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 "qemu/cutils.h"
  35 #include "qemu/memalign.h"
  36 #include <zlib.h>
  37 #include "qapi/qmp/qdict.h"
  38 #include "qapi/qmp/qstring.h"
  39 #include "qapi/qobject-input-visitor.h"
  40 #include "qapi/qapi-visit-block-core.h"
  41 #include "crypto/block.h"
  42 #include "migration/blocker.h"
  43 #include "crypto.h"
  44
  45 /**************************************************************/
  46 /* QEMU COW block driver with compression and encryption support */
  47
  48 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  49 #define QCOW_VERSION 1
  50
  51 #define QCOW_CRYPT_NONE 0
  52 #define QCOW_CRYPT_AES  1
  53
  54 #define QCOW_OFLAG_COMPRESSED (1LL << 63)
  55
  56 typedef struct QCowHeader {
  57     uint32_t magic;
  58     uint32_t version;
  59     uint64_t backing_file_offset;
  60     uint32_t backing_file_size;
  61     uint32_t mtime;
  62     uint64_t size; /* in bytes */
  63     uint8_t cluster_bits;
  64     uint8_t l2_bits;
  65     uint16_t padding;
  66     uint32_t crypt_method;
  67     uint64_t l1_table_offset;
  68 } QEMU_PACKED QCowHeader;
  69
  70 #define L2_CACHE_SIZE 16
  71
  72 typedef struct BDRVQcowState {
  73     int cluster_bits;
  74     int cluster_size;
  75     int l2_bits;
  76     int l2_size;
  77     unsigned int l1_size;
  78     uint64_t cluster_offset_mask;
  79     uint64_t l1_table_offset;
  80     uint64_t *l1_table;
  81     uint64_t *l2_cache;
  82     uint64_t l2_cache_offsets[L2_CACHE_SIZE];
  83     uint32_t l2_cache_counts[L2_CACHE_SIZE];
  84     uint8_t *cluster_cache;
  85     uint8_t *cluster_data;
  86     uint64_t cluster_cache_offset;
  87     QCryptoBlock *crypto; /* Disk encryption format driver */
  88     uint32_t crypt_method_header;
  89     CoMutex lock;
  90     Error *migration_blocker;
  91 } BDRVQcowState;
  92
  93 static QemuOptsList qcow_create_opts;
  94
  95 static int coroutine_fn GRAPH_RDLOCK
  96 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
  97
  98 static int qcow_probe(const uint8_t *buf, int buf_size, const char *filename)
  99 {
 100     const QCowHeader *cow_header = (const void *)buf;
 101
 102     if (buf_size >= sizeof(QCowHeader) &&
 103         be32_to_cpu(cow_header->magic) == QCOW_MAGIC &&
 104         be32_to_cpu(cow_header->version) == QCOW_VERSION)
 105         return 100;
 106     else
 107         return 0;
 108 }
 109
 110 static int qcow_open(BlockDriverState *bs, QDict *options, int flags,
 111                      Error **errp)
 112 {
 113     BDRVQcowState *s = bs->opaque;
 114     unsigned int len, i, shift;
 115     int ret;
 116     QCowHeader header;
 117     QCryptoBlockOpenOptions *crypto_opts = NULL;
 118     unsigned int cflags = 0;
 119     QDict *encryptopts = NULL;
 120     const char *encryptfmt;
 121
 122     qdict_extract_subqdict(options, &encryptopts, "encrypt.");
 123     encryptfmt = qdict_get_try_str(encryptopts, "format");
 124
 125     ret = bdrv_open_file_child(NULL, options, "file", bs, errp);
 126     if (ret < 0) {
 127         goto fail;
 128     }
 129
 130     ret = bdrv_pread(bs->file, 0, sizeof(header), &header, 0);
 131     if (ret < 0) {
 132         goto fail;
 133     }
 134     header.magic = be32_to_cpu(header.magic);
 135     header.version = be32_to_cpu(header.version);
 136     header.backing_file_offset = be64_to_cpu(header.backing_file_offset);
 137     header.backing_file_size = be32_to_cpu(header.backing_file_size);
 138     header.mtime = be32_to_cpu(header.mtime);
 139     header.size = be64_to_cpu(header.size);
 140     header.crypt_method = be32_to_cpu(header.crypt_method);
 141     header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
 142
 143     if (header.magic != QCOW_MAGIC) {
 144         error_setg(errp, "Image not in qcow format");
 145         ret = -EINVAL;
 146         goto fail;
 147     }
 148     if (header.version != QCOW_VERSION) {
 149         error_setg(errp, "qcow (v%d) does not support qcow version %" PRIu32,
 150                    QCOW_VERSION, header.version);
 151         if (header.version == 2 || header.version == 3) {
