block/qcow.c

   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
 163     qemu_co_mutex_init(&s->lock);
 164     return 0;
 165
 166  fail:
 167     g_free(s->l1_table);
 168     g_free(s->l2_cache);
 169     g_free(s->cluster_cache);
 170     g_free(s->cluster_data);
 171     return -1;
 172 }
 173
 174 static int qcow_set_key(BlockDriverState *bs, const char *key)
 175 {
 176     BDRVQcowState *s = bs->opaque;
 177     uint8_t keybuf[16];
 178     int len, i;
 179
 180     memset(keybuf, 0, 16);
 181     len = strlen(key);
 182     if (len > 16)
 183         len = 16;
 184     /* XXX: we could compress the chars to 7 bits to increase
 185        entropy */
 186     for(i = 0;i < len;i++) {
 187         keybuf[i] = key[i];
 188     }
 189     s->crypt_method = s->crypt_method_header;
 190
 191     if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
 192         return -1;
 193     if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
 194         return -1;
 195 #if 0
 196     /* test */
 197     {
 198         uint8_t in[16];
 199         uint8_t out[16];
 200         uint8_t tmp[16];
 201         for(i=0;i<16;i++)
 202             in[i] = i;
 203         AES_encrypt(in, tmp, &s->aes_encrypt_key);
 204         AES_decrypt(tmp, out, &s->aes_decrypt_key);
 205         for(i = 0; i < 16; i++)
 206             printf(" %02x", tmp[i]);
 207         printf("\n");
 208         for(i = 0; i < 16; i++)
 209             printf(" %02x", out[i]);
 210         printf("\n");
 211     }
 212 #endif
 213     return 0;
 214 }
 215
 216 /* The crypt function is compatible with the linux cryptoloop
 217    algorithm for < 4 GB images. NOTE: out_buf == in_buf is
 218    supported */
 219 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 220                             uint8_t *out_buf, const uint8_t *in_buf,
 221                             int nb_sectors, int enc,
 222                             const AES_KEY *key)
 223 {
 224     union {
 225         uint64_t ll[2];
 226         uint8_t b[16];
 227     } ivec;
 228     int i;
 229
 230     for(i = 0; i < nb_sectors; i++) {
 231         ivec.ll[0] = cpu_to_le64(sector_num);
 232         ivec.ll[1] = 0;
 233         AES_cbc_encrypt(in_buf, out_buf, 512, key,
 234                         ivec.b, enc);
 235         sector_num++;
 236         in_buf += 512;
 237         out_buf += 512;
 238     }
 239 }
 240
 241 /* 'allocate' is:
 242  *
 243  * 0 to not allocate.
 244  *
 245  * 1 to allocate a normal cluster (for sector indexes 'n_start' to
 246  * 'n_end')
 247  *
 248  * 2 to allocate a compressed cluster of size
 249  * 'compressed_size'. 'compressed_size' must be > 0 and <
 250  * cluster_size
 251  *
 252  * return 0 if not allocated.
