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
  25 #include "qemu/osdep.h"
  26 #include "qapi/error.h"
  27 #include "qemu/error-report.h"
  28 #include "block/block_int.h"
  29 #include "block/qdict.h"
  30 #include "sysemu/block-backend.h"
  31 #include "qemu/module.h"
  32 #include "qemu/option.h"
  33 #include "qemu/bswap.h"
  34 #include <zlib.h>
  35 #include "qapi/qmp/qdict.h"
  36 #include "qapi/qmp/qstring.h"
  37 #include "qapi/qobject-input-visitor.h"
  38 #include "qapi/qapi-visit-block-core.h"
  39 #include "crypto/block.h"
  40 #include "migration/blocker.h"
  41 #include "crypto.h"
  42
  43 /**************************************************************/
  44 /* QEMU COW block driver with compression and encryption support */
  45
  46 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  47 #define QCOW_VERSION 1
  48
  49 #define QCOW_CRYPT_NONE 0
  50 #define QCOW_CRYPT_AES  1
  51
  52 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
  53
  54 typedef struct QCowHeader {
  55     uint32_t magic;
  56     uint32_t version;
  57     uint64_t backing_file_offset;
  58     uint32_t backing_file_size;
  59     uint32_t mtime;
  60     uint64_t size; /* in bytes */
  61     uint8_t cluster_bits;
  62     uint8_t l2_bits;
  63     uint16_t padding;
  64     uint32_t crypt_method;
  65     uint64_t l1_table_offset;
  66 } QEMU_PACKED QCowHeader;
  67
  68 #define L2_CACHE_SIZE 16
  69
  70 typedef struct BDRVQcowState {
  71     int cluster_bits;
  72     int cluster_size;
  73     int cluster_sectors;
  74     int l2_bits;
  75     int l2_size;
  76     unsigned int l1_size;
  77     uint64_t cluster_offset_mask;
  78     uint64_t l1_table_offset;
  79     uint64_t *l1_table;
  80     uint64_t *l2_cache;
  81     uint64_t l2_cache_offsets[L2_CACHE_SIZE];
  82     uint32_t l2_cache_counts[L2_CACHE_SIZE];
  83     uint8_t *cluster_cache;
  84     uint8_t *cluster_data;
  85     uint64_t cluster_cache_offset;
  86     QCryptoBlock *crypto; /* Disk encryption format driver */
  87     uint32_t crypt_method_header;
  88     CoMutex lock;
  89     Error *migration_blocker;
  90 } BDRVQcowState;
  91
  92 static QemuOptsList qcow_create_opts;
  93
  94 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
  95
  96 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
  97 {
  98     const QCowHeader *cow_header = (const void *)buf;
  99
 100     if (buf_size >= sizeof(QCowHeader) &&
 101         be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
 102         be32_to_cpu(cow_header->version) == QCOW_VERSION)
 103         return 100;
 104     else
 105         return 0;
 106 }
 107
 108 static QemuOptsList qcow_runtime_opts = {
 109     .name = "qcow",
 110     .head = QTAILQ_HEAD_INITIALIZER(qcow_runtime_opts.head),
 111     .desc = {
 112         BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
 113         { /* end of list */ }
 114     },
 115 };
 116
 117 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
 118                      Error **errp)
 119 {
 120     BDRVQcowState *s = bs->opaque;
 121     unsigned int len, i, shift;
 122     int ret;
 123     QCowHeader header;
 124     Error *local_err = NULL;
 125     QCryptoBlockOpenOptions *crypto_opts = NULL;
 126     unsigned int cflags = 0;
 127     QDict *encryptopts = NULL;
 128     const char *encryptfmt;
 129
 130     qdict_extract_subqdict(options, &encryptopts, "encrypt.");
 131     encryptfmt = qdict_get_try_str(encryptopts, "format");
 132
 133     bs->file = bdrv_open_child(NULL, options, "file", bs, &child_file,
 134                                false, errp);
 135     if (!bs->file) {
 136         ret = -EINVAL;
 137         goto fail;
 138     }
 139
 140     ret = bdrv_pread(bs->file, 0, &header, sizeof(header));
 141     if (ret < 0) {
 142         goto fail;
 143     }
 144     be32_to_cpus(&header.magic);
 145     be32_to_cpus(&header.version);
 146     be64_to_cpus(&header.backing_file_offset);
 147     be32_to_cpus(&header.backing_file_size);
 148     be32_to_cpus(&header.mtime);
 149     be64_to_cpus(&header.size);
 150     be32_to_cpus(&header.crypt_method);
 151     be64_to_cpus(&header.l1_table_offset);
 152
 153     if (header.magic != QCOW_MAGIC) {
 154         error_setg(errp, "Image not in qcow format");
 155         ret = -EINVAL;
 156         goto fail;
 157     }
 158     if (header.version != QCOW_VERSION) {
 159         error_setg(errp, "Unsupported qcow version %" PRIu32, header.version);
 160         ret = -ENOTSUP;
 161         goto fail;
 162     }
 163
 164     if (header.size <= 1) {
 165         error_setg(errp, "Image size is too small (must be at least 2 bytes)");
 166         ret = -EINVAL;
 167         goto fail;
 168     }
 169     if (header.cluster_bits < 9 || header.cluster_bits > 16) {
 170         error_setg(errp, "Cluster size must be between 512 and 64k");
 171         ret = -EINVAL;
 172         goto fail;
 173     }
 174
 175     /* l2_bits specifies number of entries; storing a uint64_t in each entry,
 176      * so bytes = num_entries << 3. */
 177     if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
 178         error_setg(errp, "L2 table size must be between 512 and 64k");
 179         ret = -EINVAL;
 180         goto fail;
 181     }
 182
 183     s->crypt_method_header = header.crypt_method;
 184     if (s->crypt_method_header) {
 185         if (bdrv_uses_whitelist() &&
 186             s->crypt_method_header == QCOW_CRYPT_AES) {
 187             error_setg(errp,
 188                        "Use of AES-CBC encrypted qcow images is no longer "
 189                        "supported in system emulators");
 190             error_append_hint(errp,
 191                               "You can use 'qemu-img convert' to convert your "
