 139 header.size = be64_to_cpu(header.size); 140 header.crypt_method = be32_to_cpu(header.crypt_method); 141 header.l1_table_offset = be64_to_cpu(header.l1_table_offset); 142 143 if (header.magic != QCOW_MAGIC) { 144 error_setg(errp, "Image not in qcow format"); 145 ret = -EINVAL; 146 goto fail; 147 } 148 if (header.version != QCOW_VERSION) { 149 error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32, 150 QCOW_VERSION, header.version); 151 if (header.version == 2 || header.version == 3) { 152 error_append_hint(errp, "Try the 'qcow2' driver instead.\n"); 153 } 154 155 ret = -ENOTSUP; 156 goto fail; 157 } 158 159 if (header.size <= 1) { 160 error_setg(errp, "Image size is too small (must be at least 2 bytes)"); 161 ret = -EINVAL; 162 goto fail; 163 } 164 if (header.cluster_bits < 9 || header.cluster_bits > 16) { 165 error_setg(errp, "Cluster size must be between 512 and 64k"); 166 ret = -EINVAL; 167 goto fail; 168 } 169 170 /* l2_bits specifies number of entries; storing a uint64_t in each entry, 171 * so bytes = num_entries << 3. */ 172 if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) { 173 error_setg(errp, "L2 table size must be between 512 and 64k"); 174 ret = -EINVAL; 175 goto fail; 176 } 177 178 s->crypt_method_header = header.crypt_method; 179 if (s->crypt_method_header) { 180 if (bdrv_uses_whitelist() && 181 s->crypt_method_header == QCOW_CRYPT_AES) { 182 error_setg(errp, 183 "Use of AES-CBC encrypted qcow images is no longer " 184 "supported in system emulators"); 185 error_append_hint(errp, 186 "You can use 'qemu-img convert' to convert your " 187 "image to an alternative supported format, such " 188 "as unencrypted qcow, or raw with the LUKS " 189 "format instead.\n"); 190 ret = -ENOSYS; 191 goto fail; 192 } 193 if (s->crypt_method_header == QCOW_CRYPT_AES) { 194 if (encryptfmt && !g_str_equal(encryptfmt, "aes")) { 195 error_setg(errp, 196 "Header reported 'aes' encryption format but " 197 "options specify '%s'", encryptfmt); 198 ret = -EINVAL; 199 goto fail; 200 } 201 qdict_put_str(encryptopts, "format", "qcow"); 202 crypto_opts = block_crypto_open_opts_init(encryptopts, errp); 203 if (!crypto_opts) { 204 ret = -EINVAL; 205 goto fail; 206 } 207 208 if (flags & BDRV_O_NO_IO) { 209 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO; 210 } 211 s->crypto = qcrypto_block_open(crypto_opts, "encrypt.", 212 NULL, NULL, cflags, 1, errp); 213 if (!s->crypto) { 214 ret = -EINVAL; 215 goto fail; 216 } 217 } else { 218 error_setg(errp, "invalid encryption method in qcow header"); 219 ret = -EINVAL; 220 goto fail; 221 } 222 bs->encrypted = true; 223 } else { 224 if (encryptfmt) { 225 error_setg(errp, "No encryption in image header, but options " 226 "specified format '%s'", encryptfmt); 227 ret = -EINVAL; 228 goto fail; 229 } 230 } 231 s->cluster_bits = header.cluster_bits; 232 s->cluster_size = 1 << s->cluster_bits; 233 s->l2_bits = header.l2_bits; 234 s->l2_size = 1 << s->l2_bits; 235 bs->total_sectors = header.size / 512; 236 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 237 238 /* read the level 1 table */ 239 shift = s->cluster_bits + s->l2_bits; 240 if (header.size > UINT64_MAX - (1LL << shift)) { 241 error_setg(errp, "Image too large"); 242 ret = -EINVAL; 243 goto fail; 244 } else { 245 uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift; 246 if (l1_size > INT_MAX / sizeof(uint64_t)) { 247 error_setg(errp, "Image too large"); 248 ret = -EINVAL; 249 goto fail; 250 } 251 s->l1_size = l1_size; 252 } 253 254 s->l1_table_offset = header.l1_table_offset; 255 s->l1_table = g_try_new(uint64_t, s->l1_size); 256 if (s->l1_table == NULL) { 257 error_setg(errp, "Could not allocate memory for L1 table"); 258 ret = -ENOMEM; 259 goto fail; 260 } 261 262 ret = bdrv_pread(bs->file, s->l1_table_offset, 263 s->l1_size * sizeof(uint64_t), s->l1_table, 0); 264 if (ret < 0) { 265 goto fail; 266 } 267 268 for(i = 0;i < s->l1_size; i++) { 269 s->l1_table[i] = be64_to_cpu(s->l1_table[i]); 270 } 271 272 /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ 273 s->l2_cache = 274 qemu_try_blockalign(bs->file->bs, 275 s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 276 if (s->l2_cache == NULL) { 277 error_setg(errp, "Could not allocate L2 table cache"); 278 ret = -ENOMEM; 279 goto fail; 280 } 281 s->cluster_cache = g_malloc(s->cluster_size); 282 s->cluster_data = g_malloc(s->cluster_size); 283 s->cluster_cache_offset = -1; 284 285 /* read the backing file name */ 286 if (header.backing_file_offset != 0) { 287 len = header.backing_file_size; 288 if (len > 1023 || len >= sizeof(bs->backing_file)) { 289 error_setg(errp, "Backing file name too long"); 290 ret = -EINVAL; 291 goto fail; 292 } 293 ret = bdrv_pread(bs->file, header.backing_file_offset, len, 294 bs->auto_backing_file, 0); 295 if (ret < 0) { 296 goto fail; 297 } 298 bs->auto_backing_file[len] = '\0'; 299 pstrcpy(bs->backing_file, sizeof(bs->backing_file), 300 bs->auto_backing_file); 301 } 302 303 /* Disable migration when qcow images are used */ 304 bdrv_graph_rdlock_main_loop(); 305 error_setg(&s->migration_blocker, "The qcow format used by node '%s' " 306 "does not support live migration", 307 bdrv_get_device_or_node_name(bs)); 308 bdrv_graph_rdunlock_main_loop(); 309 310 ret = migrate_add_blocker(&s->migration_blocker, errp); 311 if (ret < 0) { 312 goto fail; 313 } 314 315 qobject_unref(encryptopts); 316 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 317 qemu_co_mutex_init(&s->lock); 318 return 0; 319 320 fail: 321 g_free(s->l1_table); 322 qemu_vfree(s->l2_cache); 323 g_free(s->cluster_cache); 324 g_free(s->cluster_data); 325 qcrypto_block_free(s->crypto); 326 qobject_unref(encryptopts); 327 qapi_free_QCryptoBlockOpenOptions(crypto_opts); 328 return ret; 329 } 330 331 332 /* We have nothing to do for QCOW reopen, stubs just return 333 * success */ 334 static int qcow_reopen_prepare(BDRVReopenState *state, 335 BlockReopenQueue *queue, Error **errp) 336 { 337 return 0; 338 } 339 340 341 /* 'allocate' is: 342 * 343 * 0 to not allocate. 344 * 345 * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start' 346 * to 'n_end' within the cluster) 347 * 348 * 2 to allocate a compressed cluster of size 349 * 'compressed_size'. 'compressed_size' must be > 0 and < 350 * cluster_size 351 * 352 * return 0 if not allocated, 1 if *result is assigned, and negative 353 * errno on failure. 354 */ 355 static int coroutine_fn GRAPH_RDLOCK 356 get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate, 357 int compressed_size, int n_start, int n_end, 358 uint64_t *result) 359 { 360 BDRVQcowState *s = bs->opaque; 361 int min_index, i, j, l1_index, l2_index, ret; 362 int64_t l2_offset; 363 uint64_t *l2_table, cluster_offset, tmp; 364 uint32_t min_count; 365 int new_l2_table; 366 367 *result = 0; 368 l1_index = offset >> (s->l2_bits + s->cluster_bits); 369 l2_offset = s->l1_table[l1_index]; 370 new_l2_table = 0; 371 if (!l2_offset) { 372 if (!allocate) 373 return 0; 374 /* allocate a new l2 entry */ 375 l2_offset = bdrv_co_getlength(bs->file->bs); 376 if (l2_offset < 0) { 377 return l2_offset; 378 } 379 /* round to cluster size */ 380 l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size); 381 /* update the L1 entry */ 382 s->l1_table[l1_index] = l2_offset; 383 tmp = cpu_to_be64(l2_offset); 384 BLKDBG_CO_EVENT(bs->file, BLKDBG_L1_UPDATE); 385 ret = bdrv_co_pwrite_sync(bs->file, 386 s->l1_table_offset + l1_index * sizeof(tmp), 387 sizeof(tmp), &tmp, 0); 388 if (ret < 0) { 389 return ret; 390 } 391 new_l2_table = 1; 392 } 393 for(i = 0; i < L2_CACHE_SIZE; i++) { 394 if (l2_offset == s->l2_cache_offsets[i]) { 395 /* increment the hit count */ 396 if (++s->l2_cache_counts[i] == 0xffffffff) { 397 for(j = 0; j < L2_CACHE_SIZE; j++) { 398 s->l2_cache_counts[j] >>= 1; 399 } 400 } 401 l2_table = s->l2_cache + (i << s->l2_bits); 402 goto found; 403 } 404 } 405 /* not found: load a new entry in the least used one */ 406 min_index = 0; 407 min_count = 0xffffffff; 408 for(i = 0; i < L2_CACHE_SIZE; i++) { 409 if (s->l2_cache_counts[i] < min_count) { 410 min_count = s->l2_cache_counts[i]; 411 min_index = i; 412 } 413 } 414 l2_table = s->l2_cache + (min_index << s->l2_bits); 415 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_LOAD); 416 if (new_l2_table) { 417 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 418 ret = bdrv_co_pwrite_sync(bs->file, l2_offset, 419 s->l2_size * sizeof(uint64_t), l2_table, 0); 420 if (ret < 0) { 421 return ret; 422 } 423 } else { 424 ret = bdrv_co_pread(bs->file, l2_offset, 425 s->l2_size * sizeof(uint64_t), l2_table, 0); 426 if (ret < 0) { 427 return ret; 428 } 429 } 430 s->l2_cache_offsets[min_index] = l2_offset; 431 s->l2_cache_counts[min_index] = 1; 432 found: 433 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 434 cluster_offset = be64_to_cpu(l2_table[l2_index]); 435 if (!cluster_offset || 436 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 437 if (!allocate) 438 return 0; 439 BLKDBG_CO_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC); 440 assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE)); 441 /* allocate a new cluster */ 442 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 443 (n_end - n_start) < s->cluster_size) { 444 /* if the cluster is already compressed, we must 445 decompress it in the case it is not completely 446 overwritten */ 447 if (decompress_cluster(bs, cluster_offset) < 0) { 448 return -EIO; 449 } 450 cluster_offset = bdrv_co_getlength(bs->file->bs); 451 if ((int64_t) cluster_offset < 0) { 452 return cluster_offset; 453 } 454 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 455 /* write the cluster content */ 456 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO); 457 ret = bdrv_co_pwrite(bs->file, cluster_offset, s->cluster_size, 458 s->cluster_cache, 0); 459 if (ret < 0) { 460 return ret; 461 } 462 } else { 463 cluster_offset = bdrv_co_getlength(bs->file->bs); 464 if ((int64_t) cluster_offset < 0) { 465 return cluster_offset; 466 } 467 if (allocate == 1) { 468 /* round to cluster size */ 469 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size); 470 if (cluster_offset + s->cluster_size > INT64_MAX) { 471 return -E2BIG; 472 } 473 ret = bdrv_co_truncate(bs->file, 474 cluster_offset + s->cluster_size, 475 false, PREALLOC_MODE_OFF, 0, NULL); 476 if (ret < 0) { 477 return ret; 478 } 479 /* if encrypted, we must initialize the cluster 480 content which won't be written */ 481 if (bs->encrypted && 482 (n_end - n_start) < s->cluster_size) { 483 uint64_t start_offset; 484 assert(s->crypto); 485 start_offset = offset & ~(s->cluster_size - 1); 486 for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) { 487 if (i < n_start || i >= n_end) { 488 memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE); 489 if (qcrypto_block_encrypt(s->crypto, 490 start_offset + i, 491 s->cluster_data, 492 BDRV_SECTOR_SIZE, 493 NULL) < 0) { 494 return -EIO; 495 } 496 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO); 497 ret = bdrv_co_pwrite(bs->file, cluster_offset + i, 498 BDRV_SECTOR_SIZE, 499 s->cluster_data, 0); 500 if (ret < 0) { 501 return ret; 502 } 503 } 504 } 505 } 506 } else if (allocate == 2) { 507 cluster_offset |= QCOW_OFLAG_COMPRESSED | 508 (uint64_t)compressed_size << (63 - s->cluster_bits); 509 } 510 } 511 /* update L2 table */ 512 tmp = cpu_to_be64(cluster_offset); 513 l2_table[l2_index] = tmp; 514 if (allocate == 2) { 515 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED); 516 } else { 517 BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE); 518 } 519 ret = bdrv_co_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 520 sizeof(tmp), &tmp, 0); 521 if (ret < 0) { 522 return ret; 523 } 524 } 525 *result = cluster_offset; 526 return 1; 527 } 528 529 static int coroutine_fn GRAPH_RDLOCK 530 qcow_co_block_status(BlockDriverState *bs, bool want_zero, 531 int64_t offset, int64_t bytes, int64_t *pnum, 532 int64_t *map, BlockDriverState **file) 533 { 534 BDRVQcowState *s = bs->opaque; 535 int index_in_cluster, ret; 536 int64_t n; 537 uint64_t cluster_offset; 538 539 qemu_co_mutex_lock(&s->lock); 540 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 541 qemu_co_mutex_unlock(&s->lock); 542 if (ret < 0) { 543 return ret; 544 } 545 index_in_cluster = offset & (s->cluster_size - 1); 546 n = s->cluster_size - index_in_cluster; 547 if (n > bytes) { 548 n = bytes; 549 } 550 *pnum = n; 551 if (!cluster_offset) { 552 return 0; 553 } 554 if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 555 return BDRV_BLOCK_DATA | BDRV_BLOCK_COMPRESSED; 556 } 557 if (s->crypto) { 558 return BDRV_BLOCK_DATA; 559 } 560 *map = cluster_offset | index_in_cluster; 561 *file = bs->file->bs; 562 return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID; 563 } 564 565 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 566 const uint8_t *buf, int buf_size) 567 { 568 z_stream strm1, *strm = &strm1; 569 int ret, out_len; 570 571 memset(strm, 0, sizeof(*strm)); 572 573 strm->next_in = (uint8_t *)buf; 574 strm->avail_in = buf_size; 575 strm->next_out = out_buf; 576 strm->avail_out = out_buf_size; 577 578 ret = inflateInit2(strm, -12); 579 if (ret != Z_OK) 580 return -1; 581 ret = inflate(strm, Z_FINISH); 582 out_len = strm->next_out - out_buf; 583 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 584 out_len != out_buf_size) { 585 inflateEnd(strm); 586 return -1; 587 } 588 inflateEnd(strm); 589 return 0; 590 } 591 592 static int coroutine_fn GRAPH_RDLOCK 593 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 594 { 595 BDRVQcowState *s = bs->opaque; 596 int ret, csize; 597 uint64_t coffset; 598 599 coffset = cluster_offset & s->cluster_offset_mask; 600 if (s->cluster_cache_offset != coffset) { 601 csize = cluster_offset >> (63 - s->cluster_bits); 602 csize &= (s->cluster_size - 1); 603 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_COMPRESSED); 604 ret = bdrv_co_pread(bs->file, coffset, csize, s->cluster_data, 