 253  */
 254 static uint64_t get_cluster_offset(BlockDriverState *bs,
 255                                    uint64_t offset, int allocate,
 256                                    int compressed_size,
 257                                    int n_start, int n_end)
 258 {
 259     BDRVQcowState *s = bs->opaque;
 260     int min_index, i, j, l1_index, l2_index;
 261     uint64_t l2_offset, *l2_table, cluster_offset, tmp;
 262     uint32_t min_count;
 263     int new_l2_table;
 264
 265     l1_index = offset >> (s->l2_bits + s->cluster_bits);
 266     l2_offset = s->l1_table[l1_index];
 267     new_l2_table = 0;
 268     if (!l2_offset) {
 269         if (!allocate)
 270             return 0;
 271         /* allocate a new l2 entry */
 272         l2_offset = bdrv_getlength(bs->file);
 273         /* round to cluster size */
 274         l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
 275         /* update the L1 entry */
 276         s->l1_table[l1_index] = l2_offset;
 277         tmp = cpu_to_be64(l2_offset);
 278         if (bdrv_pwrite_sync(bs->file,
 279                 s->l1_table_offset + l1_index * sizeof(tmp),
 280                 &tmp, sizeof(tmp)) < 0)
 281             return 0;
 282         new_l2_table = 1;
 283     }
 284     for(i = 0; i < L2_CACHE_SIZE; i++) {
 285         if (l2_offset == s->l2_cache_offsets[i]) {
 286             /* increment the hit count */
 287             if (++s->l2_cache_counts[i] == 0xffffffff) {
 288                 for(j = 0; j < L2_CACHE_SIZE; j++) {
 289                     s->l2_cache_counts[j] >>= 1;
 290                 }
 291             }
 292             l2_table = s->l2_cache + (i << s->l2_bits);
 293             goto found;
 294         }
 295     }
 296     /* not found: load a new entry in the least used one */
 297     min_index = 0;
 298     min_count = 0xffffffff;
 299     for(i = 0; i < L2_CACHE_SIZE; i++) {
 300         if (s->l2_cache_counts[i] < min_count) {
 301             min_count = s->l2_cache_counts[i];
 302             min_index = i;
 303         }
 304     }
 305     l2_table = s->l2_cache + (min_index << s->l2_bits);
 306     if (new_l2_table) {
 307         memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
 308         if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
 309                 s->l2_size * sizeof(uint64_t)) < 0)
 310             return 0;
 311     } else {
 312         if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
 313             s->l2_size * sizeof(uint64_t))
 314             return 0;
 315     }
 316     s->l2_cache_offsets[min_index] = l2_offset;
 317     s->l2_cache_counts[min_index] = 1;
 318  found:
 319     l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
 320     cluster_offset = be64_to_cpu(l2_table[l2_index]);
 321     if (!cluster_offset ||
 322         ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
 323         if (!allocate)
 324             return 0;
 325         /* allocate a new cluster */
 326         if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
 327             (n_end - n_start) < s->cluster_sectors) {
 328             /* if the cluster is already compressed, we must
 329                decompress it in the case it is not completely
 330                overwritten */
 331             if (decompress_cluster(bs, cluster_offset) < 0)
 332                 return 0;
 333             cluster_offset = bdrv_getlength(bs->file);
 334             cluster_offset = (cluster_offset + s->cluster_size - 1) &
 335                 ~(s->cluster_size - 1);
 336             /* write the cluster content */
 337             if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) !=
 338                 s->cluster_size)
 339                 return -1;
 340         } else {
 341             cluster_offset = bdrv_getlength(bs->file);
 342             if (allocate == 1) {
 343                 /* round to cluster size */
 344                 cluster_offset = (cluster_offset + s->cluster_size - 1) &
 345                     ~(s->cluster_size - 1);
 346                 bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
 347                 /* if encrypted, we must initialize the cluster
 348                    content which won't be written */