 192                               "image to an alternative supported format, such "
 193                               "as unencrypted qcow, or raw with the LUKS "
 194                               "format instead.\n");
 195             ret = -ENOSYS;
 196             goto fail;
 197         }
 198         if (s->crypt_method_header == QCOW_CRYPT_AES) {
 199             if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
 200                 error_setg(errp,
 201                            "Header reported 'aes' encryption format but "
 202                            "options specify '%s'", encryptfmt);
 203                 ret = -EINVAL;
 204                 goto fail;
 205             }
 206             qdict_del(encryptopts, "format");
 207             crypto_opts = block_crypto_open_opts_init(
 208                 Q_CRYPTO_BLOCK_FORMAT_QCOW, encryptopts, errp);
 209             if (!crypto_opts) {
 210                 ret = -EINVAL;
 211                 goto fail;
 212             }
 213
 214             if (flags & BDRV_O_NO_IO) {
 215                 cflags |= QCRYPTO_BLOCK_OPEN_NO_IO;
 216             }
 217             s->crypto = qcrypto_block_open(crypto_opts, "encrypt.",
 218                                            NULL, NULL, cflags, errp);
 219             if (!s->crypto) {
 220                 ret = -EINVAL;
 221                 goto fail;
 222             }
 223         } else {
 224             error_setg(errp, "invalid encryption method in qcow header");
 225             ret = -EINVAL;
 226             goto fail;
 227         }
 228         bs->encrypted = true;
 229     } else {
 230         if (encryptfmt) {
 231             error_setg(errp, "No encryption in image header, but options "
 232                        "specified format '%s'", encryptfmt);
 233             ret = -EINVAL;
 234             goto fail;
 235         }
 236     }
 237     s->cluster_bits = header.cluster_bits;
 238     s->cluster_size = 1 << s->cluster_bits;
 239     s->cluster_sectors = 1 << (s->cluster_bits - 9);
 240     s->l2_bits = header.l2_bits;
 241     s->l2_size = 1 << s->l2_bits;
 242     bs->total_sectors = header.size / 512;
 243     s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
 244
 245     /* read the level 1 table */
 246     shift = s->cluster_bits + s->l2_bits;
 247     if (header.size > UINT64_MAX - (1LL << shift)) {
 248         error_setg(errp, "Image too large");
 249         ret = -EINVAL;
 250         goto fail;
 251     } else {
 252         uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
 253         if (l1_size > INT_MAX / sizeof(uint64_t)) {
 254             error_setg(errp, "Image too large");
 255             ret = -EINVAL;
 256             goto fail;
 257         }
 258         s->l1_size = l1_size;
 259     }
 260
 261     s->l1_table_offset = header.l1_table_offset;
 262     s->l1_table = g_try_new(uint64_t, s->l1_size);
 263     if (s->l1_table == NULL) {
 264         error_setg(errp, "Could not allocate memory for L1 table");
 265         ret = -ENOMEM;
 266         goto fail;
 267     }
 268
 269     ret = bdrv_pread(bs->file, s->l1_table_offset, s->l1_table,
 270                s->l1_size * sizeof(uint64_t));
 271     if (ret < 0) {
 272         goto fail;
 273     }
 274
 275     for(i = 0;i < s->l1_size; i++) {
 276         be64_to_cpus(&s->l1_table[i]);
 277     }
 278
 279     /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
 280     s->l2_cache =
 281         qemu_try_blockalign(bs->file->bs,
 282                             s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 283     if (s->l2_cache == NULL) {
 284         error_setg(errp, "Could not allocate L2 table cache");
 285         ret = -ENOMEM;
 286         goto fail;
 287     }
 288     s->cluster_cache = g_malloc(s->cluster_size);
 289     s->cluster_data = g_malloc(s->cluster_size);
 290     s->cluster_cache_offset = -1;
 291
 292     /* read the backing file name */
 293     if (header.backing_file_offset != 0) {
 294         len = header.backing_file_size;
 295         if (len > 1023 || len >= sizeof(bs->backing_file)) {
 296             error_setg(errp, "Backing file name too long");
 297             ret = -EINVAL;
 298             goto fail;
 299         }
 300         ret = bdrv_pread(bs->file, header.backing_file_offset,
 301                    bs->backing_file, len);
 302         if (ret < 0) {
 303             goto fail;
 304         }
 305         bs->backing_file[len] = '\0';
 306     }
 307
 308     /* Disable migration when qcow images are used */
 309     error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
 310                "does not support live migration",
 311                bdrv_get_device_or_node_name(bs));
 312     ret = migrate_add_blocker(s->migration_blocker, &local_err);
 313     if (local_err) {
 314         error_propagate(errp, local_err);
 315         error_free(s->migration_blocker);
 316         goto fail;
 317     }
 318
 319     qobject_unref(encryptopts);
 320     qapi_free_QCryptoBlockOpenOptions(crypto_opts);
 321     qemu_co_mutex_init(&s->lock);
 322     return 0;
 323
 324  fail:
 325     g_free(s->l1_table);
 326     qemu_vfree(s->l2_cache);
 327     g_free(s->cluster_cache);
 328     g_free(s->cluster_data);
 329     qcrypto_block_free(s->crypto);
 330     qobject_unref(encryptopts);
 331     qapi_free_QCryptoBlockOpenOptions(crypto_opts);
 332     return ret;
 333 }
 334
 335
 336 /* We have nothing to do for QCOW reopen, stubs just return
 337  * success */
 338 static int qcow_reopen_prepare(BDRVReopenState *state,
 339                                BlockReopenQueue *queue, Error **errp)
 340 {
 341     return 0;
 342 }
 343
 344
 345 /* 'allocate' is:
 346  *
 347  * 0 to not allocate.
