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/block_int.h"
  26 #include "qemu/module.h"
  27 #include <zlib.h>
  28 #include "qemu/aes.h"
  29 #include "migration/migration.h"
  30
  31 /**************************************************************/
  32 /* QEMU COW block driver with compression and encryption support */
  33
  34 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  35 #define QCOW_VERSION 1
  36
  37 #define QCOW_CRYPT_NONE 0
  38 #define QCOW_CRYPT_AES  1
  39
  40 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
  41
  42 typedef struct QCowHeader {
  43     uint32_t magic;
  44     uint32_t version;
  45     uint64_t backing_file_offset;
  46     uint32_t backing_file_size;
  47     uint32_t mtime;
  48     uint64_t size; /* in bytes */
  49     uint8_t cluster_bits;
  50     uint8_t l2_bits;
  51     uint16_t padding;
  52     uint32_t crypt_method;
  53     uint64_t l1_table_offset;
  54 } QEMU_PACKED QCowHeader;
  55
  56 #define L2_CACHE_SIZE 16
  57
  58 typedef struct BDRVQcowState {
  59     int cluster_bits;
  60     int cluster_size;
  61     int cluster_sectors;
  62     int l2_bits;
  63     int l2_size;
  64     unsigned int l1_size;
  65     uint64_t cluster_offset_mask;
  66     uint64_t l1_table_offset;
  67     uint64_t *l1_table;
  68     uint64_t *l2_cache;
  69     uint64_t l2_cache_offsets[L2_CACHE_SIZE];
  70     uint32_t l2_cache_counts[L2_CACHE_SIZE];
  71     uint8_t *cluster_cache;
  72     uint8_t *cluster_data;
  73     uint64_t cluster_cache_offset;
  74     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
  75     uint32_t crypt_method_header;
  76     AES_KEY aes_encrypt_key;
  77     AES_KEY aes_decrypt_key;
  78     CoMutex lock;
  79     Error *migration_blocker;
  80 } BDRVQcowState;
  81
  82 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
  83
  84 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
  85 {
  86     const QCowHeader *cow_header = (const void *)buf;
  87
  88     if (buf_size >= sizeof(QCowHeader) &&
  89         be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
  90         be32_to_cpu(cow_header->version) == QCOW_VERSION)
  91         return 100;
  92     else
  93         return 0;
  94 }
  95
  96 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
  97                      Error **errp)
  98 {
  99     BDRVQcowState *s = bs->opaque;
 100     unsigned int len, i, shift;
 101     int ret;
 102     QCowHeader header;
 103
 104     ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
 105     if (ret < 0) {
 106         goto fail;
 107     }
 108     be32_to_cpus(&header.magic);
 109     be32_to_cpus(&header.version);
 110     be64_to_cpus(&header.backing_file_offset);
 111     be32_to_cpus(&header.backing_file_size);
 112     be32_to_cpus(&header.mtime);
 113     be64_to_cpus(&header.size);
 114     be32_to_cpus(&header.crypt_method);
 115     be64_to_cpus(&header.l1_table_offset);
 116
 117     if (header.magic != QCOW_MAGIC) {
 118         error_setg(errp, "Image not in qcow format");
 119         ret = -EINVAL;
 120         goto fail;
 121     }
 122     if (header.version != QCOW_VERSION) {
 123         char version[64];
 124         snprintf(version, sizeof(version), "QCOW version %" PRIu32,
 125                  header.version);
 126         error_set(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
 127                   bdrv_get_device_name(bs), "qcow", version);
 128         ret = -ENOTSUP;
 129         goto fail;
 130     }
 131
 132     if (header.size <= 1) {
 133         error_setg(errp, "Image size is too small (must be at least 2 bytes)");
 134         ret = -EINVAL;
 135         goto fail;
 136     }
 137     if (header.cluster_bits < 9 || header.cluster_bits > 16) {
 138         error_setg(errp, "Cluster size must be between 512 and 64k");
 139         ret = -EINVAL;
 140         goto fail;
 141     }
 142
 143     /* l2_bits specifies number of entries; storing a uint64_t in each entry,
 144      * so bytes = num_entries << 3. */
 145     if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
