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 #include "qemu-common.h" 25 #include "block_int.h" 26 #include "module.h" 27 #include <zlib.h> 28 #include "aes.h" 29 30 /**************************************************************/ 31 /* QEMU COW block driver with compression and encryption support */ 32 33 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) 34 #define QCOW_VERSION 1 35 36 #define QCOW_CRYPT_NONE 0 37 #define QCOW_CRYPT_AES 1 38 39 #define QCOW_OFLAG_COMPRESSED (1LL << 63) 40 41 typedef struct QCowHeader { 42 uint32_t magic; 43 uint32_t version; 44 uint64_t backing_file_offset; 45 uint32_t backing_file_size; 46 uint32_t mtime; 47 uint64_t size; /* in bytes */ 48 uint8_t cluster_bits; 49 uint8_t l2_bits; 50 uint32_t crypt_method; 51 uint64_t l1_table_offset; 52 } QCowHeader; 53 54 #define L2_CACHE_SIZE 16 55 56 typedef struct BDRVQcowState { 57 BlockDriverState *hd; 58 int cluster_bits; 59 int cluster_size; 60 int cluster_sectors; 61 int l2_bits; 62 int l2_size; 63 int l1_size; 64 uint64_t cluster_offset_mask; 65 uint64_t l1_table_offset; 66 uint64_t *l1_table; 67 uint64_t *l2_cache; 68 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 69 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 70 uint8_t *cluster_cache; 71 uint8_t *cluster_data; 72 uint64_t cluster_cache_offset; 73 uint32_t crypt_method; /* current crypt method, 0 if no key yet */ 74 uint32_t crypt_method_header; 75 AES_KEY aes_encrypt_key; 76 AES_KEY aes_decrypt_key; 77 } BDRVQcowState; 78 79 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 80 81 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename) 82 { 83 const QCowHeader *cow_header = (const void *)buf; 84 85 if (buf_size >= sizeof(QCowHeader) && 86 be32_to_cpu(cow_header->magic) == QCOW_MAGIC && 87 be32_to_cpu(cow_header->version) == QCOW_VERSION) 88 return 100; 89 else 90 return 0; 91 } 92 93 static int qcow_open(BlockDriverState *bs, int flags) 94 { 95 BDRVQcowState *s = bs->opaque; 96 int len, i, shift; 97 QCowHeader header; 98 99 if (bdrv_pread(bs->file, 0, &header, sizeof(header)) != sizeof(header)) 100 goto fail; 101 be32_to_cpus(&header.magic); 102 be32_to_cpus(&header.version); 103 be64_to_cpus(&header.backing_file_offset); 104 be32_to_cpus(&header.backing_file_size); 105 be32_to_cpus(&header.mtime); 106 be64_to_cpus(&header.size); 107 be32_to_cpus(&header.crypt_method); 108 be64_to_cpus(&header.l1_table_offset); 109 110 if (header.magic != QCOW_MAGIC || header.version != QCOW_VERSION) 111 goto fail; 112 if (header.size <= 1 || header.cluster_bits < 9) 113 goto fail; 114 if (header.crypt_method > QCOW_CRYPT_AES) 115 goto fail; 116 s->crypt_method_header = header.crypt_method; 117 if (s->crypt_method_header) 118 bs->encrypted = 1; 119 s->cluster_bits = header.cluster_bits; 120 s->cluster_size = 1 << s->cluster_bits; 121 s->cluster_sectors = 1 << (s->cluster_bits - 9); 122 s->l2_bits = header.l2_bits; 123 s->l2_size = 1 << s->l2_bits; 124 bs->total_sectors = header.size / 512; 125 s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1; 126 127 /* read the level 1 table */ 128 shift = s->cluster_bits + s->l2_bits; 129 s->l1_size = (header.size + (1LL << shift) - 1) >> shift; 130 131 s->l1_table_offset = header.l1_table_offset; 132 s->l1_table = qemu_malloc(s->l1_size * sizeof(uint64_t)); 133 if (!s->l1_table) 134 goto