 349                 if (s->crypt_method &&
 350                     (n_end - n_start) < s->cluster_sectors) {
 351                     uint64_t start_sect;
 352                     start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
 353                     memset(s->cluster_data + 512, 0x00, 512);
 354                     for(i = 0; i < s->cluster_sectors; i++) {
 355                         if (i < n_start || i >= n_end) {
 356                             encrypt_sectors(s, start_sect + i,
 357                                             s->cluster_data,
 358                                             s->cluster_data + 512, 1, 1,
 359                                             &s->aes_encrypt_key);
 360                             if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
 361                                             s->cluster_data, 512) != 512)
 362                                 return -1;
 363                         }
 364                     }
 365                 }
 366             } else if (allocate == 2) {
 367                 cluster_offset |= QCOW_OFLAG_COMPRESSED |
 368                     (uint64_t)compressed_size << (63 - s->cluster_bits);
 369             }
 370         }
 371         /* update L2 table */
 372         tmp = cpu_to_be64(cluster_offset);
 373         l2_table[l2_index] = tmp;
 374         if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
 375                 &tmp, sizeof(tmp)) < 0)
 376             return 0;
 377     }
 378     return cluster_offset;
 379 }
 380
 381 static int qcow_is_allocated(BlockDriverState *bs, int64_t sector_num,
 382                              int nb_sectors, int *pnum)
 383 {
 384     BDRVQcowState *s = bs->opaque;
 385     int index_in_cluster, n;
 386     uint64_t cluster_offset;
 387
 388     cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
 389     index_in_cluster = sector_num & (s->cluster_sectors - 1);
 390     n = s->cluster_sectors - index_in_cluster;
 391     if (n > nb_sectors)
 392         n = nb_sectors;
 393     *pnum = n;
 394     return (cluster_offset != 0);
 395 }
 396
 397 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
 398                              const uint8_t *buf, int buf_size)
 399 {
 400     z_stream strm1, *strm = &strm1;
 401     int ret, out_len;
 402
 403     memset(strm, 0, sizeof(*strm));
 404
 405     strm->next_in = (uint8_t *)buf;
 406     strm->avail_in = buf_size;
 407     strm->next_out = out_buf;
 408     strm->avail_out = out_buf_size;
 409
 410     ret = inflateInit2(strm, -12);
 411     if (ret != Z_OK)
 412         return -1;
 413     ret = inflate(strm, Z_FINISH);
 414     out_len = strm->next_out - out_buf;
 415     if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
 416         out_len != out_buf_size) {
 417         inflateEnd(strm);
 418         return -1;
 419     }
 420     inflateEnd(strm);
 421     return 0;
 422 }
 423
 424 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 425 {
 426     BDRVQcowState *s = bs->opaque;
 427     int ret, csize;
 428     uint64_t coffset;
 429
 430     coffset = cluster_offset & s->cluster_offset_mask;
 431     if (s->cluster_cache_offset != coffset) {
 432         csize = cluster_offset >> (63 - s->cluster_bits);
 433         csize &= (s->cluster_size - 1);
 434         ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
 435         if (ret != csize)
 436             return -1;
 437         if (decompress_buffer(s->cluster_cache, s->cluster_size,
 438                               s->cluster_data, csize) < 0) {
 439             return -1;
 440         }
 441         s->cluster_cache_offset = coffset;
 442     }
 443     return 0;
 444 }
 445
 446 #if 0
 447
 448 static int qcow_read(BlockDriverState *bs, int64_t sector_num,
 449                      uint8_t *buf, int nb_sectors)
 450 {
 451     BDRVQcowState *s = bs->opaque;
 452     int ret, index_in_cluster, n;
 453     uint64_t cluster_offset;
 454
 455     while (nb_sectors > 0) {
 456         cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
 457         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 458         n = s->cluster_sectors - index_in_cluster;
 459         if (n > nb_sectors)
 460             n = nb_sectors;