 146         error_setg(errp, "L2 table size must be between 512 and 64k");
 147         ret = -EINVAL;
 148         goto fail;
 149     }
 150
 151     if (header.crypt_method > QCOW_CRYPT_AES) {
 152         error_setg(errp, "invalid encryption method in qcow header");
 153         ret = -EINVAL;
 154         goto fail;
 155     }
 156     s->crypt_method_header = header.crypt_method;
 157     if (s->crypt_method_header) {
 158         bs->encrypted = 1;
 159     }
 160     s->cluster_bits = header.cluster_bits;
 161     s->cluster_size = 1 << s->cluster_bits;
 162     s->cluster_sectors = 1 << (s->cluster_bits - 9);
 163     s->l2_bits = header.l2_bits;
 164     s->l2_size = 1 << s->l2_bits;
 165     bs->total_sectors = header.size / 512;
 166     s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
 167
 168     /* read the level 1 table */
 169     shift = s->cluster_bits + s->l2_bits;
 170     if (header.size > UINT64_MAX - (1LL << shift)) {
 171         error_setg(errp, "Image too large");
 172         ret = -EINVAL;
 173         goto fail;
 174     } else {
 175         uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
 176         if (l1_size > INT_MAX / sizeof(uint64_t)) {
 177             error_setg(errp, "Image too large");
 178             ret = -EINVAL;
 179             goto fail;
 180         }
 181         s->l1_size = l1_size;
 182     }
 183
 184     s->l1_table_offset = header.l1_table_offset;
 185     s->l1_table = g_try_new(uint64_t, s->l1_size);
 186     if (s->l1_table == NULL) {
 187         error_setg(errp, "Could not allocate memory for L1 table");
 188         ret = -ENOMEM;
 189         goto fail;
 190     }
 191
 192     ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
 193                s->l1_size * sizeof(uint64_t));
 194     if (ret < 0) {
 195         goto fail;
 196     }
 197
 198     for(i = 0;i < s->l1_size; i++) {
 199         be64_to_cpus(&s->l1_table[i]);
 200     }
 201
 202     /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
 203     s->l2_cache =
 204         qemu_try_blockalign(bs->file,
 205                             s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 206     if (s->l2_cache == NULL) {
 207         error_setg(errp, "Could not allocate L2 table cache");
 208         ret = -ENOMEM;
 209         goto fail;
 210     }
 211     s->cluster_cache = g_malloc(s->cluster_size);
 212     s->cluster_data = g_malloc(s->cluster_size);
 213     s->cluster_cache_offset = -1;
 214
 215     /* read the backing file name */
 216     if (header.backing_file_offset != 0) {
 217         len = header.backing_file_size;
 218         if (len > 1023 || len >= sizeof(bs->backing_file)) {
 219             error_setg(errp, "Backing file name too long");
 220             ret = -EINVAL;
 221             goto fail;
 222         }
 223         ret = bdrv_pread(bs->file, header.backing_file_offset,
 224                    bs->backing_file, len);
 225         if (ret < 0) {
 226             goto fail;
 227         }
 228         bs->backing_file[len] = '\0';
 229     }
 230
 231     /* Disable migration when qcow images are used */
 232     error_set(&s->migration_blocker,
 233               QERR_BLOCK_FORMAT_FEATURE_NOT_SUPPORTED,
 234               "qcow", bdrv_get_device_name(bs), "live migration");
 235     migrate_add_blocker(s->migration_blocker);
 236
 237     qemu_co_mutex_init(&s->lock);
 238     return 0;
 239
 240  fail:
 241     g_free(s->l1_table);
 242     qemu_vfree(s->l2_cache);
 243     g_free(s->cluster_cache);
 244     g_free(s->cluster_data);
 245     return ret;
 246 }
 247
 248
 249 /* We have nothing to do for QCOW reopen, stubs just return
 250  * success */
 251 static int qcow_reopen_prepare(BDRVReopenState *state,
 252                                BlockReopenQueue *queue, Error **errp)
 253 {
 254     return 0;
 255 }
 256
 257 static int qcow_set_key(BlockDriverState *bs, const char *key)
 258 {
 259     BDRVQcowState *s = bs->opaque;
 260     uint8_t keybuf[16];
 261     int len, i;
 262
 263     memset(keybuf, 0, 16);
