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/osdep.h"
  25 #include "qapi/error.h"
  26 #include "qemu-common.h"
  27 #include "qemu/error-report.h"
  28 #include "block/block_int.h"
  29 #include "sysemu/block-backend.h"
  30 #include "qemu/module.h"
  31 #include "qemu/bswap.h"
  32 #include <zlib.h>
  33 #include "qapi/qmp/qerror.h"
  34 #include "qapi/qmp/qstring.h"
  35 #include "crypto/block.h"
  36 #include "migration/blocker.h"
  37 #include "block/crypto.h"
  38
  39 /**************************************************************/
  40 /* QEMU COW block driver with compression and encryption support */
  41
  42 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  43 #define QCOW_VERSION 1
  44
  45 #define QCOW_CRYPT_NONE 0
  46 #define QCOW_CRYPT_AES  1
  47
  48 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
  49
  50 typedef struct QCowHeader {
  51     uint32_t magic;
  52     uint32_t version;
  53     uint64_t backing_file_offset;
  54     uint32_t backing_file_size;
  55     uint32_t mtime;
  56     uint64_t size; /* in bytes */
  57     uint8_t cluster_bits;
  58     uint8_t l2_bits;
  59     uint16_t padding;
  60     uint32_t crypt_method;
  61     uint64_t l1_table_offset;
  62 } QEMU_PACKED QCowHeader;
  63
  64 #define L2_CACHE_SIZE 16
  65
  66 typedef struct BDRVQcowState {
  67     int cluster_bits;
  68     int cluster_size;
  69     int cluster_sectors;
  70     int l2_bits;
  71     int l2_size;
  72     unsigned int l1_size;
  73     uint64_t cluster_offset_mask;
  74     uint64_t l1_table_offset;
  75     uint64_t *l1_table;
  76     uint64_t *l2_cache;
  77     uint64_t l2_cache_offsets[L2_CACHE_SIZE];
  78     uint32_t l2_cache_counts[L2_CACHE_SIZE];
  79     uint8_t *cluster_cache;
  80     uint8_t *cluster_data;
  81     uint64_t cluster_cache_offset;
  82     QCryptoBlock *crypto; /* Disk encryption format driver */
  83     uint32_t crypt_method_header;
  84     CoMutex lock;
  85     Error *migration_blocker;
  86 } BDRVQcowState;
  87
  88 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
  89
  90 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
  91 {
  92     const QCowHeader *cow_header = (const void *)buf;
  93
  94     if (buf_size >= sizeof(QCowHeader) &&
  95         be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
  96         be32_to_cpu(cow_header->version) == QCOW_VERSION)
  97         return 100;
  98     else
  99         return 0;
 100 }
 101
 102 static QemuOptsList qcow_runtime_opts = {
 103     .name = "qcow",
 104     .head = QTAILQ_HEAD_INITIALIZER(qcow_runtime_opts.head),
 105     .desc = {
 106         BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
 107         { /* end of list */ }
 108     },
 109 };
 110
 111 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
 112                      Error **errp)
 113 {
 114     BDRVQcowState *s = bs->opaque;
 115     unsigned int len, i, shift;
 116     int ret;
 117     QCowHeader header;
 118     Error *local_err = NULL;
 119     QCryptoBlockOpenOptions *crypto_opts = NULL;
 120     unsigned int cflags = 0;
 121     QDict *encryptopts = NULL;
 122     const char *encryptfmt;
 123
 124     qdict_extract_subqdict(options, &encryptopts, "encrypt.");
 125     encryptfmt = qdict_get_try_str(encryptopts, "format");
 126
 127     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
 128                                false, errp);
 129     if (!bs->file) {
 130         ret = -EINVAL;
 131         goto fail;
 132     }
 133
 134     ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
 135     if (ret < 0) {
 136         goto fail;
 137     }
 138     be32_to_cpus(&header.magic);
 139     be32_to_cpus(&header.version);
 140     be64_to_cpus(&header.backing_file_offset);
 141     be32_to_cpus(&header.backing_file_size);
 142     be32_to_cpus(&header.mtime);
 143     be64_to_cpus(&header.size);
 144     be32_to_cpus(&header.crypt_method);
 145     be64_to_cpus(&header.l1_table_offset);
 146
 147     if (header.magic != QCOW_MAGIC) {
 148         error_setg(errp, "Image not in qcow format");
 149         ret = -EINVAL;
 150         goto fail;
 151     }
 152     if (header.version != QCOW_VERSION) {
 153         error_setg(errp, "Unsupported qcow version %" PRIu32, header.version);
 154         ret = -ENOTSUP;
 155         goto fail;
 156     }
 157
 158     if (header.size <= 1) {
 159         error_setg(errp, "Image size is too small (must be at least 2 bytes)");
 160         ret = -EINVAL;
 161         goto fail;
 162     }
 163     if (header.cluster_bits < 9 || header.cluster_bits > 16) {
 164         error_setg(errp, "Cluster size must be between 512 and 64k");
 165         ret = -EINVAL;
 166         goto fail;
 167     }
 168
 169     /* l2_bits specifies number of entries; storing a uint64_t in each entry,
 170      * so bytes = num_entries << 3. */
 171     if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
 172         error_setg(errp, "L2 table size must be between 512 and 64k");
 173         ret = -EINVAL;
 174         goto fail;
 175     }
 176
 177     s->crypt_method_header = header.crypt_method;
 178     if (s->crypt_method_header) {
 179         if (bdrv_uses_whitelist() &&
 180             s->crypt_method_header == QCOW_CRYPT_AES) {
 181             error_setg(errp,
 182                        "Use of AES-CBC encrypted qcow images is no longer "
 183                        "supported in system emulators");
 184             error_append_hint(errp,
 185                               "You can use 'qemu-img convert' to convert your "
 186                               "image to an alternative supported format, such "