fail; 135 if (bdrv_pread(bs->file, s->l1_table_offset, s->l1_table, s->l1_size * sizeof(uint64_t)) != 136 s->l1_size * sizeof(uint64_t)) 137 goto fail; 138 for(i = 0;i < s->l1_size; i++) { 139 be64_to_cpus(&s->l1_table[i]); 140 } 141 /* alloc L2 cache */ 142 s->l2_cache = qemu_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 143 if (!s->l2_cache) 144 goto fail; 145 s->cluster_cache = qemu_malloc(s->cluster_size); 146 if (!s->cluster_cache) 147 goto fail; 148 s->cluster_data = qemu_malloc(s->cluster_size); 149 if (!s->cluster_data) 150 goto fail; 151 s->cluster_cache_offset = -1; 152 153 /* read the backing file name */ 154 if (header.backing_file_offset != 0) { 155 len = header.backing_file_size; 156 if (len > 1023) 157 len = 1023; 158 if (bdrv_pread(bs->file, header.backing_file_offset, bs->backing_file, len) != len) 159 goto fail; 160 bs->backing_file[len] = '\0'; 161 } 162 return 0; 163 164 fail: 165 qemu_free(s->l1_table); 166 qemu_free(s->l2_cache); 167 qemu_free(s->cluster_cache); 168 qemu_free(s->cluster_data); 169 return -1; 170 } 171 172 static int qcow_set_key(BlockDriverState *bs, const char *key) 173 { 174 BDRVQcowState *s = bs->opaque; 175 uint8_t keybuf[16]; 176 int len, i; 177 178 memset(keybuf, 0, 16); 179 len = strlen(key); 180 if (len > 16) 181 len = 16; 182 /* XXX: we could compress the chars to 7 bits to increase 183 entropy */ 184 for(i = 0;i < len;i++) { 185 keybuf[i] = key[i]; 186 } 187 s->crypt_method = s->crypt_method_header; 188 189 if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0) 190 return -1; 191 if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0) 192 return -1; 193 #if 0 194 /* test */ 195 { 196 uint8_t in[16]; 197 uint8_t out[16]; 198 uint8_t tmp[16]; 199 for(i=0;i<16;i++) 200 in[i] = i; 201 AES_encrypt(in, tmp, &s->aes_encrypt_key); 202 AES_decrypt(tmp, out, &s->aes_decrypt_key); 203 for(i = 0; i < 16; i++) 204 printf(" %02x", tmp[i]); 205 printf("\n"); 206 for(i = 0; i < 16; i++) 207 printf(" %02x", out[i]); 208 printf("\n"); 209 } 210 #endif 211 return 0; 212 } 213 214 /* The crypt function is compatible with the linux cryptoloop 215 algorithm for < 4 GB images. NOTE: out_buf == in_buf is 216 supported */ 217 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 218 uint8_t *out_buf, const uint8_t *in_buf, 219 int nb_sectors, int enc, 220 const AES_KEY *key) 221 { 222 union { 223 uint64_t ll[2]; 224 uint8_t b[16]; 225 } ivec; 226 int i; 227 228 for(i = 0; i < nb_sectors; i++) { 229 ivec.ll[0] = cpu_to_le64(sector_num); 230 ivec.ll[1] = 0; 231 AES_cbc_encrypt(in_buf, out_buf, 512, key, 232 ivec.b, enc); 233 sector_num++; 234 in_buf += 512; 235 out_buf += 512; 236 } 237 } 238 239 /* 'allocate' is: 240 * 241 * 0 to not allocate. 242 * 243 * 1 to allocate a normal cluster (for sector indexes 'n_start' to 244 * 'n_end') 245 * 246 * 2 to allocate a compressed cluster of size 247 * 'compressed_size'. 'compressed_size' must be > 0 and < 248 * cluster_size 249 * 250 * return 0 if not allocated. 