 264     len = strlen(key);
 265     if (len > 16)
 266         len = 16;
 267     /* XXX: we could compress the chars to 7 bits to increase
 268        entropy */
 269     for(i = 0;i < len;i++) {
 270         keybuf[i] = key[i];
 271     }
 272     s->crypt_method = s->crypt_method_header;
 273
 274     if (AES_set_encrypt_key(keybuf, 128, &s->aes_encrypt_key) != 0)
 275         return -1;
 276     if (AES_set_decrypt_key(keybuf, 128, &s->aes_decrypt_key) != 0)
 277         return -1;
 278     return 0;
 279 }
 280
 281 /* The crypt function is compatible with the linux cryptoloop
 282    algorithm for < 4 GB images. NOTE: out_buf == in_buf is
 283    supported */
 284 static void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 285                             uint8_t *out_buf, const uint8_t *in_buf,
 286                             int nb_sectors, int enc,
 287                             const AES_KEY *key)
 288 {
 289     union {
 290         uint64_t ll[2];
 291         uint8_t b[16];
 292     } ivec;
 293     int i;
 294
 295     for(i = 0; i < nb_sectors; i++) {
 296         ivec.ll[0] = cpu_to_le64(sector_num);
 297         ivec.ll[1] = 0;
 298         AES_cbc_encrypt(in_buf, out_buf, 512, key,
 299                         ivec.b, enc);
 300         sector_num++;
 301         in_buf += 512;
 302         out_buf += 512;
 303     }
 304 }
 305
 306 /* 'allocate' is:
 307  *
 308  * 0 to not allocate.
 309  *
 310  * 1 to allocate a normal cluster (for sector indexes 'n_start' to
 311  * 'n_end')
 312  *
 313  * 2 to allocate a compressed cluster of size
 314  * 'compressed_size'. 'compressed_size' must be > 0 and <
 315  * cluster_size
 316  *
 317  * return 0 if not allocated.
 318  */
 319 static uint64_t get_cluster_offset(BlockDriverState *bs,
 320                                    uint64_t offset, int allocate,
 321                                    int compressed_size,
 322                                    int n_start, int n_end)
 323 {
 324     BDRVQcowState *s = bs->opaque;
 325     int min_index, i, j, l1_index, l2_index;
 326     uint64_t l2_offset, *l2_table, cluster_offset, tmp;
 327     uint32_t min_count;
 328     int new_l2_table;
 329
 330     l1_index = offset >> (s->l2_bits + s->cluster_bits);
 331     l2_offset = s->l1_table[l1_index];
 332     new_l2_table = 0;
 333     if (!l2_offset) {
 334         if (!allocate)
 335             return 0;
 336         /* allocate a new l2 entry */
 337         l2_offset = bdrv_getlength(bs->file);
 338         /* round to cluster size */
 339         l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
 340         /* update the L1 entry */
 341         s->l1_table[l1_index] = l2_offset;
 342         tmp = cpu_to_be64(l2_offset);
 343         if (bdrv_pwrite_sync(bs->file,
 344                 s->l1_table_offset + l1_index * sizeof(tmp),
 345                 &tmp, sizeof(tmp)) < 0)
 346             return 0;
 347         new_l2_table = 1;
 348     }
 349     for(i = 0; i < L2_CACHE_SIZE; i++) {
 350         if (l2_offset == s->l2_cache_offsets[i]) {
 351             /* increment the hit count */
 352             if (++s->l2_cache_counts[i] == 0xffffffff) {
 353                 for(j = 0; j < L2_CACHE_SIZE; j++) {
 354                     s->l2_cache_counts[j] >>= 1;
 355                 }
 356             }
 357             l2_table = s->l2_cache + (i << s->l2_bits);
 358             goto found;
 359         }
 360     }
 361     /* not found: load a new entry in the least used one */
 362     min_index = 0;
 363     min_count = 0xffffffff;
 364     for(i = 0; i < L2_CACHE_SIZE; i++) {
 365         if (s->l2_cache_counts[i] < min_count) {
 366             min_count = s->l2_cache_counts[i];
 367             min_index = i;
 368         }
 369     }
 370     l2_table = s->l2_cache + (min_index << s->l2_bits);
 371     if (new_l2_table) {
 372         memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
 373         if (bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
 374                 s->l2_size * sizeof(uint64_t)) < 0)
 375             return 0;
