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 "qapi/qmp/qerror.h"
  29 #include "crypto/cipher.h"
  30 #include "migration/migration.h"
  31
  32 /**************************************************************/
  33 /* QEMU COW block driver with compression and encryption support */
  34
  35 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  36 #define QCOW_VERSION 1
  37
  38 #define QCOW_CRYPT_NONE 0
  39 #define QCOW_CRYPT_AES  1
  40
  41 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
  42
  43 typedef struct QCowHeader {
  44     uint32_t magic;
  45     uint32_t version;
  46     uint64_t backing_file_offset;
  47     uint32_t backing_file_size;
  48     uint32_t mtime;
  49     uint64_t size; /* in bytes */
  50     uint8_t cluster_bits;
  51     uint8_t l2_bits;
  52     uint16_t padding;
  53     uint32_t crypt_method;
  54     uint64_t l1_table_offset;
  55 } QEMU_PACKED QCowHeader;
  56
  57 #define L2_CACHE_SIZE 16
  58
  59 typedef struct BDRVQcowState {
  60     int cluster_bits;
  61     int cluster_size;
  62     int cluster_sectors;
  63     int l2_bits;
  64     int l2_size;
  65     unsigned int l1_size;
  66     uint64_t cluster_offset_mask;
  67     uint64_t l1_table_offset;
  68     uint64_t *l1_table;
  69     uint64_t *l2_cache;
  70     uint64_t l2_cache_offsets[L2_CACHE_SIZE];
  71     uint32_t l2_cache_counts[L2_CACHE_SIZE];
  72     uint8_t *cluster_cache;
  73     uint8_t *cluster_data;
  74     uint64_t cluster_cache_offset;
  75     QCryptoCipher *cipher; /* NULL if no key yet */
  76     uint32_t crypt_method_header;
  77     CoMutex lock;
  78     Error *migration_blocker;
  79 } BDRVQcowState;
  80
  81 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
  82
  83 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
  84 {
  85     const QCowHeader *cow_header = (const void *)buf;
  86
  87     if (buf_size >= sizeof(QCowHeader) &&
  88         be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
  89         be32_to_cpu(cow_header->version) == QCOW_VERSION)
  90         return 100;
  91     else
  92         return 0;
  93 }
  94
  95 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
  96                      Error **errp)
  97 {
  98     BDRVQcowState *s = bs->opaque;
  99     unsigned int len, i, shift;
 100     int ret;
 101     QCowHeader header;
 102
 103     ret = bdrv_pread(bs->file->bs, 0, &header, sizeof(header));
 104     if (ret < 0) {
 105         goto fail;
 106     }
 107     be32_to_cpus(&header.magic);
 108     be32_to_cpus(&header.version);
 109     be64_to_cpus(&header.backing_file_offset);
 110     be32_to_cpus(&header.backing_file_size);
 111     be32_to_cpus(&header.mtime);
 112     be64_to_cpus(&header.size);
 113     be32_to_cpus(&header.crypt_method);
 114     be64_to_cpus(&header.l1_table_offset);
 115
 116     if (header.magic != QCOW_MAGIC) {
 117         error_setg(errp, "Image not in qcow format");
 118         ret = -EINVAL;
 119         goto fail;
 120     }
 121     if (header.version != QCOW_VERSION) {
 122         char version[64];
 123         snprintf(version, sizeof(version), "QCOW version %" PRIu32,
 124                  header.version);
 125         error_setg(errp, QERR_UNKNOWN_BLOCK_FORMAT_FEATURE,
 126                    bdrv_get_device_or_node_name(bs), "qcow", version);
 127         ret = -ENOTSUP;
 128         goto fail;
 129     }
 130
 131     if (header.size <= 1) {
 132         error_setg(errp, "Image size is too small (must be at least 2 bytes)");
 133         ret = -EINVAL;
 134         goto fail;
 135     }
 136     if (header.cluster_bits < 9 || header.cluster_bits > 16) {
 137         error_setg(errp, "Cluster size must be between 512 and 64k");
 138         ret = -EINVAL;
 139         goto fail;
 140     }
 141
 142     /* l2_bits specifies number of entries; storing a uint64_t in each entry,
 143      * so bytes = num_entries << 3. */
 144     if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
 145         error_setg(errp, "L2 table size must be between 512 and 64k");
 146         ret = -EINVAL;
 147         goto fail;
 148     }
 149
 150     if (header.crypt_method > QCOW_CRYPT_AES) {
 151         error_setg(errp, "invalid encryption method in qcow header");
 152         ret = -EINVAL;
 153         goto fail;
 154     }
 155     if (!qcrypto_cipher_supports(QCRYPTO_CIPHER_ALG_AES_128)) {
 156         error_setg(errp, "AES cipher not available");
 157         ret = -EINVAL;
 158         goto fail;
 159     }