 348  *
 349  * 1 to allocate a normal cluster (for sector indexes 'n_start' to
 350  * 'n_end')
 351  *
 352  * 2 to allocate a compressed cluster of size
 353  * 'compressed_size'. 'compressed_size' must be > 0 and <
 354  * cluster_size
 355  *
 356  * return 0 if not allocated, 1 if *result is assigned, and negative
 357  * errno on failure.
 358  */
 359 static int get_cluster_offset(BlockDriverState *bs,
 360                               uint64_t offset, int allocate,
 361                               int compressed_size,
 362                               int n_start, int n_end, uint64_t *result)
 363 {
 364     BDRVQcowState *s = bs->opaque;
 365     int min_index, i, j, l1_index, l2_index, ret;
 366     int64_t l2_offset;
 367     uint64_t *l2_table, cluster_offset, tmp;
 368     uint32_t min_count;
 369     int new_l2_table;
 370
 371     *result = 0;
 372     l1_index = offset >> (s->l2_bits + s->cluster_bits);
 373     l2_offset = s->l1_table[l1_index];
 374     new_l2_table = 0;
 375     if (!l2_offset) {
 376         if (!allocate)
 377             return 0;
 378         /* allocate a new l2 entry */
 379         l2_offset = bdrv_getlength(bs->file->bs);
 380         if (l2_offset < 0) {
 381             return l2_offset;
 382         }
 383         /* round to cluster size */
 384         l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
 385         /* update the L1 entry */
 386         s->l1_table[l1_index] = l2_offset;
 387         tmp = cpu_to_be64(l2_offset);
 388         BLKDBG_EVENT(bs->file, BLKDBG_L1_UPDATE);
 389         ret = bdrv_pwrite_sync(bs->file,
 390                                s->l1_table_offset + l1_index * sizeof(tmp),
 391                                &tmp, sizeof(tmp));
 392         if (ret < 0) {
 393             return ret;
 394         }
 395         new_l2_table = 1;
 396     }
 397     for(i = 0; i < L2_CACHE_SIZE; i++) {
 398         if (l2_offset == s->l2_cache_offsets[i]) {
 399             /* increment the hit count */
 400             if (++s->l2_cache_counts[i] == 0xffffffff) {
 401                 for(j = 0; j < L2_CACHE_SIZE; j++) {
 402                     s->l2_cache_counts[j] >>= 1;
 403                 }
 404             }
 405             l2_table = s->l2_cache + (i << s->l2_bits);
 406             goto found;
 407         }
 408     }
 409     /* not found: load a new entry in the least used one */
 410     min_index = 0;
 411     min_count = 0xffffffff;
 412     for(i = 0; i < L2_CACHE_SIZE; i++) {
 413         if (s->l2_cache_counts[i] < min_count) {
 414             min_count = s->l2_cache_counts[i];
 415             min_index = i;
 416         }
 417     }
 418     l2_table = s->l2_cache + (min_index << s->l2_bits);
 419     BLKDBG_EVENT(bs->file, BLKDBG_L2_LOAD);
 420     if (new_l2_table) {
 421         memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
 422         ret = bdrv_pwrite_sync(bs->file, l2_offset, l2_table,
 423                                s->l2_size * sizeof(uint64_t));
 424         if (ret < 0) {
 425             return ret;
 426         }
 427     } else {
 428         ret = bdrv_pread(bs->file, l2_offset, l2_table,
 429                          s->l2_size * sizeof(uint64_t));
 430         if (ret < 0) {
 431             return ret;
 432         }
 433     }
 434     s->l2_cache_offsets[min_index] = l2_offset;
 435     s->l2_cache_counts[min_index] = 1;
 436  found:
 437     l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
 438     cluster_offset = be64_to_cpu(l2_table[l2_index]);
 439     if (!cluster_offset ||
 440         ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
 441         if (!allocate)
 442             return 0;
 443         BLKDBG_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
 444         /* allocate a new cluster */
 445         if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
 446             (n_end - n_start) < s->cluster_sectors) {
 447             /* if the cluster is already compressed, we must
 448                decompress it in the case it is not completely
 449                overwritten */
 450             if (decompress_cluster(bs, cluster_offset) < 0) {
 451                 return -EIO;
 452             }
 453             cluster_offset = bdrv_getlength(bs->file->bs);
 454             if ((int64_t) cluster_offset < 0) {
 455                 return cluster_offset;
 456             }
 457             cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
 458             /* write the cluster content */
 459             BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 460             ret = bdrv_pwrite(bs->file, cluster_offset, s->cluster_cache,
 461                               s->cluster_size);
 462             if (ret < 0) {
 463                 return ret;
 464             }
 465         } else {
 466             cluster_offset = bdrv_getlength(bs->file->bs);
 467             if ((int64_t) cluster_offset < 0) {
 468                 return cluster_offset;
 469             }
 470             if (allocate == 1) {
 471                 /* round to cluster size */
 472                 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
 473                 if (cluster_offset + s->cluster_size > INT64_MAX) {
 474                     return -E2BIG;
 475                 }