 376     } else {
 377         if (bdrv_pread(bs->file, l2_offset, l2_table, s->l2_size * sizeof(uint64_t)) !=
 378             s->l2_size * sizeof(uint64_t))
 379             return 0;
 380     }
 381     s->l2_cache_offsets[min_index] = l2_offset;
 382     s->l2_cache_counts[min_index] = 1;
 383  found:
 384     l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
 385     cluster_offset = be64_to_cpu(l2_table[l2_index]);
 386     if (!cluster_offset ||
 387         ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
 388         if (!allocate)
 389             return 0;
 390         /* allocate a new cluster */
 391         if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
 392             (n_end - n_start) < s->cluster_sectors) {
 393             /* if the cluster is already compressed, we must
 394                decompress it in the case it is not completely
 395                overwritten */
 396             if (decompress_cluster(bs, cluster_offset) < 0)
 397                 return 0;
 398             cluster_offset = bdrv_getlength(bs->file);
 399             cluster_offset = (cluster_offset + s->cluster_size - 1) &
 400                 ~(s->cluster_size - 1);
 401             /* write the cluster content */
 402             if (bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache, s->cluster_size) !=
 403                 s->cluster_size)
 404                 return -1;
 405         } else {
 406             cluster_offset = bdrv_getlength(bs->file);
 407             if (allocate == 1) {
 408                 /* round to cluster size */
 409                 cluster_offset = (cluster_offset + s->cluster_size - 1) &
 410                     ~(s->cluster_size - 1);
 411                 bdrv_truncate(bs->file, cluster_offset + s->cluster_size);
 412                 /* if encrypted, we must initialize the cluster
 413                    content which won't be written */
 414                 if (s->crypt_method &&
 415                     (n_end - n_start) < s->cluster_sectors) {
 416                     uint64_t start_sect;
 417                     start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
 418                     memset(s->cluster_data + 512, 0x00, 512);
 419                     for(i = 0; i < s->cluster_sectors; i++) {
 420                         if (i < n_start || i >= n_end) {
 421                             encrypt_sectors(s, start_sect + i,
 422                                             s->cluster_data,
 423                                             s->cluster_data + 512, 1, 1,
 424                                             &s->aes_encrypt_key);
 425                             if (bdrv_pwrite(bs->file, cluster_offset + i * 512,
 426                                             s->cluster_data, 512) != 512)
 427                                 return -1;
 428                         }
 429                     }
 430                 }
 431             } else if (allocate == 2) {
 432                 cluster_offset |= QCOW_OFLAG_COMPRESSED |
 433                     (uint64_t)compressed_size << (63 - s->cluster_bits);
 434             }
 435         }
 436         /* update L2 table */
 437         tmp = cpu_to_be64(cluster_offset);
 438         l2_table[l2_index] = tmp;
 439         if (bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
 440                 &tmp, sizeof(tmp)) < 0)
 441             return 0;
 442     }
 443     return cluster_offset;
 444 }
 445
 446 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs,
 447         int64_t sector_num, int nb_sectors, int *pnum)
 448 {
 449     BDRVQcowState *s = bs->opaque;
 450     int index_in_cluster, n;
 451     uint64_t cluster_offset;
 452
 453     qemu_co_mutex_lock(&s->lock);
 454     cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
 455     qemu_co_mutex_unlock(&s->lock);
 456     index_in_cluster = sector_num & (s->cluster_sectors - 1);
 457     n = s->cluster_sectors - index_in_cluster;
 458     if (n > nb_sectors)
 459         n = nb_sectors;
 460     *pnum = n;
 461     if (!cluster_offset) {