 187                               "as unencrypted qcow, or raw with the LUKS "
 188                               "format instead.\n");
 189             ret = -ENOSYS;
 190             goto fail;
 191         }
 192         if (s->crypt_method_header == QCOW_CRYPT_AES) {
 193             if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
 194                 error_setg(errp,
 195                            "Header reported 'aes' encryption format but "
 196                            "options specify '%s'", encryptfmt);
 197                 ret = -EINVAL;
 198                 goto fail;
 199             }
 200             qdict_del(encryptopts, "format");
 201             crypto_opts = block_crypto_open_opts_init(
 202                 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp);
 203             if (!crypto_opts) {
 204                 ret = -EINVAL;
 205                 goto fail;
 206             }
 207
 208             if (flags & BDRV_O_NO_IO) {
 209                 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
 210             }
 211             s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
 212                                            NULL, NULL, cflags, errp);
 213             if (!s->crypto) {
 214                 ret = -EINVAL;
 215                 goto fail;
 216             }
 217         } else {
 218             error_setg(errp, "invalid encryption method in qcow header");
 219             ret = -EINVAL;
 220             goto fail;
 221         }
 222         bs->encrypted = true;
 223     } else {
 224         if (encryptfmt) {
 225             error_setg(errp, "No encryption in image header, but options "
 226                        "specified format '%s'", encryptfmt);
 227             ret = -EINVAL;
 228             goto fail;
 229         }
 230     }
 231     s->cluster_bits = header.cluster_bits;
 232     s->cluster_size = 1 << s->cluster_bits;
 233     s->cluster_sectors = 1 << (s->cluster_bits - 9);
 234     s->l2_bits = header.l2_bits;
 235     s->l2_size = 1 << s->l2_bits;
 236     bs->total_sectors = header.size / 512;
 237     s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
 238
 239     /* read the level 1 table */
 240     shift = s->cluster_bits + s->l2_bits;
 241     if (header.size > UINT64_MAX - (1LL << shift)) {
 242         error_setg(errp, "Image too large");
 243         ret = -EINVAL;
 244         goto fail;
 245     } else {
 246         uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
 247         if (l1_size > INT_MAX / sizeof(uint64_t)) {
 248             error_setg(errp, "Image too large");
 249             ret = -EINVAL;
 250             goto fail;
 251         }
 252         s->l1_size = l1_size;
 253     }
 254
 255     s->l1_table_offset = header.l1_table_offset;
 256     s->l1_table = g_try_new(uint64_t, s->l1_size);
 257     if (s->l1_table == NULL) {
 258         error_setg(errp, "Could not allocate memory for L1 table");
 259         ret = -ENOMEM;
 260         goto fail;
 261     }
 262
 263     ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
 264                s->l1_size * sizeof(uint64_t));
 265     if (ret < 0) {
 266         goto fail;
 267     }
 268
 269     for(i = 0;i < s->l1_size; i++) {
 270         be64_to_cpus(&s->l1_table[i]);
 271     }
 272
 273     /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
 274     s->l2_cache =
 275         qemu_try_blockalign(bs->file->bs,
 276                             s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 277     if (s->l2_cache == NULL) {
 278         error_setg(errp, "Could not allocate L2 table cache");
 279         ret = -ENOMEM;
 280         goto fail;
 281     }
 282     s->cluster_cache = g_malloc(s->cluster_size);
 283     s->cluster_data = g_malloc(s->cluster_size);
 284     s->cluster_cache_offset = -1;
 285
 286     /* read the backing file name */
 287     if (header.backing_file_offset != 0) {
 288         len = header.backing_file_size;
 289         if (len > 1023 || len >= sizeof(bs->backing_file)) {
 290             error_setg(errp, "Backing file name too long");
 291             ret = -EINVAL;
 292             goto fail;
 293         }
 294         ret = bdrv_pread(bs->file, header.backing_file_offset,
 295                    bs->backing_file, len);
 296         if (ret < 0) {
 297             goto fail;
 298         }
 299         bs->backing_file[len] = '\0';
 300     }
 301
 302     /* Disable migration when qcow images are used */
 303     error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
 304                "does not support live migration",
 305                bdrv_get_device_or_node_name(bs));
 306     ret = migrate_add_blocker(s->migration_blocker, &local_err);
 307     if (local_err) {
 308         error_propagate(errp, local_err);
 309         error_free(s->migration_blocker);
 310         goto fail;
 311     }
 312
 313     QDECREF(encryptopts);
 314     qapi_free_QCryptoBlockOpenOptions(crypto_opts);
 315     qemu_co_mutex_init(&s->lock);
 316     return 0;
 317
 318  fail:
 319     g_free(s->l1_table);
 320     qemu_vfree(s->l2_cache);
 321     g_free(s->cluster_cache);
 322     g_free(s->cluster_data);
 323     qcrypto_block_free(s->crypto);
 324     QDECREF(encryptopts);
 325     qapi_free_QCryptoBlockOpenOptions(crypto_opts);
 326     return ret;
 327 }
 328
 329
 330 /* We have nothing to do for QCOW reopen, stubs just return
 331  * success */
 332 static int qcow_reopen_prepare(BDRVReopenState *state,
 333                                BlockReopenQueue *queue, Error **errp)
 334 {
 335     return 0;
 336 }
 337
 338
 339 /* 'allocate' is:
 340  *
 341  * 0 to not allocate.