 160     s->crypt_method_header = header.crypt_method;
 161     if (s->crypt_method_header) {
 162         bs->encrypted = 1;
 163     }
 164     s->cluster_bits = header.cluster_bits;
 165     s->cluster_size = 1 << s->cluster_bits;
 166     s->cluster_sectors = 1 << (s->cluster_bits - 9);
 167     s->l2_bits = header.l2_bits;
 168     s->l2_size = 1 << s->l2_bits;
 169     bs->total_sectors = header.size / 512;
 170     s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
 171
 172     /* read the level 1 table */
 173     shift = s->cluster_bits + s->l2_bits;
 174     if (header.size > UINT64_MAX - (1LL << shift)) {
 175         error_setg(errp, "Image too large");
 176         ret = -EINVAL;
 177         goto fail;
 178     } else {
 179         uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
 180         if (l1_size > INT_MAX / sizeof(uint64_t)) {
 181             error_setg(errp, "Image too large");
 182             ret = -EINVAL;
 183             goto fail;
 184         }
 185         s->l1_size = l1_size;
 186     }
 187
 188     s->l1_table_offset = header.l1_table_offset;
 189     s->l1_table = g_try_new(uint64_t, s->l1_size);
 190     if (s->l1_table == NULL) {
 191         error_setg(errp, "Could not allocate memory for L1 table");
 192         ret = -ENOMEM;
 193         goto fail;
 194     }
 195
 196     ret = bdrv_pread(bs->file->bs, s->l1_table_offset, s->l1_table,
 197                s->l1_size * sizeof(uint64_t));
 198     if (ret < 0) {
 199         goto fail;
 200     }
 201
 202     for(i = 0;i < s->l1_size; i++) {
 203         be64_to_cpus(&s->l1_table[i]);
 204     }
 205
 206     /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
 207     s->l2_cache =
 208         qemu_try_blockalign(bs->file->bs,
 209                             s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 210     if (s->l2_cache == NULL) {
 211         error_setg(errp, "Could not allocate L2 table cache");
 212         ret = -ENOMEM;
 213         goto fail;
 214     }
 215     s->cluster_cache = g_malloc(s->cluster_size);
 216     s->cluster_data = g_malloc(s->cluster_size);
 217     s->cluster_cache_offset = -1;
 218
 219     /* read the backing file name */
 220     if (header.backing_file_offset != 0) {
 221         len = header.backing_file_size;
 222         if (len > 1023 || len >= sizeof(bs->backing_file)) {
 223             error_setg(errp, "Backing file name too long");
 224             ret = -EINVAL;
 225             goto fail;
 226         }
 227         ret = bdrv_pread(bs->file->bs, header.backing_file_offset,
 228                    bs->backing_file, len);
 229         if (ret < 0) {
 230             goto fail;
 231         }
 232         bs->backing_file[len] = '\0';
 233     }
 234
 235     /* Disable migration when qcow images are used */
 236     error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
 237                "does not support live migration",
 238                bdrv_get_device_or_node_name(bs));
 239     migrate_add_blocker(s->migration_blocker);
 240
 241     qemu_co_mutex_init(&s->lock);
 242     return 0;
 243
 244  fail:
 245     g_free(s->l1_table);
 246     qemu_vfree(s->l2_cache);
 247     g_free(s->cluster_cache);
 248     g_free(s->cluster_data);
 249     return ret;
 250 }
 251
 252
 253 /* We have nothing to do for QCOW reopen, stubs just return
 254  * success */
 255 static int qcow_reopen_prepare(BDRVReopenState *state,
 256                                BlockReopenQueue *queue, Error **errp)
 257 {
 258     return 0;
 259 }
 260
 261 static int qcow_set_key(BlockDriverState *bs, const char *key)
 262 {
 263     BDRVQcowState *s = bs->opaque;
 264     uint8_t keybuf[16];
 265     int len, i;
 266     Error *err;
 267
 268     memset(keybuf, 0, 16);
 269     len = strlen(key);
 270     if (len > 16)
 271         len = 16;
 272     /* XXX: we could compress the chars to 7 bits to increase
 273        entropy */
 274     for(i = 0;i < len;i++) {
 275         keybuf[i] = key[i];
 276     }
 277     assert(bs->encrypted);
 278
 279     qcrypto_cipher_free(s->cipher);
 280     s->cipher = qcrypto_cipher_new(
 281         QCRYPTO_CIPHER_ALG_AES_128,
 282         QCRYPTO_CIPHER_MODE_CBC,
 283         keybuf, G_N_ELEMENTS(keybuf),
 284         &err);
 285
 286     if (!s->cipher) {
 287         /* XXX would be nice if errors in this method could
 288          * be properly propagate to the caller. Would need
 289          * the bdrv_set_key() API signature to be fixed. */
 290         error_free(err);
 291         return -1;