0); 605 if (ret < 0) 606 return -1; 607 if (decompress_buffer(s->cluster_cache, s->cluster_size, 608 s->cluster_data, csize) < 0) { 609 return -1; 610 } 611 s->cluster_cache_offset = coffset; 612 } 613 return 0; 614 } 615 616 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp) 617 { 618 /* At least encrypted images require 512-byte alignment. Apply the 619 * limit universally, rather than just on encrypted images, as 620 * it's easier to let the block layer handle rounding than to 621 * audit this code further. */ 622 bs->bl.request_alignment = BDRV_SECTOR_SIZE; 623 } 624 625 static int coroutine_fn GRAPH_RDLOCK 626 qcow_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes, 627 QEMUIOVector *qiov, BdrvRequestFlags flags) 628 { 629 BDRVQcowState *s = bs->opaque; 630 int offset_in_cluster; 631 int ret = 0, n; 632 uint64_t cluster_offset; 633 uint8_t *buf; 634 void *orig_buf; 635 636 if (qiov->niov > 1) { 637 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 638 if (buf == NULL) { 639 return -ENOMEM; 640 } 641 } else { 642 orig_buf = NULL; 643 buf = (uint8_t *)qiov->iov->iov_base; 644 } 645 646 qemu_co_mutex_lock(&s->lock); 647 648 while (bytes != 0) { 649 /* prepare next request */ 650 ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset); 651 if (ret < 0) { 652 break; 653 } 654 offset_in_cluster = offset & (s->cluster_size - 1); 655 n = s->cluster_size - offset_in_cluster; 656 if (n > bytes) { 657 n = bytes; 658 } 659 660 if (!cluster_offset) { 661 if (bs->backing) { 662 /* read from the base image */ 663 qemu_co_mutex_unlock(&s->lock); 664 /* qcow2 emits this on bs->file instead of bs->backing */ 665 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); 666 ret = bdrv_co_pread(bs->backing, offset, n, buf, 0); 667 qemu_co_mutex_lock(&s->lock); 668 if (ret < 0) { 669 break; 670 } 671 } else { 672 /* Note: in this case, no need to wait */ 673 memset(buf, 0, n); 674 } 675 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 676 /* add AIO support for compressed blocks ? */ 677 if (decompress_cluster(bs, cluster_offset) < 0) { 678 ret = -EIO; 679 break; 680 } 681 memcpy(buf, s->cluster_cache + offset_in_cluster, n); 682 } else { 683 if ((cluster_offset & 511) != 0) { 684 ret = -EIO; 685 break; 686 } 687 qemu_co_mutex_unlock(&s->lock); 688 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_AIO); 689 ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster, 690 n, buf, 0); 691 qemu_co_mutex_lock(&s->lock); 692 if (ret < 0) { 693 break; 694 } 695 if (bs->encrypted) { 696 assert(s->crypto); 697 if (qcrypto_block_decrypt(s->crypto, 698 offset, buf, n, NULL) < 0) { 699 ret = -EIO; 700 break; 701 } 702 } 703 } 704 ret = 0; 705 706 bytes -= n; 707 offset += n; 708 buf += n; 709 } 710 711 qemu_co_mutex_unlock(&s->lock); 712 713 if (qiov->niov > 1) { 714 qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size); 715 qemu_vfree(orig_buf); 716 } 717 718 return ret; 719 } 720 721 static int coroutine_fn GRAPH_RDLOCK 722 qcow_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes, 723 QEMUIOVector *qiov, BdrvRequestFlags flags) 724 { 725 BDRVQcowState *s = bs->opaque; 726 int offset_in_cluster; 727 uint64_t cluster_offset; 728 int ret = 0, n; 729 uint8_t *buf; 730 void *orig_buf; 731 732 s->cluster_cache_offset = -1; /* disable compressed cache */ 733 734 /* We must always copy the iov when encrypting, so we 735 * don't modify the original data buffer during encryption */ 736 if (bs->encrypted || qiov->niov > 