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 int cluster_bits; 58 int cluster_size; 59 int cluster_sectors; 60 int l2_bits; 61 int l2_size; 62 int l1_size; 63 uint64_t cluster_offset_mask; 64 uint64_t l1_table_offset; 65 uint64_t *l1_table; 66 uint64_t *l2_cache; 67 uint64_t l2_cache_offsets[L2_CACHE_SIZE]; 68 uint32_t l2_cache_counts[L2_CACHE_SIZE]; 69 uint8_t *cluster_cache; 70 uint8_t *cluster_data; 71 uint64_t cluster_cache_offset; 72 uint32_t crypt_method; /* current crypt method, 0 if no key yet */ 73 uint32_t crypt_method_header; 74 AES_KEY aes_encrypt_key; 75 AES_KEY aes_decrypt_key; 76 CoMutex lock; 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 = g_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 = g_malloc(s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 143 if (!s->l2_cache) 144 goto fail; 145 s->cluster_cache = g_malloc(s->cluster_size); 146 if (!s->cluster_cache) 147 goto fail; 148 s->cluster_data = g_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 g_free(s->l1_table); 166 g_free(s->l2_cache); 167 g_free(s->cluster_cache); 168 g_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 bool is_write; 501 QEMUBH *bh; 502 QEMUIOVector hd_qiov; 503 BlockDriverAIOCB *hd_aiocb; 504 } QCowAIOCB; 505 506 static void qcow_aio_cancel(BlockDriverAIOCB *blockacb) 507 { 508 QCowAIOCB *acb = container_of(blockacb, QCowAIOCB, common); 509 if (acb->hd_aiocb) 510 bdrv_aio_cancel(acb->hd_aiocb); 511 qemu_aio_release(acb); 512 } 513 514 static AIOPool qcow_aio_pool = { 515 .aiocb_size = sizeof(QCowAIOCB), 516 .cancel = qcow_aio_cancel, 517 }; 518 519 static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs, 520 int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, 521 int is_write) 522 { 523 QCowAIOCB *acb; 524 525 acb = qemu_aio_get(&qcow_aio_pool, bs, NULL, NULL); 526 if (!acb) 527 return NULL; 528 acb->hd_aiocb = NULL; 529 acb->sector_num = sector_num; 530 acb->qiov = qiov; 531 acb->is_write = is_write; 532 533 if (qiov->niov > 1) { 534 acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size); 535 if (is_write) 536 qemu_iovec_to_buffer(qiov, acb->buf); 537 } else { 538 acb->buf = (uint8_t *)qiov->iov->iov_base; 539 } 540 acb->nb_sectors = nb_sectors; 541 acb->n = 0; 542 acb->cluster_offset = 0; 543 return acb; 544 } 545 546 static int qcow_aio_read_cb(void *opaque) 547 { 548 QCowAIOCB *acb = opaque; 549 BlockDriverState *bs = acb->common.bs; 550 BDRVQcowState *s = bs->opaque; 551 int index_in_cluster; 552 int ret; 553 554 acb->hd_aiocb = NULL; 555 556 redo: 557 /* post process the read buffer */ 558 if (!acb->cluster_offset) { 559 /* nothing to do */ 560 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { 561 /* nothing to do */ 562 } else { 563 if (s->crypt_method) { 564 encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf, 565 acb->n, 0, 566 &s->aes_decrypt_key); 567 } 568 } 569 570 acb->nb_sectors -= acb->n; 571 acb->sector_num += acb->n; 572 acb->buf += acb->n * 512; 573 574 if (acb->nb_sectors == 0) { 575 /* request completed */ 576 return 0; 577 } 578 579 /* prepare next AIO request */ 580 acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 581 0, 0, 0, 0); 582 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1); 583 acb->n = s->cluster_sectors - index_in_cluster; 584 if (acb->n > acb->nb_sectors) 585 acb->n = acb->nb_sectors; 586 587 if (!acb->cluster_offset) { 588 if (bs->backing_hd) { 589 /* read from the base image */ 590 acb->hd_iov.iov_base = (void *)acb->buf; 591 acb->hd_iov.iov_len = acb->n * 512; 592 