 342  *
 343  * 1 to allocate a normal cluster (for sector indexes 'n_start' to
 344  * 'n_end')
 345  *
 346  * 2 to allocate a compressed cluster of size
 347  * 'compressed_size'. 'compressed_size' must be > 0 and <
 348  * cluster_size
 349  *
 350  * return 0 if not allocated, 1 if *result is assigned, and negative
 351  * errno on failure.
 352  */
 353 static int get_cluster_offset(BlockDriverState *bs,
 354                               uint64_t offset, int allocate,
 355                               int compressed_size,
 356                               int n_start, int n_end, uint64_t *result)
 357 {
 358     BDRVQcowState *s = bs->opaque;
 359     int min_index, i, j, l1_index, l2_index, ret;
 360     int64_t l2_offset;
 361     uint64_t *l2_table, cluster_offset, tmp;
 362     uint32_t min_count;
 363     int new_l2_table;
 364
 365     *result = 0;
 366     l1_index = offset >> (s->l2_bits + s->cluster_bits);
 367     l2_offset = s->l1_table[l1_index];
 368     new_l2_table = 0;
 369     if (!l2_offset) {
 370         if (!allocate)
 371             return 0;
 372         /* allocate a new l2 entry */
 373         l2_offset = bdrv_getlength(bs->file->bs);
 374         if (l2_offset < 0) {
 375             return l2_offset;
 376         }
 377         /* round to cluster size */
 378         l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
 379         /* update the L1 entry */
 380         s->l1_table[l1_index] = l2_offset;
 381         tmp = cpu_to_be64(l2_offset);
 382         BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
 383         ret = bdrv_pwrite_sync(bs->file,
 384                                s->l1_table_offset + l1_index * sizeof(tmp),
 385                                &tmp, sizeof(tmp));
 386         if (ret < 0) {
 387             return ret;
 388         }
 389         new_l2_table = 1;
 390     }
 391     for(i = 0; i < L2_CACHE_SIZE; i++) {
 392         if (l2_offset == s->l2_cache_offsets[i]) {
 393             /* increment the hit count */
 394             if (++s->l2_cache_counts[i] == 0xffffffff) {
 395                 for(j = 0; j < L2_CACHE_SIZE; j++) {
 396                     s->l2_cache_counts[j] >>= 1;
 397                 }
 398             }
 399             l2_table = s->l2_cache + (i << s->l2_bits);
 400             goto found;
 401         }
 402     }
 403     /* not found: load a new entry in the least used one */
 404     min_index = 0;
 405     min_count = 0xffffffff;
 406     for(i = 0; i < L2_CACHE_SIZE; i++) {
 407         if (s->l2_cache_counts[i] < min_count) {
 408             min_count = s->l2_cache_counts[i];
 409             min_index = i;
 410         }
 411     }
 412     l2_table = s->l2_cache + (min_index << s->l2_bits);
 413     BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
 414     if (new_l2_table) {
 415         memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
 416         ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
 417                                s->l2_size * sizeof(uint64_t));
 418         if (ret < 0) {
 419             return ret;
 420         }
 421     } else {
 422         ret = bdrv_pread(bs->file, l2_offset, l2_table,
 423                          s->l2_size * sizeof(uint64_t));
 424         if (ret < 0) {
 425             return ret;
 426         }
 427     }
 428     s->l2_cache_offsets[min_index] = l2_offset;
 429     s->l2_cache_counts[min_index] = 1;
 430  found:
 431     l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
 432     cluster_offset = be64_to_cpu(l2_table[l2_index]);
 433     if (!cluster_offset ||
 434         ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
 435         if (!allocate)
 436             return 0;
 437         BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
 438         /* allocate a new cluster */
 439         if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
 440             (n_end - n_start) < s->cluster_sectors) {
 441             /* if the cluster is already compressed, we must
 442                decompress it in the case it is not completely
 443                overwritten */
 444             if (decompress_cluster(bs, cluster_offset) < 0) {
 445                 return -EIO;
 446             }
 447             cluster_offset = bdrv_getlength(bs->file->bs);
 448             if ((int64_t) cluster_offset < 0) {
 449                 return cluster_offset;
 450             }
 451             cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
 452             /* write the cluster content */
 453             BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 454             ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache,
 455                               s->cluster_size);
 456             if (ret < 0) {
 457                 return ret;
 458             }
 459         } else {
 460             cluster_offset = bdrv_getlength(bs->file->bs);
 461             if ((int64_t) cluster_offset < 0) {