251 */ 252 static uint64_t get_cluster_offset(BlockDriverState *bs, 253 uint64_t offset, int allocate, 254 int compressed_size, 255 int n_start, int n_end) 256 { 257 BDRVQcowState *s = bs->opaque; 258 int min_index, i, j, l1_index, l2_index; 259 uint64_t l2_offset, *l2_table, cluster_offset, tmp; 260 uint32_t min_count; 261 int new_l2_table; 262 263 l1_index = offset >> (s->l2_bits + s->cluster_bits); 264 l2_offset = s->l1_table[l1_index]; 265 new_l2_table = 0; 266 if (!l2_offset) { 267 if (!allocate) 268 return 0; 269 /* allocate a new l2 entry */ 270 l2_offset = bdrv_getlength(bs->file); 271 /* round to cluster size */ 272 l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1); 273 /* update the L1 entry */ 274 s->l1_table[l1_index] = l2_offset; 275 tmp = cpu_to_be64(l2_offset); 276 if (bdrv_pwrite_sync(bs->file, 277 s->l1_table_offset + l1_index * sizeof(tmp), 278 &tmp, sizeof(tmp)) < 0) 279 return 0; 280 new_l2_table = 1; 281 } 282 for(i = 0; i < L2_CACHE_SIZE; i++) { 283 if (l2_offset == s->l2_cache_offsets[i]) { 284 /* increment the hit count */ 285 if (++s->l2_cache_counts[i] == 0xffffffff) { 286 for(j = 0; j < L2_CACHE_SIZE; j++) { 287 s->l2_cache_counts[j] >>= 1; 288 } 289 } 290 l2_table = s->l2_cache + (i << s->l2_bits); 291 goto found; 292 } 293 } 294 /* not found: load a new entry in the least used one */ 295 min_index = 0; 296 min_count = 0xffffffff; 297 for(i = 0; i < L2_CACHE_SIZE; i++) { 298 if (s->l2_cache_counts[i] < min_count) { 299 min_count = s->l2_cache_counts[i]; 300 min_index = i; 301 } 302 } 303 l2_table = s->l2_cache + (min_index << s->l2_bits); 304 if (new_l2_table) { 305 memset(l2_table, 0, s->l2_size * sizeof(uint64_t)); 306 if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table, 307 s->l2_size * sizeof(uint64_t)) < 0) 308 return 0; 309 } else { 310 if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) != 311 s->l2_size * sizeof(uint64_t)) 312 return 0; 313 } 314 s->l2_cache_offsets[min_index] = l2_offset; 315 s->l2_cache_counts[min_index] = 1; 316 found: 317 l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1); 318 cluster_offset = be64_to_cpu(l2_table[l2_index]); 319 if (!cluster_offset || 320 ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) { 321 if (!allocate) 322 return 0; 323 /* allocate a new cluster */ 324 if ((cluster_offset & QCOW_OFLAG_COMPRESSED) && 325 (n_end - n_start) < s->cluster_sectors) { 326 /* if the cluster is already compressed, we must 327 decompress it in the case it is not completely 328 overwritten */ 329 if (decompress_cluster(bs, cluster_offset) < 0) 330 return 0; 331 cluster_offset = bdrv_getlength(bs->file); 332 cluster_offset = (cluster_offset + s->cluster_size - 1) & 333 ~(s->cluster_size - 1); 334 /* write the cluster content */ 335 if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) != 336 s->cluster_size) 337 return -1; 338 } else { 339 cluster_offset = bdrv_getlength(bs->file); 340 if (allocate == 1) { 341 /* round to cluster size */ 342 cluster_offset = (cluster_offset + s->cluster_size - 1) & 343 ~(s->cluster_size - 1); 344 bdrv_truncate(bs->file, cluster_offset + s->cluster_size); 345 /* if encrypted, we must initialize the cluster 346 content which won't be written */ 347 if (s->crypt_method && 348 (n_end - n_start) < s->cluster_sectors) { 349 uint64_t start_sect; 350 start_sect = (offset & ~(s->cluster_size - 1)) >> 9; 351 memset(s->cluster_data + 512, 0x00, 512); 352 for(i = 0; i < s->cluster_sectors; i++) { 353 if (i < n_start || i >= n_end) { 354 encrypt_sectors(s, start_sect + i, 355 s->cluster_data, 356 s->cluster_data + 512, 1, 1, 357 &s->aes_encrypt_key); 358 if (bdrv_pwrite(bs->file, cluster_offset + i * 512, 359 s->cluster_data, 