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); 593 qemu_co_mutex_unlock(&s->lock); 594 ret = bdrv_co_readv(bs->backing_hd, acb->sector_num, 595 acb->n, &acb->hd_qiov); 596 qemu_co_mutex_lock(&s->lock); 597 if (ret < 0) { 598 return -EIO; 599 } 600 } else { 601 /* Note: in this case, no need to wait */ 602 memset(acb->buf, 0, 512 * acb->n); 603 goto redo; 604 } 605 } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) { 606 /* add AIO support for compressed blocks ? */ 607 if (decompress_cluster(bs, acb->cluster_offset) < 0) { 608 return -EIO; 609 } 610 memcpy(acb->buf, 611 s->cluster_cache + index_in_cluster * 512, 512 * acb->n); 612 goto redo; 613 } else { 614 if ((acb->cluster_offset & 511) != 0) { 615 return -EIO; 616 } 617 acb->hd_iov.iov_base = (void *)acb->buf; 618 acb->hd_iov.iov_len = acb->n * 512; 619 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); 620 qemu_co_mutex_unlock(&s->lock); 621 ret = bdrv_co_readv(bs->file, 622 (acb->cluster_offset >> 9) + index_in_cluster, 623 acb->n, &acb->hd_qiov); 624 qemu_co_mutex_lock(&s->lock); 625 if (ret < 0) { 626 return ret; 627 } 628 } 629 630 return 1; 631 } 632 633 static int qcow_co_readv(BlockDriverState *bs, int64_t sector_num, 634 int nb_sectors, QEMUIOVector *qiov) 635 { 636 BDRVQcowState *s = bs->opaque; 637 QCowAIOCB *acb; 638 int ret; 639 640 acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, 0); 641 642 qemu_co_mutex_lock(&s->lock); 643 do { 644 ret = qcow_aio_read_cb(acb); 645 } while (ret > 0); 646 qemu_co_mutex_unlock(&s->lock); 647 648 if (acb->qiov->niov > 1) { 649 qemu_iovec_from_buffer(acb->qiov, acb->orig_buf, acb->qiov->size); 650 qemu_vfree(acb->orig_buf); 651 } 652 qemu_aio_release(acb); 653 654 return ret; 655 } 656 657 static int qcow_aio_write_cb(void *opaque) 658 { 659 QCowAIOCB *acb = opaque; 660 BlockDriverState *bs = acb->common.bs; 661 BDRVQcowState *s = bs->opaque; 662 int index_in_cluster; 663 uint64_t cluster_offset; 664 const uint8_t *src_buf; 665 int ret; 666 667 acb->hd_aiocb = NULL; 668 669 acb->nb_sectors -= acb->n; 670 acb->sector_num += acb->n; 671 acb->buf += acb->n * 512; 672 673 if (acb->nb_sectors == 0) { 674 /* request completed */ 675 return 0; 676 } 677 678 index_in_cluster = acb->sector_num & (s->cluster_sectors - 1); 679 acb->n = s->cluster_sectors - index_in_cluster; 680 if (acb->n > acb->nb_sectors) 681 acb->n = acb->nb_sectors; 682 cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0, 683 index_in_cluster, 684 index_in_cluster + acb->n); 685 if (!cluster_offset || (cluster_offset & 511) != 0) { 686 return -EIO; 687 } 688 if (s->crypt_method) { 689 if (!acb->cluster_data) { 690 acb->cluster_data = g_malloc0(s->cluster_size); 691 } 692 encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf, 693 acb->n, 1, &s->aes_encrypt_key); 694 src_buf = acb->cluster_data; 695 } else { 696 src_buf = acb->buf; 697 } 698 699 acb->hd_iov.iov_base = (void *)src_buf; 700 acb->hd_iov.iov_len = acb->n * 512; 701 qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1); 702 qemu_co_mutex_unlock(&s->lock); 703 ret = bdrv_co_writev(bs->file, 704 (cluster_offset >> 9) + index_in_cluster, 705 acb->n, &acb->hd_qiov); 706 qemu_co_mutex_lock(&s->lock); 707 if (ret < 0) { 708 return ret; 709 } 710 return 1; 711 } 712 713 static int qcow_co_writev(BlockDriverState *bs, int64_t sector_num, 714 int nb_sectors, QEMUIOVector *qiov) 715 { 716 BDRVQcowState *s = bs->opaque; 717 QCowAIOCB *acb; 718 int ret; 719 720 s->cluster_cache_offset = -1; /* disable compressed cache */ 721 722 acb = qcow_aio_setup(bs, sector_num, qiov, nb_sectors, 1); 723 724 qemu_co_mutex_lock(&s->lock); 725 do { 726 ret = qcow_aio_write_cb(acb); 727 } while (ret > 0); 728 qemu_co_mutex_unlock(&s->lock); 729 730 if (acb->qiov->niov > 1) { 731 qemu_vfree(acb->orig_buf); 732 } 733 qemu_aio_release(acb); 734 735 return ret; 736 } 737 738 static void qcow_close(BlockDriverState *bs) 739 { 740 BDRVQcowState *s = bs->opaque; 741 g_free(s->l1_table); 742 g_free(s->l2_cache); 743 g_free(s->cluster_cache); 744 g_free(s->cluster_data); 745 } 746 747 static int qcow_create(const char *filename, QEMUOptionParameter *options) 748 { 749 int fd, header_size, backing_filename_len, l1_size, i, shift; 750 QCowHeader header; 751 uint64_t tmp; 752 int64_t total_size = 0; 753 const char *backing_file = NULL; 754 int flags = 0; 755 int ret; 756 757 /* Read out options */ 758 while (options && options->name) { 759 if (!strcmp(options->name, BLOCK_OPT_SIZE)) { 760 total_size = options->value.n / 512; 761 } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) { 762 backing_file = options->value.s; 763 } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) { 764 flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0; 765 } 766 options++; 767 } 768 769 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644); 770 if (fd < 0) 771 return -errno; 772 memset(&header, 0, sizeof(header)); 773 header.magic = cpu_to_be32(QCOW_MAGIC); 774 header.version = cpu_to_be32(QCOW_VERSION); 775 header.size = cpu_to_be64(total_size * 512); 776 header_size = sizeof(header); 777 backing_filename_len = 0; 778 if (backing_file) { 779 if (strcmp(backing_file, "fat:")) { 780 header.backing_file_offset = cpu_to_be64(header_size); 781 backing_filename_len = strlen(backing_file); 782 header.backing_file_size = cpu_to_be32(backing_filename_len); 783 header_size += backing_filename_len; 784 } else { 785 /* special backing file for vvfat */ 786 backing_file = NULL; 787 } 788 header.cluster_bits = 9; /* 512 byte cluster to avoid copying 789 unmodifyed sectors */ 790 header.l2_bits = 12; /* 32 KB L2 tables */ 791 } else { 792 header.cluster_bits = 12; /* 4 KB clusters */ 793 header.l2_bits = 9; /* 4 KB L2 tables */ 794 } 795 header_size = (header_size + 7) & ~7; 796 shift = header.cluster_bits + header.l2_bits; 797 l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift; 798 799 header.l1_table_offset = cpu_to_be64(header_size); 800 if (flags & BLOCK_FLAG_ENCRYPT) { 801 header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES); 802 } else { 803 header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE); 804 } 805 806 /* write all the data */ 807 ret = qemu_write_full(fd, &header, sizeof(header)); 808 if (ret != sizeof(header)) { 809 ret = -errno; 810 goto exit; 811 } 812 813 if (backing_file) { 814 ret = qemu_write_full(fd, backing_file, backing_filename_len); 815 if (ret != backing_filename_len) { 816 ret = -errno; 817 goto exit; 818 } 819 820 } 821 lseek(fd, header_size, SEEK_SET); 822 tmp = 0; 823 for(i = 0;i < l1_size; i++) { 824 ret = qemu_write_full(fd, &tmp, sizeof(tmp)); 825 if (ret != sizeof(tmp)) { 826 ret = -errno; 827 goto exit; 828 } 829 } 830 831 ret = 0; 832 exit: 833 close(fd); 834 return ret; 835 } 836 837 static int qcow_make_empty(BlockDriverState *bs) 838 { 839 BDRVQcowState *s = bs->opaque; 840 uint32_t l1_length = s->l1_size * sizeof(uint64_t); 841 int ret; 842 843 memset(s->l1_table, 0, l1_length); 844 if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table, 845 l1_length) < 0) 846 return -1; 847 ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length); 848 if (ret < 0) 849 return ret; 850 851 memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t)); 852 memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t)); 853 memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t)); 854 855 return 0; 856 } 857 858 /* XXX: put compressed sectors first, then all the cluster aligned 859 tables to avoid losing bytes in alignment */ 860 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num, 861 const uint8_t *buf, int nb_sectors) 862 { 863 BDRVQcowState *s = bs->opaque; 864 z_stream strm; 865 int ret, out_len; 866 uint8_t *out_buf; 867 uint64_t cluster_offset; 868 869 if (nb_sectors != s->cluster_sectors) 870 return -EINVAL; 871 872 out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128); 873 if (!out_buf) 874 return -1; 875 876 /* best compression, small window, no zlib header */ 877 memset(&strm, 0, sizeof(strm)); 878 ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION, 879 Z_DEFLATED, -12, 880 9, Z_DEFAULT_STRATEGY); 881 if (ret != 0) { 882 g_free(out_buf); 883 return -1; 884 } 885 886 strm.avail_in = s->cluster_size; 887 strm.next_in = (uint8_t *)buf; 888 strm.avail_out = s->cluster_size; 889 strm.next_out = out_buf; 890 891 ret = deflate(&strm, Z_FINISH); 892 if (ret != Z_STREAM_END && ret != Z_OK) { 893 g_free(out_buf); 894 deflateEnd(&strm); 895 return -1; 896 } 897 out_len = strm.next_out - out_buf; 898 899 deflateEnd(&strm); 900 901 if (ret != Z_STREAM_END || out_len >= s->cluster_size) { 902 /* could not compress: write normal cluster */ 903 bdrv_write(bs, sector_num, buf, s->cluster_sectors); 904 } else { 905 cluster_offset = get_cluster_offset(bs, sector_num << 9, 2, 906 out_len, 0, 0); 907 cluster_offset &= s->cluster_offset_mask; 908 if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) { 909 g_free(out_buf); 910 return -1; 911 } 912 } 913 914 g_free(out_buf); 915 return 0; 916 } 917 918 static int qcow_flush(BlockDriverState *bs) 919 { 920 return bdrv_flush(bs->file); 921 } 922 923 static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs, 924 BlockDriverCompletionFunc *cb, void *opaque) 925 { 926 return bdrv_aio_flush(bs->file, cb, opaque); 927 } 928 929 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi) 930 { 931 BDRVQcowState *s = bs->opaque; 932 bdi->cluster_size = s->cluster_size; 933 return 0; 934 } 935 936 937 static QEMUOptionParameter qcow_create_options[] = { 938 { 939 .name = BLOCK_OPT_SIZE, 940 .type = OPT_SIZE, 941 .help = "Virtual disk size" 942 }, 943 { 944 .name = BLOCK_OPT_BACKING_FILE, 945 .type = OPT_STRING, 946 .help = "File name of a base image" 947 }, 948 { 949 .name = BLOCK_OPT_ENCRYPT, 950 .type = OPT_FLAG, 951 .help = "Encrypt the image" 952 }, 953 { NULL } 954 }; 955 956 static BlockDriver bdrv_qcow = { 957 .format_name = "qcow", 958 .instance_size = sizeof(BDRVQcowState), 959 .bdrv_probe = qcow_probe, 960 .bdrv_open = qcow_open, 961 .bdrv_close = qcow_close, 962 .bdrv_create = qcow_create, 963 .bdrv_flush = qcow_flush, 964 .bdrv_is_allocated = qcow_is_allocated, 965 .bdrv_set_key = qcow_set_key, 966 .bdrv_make_empty = qcow_make_empty, 967 .bdrv_co_readv = qcow_co_readv, 968 .bdrv_co_writev = qcow_co_writev, 969 .bdrv_aio_flush = qcow_aio_flush, 970 .bdrv_write_compressed = qcow_write_compressed, 971 .bdrv_get_info = qcow_get_info, 972 973 .create_options = qcow_create_options, 974 }; 975 976 static void bdrv_qcow_init(void) 977 { 978 bdrv_register(&bdrv_qcow); 979 } 980 981 block_init(bdrv_qcow_init); 982