 476                 ret = bdrv_truncate(bs->file, cluster_offset + s->cluster_size,
 477                                     PREALLOC_MODE_OFF, NULL);
 478                 if (ret < 0) {
 479                     return ret;
 480                 }
 481                 /* if encrypted, we must initialize the cluster
 482                    content which won't be written */
 483                 if (bs->encrypted &&
 484                     (n_end - n_start) < s->cluster_sectors) {
 485                     uint64_t start_sect;
 486                     assert(s->crypto);
 487                     start_sect = (offset & ~(s->cluster_size - 1)) >> 9;
 488                     for(i = 0; i < s->cluster_sectors; i++) {
 489                         if (i < n_start || i >= n_end) {
 490                             memset(s->cluster_data, 0x00, 512);
 491                             if (qcrypto_block_encrypt(s->crypto,
 492                                                       (start_sect + i) *
 493                                                       BDRV_SECTOR_SIZE,
 494                                                       s->cluster_data,
 495                                                       BDRV_SECTOR_SIZE,
 496                                                       NULL) < 0) {
 497                                 return -EIO;
 498                             }
 499                             BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 500                             ret = bdrv_pwrite(bs->file,
 501                                               cluster_offset + i * 512,
 502                                               s->cluster_data, 512);
 503                             if (ret < 0) {
 504                                 return ret;
 505                             }
 506                         }
 507                     }
 508                 }
 509             } else if (allocate == 2) {
 510                 cluster_offset |= QCOW_OFLAG_COMPRESSED |
 511                     (uint64_t)compressed_size << (63 - s->cluster_bits);
 512             }
 513         }
 514         /* update L2 table */
 515         tmp = cpu_to_be64(cluster_offset);
 516         l2_table[l2_index] = tmp;
 517         if (allocate == 2) {
 518             BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
 519         } else {
 520             BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
 521         }
 522         ret = bdrv_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
 523                                &tmp, sizeof(tmp));
 524         if (ret < 0) {
 525             return ret;
 526         }
 527     }
 528     *result = cluster_offset;
 529     return 1;
 530 }
 531
 532 static int coroutine_fn qcow_co_block_status(BlockDriverState *bs,
 533                                              bool want_zero,
 534                                              int64_t offset, int64_t bytes,
 535                                              int64_t *pnum, int64_t *map,
 536                                              BlockDriverState **file)
 537 {
 538     BDRVQcowState *s = bs->opaque;
 539     int index_in_cluster, ret;
 540     int64_t n;
 541     uint64_t cluster_offset;
 542
 543     qemu_co_mutex_lock(&s->lock);
 544     ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
 545     qemu_co_mutex_unlock(&s->lock);
 546     if (ret < 0) {
 547         return ret;
 548     }
 549     index_in_cluster = offset & (s->cluster_size - 1);
 550     n = s->cluster_size - index_in_cluster;
 551     if (n > bytes) {
 552         n = bytes;
 553     }
 554     *pnum = n;
 555     if (!cluster_offset) {
 556         return 0;
 557     }
 558     if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) {
 559         return BDRV_BLOCK_DATA;
 560     }
 561     *map = cluster_offset | index_in_cluster;
 562     *file = bs->file->bs;
 563     return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
 564 }
 565
 566 static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
 567                              const uint8_t *buf, int buf_size)
 568 {
 569     z_stream strm1, *strm = &strm1;
 570     int ret, out_len;
 571
 572     memset(strm, 0, sizeof(*strm));
 573
 574     strm->next_in = (uint8_t *)buf;
 575     strm->avail_in = buf_size;
 576     strm->next_out = out_buf;
 577     strm->avail_out = out_buf_size;
 578
 579     ret = inflateInit2(strm, -12);
 580     if (ret != Z_OK)
 581         return -1;
 582     ret = inflate(strm, Z_FINISH);
 583     out_len = strm->next_out - out_buf;
 584     if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
 585         out_len != out_buf_size) {
 586         inflateEnd(strm);
 587         return -1;
 588     }
 589     inflateEnd(strm);
 590     return 0;
 591 }
 592
 593 static int decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 594 {
 595     BDRVQcowState *s = bs->opaque;
 596     int ret, csize;
 597     uint64_t coffset;
 598
 599     coffset = cluster_offset & s->cluster_offset_mask;
 600     if (s->cluster_cache_offset != coffset) {
 601         csize = cluster_offset >> (63 - s->cluster_bits);
 602         csize &= (s->cluster_size - 1);
 603         BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
 604         ret = bdrv_pread(bs->file, coffset, s->cluster_data, csize);