512) != 512) 360 return -1; 361 } 362 } 363 } 364 } else if (allocate == 2) { 365 cluster_offset |= QCOW_OFLAG_COMPRESSED | 366 (uint64_t)compressed_size << (63 - s->cluster_bits); 367 } 368 } 369 /* update L2 table */ 370 tmp = cpu_to_be64(cluster_offset); 371 l2_table[l2_index] = tmp; 372 if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp), 373 &tmp, sizeof(tmp)) < 0) 374 return 0; 375 } 376 return cluster_offset; 377 } 378 379 static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num, 380 int nb_sectors, int *pnum) 381 { 382 BDRVQcowState *s = bs->opaque; 383 int index_in_cluster, n; 384 uint64_t cluster_offset; 385 386 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 387 index_in_cluster = sector_num & (s->cluster_sectors - 1); 388 n = s->cluster_sectors - index_in_cluster; 389 if (n > nb_sectors) 390 n = nb_sectors; 391 *pnum = n; 392 return (cluster_offset != 0); 393 } 394 395 static int decompress_buffer(uint8_t *out_buf, int out_buf_size, 396 const uint8_t *buf, int buf_size) 397 { 398 z_stream strm1, *strm = &strm1; 399 int ret, out_len; 400 401 memset(strm, 0, sizeof(*strm)); 402 403 strm->next_in = (uint8_t *)buf; 404 strm->avail_in = buf_size; 405 strm->next_out = out_buf; 406 strm->avail_out = out_buf_size; 407 408 ret = inflateInit2(strm, -12); 409 if (ret != Z_OK) 410 return -1; 411 ret = inflate(strm, Z_FINISH); 412 out_len = strm->next_out - out_buf; 413 if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) || 414 out_len != out_buf_size) { 415 inflateEnd(strm); 416 return -1; 417 } 418 inflateEnd(strm); 419 return 0; 420 } 421 422 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset) 423 { 424 BDRVQcowState *s = bs->opaque; 425 int ret, csize; 426 uint64_t coffset; 427 428 coffset = cluster_offset & s->cluster_offset_mask; 429 if (s->cluster_cache_offset != coffset) { 430 csize = cluster_offset >> (63 - s->cluster_bits); 431 csize &= (s->cluster_size - 1); 432 ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize); 433 if (ret != csize) 434 return -1; 435 if (decompress_buffer(s->cluster_cache, s->cluster_size, 436 s->cluster_data, csize) < 0) { 437 return -1; 438 } 439 s->cluster_cache_offset = coffset; 440 } 441 return 0; 442 } 443 444 #if 0 445 446 static int qcow_read(BlockDriverState *bs, int64_t sector_num, 447 uint8_t *buf, int nb_sectors) 448 { 449 BDRVQcowState *s = bs->opaque; 450 int ret, index_in_cluster, n; 451 uint64_t cluster_offset; 452 453 while (nb_sectors > 0) { 454 cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0); 455 index_in_cluster = sector_num & (s->cluster_sectors - 1); 456 n = s->cluster_sectors - index_in_cluster; 457 if (n > nb_sectors) 458 n = nb_sectors; 459 if (!cluster_offset) { 460 if (bs->backing_hd) { 461 /* read from the base image */ 462 ret = bdrv_read(bs->backing_hd, sector_num, buf, n); 463 if (ret < 0) 464 return -1; 465 } else { 466 memset(buf, 0, 512 * n); 467 } 468 } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) { 469 if (decompress_cluster(bs, cluster_offset) < 0) 470 return -1; 471 memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n); 472 } else { 473 ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512); 474 if (ret != n * 512) 475 return -1; 476 if (s->crypt_method) { 477 encrypt_sectors(s, sector_num, buf, buf, n, 0, 478 &s->aes_decrypt_key); 479 } 480 } 481 nb_sectors -= n; 