 462         return 0;
 463     }
 464     if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypt_method) {
 465         return BDRV_BLOCK_DATA;
 466     }
 467     cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
 468     return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset;
 469 }
 470
 471 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
 472                              const uint8_t *buf, int buf_size)
 473 {
 474     z_stream strm1, *strm = &strm1;
 475     int ret, out_len;
 476
 477     memset(strm, 0, sizeof(*strm));
 478
 479     strm->next_in = (uint8_t *)buf;
 480     strm->avail_in = buf_size;
 481     strm->next_out = out_buf;
 482     strm->avail_out = out_buf_size;
 483
 484     ret = inflateInit2(strm, -12);
 485     if (ret != Z_OK)
 486         return -1;
 487     ret = inflate(strm, Z_FINISH);
 488     out_len = strm->next_out - out_buf;
 489     if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
 490         out_len != out_buf_size) {
 491         inflateEnd(strm);
 492         return -1;
 493     }
 494     inflateEnd(strm);
 495     return 0;
 496 }
 497
 498 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 499 {
 500     BDRVQcowState *s = bs->opaque;
 501     int ret, csize;
 502     uint64_t coffset;
 503
 504     coffset = cluster_offset & s->cluster_offset_mask;
 505     if (s->cluster_cache_offset != coffset) {
 506         csize = cluster_offset >> (63 - s->cluster_bits);
 507         csize &= (s->cluster_size - 1);
 508         ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
 509         if (ret != csize)
 510             return -1;
 511         if (decompress_buffer(s->cluster_cache, s->cluster_size,
 512                               s->cluster_data, csize) < 0) {
 513             return -1;
 514         }
 515         s->cluster_cache_offset = coffset;
 516     }
 517     return 0;
 518 }
 519
 520 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
 521                          int nb_sectors, QEMUIOVector *qiov)
 522 {
 523     BDRVQcowState *s = bs->opaque;
 524     int index_in_cluster;
 525     int ret = 0, n;
 526     uint64_t cluster_offset;
 527     struct iovec hd_iov;
 528     QEMUIOVector hd_qiov;
 529     uint8_t *buf;
 530     void *orig_buf;
 531
 532     if (qiov->niov > 1) {
 533         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 534         if (buf == NULL) {
 535             return -ENOMEM;
 536         }
 537     } else {
 538         orig_buf = NULL;
 539         buf = (uint8_t *)qiov->iov->iov_base;
 540     }
 541
 542     qemu_co_mutex_lock(&s->lock);
 543
 544     while (nb_sectors != 0) {
 545         /* prepare next request */
 546         cluster_offset = get_cluster_offset(bs, sector_num << 9,
 547                                                  0, 0, 0, 0);
 548         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 549         n = s->cluster_sectors - index_in_cluster;
 550         if (n > nb_sectors) {
 551             n = nb_sectors;
 552         }
 553
 554         if (!cluster_offset) {
 555             if (bs->backing_hd) {
 556                 /* read from the base image */
 557                 hd_iov.iov_base = (void *)buf;
 558                 hd_iov.iov_len = n * 512;
 559                 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 560                 qemu_co_mutex_unlock(&s->lock);
 561                 ret = bdrv_co_readv(bs->backing_hd, sector_num,
 562                                     n, &hd_qiov);
 563                 qemu_co_mutex_lock(&s->lock);
 564                 if (ret < 0) {
 565                     goto fail;
 566                 }
 567             } else {
 568                 /* Note: in this case, no need to wait */
 569                 memset(buf, 0, 512 * n);
 570             }
 571         } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
 572             /* add AIO support for compressed blocks ? */
 573             if (decompress_cluster(bs, cluster_offset) < 0) {
 574                 goto fail;
 575             }
 576             memcpy(buf,