 461         if (!cluster_offset) {
 462             if (bs->backing_hd) {
 463                 /* read from the base image */
 464                 ret = bdrv_read(bs->backing_hd, sector_num, buf, n);
 465                 if (ret < 0)
 466                     return -1;
 467             } else {
 468                 memset(buf, 0, 512 * n);
 469             }
 470         } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
 471             if (decompress_cluster(bs, cluster_offset) < 0)
 472                 return -1;
 473             memcpy(buf, s->cluster_cache + index_in_cluster * 512, 512 * n);
 474         } else {
 475             ret = bdrv_pread(bs->file, cluster_offset + index_in_cluster * 512, buf, n * 512);
 476             if (ret != n * 512)
 477                 return -1;
 478             if (s->crypt_method) {
 479                 encrypt_sectors(s, sector_num, buf, buf, n, 0,
 480                                 &s->aes_decrypt_key);
 481             }
 482         }
 483         nb_sectors -= n;
 484         sector_num += n;
 485         buf += n * 512;
 486     }
 487     return 0;
 488 }
 489 #endif
 490
 491 typedef struct QCowAIOCB {
 492     BlockDriverAIOCB common;
 493     int64_t sector_num;
 494     QEMUIOVector *qiov;
 495     uint8_t *buf;
 496     void *orig_buf;
 497     int nb_sectors;
 498     int n;
 499     uint64_t cluster_offset;
 500     uint8_t *cluster_data;
 501     struct iovec hd_iov;
 502     bool is_write;
 503     QEMUBH *bh;
 504     QEMUIOVector hd_qiov;
 505     BlockDriverAIOCB *hd_aiocb;
 506 } QCowAIOCB;
 507
 508 static QCowAIOCB *qcow_aio_setup(BlockDriverState *bs,
 509         int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
 510         int is_write, QCowAIOCB *acb)
 511 {
 512     memset(acb, 0, sizeof(*acb));
 513     acb->common.bs = bs;
 514     acb->hd_aiocb = NULL;
 515     acb->sector_num = sector_num;
 516     acb->qiov = qiov;
 517     acb->is_write = is_write;
 518
 519     if (qiov->niov > 1) {
 520         acb->buf = acb->orig_buf = qemu_blockalign(bs, qiov->size);
 521         if (is_write)
 522             qemu_iovec_to_buffer(qiov, acb->buf);
 523     } else {
 524         acb->buf = (uint8_t *)qiov->iov->iov_base;
 525     }
 526     acb->nb_sectors = nb_sectors;
 527     acb->n = 0;
 528     acb->cluster_offset = 0;
 529     return acb;
 530 }
 531
 532 static int qcow_aio_read_cb(QCowAIOCB *acb)
 533 {
 534     BlockDriverState *bs = acb->common.bs;
 535     BDRVQcowState *s = bs->opaque;
 536     int index_in_cluster;
 537     int ret;
 538
 539     acb->hd_aiocb = NULL;
 540
 541  redo:
 542     /* post process the read buffer */
 543     if (!acb->cluster_offset) {
 544         /* nothing to do */
 545     } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
 546         /* nothing to do */
 547     } else {
 548         if (s->crypt_method) {
 549             encrypt_sectors(s, acb->sector_num, acb->buf, acb->buf,
 550                             acb->n, 0,
 551                             &s->aes_decrypt_key);
 552         }
 553     }
 554
 555     acb->nb_sectors -= acb->n;
 556     acb->sector_num += acb->n;
 557     acb->buf += acb->n * 512;
 558
 559     if (acb->nb_sectors == 0) {
 560         /* request completed */
 561         return 0;
 562     }
 563
 564     /* prepare next AIO request */
 565     acb->cluster_offset = get_cluster_offset(bs, acb->sector_num << 9,
 566                                              0, 0, 0, 0);
 567     index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
 568     acb->n = s->cluster_sectors - index_in_cluster;
 569     if (acb->n > acb->nb_sectors)
 570         acb->n = acb->nb_sectors;
 571
 572     if (!acb->cluster_offset) {
 573         if (bs->backing_hd) {
 574             /* read from the base image */
 575             acb->hd_iov.iov_base = (void *)acb->buf;
 576             acb->hd_iov.iov_len = acb->n * 512;
 577             qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
 578             qemu_co_mutex_unlock(&s->lock);
 579             ret = bdrv_co_readv(bs->backing_hd, acb->sector_num,
 580                                 acb->n, &acb->hd_qiov);
 581             qemu_co_mutex_lock(&s->lock);
 582             if (ret < 0) {