482 sector_num += n; 483 buf += n * 512; 484 } 485 return 0; 486 } 487 #endif 488 489 typedef struct QCowAIOCB { 490 BlockDriverAIOCB common; 491 int64_t sector_num; 492 QEMUIOVector *qiov; 493 uint8_t *buf; 494 void *orig_buf; 495 int nb_sectors; 496 int n; 497 uint64_t cluster_offset; 498 uint8_t *cluster_data; 499 struct iovec hd_iov; 500 QEMUIOVector hd_qiov; 501 BlockDriverAIOCB *hd_aiocb; 502 } QCowAIOCB; 503 504 static void qcow_aio_cancel(BlockDriverAIOCB *blockacb) 505 { 506 QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common); 507 if (acb->hd_aiocb) 508 bdrv_aio_cancel(acb->hd_aiocb); 509 qemu_aio_release(acb); 510 } 511 512 static AIOPool qcow_aio_pool = { 513 .aiocb_size = sizeof(QCowAIOCB), 514 .cancel = qcow_aio_cancel, 515 }; 516 517 static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs, 518 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 519 BlockDriverCompletionFunc *cb, void *opaque, int is_write) 520 { 521 QCowAIOCB *acb; 522 523 acb = qemu_aio_get(&qcow_aio_pool, bs, cb, opaque); 524 if (!acb) 525 return NULL; 526 acb->hd_aiocb = NULL; 527 acb->sector_num = sector_num; 528 acb->qiov = qiov; 529 if (qiov->niov > 1) { 530 acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size); 531 if (is_write) 532 qemu_iovec_to_buffer(qiov, acb->buf); 533 } else { 534 acb->buf = (uint8_t *)qiov->iov->iov_base; 535 } 536 acb->nb_sectors = nb_sectors; 537 acb->n = 0; 538 acb->cluster_offset = 0; 539 return acb; 540 } 541 542 static void qcow_aio_read_cb(void *opaque, int ret) 543 { 544 QCowAIOCB *acb = opaque; 545 BlockDriverState *bs = acb->common.bs; 546 BDRVQcowState *s = bs->opaque; 547 int index_in_cluster; 548 549 acb->hd_aiocb = NULL; 550 if (ret < 0) 551 goto done; 552 553 redo: 554 /* post process the read buffer */ 555 if (!acb->cluster_offset) { 556 /* nothing to do */ 557 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { 558 /* nothing to do */ 559 } else { 560 if (s->crypt_method) { 561 encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf, 562 acb->n, 0, 563 &s->aes_decrypt_key); 564 } 565 } 566 567 acb->nb_sectors -= acb->n; 568 acb->sector_num += acb->n; 569 acb->buf += acb->n * 512; 570 571 if (acb->nb_sectors == 0) { 572 /* request completed */ 573 ret = 0; 574 goto done; 575 } 576 577 /* prepare next AIO request */ 578 acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 579 0, 0, 0, 0); 580 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1); 581 acb->n = s->cluster_sectors - index_in_cluster; 582 if (acb->n > acb->nb_sectors) 583 acb->n = acb->nb_sectors; 584 585 if (!acb->cluster_offset) { 586 if (bs->backing_hd) { 587 /* read from the base image */ 588 acb->hd_iov.iov_base = (void *)acb->buf; 589 acb->hd_iov.iov_len = acb->n * 512; 590 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); 591 acb->hd_aiocb = bdrv_aio_readv(bs->backing_hd, acb->sector_num, 592 &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb); 593 if (acb->hd_aiocb == NULL) 594 goto done; 595 } else { 596 /* Note: in this case, no need to wait */ 597 memset(acb->buf, 0, 512 * acb->n); 598 goto redo; 599 } 600 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { 601 /* add AIO support for compressed blocks ? */ 602 if (decompress_cluster(bs, acb->cluster_offset) < 0) 603 goto done; 604 memcpy(acb->buf, 605 s->cluster_cache + index_in_cluster * 