 292     }
 293     return 0;
 294 }
 295
 296 /* The crypt function is compatible with the linux cryptoloop
 297    algorithm for < 4 GB images. NOTE: out_buf == in_buf is
 298    supported */
 299 static int encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 300                            uint8_t *out_buf, const uint8_t *in_buf,
 301                            int nb_sectors, bool enc, Error **errp)
 302 {
 303     union {
 304         uint64_t ll[2];
 305         uint8_t b[16];
 306     } ivec;
 307     int i;
 308     int ret;
 309
 310     for(i = 0; i < nb_sectors; i++) {
 311         ivec.ll[0] = cpu_to_le64(sector_num);
 312         ivec.ll[1] = 0;
 313         if (qcrypto_cipher_setiv(s->cipher,
 314                                  ivec.b, G_N_ELEMENTS(ivec.b),
 315                                  errp) < 0) {
 316             return -1;
 317         }
 318         if (enc) {
 319             ret = qcrypto_cipher_encrypt(s->cipher,
 320                                          in_buf,
 321                                          out_buf,
 322                                          512,
 323                                          errp);
 324         } else {
 325             ret = qcrypto_cipher_decrypt(s->cipher,
 326                                          in_buf,
 327                                          out_buf,
 328                                          512,
 329                                          errp);
 330         }
 331         if (ret < 0) {
 332             return -1;
 333         }
 334         sector_num++;
 335         in_buf += 512;
 336         out_buf += 512;
 337     }
 338     return 0;
 339 }
 340
 341 /* 'allocate' is:
 342  *
 343  * 0 to not allocate.
 344  *
 345  * 1 to allocate a normal cluster (for sector indexes 'n_start' to
 346  * 'n_end')
 347  *
 348  * 2 to allocate a compressed cluster of size
 349  * 'compressed_size'. 'compressed_size' must be > 0 and <
 350  * cluster_size
 351  *
 352  * return 0 if not allocated.
 353  */
 354 static uint64_t get_cluster_offset(BlockDriverState *bs,
 355                                    uint64_t offset, int allocate,
 356                                    int compressed_size,
 357                                    int n_start, int n_end)
 358 {
 359     BDRVQcowState *s = bs->opaque;
 360     int min_index, i, j, l1_index, l2_index;
 361     uint64_t l2_offset, *l2_table, cluster_offset, tmp;
 362     uint32_t min_count;
 363     int new_l2_table;
 364
 365     l1_index = offset >> (s->l2_bits + s->cluster_bits);
 366     l2_offset = s->l1_table[l1_index];
 367     new_l2_table = 0;
 368     if (!l2_offset) {
 369         if (!allocate)
 370             return 0;
 371         /* allocate a new l2 entry */
 372         l2_offset = bdrv_getlength(bs->file->bs);
 373         /* round to cluster size */
 374         l2_offset = (l2_offset + s->cluster_size - 1) & ~(s->cluster_size - 1);
 375         /* update the L1 entry */
 376         s->l1_table[l1_index] = l2_offset;
 377         tmp = cpu_to_be64(l2_offset);
 378         if (bdrv_pwrite_sync(bs->file->bs,
 379                 s->l1_table_offset + l1_index * sizeof(tmp),
 380                 &tmp, sizeof(tmp)) < 0)
 381             return 0;
 382         new_l2_table = 1;
 383     }
 384     for(i = 0; i < L2_CACHE_SIZE; i++) {
 385         if (l2_offset == s->l2_cache_offsets[i]) {
 386             /* increment the hit count */
 387             if (++s->l2_cache_counts[i] == 0xffffffff) {
 388                 for(j = 0; j < L2_CACHE_SIZE; j++) {
 389                     s->l2_cache_counts[j] >>= 1;
 390                 }
 391             }
 392             l2_table = s->l2_cache + (i << s->l2_bits);
 393             goto found;
 394         }
 395     }
 396     /* not found: load a new entry in the least used one */
 397     min_index = 0;
 398     min_count = 0xffffffff;
 399     for(i = 0; i < L2_CACHE_SIZE; i++) {
 400         if (s->l2_cache_counts[i] < min_count) {
 401             min_count = s->l2_cache_counts[i];
 402             min_index = i;
 403         }
 404     }
 405     l2_table = s->l2_cache + (min_index << s->l2_bits);
 406     if (new_l2_table) {
 407         memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
 408         if (bdrv_pwrite_sync(bs->file->bs, l2_offset, l2_table,
 409                 s->l2_size * sizeof(uint64_t)) < 0)
 410             return 0;
 411     } else {
 412         if (bdrv_pread(bs->file->bs, l2_offset, l2_table,