 605         if (ret != csize)
 606             return -1;
 607         if (decompress_buffer(s->cluster_cache, s->cluster_size,
 608                               s->cluster_data, csize) < 0) {
 609             return -1;
 610         }
 611         s->cluster_cache_offset = coffset;
 612     }
 613     return 0;
 614 }
 615
 616 static coroutine_fn int qcow_co_readv(BlockDriverState *bs, int64_t sector_num,
 617                          int nb_sectors, QEMUIOVector *qiov)
 618 {
 619     BDRVQcowState *s = bs->opaque;
 620     int index_in_cluster;
 621     int ret = 0, n;
 622     uint64_t cluster_offset;
 623     struct iovec hd_iov;
 624     QEMUIOVector hd_qiov;
 625     uint8_t *buf;
 626     void *orig_buf;
 627
 628     if (qiov->niov > 1) {
 629         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 630         if (buf == NULL) {
 631             return -ENOMEM;
 632         }
 633     } else {
 634         orig_buf = NULL;
 635         buf = (uint8_t *)qiov->iov->iov_base;
 636     }
 637
 638     qemu_co_mutex_lock(&s->lock);
 639
 640     while (nb_sectors != 0) {
 641         /* prepare next request */
 642         ret = get_cluster_offset(bs, sector_num << 9,
 643                                  0, 0, 0, 0, &cluster_offset);
 644         if (ret < 0) {
 645             break;
 646         }
 647         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 648         n = s->cluster_sectors - index_in_cluster;
 649         if (n > nb_sectors) {
 650             n = nb_sectors;
 651         }
 652
 653         if (!cluster_offset) {
 654             if (bs->backing) {
 655                 /* read from the base image */
 656                 hd_iov.iov_base = (void *)buf;
 657                 hd_iov.iov_len = n * 512;
 658                 qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 659                 qemu_co_mutex_unlock(&s->lock);
 660                 /* qcow2 emits this on bs->file instead of bs->backing */
 661                 BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
 662                 ret = bdrv_co_readv(bs->backing, sector_num, n, &hd_qiov);
 663                 qemu_co_mutex_lock(&s->lock);
 664                 if (ret < 0) {
 665                     break;
 666                 }
 667             } else {
 668                 /* Note: in this case, no need to wait */
 669                 memset(buf, 0, 512 * n);
 670             }
 671         } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
 672             /* add AIO support for compressed blocks ? */
 673             if (decompress_cluster(bs, cluster_offset) < 0) {
 674                 ret = -EIO;
 675                 break;
 676             }
 677             memcpy(buf,
 678                    s->cluster_cache + index_in_cluster * 512, 512 * n);
 679         } else {
 680             if ((cluster_offset & 511) != 0) {
 681                 ret = -EIO;
 682                 break;
 683             }
 684             hd_iov.iov_base = (void *)buf;
 685             hd_iov.iov_len = n * 512;
 686             qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 687             qemu_co_mutex_unlock(&s->lock);
 688             BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 689             ret = bdrv_co_readv(bs->file,
 690                                 (cluster_offset >> 9) + index_in_cluster,
 691                                 n, &hd_qiov);
 692             qemu_co_mutex_lock(&s->lock);
 693             if (ret < 0) {
 694                 break;
 695             }
 696             if (bs->encrypted) {
 697                 assert(s->crypto);
 698                 if (qcrypto_block_decrypt(s->crypto,
 699                                           sector_num * BDRV_SECTOR_SIZE, buf,
 700                                           n * BDRV_SECTOR_SIZE, NULL) < 0) {
 701                     ret = -EIO;
 702                     break;
 703                 }
 704             }
 705         }
 706         ret = 0;
 707
 708         nb_sectors -= n;
 709         sector_num += n;
 710         buf += n * 512;
 711     }
 712
 713     qemu_co_mutex_unlock(&s->lock);
 714
 715     if (qiov->niov > 1) {
 716         qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
 717         qemu_vfree(orig_buf);
 718     }
 719
 720     return ret;
 721 }
 722
 723 static coroutine_fn int qcow_co_writev(BlockDriverState *bs, int64_t sector_num,
 724                                        int nb_sectors, QEMUIOVector *qiov,
 725                                        int flags)
 726 {
 727     BDRVQcowState *s = bs->opaque;
 728     int index_in_cluster;
 729     uint64_t cluster_offset;
 730     int ret = 0, n;
 731     struct iovec hd_iov;
 732     QEMUIOVector hd_qiov;
 733     uint8_t *buf;
 734     void *orig_buf;
 735
 736     assert(!flags);
 737     s->cluster_cache_offset = -1; /* disable compressed cache */
 738
 739     /* We must always copy the iov when encrypting, so we
 740      * don't modify the original data buffer during encryption */
 741     if (bs->encrypted || qiov->niov > 1) {
 742         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 743         if (buf == NULL) {
 744             return -ENOMEM;
 745         }
 746         qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
 747     } else {