 577                    s->cluster_cache + index_in_cluster * 512, 512 * n);
 578         } else {
 579             if ((cluster_offset & 511) != 0) {
 580                 goto fail;
 581             }
 582             hd_iov.iov_base = (void *)buf;
 583             hd_iov.iov_len = n * 512;
 584             qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 585             qemu_co_mutex_unlock(&s->lock);
 586             ret = bdrv_co_readv(bs->file,
 587                                 (cluster_offset >> 9) + index_in_cluster,
 588                                 n, &hd_qiov);
 589             qemu_co_mutex_lock(&s->lock);
 590             if (ret < 0) {
 591                 break;
 592             }
 593             if (s->crypt_method) {
 594                 encrypt_sectors(s, sector_num, buf, buf,
 595                                 n, 0,
 596                                 &s->aes_decrypt_key);
 597             }
 598         }
 599         ret = 0;
 600
 601         nb_sectors -= n;
 602         sector_num += n;
 603         buf += n * 512;
 604     }
 605
 606 done:
 607     qemu_co_mutex_unlock(&s->lock);
 608
 609     if (qiov->niov > 1) {
 610         qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
 611         qemu_vfree(orig_buf);
 612     }
 613
 614     return ret;
 615
 616 fail:
 617     ret = -EIO;
 618     goto done;
 619 }
 620
 621 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
 622                           int nb_sectors, QEMUIOVector *qiov)
 623 {
 624     BDRVQcowState *s = bs->opaque;
 625     int index_in_cluster;
 626     uint64_t cluster_offset;
 627     const uint8_t *src_buf;
 628     int ret = 0, n;
 629     uint8_t *cluster_data = NULL;
 630     struct iovec hd_iov;
 631     QEMUIOVector hd_qiov;
 632     uint8_t *buf;
 633     void *orig_buf;
 634
 635     s->cluster_cache_offset = -1; /* disable compressed cache */
 636
 637     if (qiov->niov > 1) {
 638         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 639         if (buf == NULL) {
 640             return -ENOMEM;
 641         }
 642         qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
 643     } else {
 644         orig_buf = NULL;
 645         buf = (uint8_t *)qiov->iov->iov_base;
 646     }
 647
 648     qemu_co_mutex_lock(&s->lock);
 649
 650     while (nb_sectors != 0) {
 651
 652         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 653         n = s->cluster_sectors - index_in_cluster;
 654         if (n > nb_sectors) {
 655             n = nb_sectors;
 656         }
 657         cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
 658                                             index_in_cluster,
 659                                             index_in_cluster + n);
 660         if (!cluster_offset || (cluster_offset & 511) != 0) {
 661             ret = -EIO;
 662             break;
 663         }
 664         if (s->crypt_method) {
 665             if (!cluster_data) {
 666                 cluster_data = g_malloc0(s->cluster_size);
 667             }
 668             encrypt_sectors(s, sector_num, cluster_data, buf,
 669                             n, 1, &s->aes_encrypt_key);
 670             src_buf = cluster_data;
 671         } else {
 672             src_buf = buf;
 673         }
 674
 675         hd_iov.iov_base = (void *)src_buf;
 676         hd_iov.iov_len = n * 512;
 677         qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 678         qemu_co_mutex_unlock(&s->lock);
 679         ret = bdrv_co_writev(bs->file,
 680                              (cluster_offset >> 9) + index_in_cluster,
 681                              n, &hd_qiov);
 682         qemu_co_mutex_lock(&s->lock);
 683         if (ret < 0) {
 684             break;
 685         }
 686         ret = 0;
 687
 688         nb_sectors -= n;
 689         sector_num += n;
 690         buf += n * 512;
 691     }
 692     qemu_co_mutex_unlock(&s->lock);
 693
 694     if (qiov->niov > 1) {
 695         qemu_vfree(orig_buf);
 696     }
 697     g_free(cluster_data);
 698
 699     return ret;
 700 }
 701