 413                        s->l2_size * sizeof(uint64_t)) !=
 414             s->l2_size * sizeof(uint64_t))
 415             return 0;
 416     }
 417     s->l2_cache_offsets[min_index] = l2_offset;
 418     s->l2_cache_counts[min_index] = 1;
 419  found:
 420     l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
 421     cluster_offset = be64_to_cpu(l2_table[l2_index]);
 422     if (!cluster_offset ||
 423         ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
 424         if (!allocate)
 425             return 0;
 426         /* allocate a new cluster */
 427         if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
 428             (n_end - n_start) < s->cluster_sectors) {
 429             /* if the cluster is already compressed, we must
 430                decompress it in the case it is not completely
 431                overwritten */
 432             if (decompress_cluster(bs, cluster_offset) < 0)
 433                 return 0;
 434             cluster_offset = bdrv_getlength(bs->file->bs);
 435             cluster_offset = (cluster_offset + s->cluster_size - 1) &
 436                 ~(s->cluster_size - 1);
 437             /* write the cluster content */
 438             if (bdrv_pwrite(bs->file->bs, cluster_offset, s->cluster_cache,
 439                             s->cluster_size) !=
 440                 s->cluster_size)
 441                 return -1;
 442         } else {
 443             cluster_offset = bdrv_getlength(bs->file->bs);
 444             if (allocate == 1) {
 445                 /* round to cluster size */
 446                 cluster_offset = (cluster_offset + s->cluster_size - 1) &
 447                     ~(s->cluster_size - 1);
 448                 bdrv_truncate(bs->file->bs, cluster_offset + s->cluster_size);
 449                 /* if encrypted, we must initialize the cluster
 450                    content which won't be written */
 451                 if (bs->encrypted &&
 452                     (n_end - n_start) < s->cluster_sectors) {
 453                     uint64_t start_sect;
 454                     assert(s->cipher);
 455                     start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
 456                     memset(s->cluster_data + 512, 0x00, 512);
 457                     for(i = 0; i < s->cluster_sectors; i++) {
 458                         if (i < n_start || i >= n_end) {
 459                             Error *err = NULL;
 460                             if (encrypt_sectors(s, start_sect + i,
 461                                                 s->cluster_data,
 462                                                 s->cluster_data + 512, 1,
 463                                                 true, &err) < 0) {
 464                                 error_free(err);
 465                                 errno = EIO;
 466                                 return -1;
 467                             }
 468                             if (bdrv_pwrite(bs->file->bs,
 469                                             cluster_offset + i * 512,
 470                                             s->cluster_data, 512) != 512)
 471                                 return -1;
 472                         }
 473                     }
 474                 }
 475             } else if (allocate == 2) {
 476                 cluster_offset |= QCOW_OFLAG_COMPRESSED |
 477                     (uint64_t)compressed_size << (63 - s->cluster_bits);
 478             }
 479         }
 480         /* update L2 table */
 481         tmp = cpu_to_be64(cluster_offset);
 482         l2_table[l2_index] = tmp;
 483         if (bdrv_pwrite_sync(bs->file->bs, l2_offset + l2_index * sizeof(tmp),
 484                 &tmp, sizeof(tmp)) < 0)
 485             return 0;
 486     }
 487     return cluster_offset;
 488 }
 489
 490 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs,
 491         int64_t sector_num, int nb_sectors, int *pnum)
 492 {
 493     BDRVQcowState *s = bs->opaque;
 494     int index_in_cluster, n;
 495     uint64_t cluster_offset;
 496
 497     qemu_co_mutex_lock(&s->lock);
 498     cluster_offset = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0);
 499     qemu_co_mutex_unlock(&s->lock);
 500     index_in_cluster = sector_num & (s->cluster_sectors - 1);
 501     n = s->cluster_sectors - index_in_cluster;
 502     if (n > nb_sectors)
 503         n = nb_sectors;
 504     *pnum = n;
 505     if (!cluster_offset) {
 506         return 0;
 507     }
 508     if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->cipher) {