512, 512 * acb->n); 606 goto redo; 607 } else { 608 if ((acb->cluster_offset & 511) != 0) { 609 ret = -EIO; 610 goto done; 611 } 612 acb->hd_iov.iov_base = (void *)acb->buf; 613 acb->hd_iov.iov_len = acb->n * 512; 614 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); 615 acb->hd_aiocb = bdrv_aio_readv(bs->file, 616 (acb->cluster_offset >> 9) + index_in_cluster, 617 &acb->hd_qiov, acb->n, qcow_aio_read_cb, acb); 618 if (acb->hd_aiocb == NULL) 619 goto done; 620 } 621 622 return; 623 624 done: 625 if (acb->qiov->niov > 1) { 626 qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size); 627 qemu_vfree(acb->orig_buf); 628 } 629 acb->common.cb(acb->common.opaque, ret); 630 qemu_aio_release(acb); 631 } 632 633 static BlockDriverAIOCB *qcow_aio_readv(BlockDriverState *bs, 634 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 635 BlockDriverCompletionFunc *cb, void *opaque) 636 { 637 QCowAIOCB *acb; 638 639 acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 0); 640 if (!acb) 641 return NULL; 642 643 qcow_aio_read_cb(acb, 0); 644 return &acb->common; 645 } 646 647 static void qcow_aio_write_cb(void *opaque, int ret) 648 { 649 QCowAIOCB *acb = opaque; 650 BlockDriverState *bs = acb->common.bs; 651 BDRVQcowState *s = bs->opaque; 652 int index_in_cluster; 653 uint64_t cluster_offset; 654 const uint8_t *src_buf; 655 656 acb->hd_aiocb = NULL; 657 658 if (ret < 0) 659 goto done; 660 661 acb->nb_sectors -= acb->n; 662 acb->sector_num += acb->n; 663 acb->buf += acb->n * 512; 664 665 if (acb->nb_sectors == 0) { 666 /* request completed */ 667 ret = 0; 668 goto done; 669 } 670 671 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1); 672 acb->n = s->cluster_sectors - index_in_cluster; 673 if (acb->n > acb->nb_sectors) 674 acb->n = acb->nb_sectors; 675 cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0, 676 index_in_cluster, 677 index_in_cluster + acb->n); 678 if (!cluster_offset || (cluster_offset & 511) != 0) { 679 ret = -EIO; 680 goto done; 681 } 682 if (s->crypt_method) { 683 if (!acb->cluster_data) { 684 acb->cluster_data = qemu_mallocz(s->cluster_size); 685 if (!acb->cluster_data) { 686 ret = -ENOMEM; 687 goto done; 688 } 689 } 690 encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf, 691 acb->n, 1, &s->aes_encrypt_key); 692 src_buf = acb->cluster_data; 693 } else { 694 src_buf = acb->buf; 695 } 696 697 acb->hd_iov.iov_base = (void *)src_buf; 698 acb->hd_iov.iov_len = acb->n * 512; 699 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); 700 acb->hd_aiocb = bdrv_aio_writev(bs->file, 701 (cluster_offset >> 9) + index_in_cluster, 702 &acb->hd_qiov, acb->n, 703 qcow_aio_write_cb, acb); 704 if (acb->hd_aiocb == NULL) 705 goto done; 706 return; 707 708 done: 709 if (acb->qiov->niov > 1) 710 qemu_vfree(acb->orig_buf); 711 acb->common.cb(acb->common.opaque, ret); 712 qemu_aio_release(acb); 713 } 714 715 static BlockDriverAIOCB *qcow_aio_writev(BlockDriverState *bs, 716 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 717 BlockDriverCompletionFunc *cb, void *opaque) 718 { 719 BDRVQcowState *s = bs->opaque; 720 QCowAIOCB *acb; 721 722 s->cluster_cache_offset = -1; /* disable compressed cache */ 723 724 acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, cb, opaque, 1); 725 if (!acb) 726 return NULL; 727 728 729 qcow_aio_write_cb(acb, 0); 730 return &acb->common; 731 } 732 733 static void qcow_close(BlockDriverState *bs) 734 { 735 BDRVQcowState *s = bs->opaque; 736 qemu_free(s->l1_table); 737 qemu_free(s->l2_cache); 738 qemu_free(s->cluster_cache); 739 qemu_free(s->cluster_data); 740 } 741 742 static int qcow_create(const char *filename, QEMUOptionParameter *options) 743 { 744 int fd, header_size, backing_filename_len, l1_size, i, shift; 745 QCowHeader header; 746 uint64_t tmp; 747 int64_t total_size = 0; 748 const char *backing_file = NULL; 749 int flags = 0; 750 int ret; 751 752 /* Read out options */ 753 while (options && options->name) { 754 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 755 total_size = options->value.n / 512; 756 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 757 backing_file = options->value.s; 758 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { 759 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; 760 } 761 options++; 762 } 763 764 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); 765 if (fd < 0) 766 return -errno; 767 memset(&header, 0, sizeof(header)); 768 header.magic = cpu_to_be32(QCOW_MAGIC); 769 header.version = cpu_to_be32(QCOW_VERSION); 770 header.size = cpu_to_be64(total_size * 512); 771 header_size = sizeof(header); 772 backing_filename_len = 0; 773 if (backing_file) { 774 if (strcmp(backing_file, "fat:")) { 775 header.backing_file_offset = cpu_to_be64(header_size); 776 backing_filename_len = strlen(backing_file); 777 header.backing_file_size = cpu_to_be32(backing_filename_len); 778 header_size += backing_filename_len; 779 } else { 780 /* special backing file for vvfat */ 781 backing_file = NULL; 782 } 783 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 784 unmodifyed sectors */ 785 header.l2_bits = 12; /* 32 KB L2 tables */ 786 } else { 787 header.cluster_bits = 12; /* 4 KB clusters */ 788 header.l2_bits = 9; /* 4 KB L2 tables */ 789 } 790 header_size = (header_size + 7) & ~7; 791 shift = header.cluster_bits + header.l2_bits; 792 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 793 794 header.l1_table_offset = cpu_to_be64(header_size); 795 if (flags & BLOCK_FLAG_ENCRYPT) { 796 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 797 } else { 798 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 799 } 800 801 /* write all the data */ 802 ret = qemu_write_full(fd, &header, sizeof(header)); 803 if (ret != sizeof(header)) { 804 ret = -errno; 805 goto exit; 806 } 807 808 if (backing_file) { 809 ret = qemu_write_full(fd, backing_file, backing_filename_len); 810 if (ret != backing_filename_len) { 811 ret = -errno; 812 goto exit; 813 } 814 815 } 816 lseek(fd, header_size, SEEK_SET); 817 tmp = 0; 818 for(i = 0;i < l1_size; i++) { 819 ret = qemu_write_full(fd, &tmp, sizeof(tmp)); 820 if (ret != sizeof(tmp)) { 821 ret = -errno; 822 goto exit; 823 } 824 } 825 826 ret = 0; 827 exit: 828 close(fd); 829 return ret; 830 } 831 832 static int qcow_make_empty(BlockDriverState *bs) 833 { 834 BDRVQcowState *s = bs->opaque; 835 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 836 int ret; 837 838 memset(s->l1_table, 0, l1_length); 839 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 840 l1_length) < 0) 841 return -1; 842 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 843 if (ret < 0) 844 return ret; 845 846 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 847 