 702 static void qcow_close(BlockDriverState *bs)
 703 {
 704     BDRVQcowState *s = bs->opaque;
 705
 706     g_free(s->l1_table);
 707     qemu_vfree(s->l2_cache);
 708     g_free(s->cluster_cache);
 709     g_free(s->cluster_data);
 710
 711     migrate_del_blocker(s->migration_blocker);
 712     error_free(s->migration_blocker);
 713 }
 714
 715 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
 716 {
 717     int header_size, backing_filename_len, l1_size, shift, i;
 718     QCowHeader header;
 719     uint8_t *tmp;
 720     int64_t total_size = 0;
 721     char *backing_file = NULL;
 722     int flags = 0;
 723     Error *local_err = NULL;
 724     int ret;
 725     BlockDriverState *qcow_bs;
 726
 727     /* Read out options */
 728     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 729                           BDRV_SECTOR_SIZE);
 730     backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
 731     if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
 732         flags |= BLOCK_FLAG_ENCRYPT;
 733     }
 734
 735     ret = bdrv_create_file(filename, opts, &local_err);
 736     if (ret < 0) {
 737         error_propagate(errp, local_err);
 738         goto cleanup;
 739     }
 740
 741     qcow_bs = NULL;
 742     ret = bdrv_open(&qcow_bs, filename, NULL, NULL,
 743                     BDRV_O_RDWR | BDRV_O_PROTOCOL, NULL, &local_err);
 744     if (ret < 0) {
 745         error_propagate(errp, local_err);
 746         goto cleanup;
 747     }
 748
 749     ret = bdrv_truncate(qcow_bs, 0);
 750     if (ret < 0) {
 751         goto exit;
 752     }
 753
 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);
 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                                     unmodified 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 + (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 = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header));
 790     if (ret != sizeof(header)) {
 791         goto exit;
 792     }
 793
 794     if (backing_file) {
 795         ret = bdrv_pwrite(qcow_bs, sizeof(header),
 796             backing_file, backing_filename_len);
 797         if (ret != backing_filename_len) {
 798             goto exit;
 799         }
 800     }
 801
 802     tmp = g_malloc0(BDRV_SECTOR_SIZE);
 803     for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/
 804         BDRV_SECTOR_SIZE); i++) {
 805         ret = bdrv_pwrite(qcow_bs, header_size +
 806             BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE);
 807         if (ret != BDRV_SECTOR_SIZE) {
 808             g_free(tmp);
 809             goto exit;
 810         }
 811     }
 812
 813     g_free(tmp);
 814     ret = 0;
 815 exit:
 816     bdrv_unref(qcow_bs);
 817 cleanup:
 818     g_free(backing_file);
 819     return ret;
 820 }
 821
 822 static int qcow_make_empty(BlockDriverState *bs)
 823 {
 824     BDRVQcowState *s = bs->opaque;
 825     uint32_t l1_length = s->l1_size * sizeof(uint64_t);
 826     int ret;
 827
 828     memset(s->l1_table, 0, l1_length);
 829     if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
 830             l1_length) < 0)
 831         return -1;
 832     ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length);
 833     if (ret < 0)
 834         return ret;
 835
 836     memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 837     memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
 838     memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
 839
 840     return 0;
 841 }
 842
 843 /* XXX: put compressed sectors first, then all the cluster aligned
 844    tables to avoid losing bytes in alignment */
 845 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
 846                                  const uint8_t *buf, int nb_sectors)
 847 {
 848     BDRVQcowState *s = bs->opaque;
 849     z_stream strm;
 850     int ret, out_len;
 851     uint8_t *out_buf;
 852     uint64_t cluster_offset;
 853
 854     if (nb_sectors != s->cluster_sectors) {
 855         ret = -EINVAL;
 856
 857         /* Zero-pad last write if image size is not cluster aligned */