 509         return BDRV_BLOCK_DATA;
 510     }
 511     cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
 512     return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset;
 513 }
 514
 515 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
 516                              const uint8_t *buf, int buf_size)
 517 {
 518     z_stream strm1, *strm = &strm1;
 519     int ret, out_len;
 520
 521     memset(strm, 0, sizeof(*strm));
 522
 523     strm->next_in = (uint8_t *)buf;
 524     strm->avail_in = buf_size;
 525     strm->next_out = out_buf;
 526     strm->avail_out = out_buf_size;
 527
 528     ret = inflateInit2(strm, -12);
 529     if (ret != Z_OK)
 530         return -1;
 531     ret = inflate(strm, Z_FINISH);
 532     out_len = strm->next_out - out_buf;
 533     if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
 534         out_len != out_buf_size) {
 535         inflateEnd(strm);
 536         return -1;
 537     }
 538     inflateEnd(strm);
 539     return 0;
 540 }
 541
 542 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 543 {
 544     BDRVQcowState *s = bs->opaque;
 545     int ret, csize;
 546     uint64_t coffset;
 547
 548     coffset = cluster_offset & s->cluster_offset_mask;
 549     if (s->cluster_cache_offset != coffset) {
 550         csize = cluster_offset >> (63 - s->cluster_bits);
 551         csize &= (s->cluster_size - 1);
 552         ret = bdrv_pread(bs->file->bs, coffset, s->cluster_data, csize);
 553         if (ret != csize)
 554             return -1;
 555         if (decompress_buffer(s->cluster_cache, s->cluster_size,
 556                               s->cluster_data, csize) < 0) {
 557             return -1;
 558         }
 559         s->cluster_cache_offset = coffset;
 560     }
 561     return 0;
 562 }
 563
 564 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
 565                          int nb_sectors, QEMUIOVector *qiov)
 566 {
 567     BDRVQcowState *s = bs->opaque;
 568     int index_in_cluster;
 569     int ret = 0, n;
 570     uint64_t cluster_offset;
 571     struct iovec hd_iov;
 572     QEMUIOVector hd_qiov;
 573     uint8_t *buf;
 574     void *orig_buf;
 575     Error *err = NULL;
 576
 577     if (qiov->niov > 1) {
 578         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 579         if (buf == NULL) {
 580             return -ENOMEM;
 581         }
 582     } else {
 583         orig_buf = NULL;
 584         buf = (uint8_t *)qiov->iov->iov_base;
 585     }
 586
 587     qemu_co_mutex_lock(&s->lock);
 588
 589     while (nb_sectors != 0) {
 590         /* prepare next request */
 591         cluster_offset = get_cluster_offset(bs, sector_num << 9,
 592                                                  0, 0, 0, 0);
 593         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 594         n = s->cluster_sectors - index_in_cluster;
 595         if (n > nb_sectors) {
 596             n = nb_sectors;
 597         }
 598
 599         if (!cluster_offset) {
 600             if (bs->backing) {
 601                 /* read from the base image */
 602                 hd_iov.iov_base = (void *)buf;
 603                 hd_iov.iov_len = n * 512;
 604                 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 605                 qemu_co_mutex_unlock(&s->lock);
 606                 ret = bdrv_co_readv(bs->backing->bs, sector_num,
 607                                     n, &hd_qiov);
 608                 qemu_co_mutex_lock(&s->lock);
 609                 if (ret < 0) {
 610                     goto fail;
 611                 }
 612             } else {
 613                 /* Note: in this case, no need to wait */
 614                 memset(buf, 0, 512 * n);
 615             }
 616         } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
 617             /* add AIO support for compressed blocks ? */
 618             if (decompress_cluster(bs, cluster_offset) < 0) {
 619                 goto fail;
 620             }
 621             memcpy(buf,
 622                    s->cluster_cache + index_in_cluster * 512, 512 * n);
 623         } else {
 624             if ((cluster_offset & 511) != 0) {
 625                 goto fail;
 626             }
 627             hd_iov.iov_base = (void *)buf;
 628             hd_iov.iov_len = n * 512;
 629             qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 630             qemu_co_mutex_unlock(&s->lock);
 631             ret = bdrv_co_readv(bs->file->bs,
 632                                 (cluster_offset >> 9) + index_in_cluster,