 583                 return -EIO;
 584             }
 585         } else {
 586             /* Note: in this case, no need to wait */
 587             memset(acb->buf, 0, 512 * acb->n);
 588             goto redo;
 589         }
 590     } else if (acb->cluster_offset & QCOW_OFLAG_COMPRESSED) {
 591         /* add AIO support for compressed blocks ? */
 592         if (decompress_cluster(bs, acb->cluster_offset) < 0) {
 593             return -EIO;
 594         }
 595         memcpy(acb->buf,
 596                s->cluster_cache + index_in_cluster * 512, 512 * acb->n);
 597         goto redo;
 598     } else {
 599         if ((acb->cluster_offset & 511) != 0) {
 600             return -EIO;
 601         }
 602         acb->hd_iov.iov_base = (void *)acb->buf;
 603         acb->hd_iov.iov_len = acb->n * 512;
 604         qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
 605         qemu_co_mutex_unlock(&s->lock);
 606         ret = bdrv_co_readv(bs->file,
 607                             (acb->cluster_offset >> 9) + index_in_cluster,
 608                             acb->n, &acb->hd_qiov);
 609         qemu_co_mutex_lock(&s->lock);
 610         if (ret < 0) {
 611             return ret;
 612         }
 613     }
 614
 615     return 1;
 616 }
 617
 618 static int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
 619                          int nb_sectors, QEMUIOVector *qiov)
 620 {
 621     BDRVQcowState *s = bs->opaque;
 622     QCowAIOCB acb;
 623     int ret;
 624
 625     qcow_aio_setup(bs, sector_num, qiov, nb_sectors, 0, &acb);
 626
 627     qemu_co_mutex_lock(&s->lock);
 628     do {
 629         ret = qcow_aio_read_cb(&acb);
 630     } while (ret > 0);
 631     qemu_co_mutex_unlock(&s->lock);
 632
 633     if (acb.qiov->niov > 1) {
 634         qemu_iovec_from_buffer(acb.qiov, acb.orig_buf, acb.qiov->size);
 635         qemu_vfree(acb.orig_buf);
 636     }
 637
 638     return ret;
 639 }
 640
 641 static int qcow_aio_write_cb(QCowAIOCB *acb)
 642 {
 643     BlockDriverState *bs = acb->common.bs;
 644     BDRVQcowState *s = bs->opaque;
 645     int index_in_cluster;
 646     uint64_t cluster_offset;
 647     const uint8_t *src_buf;
 648     int ret;
 649
 650     acb->hd_aiocb = NULL;
 651
 652     acb->nb_sectors -= acb->n;
 653     acb->sector_num += acb->n;
 654     acb->buf += acb->n * 512;
 655
 656     if (acb->nb_sectors == 0) {
 657         /* request completed */
 658         return 0;
 659     }
 660
 661     index_in_cluster = acb->sector_num & (s->cluster_sectors - 1);
 662     acb->n = s->cluster_sectors - index_in_cluster;
 663     if (acb->n > acb->nb_sectors)
 664         acb->n = acb->nb_sectors;
 665     cluster_offset = get_cluster_offset(bs, acb->sector_num << 9, 1, 0,
 666                                         index_in_cluster,
 667                                         index_in_cluster + acb->n);
 668     if (!cluster_offset || (cluster_offset & 511) != 0) {
 669         return -EIO;
 670     }
 671     if (s->crypt_method) {
 672         if (!acb->cluster_data) {
 673             acb->cluster_data = g_malloc0(s->cluster_size);
 674         }
 675         encrypt_sectors(s, acb->sector_num, acb->cluster_data, acb->buf,
 676                         acb->n, 1, &s->aes_encrypt_key);
 677         src_buf = acb->cluster_data;
 678     } else {
 679         src_buf = acb->buf;
 680     }
 681
 682     acb->hd_iov.iov_base = (void *)src_buf;
 683     acb->hd_iov.iov_len = acb->n * 512;
 684     qemu_iovec_init_external(&acb->hd_qiov, &acb->hd_iov, 1);
 685     qemu_co_mutex_unlock(&s->lock);
 686     ret = bdrv_co_writev(bs->file,
 687                          (cluster_offset >> 9) + index_in_cluster,
 688                          acb->n, &acb->hd_qiov);
 689     qemu_co_mutex_lock(&s->lock);
 690     if (ret < 0) {
 691         return ret;
 692     }
 693     return 1;
 694 }
 695
 696 static int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
 697                           int nb_sectors, QEMUIOVector *qiov)
 698 {
 699     BDRVQcowState *s = bs->opaque;
 700     QCowAIOCB acb;
 701     int ret;
 702
 703     s->cluster_cache_offset = -1; /* disable compressed cache */
 704
 705     qcow_aio_setup(bs, sector_num, qiov, nb_sectors, 1, &acb);