 462                 return cluster_offset;
 463             }
 464             if (allocate == 1) {
 465                 /* round to cluster size */
 466                 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
 467                 if (cluster_offset + s->cluster_size > INT64_MAX) {
 468                     return -E2BIG;
 469                 }
 470                 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size,
 471                                     PREALLOC_MODE_OFF, NULL);
 472                 if (ret < 0) {
 473                     return ret;
 474                 }
 475                 /* if encrypted, we must initialize the cluster
 476                    content which won't be written */
 477                 if (bs->encrypted &&
 478                     (n_end - n_start) < s->cluster_sectors) {
 479                     uint64_t start_sect;
 480                     assert(s->crypto);
 481                     start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
 482                     for(i = 0; i < s->cluster_sectors; i++) {
 483                         if (i < n_start || i >= n_end) {
 484                             memset(s->cluster_data, 0x00, 512);
 485                             if (qcrypto_block_encrypt(s->crypto,
 486                                                       (start_sect + i) *
 487                                                       BDRV_SECTOR_SIZE,
 488                                                       s->cluster_data,
 489                                                       BDRV_SECTOR_SIZE,
 490                                                       NULL) < 0) {
 491                                 return -EIO;
 492                             }
 493                             BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 494                             ret = bdrv_pwrite(bs->file,
 495                                               cluster_offset + i * 512,
 496                                               s->cluster_data, 512);
 497                             if (ret < 0) {
 498                                 return ret;
 499                             }
 500                         }
 501                     }
 502                 }
 503             } else if (allocate == 2) {
 504                 cluster_offset |= QCOW_OFLAG_COMPRESSED |
 505                     (uint64_t)compressed_size << (63 - s->cluster_bits);
 506             }
 507         }
 508         /* update L2 table */
 509         tmp = cpu_to_be64(cluster_offset);
 510         l2_table[l2_index] = tmp;
 511         if (allocate == 2) {
 512             BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
 513         } else {
 514             BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
 515         }
 516         ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
 517                                &tmp, sizeof(tmp));
 518         if (ret < 0) {
 519             return ret;
 520         }
 521     }
 522     *result = cluster_offset;
 523     return 1;
 524 }
 525
 526 static int64_t coroutine_fn qcow_co_get_block_status(BlockDriverState *bs,
 527         int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState **file)
 528 {
 529     BDRVQcowState *s = bs->opaque;
 530     int index_in_cluster, n, ret;
 531     uint64_t cluster_offset;
 532
 533     qemu_co_mutex_lock(&s->lock);
 534     ret = get_cluster_offset(bs, sector_num << 9, 0, 0, 0, 0, &cluster_offset);
 535     qemu_co_mutex_unlock(&s->lock);
 536     if (ret < 0) {
 537         return ret;
 538     }
 539     index_in_cluster = sector_num & (s->cluster_sectors - 1);
 540     n = s->cluster_sectors - index_in_cluster;
 541     if (n > nb_sectors)
 542         n = nb_sectors;
 543     *pnum = n;
 544     if (!cluster_offset) {
 545         return 0;
 546     }
 547     if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) {
 548         return BDRV_BLOCK_DATA;
 549     }
 550     cluster_offset |= (index_in_cluster << BDRV_SECTOR_BITS);
 551     *file = bs->file->bs;
 552     return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | cluster_offset;
 553 }
 554
 555 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
 556                              const uint8_t *buf, int buf_size)
 557 {
 558     z_stream strm1, *strm = &strm1;
 559     int ret, out_len;
 560
 561     memset(strm, 0, sizeof(*strm));
 562
 563     strm->next_in = (uint8_t *)buf;
 564     strm->avail_in = buf_size;
 565     strm->next_out = out_buf;
 566     strm->avail_out = out_buf_size;
 567
 568     ret = inflateInit2(strm, -12);
 569     if (ret != Z_OK)
 570         return -1;
 571     ret = inflate(strm, Z_FINISH);
 572     out_len = strm->next_out - out_buf;
 573     if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
 574         out_len != out_buf_size) {
 575         inflateEnd(strm);
 576         return -1;
 577     }
 578     inflateEnd(strm);
 579     return 0;
 580 }
 581