 633                                 n, &hd_qiov);
 634             qemu_co_mutex_lock(&s->lock);
 635             if (ret < 0) {
 636                 break;
 637             }
 638             if (bs->encrypted) {
 639                 assert(s->cipher);
 640                 if (encrypt_sectors(s, sector_num, buf, buf,
 641                                     n, false, &err) < 0) {
 642                     goto fail;
 643                 }
 644             }
 645         }
 646         ret = 0;
 647
 648         nb_sectors -= n;
 649         sector_num += n;
 650         buf += n * 512;
 651     }
 652
 653 done:
 654     qemu_co_mutex_unlock(&s->lock);
 655
 656     if (qiov->niov > 1) {
 657         qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
 658         qemu_vfree(orig_buf);
 659     }
 660
 661     return ret;
 662
 663 fail:
 664     error_free(err);
 665     ret = -EIO;
 666     goto done;
 667 }
 668
 669 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
 670                           int nb_sectors, QEMUIOVector *qiov)
 671 {
 672     BDRVQcowState *s = bs->opaque;
 673     int index_in_cluster;
 674     uint64_t cluster_offset;
 675     const uint8_t *src_buf;
 676     int ret = 0, n;
 677     uint8_t *cluster_data = NULL;
 678     struct iovec hd_iov;
 679     QEMUIOVector hd_qiov;
 680     uint8_t *buf;
 681     void *orig_buf;
 682
 683     s->cluster_cache_offset = -1; /* disable compressed cache */
 684
 685     if (qiov->niov > 1) {
 686         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 687         if (buf == NULL) {
 688             return -ENOMEM;
 689         }
 690         qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
 691     } else {
 692         orig_buf = NULL;
 693         buf = (uint8_t *)qiov->iov->iov_base;
 694     }
 695
 696     qemu_co_mutex_lock(&s->lock);
 697
 698     while (nb_sectors != 0) {
 699
 700         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 701         n = s->cluster_sectors - index_in_cluster;
 702         if (n > nb_sectors) {
 703             n = nb_sectors;
 704         }
 705         cluster_offset = get_cluster_offset(bs, sector_num << 9, 1, 0,
 706                                             index_in_cluster,
 707                                             index_in_cluster + n);
 708         if (!cluster_offset || (cluster_offset & 511) != 0) {
 709             ret = -EIO;
 710             break;
 711         }
 712         if (bs->encrypted) {
 713             Error *err = NULL;
 714             assert(s->cipher);
 715             if (!cluster_data) {
 716                 cluster_data = g_malloc0(s->cluster_size);
 717             }
 718             if (encrypt_sectors(s, sector_num, cluster_data, buf,
 719                                 n, true, &err) < 0) {
 720                 error_free(err);
 721                 ret = -EIO;
 722                 break;
 723             }
 724             src_buf = cluster_data;
 725         } else {
 726             src_buf = buf;
 727         }
 728
 729         hd_iov.iov_base = (void *)src_buf;
 730         hd_iov.iov_len = n * 512;
 731         qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 732         qemu_co_mutex_unlock(&s->lock);
 733         ret = bdrv_co_writev(bs->file->bs,
 734                              (cluster_offset >> 9) + index_in_cluster,
 735                              n, &hd_qiov);
 736         qemu_co_mutex_lock(&s->lock);
 737         if (ret < 0) {
 738             break;
 739         }
 740         ret = 0;
 741
 742         nb_sectors -= n;
 743         sector_num += n;
 744         buf += n * 512;
 745     }
 746     qemu_co_mutex_unlock(&s->lock);
 747
 748     if (qiov->niov > 1) {
 749         qemu_vfree(orig_buf);
 750     }
 751     g_free(cluster_data);
 752
 753     return ret;
 754 }
 755
 756 static void qcow_close(BlockDriverState *bs)
 757 {
 758     BDRVQcowState *s = bs->opaque;
 759
 760     qcrypto_cipher_free(s->cipher);
 761     s->cipher = NULL;
 762     g_free(s->l1_table);
 763     qemu_vfree(s->l2_cache);
 764     g_free(s->cluster_cache);
 765     g_free(s->cluster_data);
 766
 767     migrate_del_blocker(s->migration_blocker);
 768     error_free(s->migration_blocker);
 769 }
 770
 771 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
 772 {
 773     int header_size, backing_filename_len, l1_size, shift, i;
 774     QCowHeader header;
 775     uint8_t *tmp;
 776     int64_t total_size = 0;
 777     char *backing_file = NULL;
 778     int flags = 0;