 748         orig_buf = NULL;
 749         buf = (uint8_t *)qiov->iov->iov_base;
 750     }
 751
 752     qemu_co_mutex_lock(&s->lock);
 753
 754     while (nb_sectors != 0) {
 755
 756         index_in_cluster = sector_num & (s->cluster_sectors - 1);
 757         n = s->cluster_sectors - index_in_cluster;
 758         if (n > nb_sectors) {
 759             n = nb_sectors;
 760         }
 761         ret = get_cluster_offset(bs, sector_num << 9, 1, 0,
 762                                  index_in_cluster,
 763                                  index_in_cluster + n, &cluster_offset);
 764         if (ret < 0) {
 765             break;
 766         }
 767         if (!cluster_offset || (cluster_offset & 511) != 0) {
 768             ret = -EIO;
 769             break;
 770         }
 771         if (bs->encrypted) {
 772             assert(s->crypto);
 773             if (qcrypto_block_encrypt(s->crypto, sector_num * BDRV_SECTOR_SIZE,
 774                                       buf, n * BDRV_SECTOR_SIZE, NULL) < 0) {
 775                 ret = -EIO;
 776                 break;
 777             }
 778         }
 779
 780         hd_iov.iov_base = (void *)buf;
 781         hd_iov.iov_len = n * 512;
 782         qemu_iovec_init_external(&hd_qiov, &hd_iov, 1);
 783         qemu_co_mutex_unlock(&s->lock);
 784         BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 785         ret = bdrv_co_writev(bs->file,
 786                              (cluster_offset >> 9) + index_in_cluster,
 787                              n, &hd_qiov);
 788         qemu_co_mutex_lock(&s->lock);
 789         if (ret < 0) {
 790             break;
 791         }
 792         ret = 0;
 793
 794         nb_sectors -= n;
 795         sector_num += n;
 796         buf += n * 512;
 797     }
 798     qemu_co_mutex_unlock(&s->lock);
 799
 800     qemu_vfree(orig_buf);
 801
 802     return ret;
 803 }
 804
 805 static void qcow_close(BlockDriverState *bs)
 806 {
 807     BDRVQcowState *s = bs->opaque;
 808
 809     qcrypto_block_free(s->crypto);
 810     s->crypto = NULL;
 811     g_free(s->l1_table);
 812     qemu_vfree(s->l2_cache);
 813     g_free(s->cluster_cache);
 814     g_free(s->cluster_data);
 815
 816     migrate_del_blocker(s->migration_blocker);
 817     error_free(s->migration_blocker);
 818 }
 819
 820 static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts,
 821                                        Error **errp)
 822 {
 823     BlockdevCreateOptionsQcow *qcow_opts;
 824     int header_size, backing_filename_len, l1_size, shift, i;
 825     QCowHeader header;
 826     uint8_t *tmp;
 827     int64_t total_size = 0;
 828     int ret;
 829     BlockDriverState *bs;
 830     BlockBackend *qcow_blk;
 831     QCryptoBlock *crypto = NULL;
 832
 833     assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
 834     qcow_opts = &opts->u.qcow;
 835
 836     /* Sanity checks */
 837     total_size = qcow_opts->size;
 838     if (total_size == 0) {
 839         error_setg(errp, "Image size is too small, cannot be zero length");
 840         return -EINVAL;
 841     }
 842
 843     if (qcow_opts->has_encrypt &&
 844         qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW)
 845     {
 846         error_setg(errp, "Unsupported encryption format");
 847         return -EINVAL;
 848     }
 849
 850     /* Create BlockBackend to write to the image */
 851     bs = bdrv_open_blockdev_ref(qcow_opts->file, errp);
 852     if (bs == NULL) {
 853         return -EIO;
 854     }
 855
 856     qcow_blk = blk_new(BLK_PERM_WRITE | BLK_PERM_RESIZE, BLK_PERM_ALL);
 857     ret = blk_insert_bs(qcow_blk, bs, errp);
 858     if (ret < 0) {
 859         goto exit;
 860     }
 861     blk_set_allow_write_beyond_eof(qcow_blk, true);
 862
 863     /* Create image format */
 864     ret = blk_truncate(qcow_blk, 0, PREALLOC_MODE_OFF, errp);
 865     if (ret < 0) {
 866         goto exit;
 867     }
 868
 869     memset(&header, 0, sizeof(header));
 870     header.magic = cpu_to_be32(QCOW_MAGIC);
 871     header.version = cpu_to_be32(QCOW_VERSION);
 872     header.size = cpu_to_be64(total_size);
 873     header_size = sizeof(header);
 874     backing_filename_len = 0;
 875     if (qcow_opts->has_backing_file) {
 876         if (strcmp(qcow_opts->backing_file, "fat:")) {
 877             header.backing_file_offset = cpu_to_be64(header_size);
 878             backing_filename_len = strlen(qcow_opts->backing_file);
 879             header.backing_file_size = cpu_to_be32(backing_filename_len);
 880             header_size += backing_filename_len;
 881         } else {
 882             /* special backing file for vvfat */
 883             qcow_opts->has_backing_file = false;
 884         }
 885         header.cluster_bits = 9; /* 512 byte cluster to avoid copying
 886                                     unmodified sectors */
 887         header.l2_bits = 12; /* 32 KB L2 tables */
 888     } else {
 889         header.cluster_bits = 12; /* 4 KB clusters */
 890         header.l2_bits = 9; /* 4 KB L2 tables */
 891     }
 892     header_size = (header_size + 7) & ~7;
 893     shift = header.cluster_bits + header.l2_bits;
 894     l1_size = (total_size + (1LL << shift) - 1) >> shift;
 895
 896     header.l1_table_offset = cpu_to_be64(header_size);
 897
 898     if (qcow_opts->has_encrypt) {