1) { 737 buf = orig_buf = qemu_try_blockalign(bs, qiov->size); 738 if (buf == NULL) { 739 return -ENOMEM; 740 } 741 qemu_iovec_to_buf(qiov, 0, buf, qiov->size); 742 } else { 743 orig_buf = NULL; 744 buf = (uint8_t *)qiov->iov->iov_base; 745 } 746 747 qemu_co_mutex_lock(&s->lock); 748 749 while (bytes != 0) { 750 offset_in_cluster = offset & (s->cluster_size - 1); 751 n = s->cluster_size - offset_in_cluster; 752 if (n > bytes) { 753 n = bytes; 754 } 755 ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster, 756 offset_in_cluster + n, &cluster_offset); 757 if (ret < 0) { 758 break; 759 } 760 if (!cluster_offset || (cluster_offset & 511) != 0) { 761 ret = -EIO; 762 break; 763 } 764 if (bs->encrypted) { 765 assert(s->crypto); 766 if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) { 767 ret = -EIO; 768 break; 769 } 770 } 771 772 qemu_co_mutex_unlock(&s->lock); 773 BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO); 774 ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster, 775 n, buf, 0); 776 qemu_co_mutex_lock(&s->lock); 777 if (ret < 0) { 778 break; 779 } 780 ret = 0; 781 782 bytes -= n; 783 offset += n; 784 buf += n; 785 } 786 qemu_co_mutex_unlock(&s->lock); 787 788 qemu_vfree(orig_buf); 789 790 return ret; 791 } 792 793 static void qcow_close(BlockDriverState *bs) 794 { 795 BDRVQcowState *s = bs->opaque; 796 797 qcrypto_block_free(s->crypto); 798 s->crypto = NULL; 799 g_free(s->l1_table); 800 qemu_vfree(s->l2_cache); 801 g_free(s->cluster_cache); 802 g_free(s->cluster_data); 803 804 migrate_del_blocker(&s->migration_blocker); 805 } 806 807 static int coroutine_fn GRAPH_UNLOCKED 808 qcow_co_create(BlockdevCreateOptions *opts, Error **errp) 809 { 810 BlockdevCreateOptionsQcow *qcow_opts; 811 int header_size, backing_filename_len, l1_size, shift, i; 812 QCowHeader header; 813 uint8_t *tmp; 814 int64_t total_size = 0; 815 int ret; 816 BlockDriverState *bs; 817 BlockBackend *qcow_blk; 818 QCryptoBlock *crypto = NULL; 819 820 assert(opts->driver == BLOCKDEV_DRIVER_QCOW); 821 qcow_opts = &opts->u.qcow; 822 823 /* Sanity checks */ 824 total_size = qcow_opts->size; 825 if (total_size == 0) { 826 error_setg(errp, "Image size is too small, cannot be zero length"); 827 return -EINVAL; 828 } 829 830 if (qcow_opts->encrypt && 831 qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW) 832 { 833 error_setg(errp, "Unsupported encryption format"); 834 return -EINVAL; 835 } 836 837 /* Create BlockBackend to write to the image */ 838 bs = bdrv_co_open_blockdev_ref(qcow_opts->file, errp); 839 if (bs == NULL) { 840 return -EIO; 841 } 842 843 qcow_blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE, 844 BLK_PERM_ALL, errp); 845 if (!qcow_blk) { 846 ret = -EPERM; 847 goto exit; 848 } 849 blk_set_allow_write_beyond_eof(qcow_blk, true); 850 851 /* Create image format */ 852 memset(&header, 0, sizeof(header)); 853 header.magic = cpu_to_be32(QCOW_MAGIC); 854 header.version = cpu_to_be32(QCOW_VERSION); 855 header.size = cpu_to_be64(total_size); 856 header_size = sizeof(header); 857 backing_filename_len = 0; 858 if (qcow_opts->backing_file) { 859 if (strcmp(qcow_opts->backing_file, "fat:")) { 860 header.backing_file_offset = cpu_to_be64(header_size); 861 backing_filename_len = strlen(qcow_opts->backing_file); 862 header.backing_file_size = cpu_to_be32(backing_filename_len); 863 header_size += backing_filename_len; 864 } else { 865 /* special backing file for vvfat */ 866 qcow_opts->backing_file = NULL; 867 } 868 