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 848 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 849 850 return 0; 851 } 852 853 /* XXX: put compressed sectors first, then all the cluster aligned 854 tables to avoid losing bytes in alignment */ 855 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 856 const uint8_t *buf, int nb_sectors) 857 { 858 BDRVQcowState *s = bs->opaque; 859 z_stream strm; 860 int ret, out_len; 861 uint8_t *out_buf; 862 uint64_t cluster_offset; 863 864 if (nb_sectors != s->cluster_sectors) 865 return -EINVAL; 866 867 out_buf = qemu_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 868 if (!out_buf) 869 return -1; 870 871 /* best compression, small window, no zlib header */ 872 memset(&strm, 0, sizeof(strm)); 873 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 874 Z_DEFLATED, -12, 875 9, Z_DEFAULT_STRATEGY); 876 if (ret != 0) { 877 qemu_free(out_buf); 878 return -1; 879 } 880 881 strm.avail_in = s->cluster_size; 882 strm.next_in = (uint8_t *)buf; 883 strm.avail_out = s->cluster_size; 884 strm.next_out = out_buf; 885 886 ret = deflate(&strm, Z_FINISH); 887 if (ret != Z_STREAM_END && ret != Z_OK) { 888 qemu_free(out_buf); 889 deflateEnd(&strm); 890 return -1; 891 } 892 out_len = strm.next_out - out_buf; 893 894 deflateEnd(&strm); 895 896 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 897 /* could not compress: write normal cluster */ 898 bdrv_write(bs, sector_num, buf, s->cluster_sectors); 899 } else { 900 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 901 out_len, 0, 0); 902 cluster_offset &= s->cluster_offset_mask; 903 if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) { 904 qemu_free(out_buf); 905 return -1; 906 } 907 } 908 909 qemu_free(out_buf); 910 return 0; 911 } 912 913 static void qcow_flush(BlockDriverState *bs) 914 { 915 bdrv_flush(bs->file); 916 } 917 918 static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs, 919 BlockDriverCompletionFunc *cb, void *opaque) 920 { 921 return bdrv_aio_flush(bs->file, cb, opaque); 922 } 923 924 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 925 { 926 BDRVQcowState *s = bs->opaque; 927 bdi->cluster_size = s->cluster_size; 928 return 0; 929 } 930 931 932 static QEMUOptionParameter qcow_create_options[] = { 933 { 934 .name = BLOCK_OPT_SIZE, 935 .type = OPT_SIZE, 936 .help = "Virtual disk size" 937 }, 938 { 939 .name = BLOCK_OPT_BACKING_FILE, 940 .type = OPT_STRING, 941 .help = "File name of a base image" 942 }, 943 { 944 .name = BLOCK_OPT_ENCRYPT, 945 .type = OPT_FLAG, 946 .help = "Encrypt the image" 947 }, 948 { NULL } 949 }; 950 951 static BlockDriver bdrv_qcow = { 952 .format_name = "qcow", 953 .instance_size = sizeof(BDRVQcowState), 954 .bdrv_probe = qcow_probe, 955 .bdrv_open = qcow_open, 956 .bdrv_close = qcow_close, 957 .bdrv_create = qcow_create, 958 .bdrv_flush = qcow_flush, 959 .bdrv_is_allocated = qcow_is_allocated, 960 .bdrv_set_key = qcow_set_key, 961 .bdrv_make_empty = qcow_make_empty, 962 .bdrv_aio_readv = qcow_aio_readv, 963 .bdrv_aio_writev = qcow_aio_writev, 964 .bdrv_aio_flush = qcow_aio_flush, 965 .bdrv_write_compressed = qcow_write_compressed, 966 .bdrv_get_info = qcow_get_info, 967 968 .create_options = qcow_create_options, 969 }; 970 971 static void bdrv_qcow_init(void) 972 { 973 bdrv_register(&bdrv_qcow); 974 } 975 976 block_init(bdrv_qcow_init); 977