 706
 707     qemu_co_mutex_lock(&s->lock);
 708     do {
 709         ret = qcow_aio_write_cb(&acb);
 710     } while (ret > 0);
 711     qemu_co_mutex_unlock(&s->lock);
 712
 713     if (acb.qiov->niov > 1) {
 714         qemu_vfree(acb.orig_buf);
 715     }
 716
 717     return ret;
 718 }
 719
 720 static void qcow_close(BlockDriverState *bs)
 721 {
 722     BDRVQcowState *s = bs->opaque;
 723     g_free(s->l1_table);
 724     g_free(s->l2_cache);
 725     g_free(s->cluster_cache);
 726     g_free(s->cluster_data);
 727 }
 728
 729 static int qcow_create(const char *filename, QEMUOptionParameter *options)
 730 {
 731     int fd, header_size, backing_filename_len, l1_size, i, shift;
 732     QCowHeader header;
 733     uint64_t tmp;
 734     int64_t total_size = 0;
 735     const char *backing_file = NULL;
 736     int flags = 0;
 737     int ret;
 738
 739     /* Read out options */
 740     while (options && options->name) {
 741         if (!strcmp(options->name, BLOCK_OPT_SIZE)) {
 742             total_size = options->value.n / 512;
 743         } else if (!strcmp(options->name, BLOCK_OPT_BACKING_FILE)) {
 744             backing_file = options->value.s;
 745         } else if (!strcmp(options->name, BLOCK_OPT_ENCRYPT)) {
 746             flags |= options->value.n ? BLOCK_FLAG_ENCRYPT : 0;
 747         }
 748         options++;
 749     }
 750
 751     fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
 752     if (fd < 0)
 753         return -errno;
 754     memset(&header, 0, sizeof(header));
 755     header.magic = cpu_to_be32(QCOW_MAGIC);
 756     header.version = cpu_to_be32(QCOW_VERSION);
 757     header.size = cpu_to_be64(total_size * 512);
 758     header_size = sizeof(header);
 759     backing_filename_len = 0;
 760     if (backing_file) {
 761         if (strcmp(backing_file, "fat:")) {
 762             header.backing_file_offset = cpu_to_be64(header_size);
 763             backing_filename_len = strlen(backing_file);
 764             header.backing_file_size = cpu_to_be32(backing_filename_len);
 765             header_size += backing_filename_len;
 766         } else {
 767             /* special backing file for vvfat */
 768             backing_file = NULL;
 769         }
 770         header.cluster_bits = 9; /* 512 byte cluster to avoid copying
 771                                     unmodifyed sectors */
 772         header.l2_bits = 12; /* 32 KB L2 tables */
 773     } else {
 774         header.cluster_bits = 12; /* 4 KB clusters */
 775         header.l2_bits = 9; /* 4 KB L2 tables */
 776     }
 777     header_size = (header_size + 7) & ~7;
 778     shift = header.cluster_bits + header.l2_bits;
 779     l1_size = ((total_size * 512) + (1LL << shift) - 1) >> shift;
 780
 781     header.l1_table_offset = cpu_to_be64(header_size);
 782     if (flags & BLOCK_FLAG_ENCRYPT) {
 783         header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
 784     } else {
 785         header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
 786     }
 787
 788     /* write all the data */
 789     ret = qemu_write_full(fd, &header, sizeof(header));
 790     if (ret != sizeof(header)) {
 791         ret = -errno;
 792         goto exit;
 793     }
 794
 795     if (backing_file) {
 796         ret = qemu_write_full(fd, backing_file, backing_filename_len);
 797         if (ret != backing_filename_len) {
 798             ret = -errno;
 799             goto exit;
 800         }
 801
 802     }
 803     lseek(fd, header_size, SEEK_SET);
 804     tmp = 0;
 805     for(i = 0;i < l1_size; i++) {
 806         ret = qemu_write_full(fd, &tmp, sizeof(tmp));
 807         if (ret != sizeof(tmp)) {
 808             ret = -errno;
 809             goto exit;
 810         }
 811     }
 812
 813     ret = 0;
 814 exit:
 815     close(fd);
 816     return ret;
 817 }
 818
 819 static int qcow_make_empty(BlockDriverState *bs)
 820 {
 821     BDRVQcowState *s = bs->opaque;
 822     uint32_t l1_length = s->l1_size * sizeof(uint64_t);
 823     int ret;
 824
 825     memset(s->l1_table, 0, l1_length);
 826     if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
 827             l1_length) < 0)
 828         return -1;
 829     ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