 582 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 583 {
 584     BDRVQcowState *s = bs->opaque;
 585     int ret, csize;
 586     uint64_t coffset;
 587
 588     coffset = cluster_offset & s->cluster_offset_mask;
 589     if (s->cluster_cache_offset != coffset) {
 590         csize = cluster_offset >> (63 - s->cluster_bits);
 591         csize &= (s->cluster_size - 1);
 592         BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
 593         ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
 594         if (ret != csize)
 595             return -1;
 596         if (decompress_buffer(s->cluster_cache, s->cluster_size,
 597                               s->cluster_data, csize) < 0) {
 598             return -1;
 599         }
 600         s->cluster_cache_offset = coffset;
 601     }
 602     return 0;
 603 }
 604
 605 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
 606                          int nb_sectors, QEMUIOVector *qiov)
 607 {
 608     BDRVQcowState *s = bs->opaque;
 609     int index_in_cluster;
 610     int ret = 0, n;
 611     uint64_t cluster_offset;
 612     struct iovec hd_iov;
 613     QEMUIOVector hd_qiov;
 614     uint8_t *buf;
 615     void *orig_buf;
 616
 617     if (qiov->niov > 1) {
 618         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 619         if (buf == NULL) {
 620             return -ENOMEM;
 621         }
 622     } else {
 623         orig_buf = NULL;
 624         buf = (uint8_t *)qiov->iov->iov_base;
 625     }
 626
 627     qemu_co_mutex_lock(&s->lock);
 628
 629     while (nb_sectors != 0) {
 630         /* prepare next request */
 631         ret = get_cluster_offset(bs, sector_num << 9,
 632                                  0, 0, 0, 0, &cluster_offset);
 633         if (ret < 0) {
 634             break;
 635         }
 636         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 637         n = s->cluster_sectors - index_in_cluster;
 638         if (n > nb_sectors) {
 639             n = nb_sectors;
 640         }
 641
 642         if (!cluster_offset) {
 643             if (bs->backing) {
 644                 /* read from the base image */
 645                 hd_iov.iov_base = (void *)buf;
 646                 hd_iov.iov_len = n * 512;
 647                 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 648                 qemu_co_mutex_unlock(&s->lock);
 649                 /* qcow2 emits this on bs->file instead of bs->backing */
 650                 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
 651                 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov);
 652                 qemu_co_mutex_lock(&s->lock);
 653                 if (ret < 0) {
 654                     break;
 655                 }
 656             } else {
 657                 /* Note: in this case, no need to wait */
 658                 memset(buf, 0, 512 * n);
 659             }
 660         } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
 661             /* add AIO support for compressed blocks ? */
 662             if (decompress_cluster(bs, cluster_offset) < 0) {
 663                 ret = -EIO;
 664                 break;
 665             }
 666             memcpy(buf,
 667                    s->cluster_cache + index_in_cluster * 512, 512 * n);
 668         } else {
 669             if ((cluster_offset & 511) != 0) {
 670                 ret = -EIO;
 671                 break;
 672             }
 673             hd_iov.iov_base = (void *)buf;
 674             hd_iov.iov_len = n * 512;
 675             qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 676             qemu_co_mutex_unlock(&s->lock);
 677             BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 678             ret = bdrv_co_readv(bs->file,
 679                                 (cluster_offset >> 9) + index_in_cluster,
 680                                 n, &hd_qiov);
 681             qemu_co_mutex_lock(&s->lock);
 682             if (ret < 0) {
 683                 break;
 684             }
 685             if (bs->encrypted) {
 686                 assert(s->crypto);
 687                 if (qcrypto_block_decrypt(s->crypto,
 688                                           sector_num * BDRV_SECTOR_SIZE, buf,
 689                                           n * BDRV_SECTOR_SIZE, NULL) < 0) {
 690                     ret = -EIO;
 691                     break;
 692                 }
 693             }
 694         }
 695         ret = 0;
 696
 697         nb_sectors -= n;
 698         sector_num += n;
 699         buf += n * 512;
 700     }
 701
 702     qemu_co_mutex_unlock(&s->lock);
 703
 704     if (qiov->niov > 1) {
 705         qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
 706         qemu_vfree(orig_buf);
 707     }
 708
 709     return ret;
 710 }
 711
 712 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
 713                           int nb_sectors, QEMUIOVector *qiov)
 714 {
 715     BDRVQcowState *s = bs->opaque;