 858         if (sector_num + nb_sectors == bs->total_sectors &&
 859             nb_sectors < s->cluster_sectors) {
 860             uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
 861             memset(pad_buf, 0, s->cluster_size);
 862             memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
 863             ret = qcow_write_compressed(bs, sector_num,
 864                                         pad_buf, s->cluster_sectors);
 865             qemu_vfree(pad_buf);
 866         }
 867         return ret;
 868     }
 869
 870     out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
 871
 872     /* best compression, small window, no zlib header */
 873     memset(&strm, 0, sizeof(strm));
 874     ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
 875                        Z_DEFLATED, -12,
 876                        9, Z_DEFAULT_STRATEGY);
 877     if (ret != 0) {
 878         ret = -EINVAL;
 879         goto fail;
 880     }
 881
 882     strm.avail_in = s->cluster_size;
 883     strm.next_in = (uint8_t *)buf;
 884     strm.avail_out = s->cluster_size;
 885     strm.next_out = out_buf;
 886
 887     ret = deflate(&strm, Z_FINISH);
 888     if (ret != Z_STREAM_END && ret != Z_OK) {
 889         deflateEnd(&strm);
 890         ret = -EINVAL;
 891         goto fail;
 892     }
 893     out_len = strm.next_out - out_buf;
 894
 895     deflateEnd(&strm);
 896
 897     if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
 898         /* could not compress: write normal cluster */
 899         ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
 900         if (ret < 0) {
 901             goto fail;
 902         }
 903     } else {
 904         cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
 905                                             out_len, 0, 0);
 906         if (cluster_offset == 0) {
 907             ret = -EIO;
 908             goto fail;
 909         }
 910
 911         cluster_offset &= s->cluster_offset_mask;
 912         ret = bdrv_pwrite(bs->file, cluster_offset, out_buf, out_len);
 913         if (ret < 0) {
 914             goto fail;
 915         }
 916     }
 917
 918     ret = 0;
 919 fail:
 920     g_free(out_buf);
 921     return ret;
 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 static QemuOptsList qcow_create_opts = {
 932     .name = "qcow-create-opts",
 933     .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
 934     .desc = {
 935         {
 936             .name = BLOCK_OPT_SIZE,
 937             .type = QEMU_OPT_SIZE,
 938             .help = "Virtual disk size"
 939         },
 940         {
 941             .name = BLOCK_OPT_BACKING_FILE,
 942             .type = QEMU_OPT_STRING,
 943             .help = "File name of a base image"
 944         },
 945         {
 946             .name = BLOCK_OPT_ENCRYPT,
 947             .type = QEMU_OPT_BOOL,
 948             .help = "Encrypt the image",
 949             .def_value_str = "off"
 950         },
 951         { /* end of list */ }
 952     }
 953 };
 954
 955 static BlockDriver bdrv_qcow = {
 956     .format_name        = "qcow",
 957     .instance_size      = sizeof(BDRVQcowState),
 958     .bdrv_probe         = qcow_probe,
 959     .bdrv_open          = qcow_open,
 960     .bdrv_close         = qcow_close,
 961     .bdrv_reopen_prepare    = qcow_reopen_prepare,
 962     .bdrv_create            = qcow_create,
 963     .bdrv_has_zero_init     = bdrv_has_zero_init_1,
 964     .supports_backing       = true,
 965
 966     .bdrv_co_readv          = qcow_co_readv,
 967     .bdrv_co_writev         = qcow_co_writev,
 968     .bdrv_co_get_block_status   = qcow_co_get_block_status,
 969
 970     .bdrv_set_key           = qcow_set_key,
 971     .bdrv_make_empty        = qcow_make_empty,
 972     .bdrv_write_compressed  = qcow_write_compressed,
 973     .bdrv_get_info          = qcow_get_info,
 974
 975     .create_opts            = &qcow_create_opts,
 976 };
 977
 978 static void bdrv_qcow_init(void)
 979 {
 980     bdrv_register(&bdrv_qcow);
 981 }
 982
 983 block_init(bdrv_qcow_init);