 830     if (ret < 0)
 831         return ret;
 832
 833     memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 834     memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
 835     memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
 836
 837     return 0;
 838 }
 839
 840 /* XXX: put compressed sectors first, then all the cluster aligned
 841    tables to avoid losing bytes in alignment */
 842 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
 843                                  const uint8_t *buf, int nb_sectors)
 844 {
 845     BDRVQcowState *s = bs->opaque;
 846     z_stream strm;
 847     int ret, out_len;
 848     uint8_t *out_buf;
 849     uint64_t cluster_offset;
 850
 851     if (nb_sectors != s->cluster_sectors)
 852         return -EINVAL;
 853
 854     out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
 855     if (!out_buf)
 856         return -1;
 857
 858     /* best compression, small window, no zlib header */
 859     memset(&strm, 0, sizeof(strm));
 860     ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
 861                        Z_DEFLATED, -12,
 862                        9, Z_DEFAULT_STRATEGY);
 863     if (ret != 0) {
 864         g_free(out_buf);
 865         return -1;
 866     }
 867
 868     strm.avail_in = s->cluster_size;
 869     strm.next_in = (uint8_t *)buf;
 870     strm.avail_out = s->cluster_size;
 871     strm.next_out = out_buf;
 872
 873     ret = deflate(&strm, Z_FINISH);
 874     if (ret != Z_STREAM_END && ret != Z_OK) {
 875         g_free(out_buf);
 876         deflateEnd(&strm);
 877         return -1;
 878     }
 879     out_len = strm.next_out - out_buf;
 880
 881     deflateEnd(&strm);
 882
 883     if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
 884         /* could not compress: write normal cluster */
 885         bdrv_write(bs, sector_num, buf, s->cluster_sectors);
 886     } else {
 887         cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
 888                                             out_len, 0, 0);
 889         cluster_offset &= s->cluster_offset_mask;
 890         if (bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len) != out_len) {
 891             g_free(out_buf);
 892             return -1;
 893         }
 894     }
 895
 896     g_free(out_buf);
 897     return 0;
 898 }
 899
 900 static int qcow_flush(BlockDriverState *bs)
 901 {
 902     return bdrv_flush(bs->file);
 903 }
 904
 905 static BlockDriverAIOCB *qcow_aio_flush(BlockDriverState *bs,
 906         BlockDriverCompletionFunc *cb, void *opaque)
 907 {
 908     return bdrv_aio_flush(bs->file, cb, opaque);
 909 }
 910
 911 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 912 {
 913     BDRVQcowState *s = bs->opaque;
 914     bdi->cluster_size = s->cluster_size;
 915     return 0;
 916 }
 917
 918
 919 static QEMUOptionParameter qcow_create_options[] = {
 920     {
 921         .name = BLOCK_OPT_SIZE,
 922         .type = OPT_SIZE,
 923         .help = "Virtual disk size"
 924     },
 925     {
 926         .name = BLOCK_OPT_BACKING_FILE,
 927         .type = OPT_STRING,
 928         .help = "File name of a base image"
 929     },
 930     {
 931         .name = BLOCK_OPT_ENCRYPT,
 932         .type = OPT_FLAG,
 933         .help = "Encrypt the image"
 934     },
 935     { NULL }
 936 };
 937
 938 static BlockDriver bdrv_qcow = {
 939     .format_name        = "qcow",
 940     .instance_size      = sizeof(BDRVQcowState),
 941     .bdrv_probe         = qcow_probe,
 942     .bdrv_open          = qcow_open,
 943     .bdrv_close         = qcow_close,
 944     .bdrv_create        = qcow_create,
 945     .bdrv_flush         = qcow_flush,
 946     .bdrv_is_allocated  = qcow_is_allocated,
 947     .bdrv_set_key       = qcow_set_key,
 948     .bdrv_make_empty    = qcow_make_empty,
 949     .bdrv_co_readv  = qcow_co_readv,
 950     .bdrv_co_writev = qcow_co_writev,
 951     .bdrv_aio_flush     = qcow_aio_flush,
 952     .bdrv_write_compressed = qcow_write_compressed,
 953     .bdrv_get_info      = qcow_get_info,
 954
 955     .create_options = qcow_create_options,
 956 };
 957
 958 static void bdrv_qcow_init(void)
 959 {
 960     bdrv_register(&bdrv_qcow);
 961 }
 962
 963 block_init(bdrv_qcow_init);