 779     Error *local_err = NULL;
 780     int ret;
 781     BlockDriverState *qcow_bs;
 782
 783     /* Read out options */
 784     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 785                           BDRV_SECTOR_SIZE);
 786     backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
 787     if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
 788         flags |= BLOCK_FLAG_ENCRYPT;
 789     }
 790
 791     ret = bdrv_create_file(filename, opts, &local_err);
 792     if (ret < 0) {
 793         error_propagate(errp, local_err);
 794         goto cleanup;
 795     }
 796
 797     qcow_bs = NULL;
 798     ret = bdrv_open(&qcow_bs, filename, NULL, NULL,
 799                     BDRV_O_RDWR | BDRV_O_PROTOCOL, &local_err);
 800     if (ret < 0) {
 801         error_propagate(errp, local_err);
 802         goto cleanup;
 803     }
 804
 805     ret = bdrv_truncate(qcow_bs, 0);
 806     if (ret < 0) {
 807         goto exit;
 808     }
 809
 810     memset(&header, 0, sizeof(header));
 811     header.magic = cpu_to_be32(QCOW_MAGIC);
 812     header.version = cpu_to_be32(QCOW_VERSION);
 813     header.size = cpu_to_be64(total_size);
 814     header_size = sizeof(header);
 815     backing_filename_len = 0;
 816     if (backing_file) {
 817         if (strcmp(backing_file, "fat:")) {
 818             header.backing_file_offset = cpu_to_be64(header_size);
 819             backing_filename_len = strlen(backing_file);
 820             header.backing_file_size = cpu_to_be32(backing_filename_len);
 821             header_size += backing_filename_len;
 822         } else {
 823             /* special backing file for vvfat */
 824             backing_file = NULL;
 825         }
 826         header.cluster_bits = 9; /* 512 byte cluster to avoid copying
 827                                     unmodified sectors */
 828         header.l2_bits = 12; /* 32 KB L2 tables */
 829     } else {
 830         header.cluster_bits = 12; /* 4 KB clusters */
 831         header.l2_bits = 9; /* 4 KB L2 tables */
 832     }
 833     header_size = (header_size + 7) & ~7;
 834     shift = header.cluster_bits + header.l2_bits;
 835     l1_size = (total_size + (1LL << shift) - 1) >> shift;
 836
 837     header.l1_table_offset = cpu_to_be64(header_size);
 838     if (flags & BLOCK_FLAG_ENCRYPT) {
 839         header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
 840     } else {
 841         header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
 842     }
 843
 844     /* write all the data */
 845     ret = bdrv_pwrite(qcow_bs, 0, &header, sizeof(header));
 846     if (ret != sizeof(header)) {
 847         goto exit;
 848     }
 849
 850     if (backing_file) {
 851         ret = bdrv_pwrite(qcow_bs, sizeof(header),
 852             backing_file, backing_filename_len);
 853         if (ret != backing_filename_len) {
 854             goto exit;
 855         }
 856     }
 857
 858     tmp = g_malloc0(BDRV_SECTOR_SIZE);
 859     for (i = 0; i < ((sizeof(uint64_t)*l1_size + BDRV_SECTOR_SIZE - 1)/
 860         BDRV_SECTOR_SIZE); i++) {
 861         ret = bdrv_pwrite(qcow_bs, header_size +
 862             BDRV_SECTOR_SIZE*i, tmp, BDRV_SECTOR_SIZE);
 863         if (ret != BDRV_SECTOR_SIZE) {
 864             g_free(tmp);
 865             goto exit;
 866         }
 867     }
 868
 869     g_free(tmp);
 870     ret = 0;
 871 exit:
 872     bdrv_unref(qcow_bs);
 873 cleanup:
 874     g_free(backing_file);
 875     return ret;
 876 }
 877
 878 static int qcow_make_empty(BlockDriverState *bs)
 879 {
 880     BDRVQcowState *s = bs->opaque;
 881     uint32_t l1_length = s->l1_size * sizeof(uint64_t);
 882     int ret;
 883
 884     memset(s->l1_table, 0, l1_length);
 885     if (bdrv_pwrite_sync(bs->file->bs, s->l1_table_offset, s->l1_table,
 886             l1_length) < 0)
 887         return -1;
 888     ret = bdrv_truncate(bs->file->bs, s->l1_table_offset + l1_length);
 889     if (ret < 0)
 890         return ret;
 891
 892     memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 893     memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
 894     memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
 895
 896     return 0;
 897 }
 898
 899 /* XXX: put compressed sectors first, then all the cluster aligned
 900    tables to avoid losing bytes in alignment */
 901 static int qcow_write_compressed(BlockDriverState *bs, int64_t sector_num,
 902                                  const uint8_t *buf, int nb_sectors)
 903 {
 904     BDRVQcowState *s = bs->opaque;