 152             error_append_hint(errp, "Try the 'qcow2' driver instead.\n");
 153         }
 154
 155         ret = -ENOTSUP;
 156         goto fail;
 157     }
 158
 159     if (header.size <= 1) {
 160         error_setg(errp, "Image size is too small (must be at least 2 bytes)");
 161         ret = -EINVAL;
 162         goto fail;
 163     }
 164     if (header.cluster_bits < 9 || header.cluster_bits > 16) {
 165         error_setg(errp, "Cluster size must be between 512 and 64k");
 166         ret = -EINVAL;
 167         goto fail;
 168     }
 169
 170     /* l2_bits specifies number of entries; storing a uint64_t in each entry,
 171      * so bytes = num_entries << 3. */
 172     if (header.l2_bits < 9 - 3 || header.l2_bits > 16 - 3) {
 173         error_setg(errp, "L2 table size must be between 512 and 64k");
 174         ret = -EINVAL;
 175         goto fail;
 176     }
 177
 178     s->crypt_method_header = header.crypt_method;
 179     if (s->crypt_method_header) {
 180         if (bdrv_uses_whitelist() &&
 181             s->crypt_method_header == QCOW_CRYPT_AES) {
 182             error_setg(errp,
 183                        "Use of AES-CBC encrypted qcow images is no longer "
 184                        "supported in system emulators");
 185             error_append_hint(errp,
 186                               "You can use 'qemu-img convert' to convert your "
 187                               "image to an alternative supported format, such "
 188                               "as unencrypted qcow, or raw with the LUKS "
 189                               "format instead.\n");
 190             ret = -ENOSYS;
 191             goto fail;
 192         }
 193         if (s->crypt_method_header == QCOW_CRYPT_AES) {
 194             if (encryptfmt && !g_str_equal(encryptfmt, "aes")) {
 195                 error_setg(errp,
 196                            "Header reported 'aes' encryption format but "
 197                            "options specify '%s'", encryptfmt);
 198                 ret = -EINVAL;
 199                 goto fail;
 200             }
 201             qdict_put_str(encryptopts, "format", "qcow");
 202             crypto_opts = block_crypto_open_opts_init(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, 1, 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->l2_bits = header.l2_bits;
 234     s->l2_size = 1 << s->l2_bits;
 235     bs->total_sectors = header.size / 512;
 236     s->cluster_offset_mask = (1LL << (63 - s->cluster_bits)) - 1;
 237
 238     /* read the level 1 table */
 239     shift = s->cluster_bits + s->l2_bits;
 240     if (header.size > UINT64_MAX - (1LL << shift)) {
 241         error_setg(errp, "Image too large");
 242         ret = -EINVAL;
 243         goto fail;
 244     } else {
 245         uint64_t l1_size = (header.size + (1LL << shift) - 1) >> shift;
 246         if (l1_size > INT_MAX / sizeof(uint64_t)) {
 247             error_setg(errp, "Image too large");
 248             ret = -EINVAL;
 249             goto fail;
 250         }
 251         s->l1_size = l1_size;
 252     }
 253
 254     s->l1_table_offset = header.l1_table_offset;
 255     s->l1_table = g_try_new(uint64_t, s->l1_size);
 256     if (s->l1_table == NULL) {
 257         error_setg(errp, "Could not allocate memory for L1 table");
 258         ret = -ENOMEM;
 259         goto fail;
 260     }
 261
 262     ret = bdrv_pread(bs->file, s->l1_table_offset,
 263                      s->l1_size * sizeof(uint64_t), s->l1_table, 0);
 264     if (ret < 0) {
 265         goto fail;
 266     }
 267
 268     for(i = 0;i < s->l1_size; i++) {
 269         s->l1_table[i] = be64_to_cpu(s->l1_table[i]);
 270     }
 271
 272     /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */
 273     s->l2_cache =
 274         qemu_try_blockalign(bs->file->bs,
 275                             s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
 276     if (s->l2_cache == NULL) {
 277         error_setg(errp, "Could not allocate L2 table cache");
 278         ret = -ENOMEM;
 279         goto fail;
 280     }
 281     s->cluster_cache = g_malloc(s->cluster_size);