 716     int index_in_cluster;
 717     uint64_t cluster_offset;
 718     int ret = 0, n;
 719     struct iovec hd_iov;
 720     QEMUIOVector hd_qiov;
 721     uint8_t *buf;
 722     void *orig_buf;
 723
 724     s->cluster_cache_offset = -1; /* disable compressed cache */
 725
 726     /* We must always copy the iov when encrypting, so we
 727      * don't modify the original data buffer during encryption */
 728     if (bs->encrypted || qiov->niov > 1) {
 729         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 730         if (buf == NULL) {
 731             return -ENOMEM;
 732         }
 733         qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
 734     } else {
 735         orig_buf = NULL;
 736         buf = (uint8_t *)qiov->iov->iov_base;
 737     }
 738
 739     qemu_co_mutex_lock(&s->lock);
 740
 741     while (nb_sectors != 0) {
 742
 743         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 744         n = s->cluster_sectors - index_in_cluster;
 745         if (n > nb_sectors) {
 746             n = nb_sectors;
 747         }
 748         ret = get_cluster_offset(bs, sector_num << 9, 1, 0,
 749                                  index_in_cluster,
 750                                  index_in_cluster + n, &cluster_offset);
 751         if (ret < 0) {
 752             break;
 753         }
 754         if (!cluster_offset || (cluster_offset & 511) != 0) {
 755             ret = -EIO;
 756             break;
 757         }
 758         if (bs->encrypted) {
 759             assert(s->crypto);
 760             if (qcrypto_block_encrypt(s->crypto, sector_num * BDRV_SECTOR_SIZE,
 761                                       buf, n * BDRV_SECTOR_SIZE, NULL) < 0) {
 762                 ret = -EIO;
 763                 break;
 764             }
 765         }
 766
 767         hd_iov.iov_base = (void *)buf;
 768         hd_iov.iov_len = n * 512;
 769         qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 770         qemu_co_mutex_unlock(&s->lock);
 771         BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 772         ret = bdrv_co_writev(bs->file,
 773                              (cluster_offset >> 9) + index_in_cluster,
 774                              n, &hd_qiov);
 775         qemu_co_mutex_lock(&s->lock);
 776         if (ret < 0) {
 777             break;
 778         }
 779         ret = 0;
 780
 781         nb_sectors -= n;
 782         sector_num += n;
 783         buf += n * 512;
 784     }
 785     qemu_co_mutex_unlock(&s->lock);
 786
 787     qemu_vfree(orig_buf);
 788
 789     return ret;
 790 }
 791
 792 static void qcow_close(BlockDriverState *bs)
 793 {
 794     BDRVQcowState *s = bs->opaque;
 795
 796     qcrypto_block_free(s->crypto);
 797     s->crypto = NULL;
 798     g_free(s->l1_table);
 799     qemu_vfree(s->l2_cache);
 800     g_free(s->cluster_cache);
 801     g_free(s->cluster_data);
 802
 803     migrate_del_blocker(s->migration_blocker);
 804     error_free(s->migration_blocker);
 805 }
 806
 807 static int qcow_create(const char *filename, QemuOpts *opts, Error **errp)
 808 {
 809     int header_size, backing_filename_len, l1_size, shift, i;
 810     QCowHeader header;
 811     uint8_t *tmp;
 812     int64_t total_size = 0;
 813     char *backing_file = NULL;
 814     Error *local_err = NULL;
 815     int ret;
 816     BlockBackend *qcow_blk;
 817     char *encryptfmt = NULL;
 818     QDict *options;
 819     QDict *encryptopts = NULL;
 820     QCryptoBlockCreateOptions *crypto_opts = NULL;
 821     QCryptoBlock *crypto = NULL;
 822
 823     /* Read out options */
 824     total_size = ROUND_UP(qemu_opt_get_size_del(opts, BLOCK_OPT_SIZE, 0),
 825                           BDRV_SECTOR_SIZE);
 826     if (total_size == 0) {
 827         error_setg(errp, "Image size is too small, cannot be zero length");
 828         ret = -EINVAL;
 829         goto cleanup;
 830     }
 831
 832     backing_file = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FILE);
 833     encryptfmt = qemu_opt_get_del(opts, BLOCK_OPT_ENCRYPT_FORMAT);
 834     if (encryptfmt) {
 835         if (qemu_opt_get(opts, BLOCK_OPT_ENCRYPT)) {
 836             error_setg(errp, "Options " BLOCK_OPT_ENCRYPT " and "
 837                        BLOCK_OPT_ENCRYPT_FORMAT " are mutually exclusive");
 838             ret = -EINVAL;
 839             goto cleanup;
 840         }
 841     } else if (qemu_opt_get_bool_del(opts, BLOCK_OPT_ENCRYPT, false)) {
 842         encryptfmt = g_strdup("aes");
 843     }
 844
 845     ret = bdrv_create_file(filename, opts, &local_err);
 846     if (ret < 0) {
 847         error_propagate(errp, local_err);
 848         goto cleanup;
 849     }
 850
 851     qcow_blk = blk_new_open(filename, NULL, NULL,
 852                             BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL,
 853                             &local_err);
 854     if (qcow_blk == NULL) {
 855         error_propagate(errp, local_err);
 856         ret = -EIO;