 899         header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
 900
 901         crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
 902                                       NULL, NULL, NULL, errp);
 903         if (!crypto) {
 904             ret = -EINVAL;
 905             goto exit;
 906         }
 907     } else {
 908         header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
 909     }
 910
 911     /* write all the data */
 912     ret = blk_pwrite(qcow_blk, 0, &header, sizeof(header), 0);
 913     if (ret != sizeof(header)) {
 914         goto exit;
 915     }
 916
 917     if (qcow_opts->has_backing_file) {
 918         ret = blk_pwrite(qcow_blk, sizeof(header),
 919                          qcow_opts->backing_file, backing_filename_len, 0);
 920         if (ret != backing_filename_len) {
 921             goto exit;
 922         }
 923     }
 924
 925     tmp = g_malloc0(BDRV_SECTOR_SIZE);
 926     for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
 927          i++) {
 928         ret = blk_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
 929                          tmp, BDRV_SECTOR_SIZE, 0);
 930         if (ret != BDRV_SECTOR_SIZE) {
 931             g_free(tmp);
 932             goto exit;
 933         }
 934     }
 935
 936     g_free(tmp);
 937     ret = 0;
 938 exit:
 939     blk_unref(qcow_blk);
 940     qcrypto_block_free(crypto);
 941     return ret;
 942 }
 943
 944 static int coroutine_fn qcow_co_create_opts(const char *filename,
 945                                             QemuOpts *opts, Error **errp)
 946 {
 947     BlockdevCreateOptions *create_options = NULL;
 948     BlockDriverState *bs = NULL;
 949     QDict *qdict;
 950     Visitor *v;
 951     const char *val;
 952     Error *local_err = NULL;
 953     int ret;
 954
 955     static const QDictRenames opt_renames[] = {
 956         { BLOCK_OPT_BACKING_FILE,       "backing-file" },
 957         { BLOCK_OPT_ENCRYPT,            BLOCK_OPT_ENCRYPT_FORMAT },
 958         { NULL, NULL },
 959     };
 960
 961     /* Parse options and convert legacy syntax */
 962     qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
 963
 964     val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
 965     if (val && !strcmp(val, "on")) {
 966         qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
 967     } else if (val && !strcmp(val, "off")) {
 968         qdict_del(qdict, BLOCK_OPT_ENCRYPT);
 969     }
 970
 971     val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
 972     if (val && !strcmp(val, "aes")) {
 973         qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
 974     }
 975
 976     if (!qdict_rename_keys(qdict, opt_renames, errp)) {
 977         ret = -EINVAL;
 978         goto fail;
 979     }
 980
 981     /* Create and open the file (protocol layer) */
 982     ret = bdrv_create_file(filename, opts, &local_err);
 983     if (ret < 0) {
 984         error_propagate(errp, local_err);
 985         goto fail;
 986     }
 987
 988     bs = bdrv_open(filename, NULL, NULL,
 989                    BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
 990     if (bs == NULL) {
 991         ret = -EIO;
 992         goto fail;
 993     }
 994
 995     /* Now get the QAPI type BlockdevCreateOptions */
 996     qdict_put_str(qdict, "driver", "qcow");
 997     qdict_put_str(qdict, "file", bs->node_name);
 998
 999     v = qobject_input_visitor_new_flat_confused(qdict, errp);
1000     if (!v) {
1001         ret = -EINVAL;
1002         goto fail;
1003     }
1004
1005     visit_type_BlockdevCreateOptions(v, NULL, &create_options, &local_err);
1006     visit_free(v);
1007
1008     if (local_err) {
1009         error_propagate(errp, local_err);
1010         ret = -EINVAL;
1011         goto fail;
1012     }
1013
1014     /* Silently round up size */
1015     assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
1016     create_options->u.qcow.size =
1017         ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
1018
1019     /* Create the qcow image (format layer) */
1020     ret = qcow_co_create(create_options, errp);
1021     if (ret < 0) {
1022         goto fail;
1023     }
1024
1025     ret = 0;
1026 fail:
1027     qobject_unref(qdict);
1028     bdrv_unref(bs);
1029     qapi_free_BlockdevCreateOptions(create_options);
1030     return ret;
1031 }
1032
1033 static int qcow_make_empty(BlockDriverState *bs)
1034 {
1035     BDRVQcowState *s = bs->opaque;
1036     uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1037     int ret;
1038
1039     memset(s->l1_table, 0, l1_length);
1040     if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, s->l1_table,
1041             l1_length) < 0)
1042         return -1;
1043     ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length,
1044                         PREALLOC_MODE_OFF, NULL);
1045     if (ret < 0)
1046         return ret;
1047
1048     memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
1049     memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
1050     memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
1051
1052     return 0;
1053 }
1054
1055 /* XXX: put compressed sectors first, then all the cluster aligned
1056    tables to avoid losing bytes in alignment */
1057 static coroutine_fn int