 282     s->cluster_data = g_malloc(s->cluster_size);
 283     s->cluster_cache_offset = -1;
 284
 285     /* read the backing file name */
 286     if (header.backing_file_offset != 0) {
 287         len = header.backing_file_size;
 288         if (len > 1023 || len >= sizeof(bs->backing_file)) {
 289             error_setg(errp, "Backing file name too long");
 290             ret = -EINVAL;
 291             goto fail;
 292         }
 293         ret = bdrv_pread(bs->file, header.backing_file_offset, len,
 294                          bs->auto_backing_file, 0);
 295         if (ret < 0) {
 296             goto fail;
 297         }
 298         bs->auto_backing_file[len] = '\0';
 299         pstrcpy(bs->backing_file, sizeof(bs->backing_file),
 300                 bs->auto_backing_file);
 301     }
 302
 303     /* Disable migration when qcow images are used */
 304     bdrv_graph_rdlock_main_loop();
 305     error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
 306                "does not support live migration",
 307                bdrv_get_device_or_node_name(bs));
 308     bdrv_graph_rdunlock_main_loop();
 309
 310     ret = migrate_add_blocker(s->migration_blocker, errp);
 311     if (ret < 0) {
 312         error_free(s->migration_blocker);
 313         goto fail;
 314     }
 315
 316     qobject_unref(encryptopts);
 317     qapi_free_QCryptoBlockOpenOptions(crypto_opts);
 318     qemu_co_mutex_init(&s->lock);
 319     return 0;
 320
 321  fail:
 322     g_free(s->l1_table);
 323     qemu_vfree(s->l2_cache);
 324     g_free(s->cluster_cache);
 325     g_free(s->cluster_data);
 326     qcrypto_block_free(s->crypto);
 327     qobject_unref(encryptopts);
 328     qapi_free_QCryptoBlockOpenOptions(crypto_opts);
 329     return ret;
 330 }
 331
 332
 333 /* We have nothing to do for QCOW reopen, stubs just return
 334  * success */
 335 static int qcow_reopen_prepare(BDRVReopenState *state,
 336                                BlockReopenQueue *queue, Error **errp)
 337 {
 338     return 0;
 339 }
 340
 341
 342 /* 'allocate' is:
 343  *
 344  * 0 to not allocate.
 345  *
 346  * 1 to allocate a normal cluster (for sector-aligned byte offsets 'n_start'
 347  * to 'n_end' within the cluster)
 348  *
 349  * 2 to allocate a compressed cluster of size
 350  * 'compressed_size'. 'compressed_size' must be > 0 and <
 351  * cluster_size
 352  *
 353  * return 0 if not allocated, 1 if *result is assigned, and negative
 354  * errno on failure.
 355  */
 356 static int coroutine_fn GRAPH_RDLOCK
 357 get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate,
 358                    int compressed_size, int n_start, int n_end,
 359                    uint64_t *result)
 360 {
 361     BDRVQcowState *s = bs->opaque;
 362     int min_index, i, j, l1_index, l2_index, ret;
 363     int64_t l2_offset;
 364     uint64_t *l2_table, cluster_offset, tmp;
 365     uint32_t min_count;
 366     int new_l2_table;
 367
 368     *result = 0;
 369     l1_index = offset >> (s->l2_bits + s->cluster_bits);
 370     l2_offset = s->l1_table[l1_index];
 371     new_l2_table = 0;
 372     if (!l2_offset) {
 373         if (!allocate)
 374             return 0;
 375         /* allocate a new l2 entry */
 376         l2_offset = bdrv_co_getlength(bs->file->bs);
 377         if (l2_offset < 0) {
 378             return l2_offset;
 379         }
 380         /* round to cluster size */
 381         l2_offset = QEMU_ALIGN_UP(l2_offset, s->cluster_size);
 382         /* update the L1 entry */
 383         s->l1_table[l1_index] = l2_offset;
 384         tmp = cpu_to_be64(l2_offset);
 385         BLKDBG_CO_EVENT(bs->file, BLKDBG_L1_UPDATE);
 386         ret = bdrv_co_pwrite_sync(bs->file,
 387                                   s->l1_table_offset + l1_index * sizeof(tmp),
 388                                   sizeof(tmp), &tmp, 0);
 389         if (ret < 0) {
 390             return ret;
 391         }
 392         new_l2_table = 1;
 393     }
 394     for(i = 0; i < L2_CACHE_SIZE; i++) {
 395         if (l2_offset == s->l2_cache_offsets[i]) {
 396             /* increment the hit count */