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 869 unmodified sectors */ 870 header.l2_bits = 12; /* 32 KB L2 tables */ 871 } else { 872 header.cluster_bits = 12; /* 4 KB clusters */ 873 header.l2_bits = 9; /* 4 KB L2 tables */ 874 } 875 header_size = (header_size + 7) & ~7; 876 shift = header.cluster_bits + header.l2_bits; 877 l1_size = (total_size + (1LL << shift) - 1) >> shift; 878 879 header.l1_table_offset = cpu_to_be64(header_size); 880 881 if (qcow_opts->encrypt) { 882 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 883 884 crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.", 885 NULL, NULL, NULL, errp); 886 if (!crypto) { 887 ret = -EINVAL; 888 goto exit; 889 } 890 } else { 891 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 892 } 893 894 /* write all the data */ 895 ret = blk_co_pwrite(qcow_blk, 0, sizeof(header), &header, 0); 896 if (ret < 0) { 897 goto exit; 898 } 899 900 if (qcow_opts->backing_file) { 901 ret = blk_co_pwrite(qcow_blk, sizeof(header), backing_filename_len, 902 qcow_opts->backing_file, 0); 903 if (ret < 0) { 904 goto exit; 905 } 906 } 907 908 tmp = g_malloc0(BDRV_SECTOR_SIZE); 909 for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE); 910 i++) { 911 ret = blk_co_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i, 912 BDRV_SECTOR_SIZE, tmp, 0); 913 if (ret < 0) { 914 g_free(tmp); 915 goto exit; 916 } 917 } 918 919 g_free(tmp); 920 ret = 0; 921 exit: 922 blk_co_unref(qcow_blk); 923 bdrv_co_unref(bs); 924 qcrypto_block_free(crypto); 925 return ret; 926 } 927 928 static int coroutine_fn GRAPH_UNLOCKED 929 qcow_co_create_opts(BlockDriver *drv, const char *filename, 930 QemuOpts *opts, Error **errp) 931 { 932 BlockdevCreateOptions *create_options = NULL; 933 BlockDriverState *bs = NULL; 934 QDict *qdict = NULL; 935 Visitor *v; 936 const char *val; 937 int ret; 938 char *backing_fmt; 939 940 static const QDictRenames opt_renames[] = { 941 { BLOCK_OPT_BACKING_FILE, "backing-file" }, 942 { BLOCK_OPT_ENCRYPT, BLOCK_OPT_ENCRYPT_FORMAT }, 943 { NULL, NULL }, 944 }; 945 946 /* 947 * We can't actually store a backing format, but can check that 948 * the user's request made sense. 949 */ 950 backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT); 951 if (backing_fmt && !bdrv_find_format(backing_fmt)) { 952 error_setg(errp, "unrecognized backing format '%s'", backing_fmt); 953 ret = -EINVAL; 954 goto fail; 955 } 956 957 /* Parse options and convert legacy syntax */ 958 qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true); 959 960 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT); 961 if (val && !strcmp(val, "on")) { 962 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow"); 963 } else if (val && !strcmp(val, "off")) { 964 qdict_del(qdict, BLOCK_OPT_ENCRYPT); 965 } 966 967 val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT); 968 if (val && !strcmp(val, "aes")) { 969 qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow"); 970 } 971 972 if (!qdict_rename_keys(qdict, opt_renames, errp)) { 973 ret = -EINVAL; 974 goto fail; 975 } 976 977 /* Create and open the file (protocol layer) */ 978 ret = bdrv_co_create_file(filename, opts, errp); 979 if (ret < 0) { 980 goto fail; 981 } 982 983 bs = bdrv_co_open(filename, NULL, NULL, 984 BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp); 985 if (bs == NULL) { 986 ret = -EIO; 987 goto fail; 988 } 989 990 /* Now get the QAPI type BlockdevCreateOptions */ 991 qdict_put_str(qdict, "driver", "qcow"); 992 