1058 qcow_co_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
1059                            uint64_t bytes, QEMUIOVector *qiov)
1060 {
1061     BDRVQcowState *s = bs->opaque;
1062     QEMUIOVector hd_qiov;
1063     struct iovec iov;
1064     z_stream strm;
1065     int ret, out_len;
1066     uint8_t *buf, *out_buf;
1067     uint64_t cluster_offset;
1068
1069     buf = qemu_blockalign(bs, s->cluster_size);
1070     if (bytes != s->cluster_size) {
1071         if (bytes > s->cluster_size ||
1072             offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1073         {
1074             qemu_vfree(buf);
1075             return -EINVAL;
1076         }
1077         /* Zero-pad last write if image size is not cluster aligned */
1078         memset(buf + bytes, 0, s->cluster_size - bytes);
1079     }
1080     qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1081
1082     out_buf = g_malloc(s->cluster_size);
1083
1084     /* best compression, small window, no zlib header */
1085     memset(&strm, 0, sizeof(strm));
1086     ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1087                        Z_DEFLATED, -12,
1088                        9, Z_DEFAULT_STRATEGY);
1089     if (ret != 0) {
1090         ret = -EINVAL;
1091         goto fail;
1092     }
1093
1094     strm.avail_in = s->cluster_size;
1095     strm.next_in = (uint8_t *)buf;
1096     strm.avail_out = s->cluster_size;
1097     strm.next_out = out_buf;
1098
1099     ret = deflate(&strm, Z_FINISH);
1100     if (ret != Z_STREAM_END && ret != Z_OK) {
1101         deflateEnd(&strm);
1102         ret = -EINVAL;
1103         goto fail;
1104     }
1105     out_len = strm.next_out - out_buf;
1106
1107     deflateEnd(&strm);
1108
1109     if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1110         /* could not compress: write normal cluster */
1111         ret = qcow_co_writev(bs, offset >> BDRV_SECTOR_BITS,
1112                              bytes >> BDRV_SECTOR_BITS, qiov, 0);
1113         if (ret < 0) {
1114             goto fail;
1115         }
1116         goto success;
1117     }
1118     qemu_co_mutex_lock(&s->lock);
1119     ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1120     qemu_co_mutex_unlock(&s->lock);
1121     if (ret < 0) {
1122         goto fail;
1123     }
1124     if (cluster_offset == 0) {
1125         ret = -EIO;
1126         goto fail;
1127     }
1128     cluster_offset &= s->cluster_offset_mask;
1129
1130     iov = (struct iovec) {
1131         .iov_base   = out_buf,
1132         .iov_len    = out_len,
1133     };
1134     qemu_iovec_init_external(&hd_qiov, &iov, 1);
1135     BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1136     ret = bdrv_co_pwritev(bs->file, cluster_offset, out_len, &hd_qiov, 0);
1137     if (ret < 0) {
1138         goto fail;
1139     }
1140 success:
1141     ret = 0;
1142 fail:
1143     qemu_vfree(buf);
1144     g_free(out_buf);
1145     return ret;
1146 }
1147
1148 static int qcow_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1149 {
1150     BDRVQcowState *s = bs->opaque;
1151     bdi->cluster_size = s->cluster_size;
1152     return 0;
1153 }
1154
1155 static QemuOptsList qcow_create_opts = {
1156     .name = "qcow-create-opts",
1157     .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1158     .desc = {
1159         {
1160             .name = BLOCK_OPT_SIZE,
1161             .type = QEMU_OPT_SIZE,
1162             .help = "Virtual disk size"
1163         },
1164         {
1165             .name = BLOCK_OPT_BACKING_FILE,
1166             .type = QEMU_OPT_STRING,
1167             .help = "File name of a base image"
1168         },
1169         {
1170             .name = BLOCK_OPT_ENCRYPT,
1171             .type = QEMU_OPT_BOOL,
1172             .help = "Encrypt the image with format 'aes'. (Deprecated "
1173                     "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1174         },
1175         {
1176             .name = BLOCK_OPT_ENCRYPT_FORMAT,
1177             .type = QEMU_OPT_STRING,
1178             .help = "Encrypt the image, format choices: 'aes'",
1179         },
1180         BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1181         { /* end of list */ }
1182     }
1183 };
1184
1185 static BlockDriver bdrv_qcow = {
1186     .format_name        = "qcow",
1187     .instance_size      = sizeof(BDRVQcowState),
1188     .bdrv_probe         = qcow_probe,
1189     .bdrv_open          = qcow_open,
1190     .bdrv_close         = qcow_close,
1191     .bdrv_child_perm        = bdrv_format_default_perms,
1192     .bdrv_reopen_prepare    = qcow_reopen_prepare,
1193     .bdrv_co_create         = qcow_co_create,
1194     .bdrv_co_create_opts    = qcow_co_create_opts,
1195     .bdrv_has_zero_init     = bdrv_has_zero_init_1,
1196     .supports_backing       = true,
1197
1198     .bdrv_co_readv          = qcow_co_readv,
1199     .bdrv_co_writev         = qcow_co_writev,
1200     .bdrv_co_block_status   = qcow_co_block_status,
1201
1202     .bdrv_make_empty        = qcow_make_empty,
1203     .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1204     .bdrv_get_info          = qcow_get_info,
1205
1206     .create_opts            = &qcow_create_opts,
1207 };
1208
1209 static void bdrv_qcow_init(void)
1210 {
1211     bdrv_register(&bdrv_qcow);
1212 }
1213
1214 block_init(bdrv_qcow_init);