 857         goto cleanup;
 858     }
 859
 860     blk_set_allow_write_beyond_eof(qcow_blk, true);
 861
 862     ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp);
 863     if (ret < 0) {
 864         goto exit;
 865     }
 866
 867     memset(&header, 0, sizeof(header));
 868     header.magic = cpu_to_be32(QCOW_MAGIC);
 869     header.version = cpu_to_be32(QCOW_VERSION);
 870     header.size = cpu_to_be64(total_size);
 871     header_size = sizeof(header);
 872     backing_filename_len = 0;
 873     if (backing_file) {
 874         if (strcmp(backing_file, "fat:")) {
 875             header.backing_file_offset = cpu_to_be64(header_size);
 876             backing_filename_len = strlen(backing_file);
 877             header.backing_file_size = cpu_to_be32(backing_filename_len);
 878             header_size += backing_filename_len;
 879         } else {
 880             /* special backing file for vvfat */
 881             g_free(backing_file);
 882             backing_file = NULL;
 883         }
 884         header.cluster_bits = 9; /* 512 byte cluster to avoid copying
 885                                     unmodified sectors */
 886         header.l2_bits = 12; /* 32 KB L2 tables */
 887     } else {
 888         header.cluster_bits = 12; /* 4 KB clusters */
 889         header.l2_bits = 9; /* 4 KB L2 tables */
 890     }
 891     header_size = (header_size + 7) & ~7;
 892     shift = header.cluster_bits + header.l2_bits;
 893     l1_size = (total_size + (1LL << shift) - 1) >> shift;
 894
 895     header.l1_table_offset = cpu_to_be64(header_size);
 896
 897     options = qemu_opts_to_qdict(opts, NULL);
 898     qdict_extract_subqdict(options, &encryptopts, "encrypt.");
 899     QDECREF(options);
 900     if (encryptfmt) {
 901         if (!g_str_equal(encryptfmt, "aes")) {
 902             error_setg(errp, "Unknown encryption format '%s', expected 'aes'",
 903                        encryptfmt);
 904             ret = -EINVAL;
 905             goto exit;
 906         }
 907         header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
 908
 909         crypto_opts = block_crypto_create_opts_init(
 910             Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp);
 911         if (!crypto_opts) {
 912             ret = -EINVAL;
 913             goto exit;
 914         }
 915
 916         crypto = qcrypto_block_create(crypto_opts, "encrypt.",
 917                                       NULL, NULL, NULL, errp);
 918         if (!crypto) {
 919             ret = -EINVAL;
 920             goto exit;
 921         }
 922     } else {
 923         header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
 924     }
 925
 926     /* write all the data */
 927     ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0);
 928     if (ret != sizeof(header)) {
 929         goto exit;
 930     }
 931
 932     if (backing_file) {
 933         ret = blk_pwrite(qcow_blk, sizeof(header),
 934                          backing_file, backing_filename_len, 0);
 935         if (ret != backing_filename_len) {
 936             goto exit;
 937         }
 938     }
 939
 940     tmp = g_malloc0(BDRV_SECTOR_SIZE);
 941     for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
 942          i++) {
 943         ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
 944                          tmp, BDRV_SECTOR_SIZE, 0);
 945         if (ret != BDRV_SECTOR_SIZE) {
 946             g_free(tmp);
 947             goto exit;
 948         }
 949     }
 950
 951     g_free(tmp);
 952     ret = 0;
 953 exit:
 954     blk_unref(qcow_blk);
 955 cleanup:
 956     QDECREF(encryptopts);
 957     g_free(encryptfmt);
 958     qcrypto_block_free(crypto);
 959     qapi_free_QCryptoBlockCreateOptions(crypto_opts);
 960     g_free(backing_file);
 961     return ret;
 962 }
 963
 964 static int qcow_make_empty(BlockDriverState *bs)
 965 {
 966     BDRVQcowState *s = bs->opaque;
 967     uint32_t l1_length = s->l1_size * sizeof(uint64_t);
 968     int ret;
 969
 970     memset(s->l1_table, 0, l1_length);
 971     if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
 972             l1_length) < 0)
 973         return -1;
 974     ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length,
 975                         PREALLOC_MODE_OFF, NULL);
 976     if (ret < 0)
 977         return ret;
 978
 979     memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 980     memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
 981     memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
 982
 983     return 0;
 984 }
 985
 986 /* XXX: put compressed sectors first, then all the cluster aligned
 987    tables to avoid losing bytes in alignment */
 988 static coroutine_fn int
 989 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
 990                            uint64_t bytes, QEMUIOVector *qiov)
 991 {
 992     BDRVQcowState *s = bs->opaque;
 993     QEMUIOVector hd_qiov;
 994     struct iovec iov;
 995     z_stream strm;