qdict_put_str(qdict, "file", bs->node_name); 993 994 v = qobject_input_visitor_new_flat_confused(qdict, errp); 995 if (!v) { 996 ret = -EINVAL; 997 goto fail; 998 } 999 1000 visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp); 1001 visit_free(v); 1002 if (!create_options) { 1003 ret = -EINVAL; 1004 goto fail; 1005 } 1006 1007 /* Silently round up size */ 1008 assert(create_options->driver == BLOCKDEV_DRIVER_QCOW); 1009 create_options->u.qcow.size = 1010 ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE); 1011 1012 /* Create the qcow image (format layer) */ 1013 ret = qcow_co_create(create_options, errp); 1014 if (ret < 0) { 1015 goto fail; 1016 } 1017 1018 ret = 0; 1019 fail: 1020 g_free(backing_fmt); 1021 qobject_unref(qdict); 1022 bdrv_co_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, l1_length, s->l1_table, 1035 0) < 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 int coroutine_fn GRAPH_RDLOCK 1052 qcow_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes, 1053 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_CO_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 coroutine_fn 1135 qcow_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 1136 { 1137 BDRVQcowState *s = bs->opaque; 1138 bdi->cluster_size = s->cluster_size; 1139 return 0; 1140 } 1141 1142 static QemuOptsList qcow_create_opts = { 1143 .name = "qcow-create-opts", 1144 .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head), 1145 .desc = { 1146 { 1147 .name = BLOCK_OPT_SIZE, 1148 .type = QEMU_OPT_SIZE, 1149 .help = "Virtual disk size" 1150 }, 1151 { 1152 .name = BLOCK_OPT_BACKING_FILE, 1153 .type = QEMU_OPT_STRING, 1154 .help = "File name of a base image" 1155 }, 1156 { 1157 .name = BLOCK_OPT_BACKING_FMT, 1158 .type = QEMU_OPT_STRING, 1159 .help = "Format of the backing image", 1160 }, 1161 { 1162 .name = BLOCK_OPT_ENCRYPT, 1163 .type = QEMU_OPT_BOOL, 1164 .help = "Encrypt the image with format 'aes'. (Deprecated " 1165 "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)", 1166 }, 1167 { 1168 .name = BLOCK_OPT_ENCRYPT_FORMAT, 1169 .type = QEMU_OPT_STRING, 1170 .help = "Encrypt the image, format choices: 'aes'", 1171 }, 1172 BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."), 1173 { /* end of list */ } 1174 } 1175 }; 1176 1177 static const char *const qcow_strong_runtime_opts[] = { 1178 "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET, 1179 1180 NULL 1181 }; 1182 1183 static BlockDriver bdrv_qcow = { 1184 .format_name = "qcow", 1185 .instance_size = sizeof(BDRVQcowState), 1186 .bdrv_probe = qcow_probe, 1187 .bdrv_open = qcow_open, 1188 .bdrv_close = qcow_close, 1189 .bdrv_child_perm = bdrv_default_perms, 1190 .bdrv_reopen_prepare = qcow_reopen_prepare, 1191 .bdrv_co_create = qcow_co_create, 1192 .bdrv_co_create_opts = qcow_co_create_opts, 1193 .bdrv_has_zero_init = bdrv_has_zero_init_1, 1194 .is_format = true, 1195 .supports_backing = true, 1196 .bdrv_refresh_limits = qcow_refresh_limits, 1197 1198 .bdrv_co_preadv = qcow_co_preadv, 1199 .bdrv_co_pwritev = qcow_co_pwritev, 1200 .bdrv_co_block_status = qcow_co_block_status, 1201 1202 .bdrv_make_empty = qcow_make_empty, 1203 .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed, 1204 .bdrv_co_get_info = qcow_co_get_info, 1205 1206 .create_opts = &qcow_create_opts, 1207 .strong_runtime_opts = qcow_strong_runtime_opts, 1208 }; 1209 1210 static void bdrv_qcow_init(void) 1211 { 1212 bdrv_register(&bdrv_qcow); 1213 } 1214 1215 block_init(bdrv_qcow_init); 1216