 905     z_stream strm;
 906     int ret, out_len;
 907     uint8_t *out_buf;
 908     uint64_t cluster_offset;
 909
 910     if (nb_sectors != s->cluster_sectors) {
 911         ret = -EINVAL;
 912
 913         /* Zero-pad last write if image size is not cluster aligned */
 914         if (sector_num + nb_sectors == bs->total_sectors &&
 915             nb_sectors < s->cluster_sectors) {
 916             uint8_t *pad_buf = qemu_blockalign(bs, s->cluster_size);
 917             memset(pad_buf, 0, s->cluster_size);
 918             memcpy(pad_buf, buf, nb_sectors * BDRV_SECTOR_SIZE);
 919             ret = qcow_write_compressed(bs, sector_num,
 920                                         pad_buf, s->cluster_sectors);
 921             qemu_vfree(pad_buf);
 922         }
 923         return ret;
 924     }
 925
 926     out_buf = g_malloc(s->cluster_size + (s->cluster_size / 1000) + 128);
 927
 928     /* best compression, small window, no zlib header */
 929     memset(&strm, 0, sizeof(strm));
 930     ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
 931                        Z_DEFLATED, -12,
 932                        9, Z_DEFAULT_STRATEGY);
 933     if (ret != 0) {
 934         ret = -EINVAL;
 935         goto fail;
 936     }
 937
 938     strm.avail_in = s->cluster_size;
 939     strm.next_in = (uint8_t *)buf;
 940     strm.avail_out = s->cluster_size;
 941     strm.next_out = out_buf;
 942
 943     ret = deflate(&strm, Z_FINISH);
 944     if (ret != Z_STREAM_END && ret != Z_OK) {
 945         deflateEnd(&strm);
 946         ret = -EINVAL;
 947         goto fail;
 948     }
 949     out_len = strm.next_out - out_buf;
 950
 951     deflateEnd(&strm);
 952
 953     if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
 954         /* could not compress: write normal cluster */
 955         ret = bdrv_write(bs, sector_num, buf, s->cluster_sectors);
 956         if (ret < 0) {
 957             goto fail;
 958         }
 959     } else {
 960         cluster_offset = get_cluster_offset(bs, sector_num << 9, 2,
 961                                             out_len, 0, 0);
 962         if (cluster_offset == 0) {
 963             ret = -EIO;
 964             goto fail;
 965         }
 966
 967         cluster_offset &= s->cluster_offset_mask;
 968         ret = bdrv_pwrite(bs->file->bs, cluster_offset, out_buf, out_len);
 969         if (ret < 0) {
 970             goto fail;
 971         }
 972     }
 973
 974     ret = 0;
 975 fail:
 976     g_free(out_buf);
 977     return ret;
 978 }
 979
 980 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
 981 {
 982     BDRVQcowState *s = bs->opaque;
 983     bdi->cluster_size = s->cluster_size;
 984     return 0;
 985 }
 986
 987 static QemuOptsList qcow_create_opts = {
 988     .name = "qcow-create-opts",
 989     .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
 990     .desc = {
 991         {
 992             .name = BLOCK_OPT_SIZE,
 993             .type = QEMU_OPT_SIZE,
 994             .help = "Virtual disk size"
 995         },
 996         {
 997             .name = BLOCK_OPT_BACKING_FILE,
 998             .type = QEMU_OPT_STRING,
 999             .help = "File name of a base image"
1000         },
1001         {
1002             .name = BLOCK_OPT_ENCRYPT,
1003             .type = QEMU_OPT_BOOL,
1004             .help = "Encrypt the image",
1005             .def_value_str = "off"
1006         },
1007         { /* end of list */ }
1008     }
1009 };
1010
1011 static BlockDriver bdrv_qcow = {
1012     .format_name        = "qcow",
1013     .instance_size      = sizeof(BDRVQcowState),
1014     .bdrv_probe         = qcow_probe,
1015     .bdrv_open          = qcow_open,
1016     .bdrv_close         = qcow_close,
1017     .bdrv_reopen_prepare    = qcow_reopen_prepare,
1018     .bdrv_create            = qcow_create,
1019     .bdrv_has_zero_init     = bdrv_has_zero_init_1,
1020     .supports_backing       = true,
1021
1022     .bdrv_co_readv          = qcow_co_readv,
1023     .bdrv_co_writev         = qcow_co_writev,
1024     .bdrv_co_get_block_status   = qcow_co_get_block_status,
1025
1026     .bdrv_set_key           = qcow_set_key,
1027     .bdrv_make_empty        = qcow_make_empty,
1028     .bdrv_write_compressed  = qcow_write_compressed,
1029     .bdrv_get_info          = qcow_get_info,
1030
1031     .create_opts            = &qcow_create_opts,
1032 };
1033
1034 static void bdrv_qcow_init(void)
1035 {
1036     bdrv_register(&bdrv_qcow);
1037 }
1038
1039 block_init(bdrv_qcow_init);