 996     int ret, out_len;
 997     uint8_t *buf, *out_buf;
 998     uint64_t cluster_offset;
 999
1000     buf = qemu_blockalign(bs, s->cluster_size);
1001     if (bytes != s->cluster_size) {
1002         if (bytes > s->cluster_size ||
1003             offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1004         {
1005             qemu_vfree(buf);
1006             return -EINVAL;
1007         }
1008         /* Zero-pad last write if image size is not cluster aligned */
1009         memset(buf + bytes, 0, s->cluster_size - bytes);
1010     }
1011     qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1012
1013     out_buf = g_malloc(s->cluster_size);
1014
1015     /* best compression, small window, no zlib header */
1016     memset(&strm, 0, sizeof(strm));
1017     ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1018                        Z_DEFLATED, -12,
1019                        9, Z_DEFAULT_STRATEGY);
1020     if (ret != 0) {
1021         ret = -EINVAL;
1022         goto fail;
1023     }
1024
1025     strm.avail_in = s->cluster_size;
1026     strm.next_in = (uint8_t *)buf;
1027     strm.avail_out = s->cluster_size;
1028     strm.next_out = out_buf;
1029
1030     ret = deflate(&strm, Z_FINISH);
1031     if (ret != Z_STREAM_END && ret != Z_OK) {
1032         deflateEnd(&strm);
1033         ret = -EINVAL;
1034         goto fail;
1035     }
1036     out_len = strm.next_out - out_buf;
1037
1038     deflateEnd(&strm);
1039
1040     if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1041         /* could not compress: write normal cluster */
1042         ret = qcow_co_writev(bs, offset >> BDRV_SECTOR_BITS,
1043                              bytes >> BDRV_SECTOR_BITS, qiov);
1044         if (ret < 0) {
1045             goto fail;
1046         }
1047         goto success;
1048     }
1049     qemu_co_mutex_lock(&s->lock);
1050     ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1051     qemu_co_mutex_unlock(&s->lock);
1052     if (ret < 0) {
1053         goto fail;
1054     }
1055     if (cluster_offset == 0) {
1056         ret = -EIO;
1057         goto fail;
1058     }
1059     cluster_offset &= s->cluster_offset_mask;
1060
1061     iov = (struct iovec) {
1062         .iov_base   = out_buf,
1063         .iov_len    = out_len,
1064     };
1065     qemu_iovec_init_external(&hd_qiov, &iov, 1);
1066     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1067     ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0);
1068     if (ret < 0) {
1069         goto fail;
1070     }
1071 success:
1072     ret = 0;
1073 fail:
1074     qemu_vfree(buf);
1075     g_free(out_buf);
1076     return ret;
1077 }
1078
1079 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1080 {
1081     BDRVQcowState *s = bs->opaque;
1082     bdi->cluster_size = s->cluster_size;
1083     return 0;
1084 }
1085
1086 static QemuOptsList qcow_create_opts = {
1087     .name = "qcow-create-opts",
1088     .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1089     .desc = {
1090         {
1091             .name = BLOCK_OPT_SIZE,
1092             .type = QEMU_OPT_SIZE,
1093             .help = "Virtual disk size"
1094         },
1095         {
1096             .name = BLOCK_OPT_BACKING_FILE,
1097             .type = QEMU_OPT_STRING,
1098             .help = "File name of a base image"
1099         },
1100         {
1101             .name = BLOCK_OPT_ENCRYPT,
1102             .type = QEMU_OPT_BOOL,
1103             .help = "Encrypt the image with format 'aes'. (Deprecated "
1104                     "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1105         },
1106         {
1107             .name = BLOCK_OPT_ENCRYPT_FORMAT,
1108             .type = QEMU_OPT_STRING,
1109             .help = "Encrypt the image, format choices: 'aes'",
1110         },
1111         BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1112         { /* end of list */ }
1113     }
1114 };
1115
1116 static BlockDriver bdrv_qcow = {
1117     .format_name        = "qcow",
1118     .instance_size      = sizeof(BDRVQcowState),
1119     .bdrv_probe         = qcow_probe,
1120     .bdrv_open          = qcow_open,
1121     .bdrv_close         = qcow_close,
1122     .bdrv_child_perm        = bdrv_format_default_perms,
1123     .bdrv_reopen_prepare    = qcow_reopen_prepare,
1124     .bdrv_create            = qcow_create,
1125     .bdrv_has_zero_init     = bdrv_has_zero_init_1,
1126     .supports_backing       = true,
1127
1128     .bdrv_co_readv          = qcow_co_readv,
1129     .bdrv_co_writev         = qcow_co_writev,
1130     .bdrv_co_get_block_status   = qcow_co_get_block_status,
1131
1132     .bdrv_make_empty        = qcow_make_empty,
1133     .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1134     .bdrv_get_info          = qcow_get_info,
1135
1136     .create_opts            = &qcow_create_opts,
1137 };
1138
1139 static void bdrv_qcow_init(void)
1140 {
1141     bdrv_register(&bdrv_qcow);
1142 }
1143
1144 block_init(bdrv_qcow_init);