 397             if (++s->l2_cache_counts[i] == 0xffffffff) {
 398                 for(j = 0; j < L2_CACHE_SIZE; j++) {
 399                     s->l2_cache_counts[j] >>= 1;
 400                 }
 401             }
 402             l2_table = s->l2_cache + (i << s->l2_bits);
 403             goto found;
 404         }
 405     }
 406     /* not found: load a new entry in the least used one */
 407     min_index = 0;
 408     min_count = 0xffffffff;
 409     for(i = 0; i < L2_CACHE_SIZE; i++) {
 410         if (s->l2_cache_counts[i] < min_count) {
 411             min_count = s->l2_cache_counts[i];
 412             min_index = i;
 413         }
 414     }
 415     l2_table = s->l2_cache + (min_index << s->l2_bits);
 416     BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_LOAD);
 417     if (new_l2_table) {
 418         memset(l2_table, 0, s->l2_size * sizeof(uint64_t));
 419         ret = bdrv_co_pwrite_sync(bs->file, l2_offset,
 420                                   s->l2_size * sizeof(uint64_t), l2_table, 0);
 421         if (ret < 0) {
 422             return ret;
 423         }
 424     } else {
 425         ret = bdrv_co_pread(bs->file, l2_offset,
 426                             s->l2_size * sizeof(uint64_t), l2_table, 0);
 427         if (ret < 0) {
 428             return ret;
 429         }
 430     }
 431     s->l2_cache_offsets[min_index] = l2_offset;
 432     s->l2_cache_counts[min_index] = 1;
 433  found:
 434     l2_index = (offset >> s->cluster_bits) & (s->l2_size - 1);
 435     cluster_offset = be64_to_cpu(l2_table[l2_index]);
 436     if (!cluster_offset ||
 437         ((cluster_offset & QCOW_OFLAG_COMPRESSED) && allocate == 1)) {
 438         if (!allocate)
 439             return 0;
 440         BLKDBG_CO_EVENT(bs->file, BLKDBG_CLUSTER_ALLOC);
 441         assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE));
 442         /* allocate a new cluster */
 443         if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
 444             (n_end - n_start) < s->cluster_size) {
 445             /* if the cluster is already compressed, we must
 446                decompress it in the case it is not completely
 447                overwritten */
 448             if (decompress_cluster(bs, cluster_offset) < 0) {
 449                 return -EIO;
 450             }
 451             cluster_offset = bdrv_co_getlength(bs->file->bs);
 452             if ((int64_t) cluster_offset < 0) {
 453                 return cluster_offset;
 454             }
 455             cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
 456             /* write the cluster content */
 457             BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
 458             ret = bdrv_co_pwrite(bs->file, cluster_offset, s->cluster_size,
 459                                  s->cluster_cache, 0);
 460             if (ret < 0) {
 461                 return ret;
 462             }
 463         } else {
 464             cluster_offset = bdrv_co_getlength(bs->file->bs);
 465             if ((int64_t) cluster_offset < 0) {
 466                 return cluster_offset;
 467             }
 468             if (allocate == 1) {
 469                 /* round to cluster size */
 470                 cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
 471                 if (cluster_offset + s->cluster_size > INT64_MAX) {
 472                     return -E2BIG;
 473                 }
 474                 ret = bdrv_co_truncate(bs->file,
 475                                        cluster_offset + s->cluster_size,
 476                                        false, PREALLOC_MODE_OFF, 0, NULL);
 477                 if (ret < 0) {
 478                     return ret;
 479                 }
 480                 /* if encrypted, we must initialize the cluster
 481                    content which won't be written */
 482                 if (bs->encrypted &&
 483                     (n_end - n_start) < s->cluster_size) {
 484                     uint64_t start_offset;
 485                     assert(s->crypto);
 486                     start_offset = offset & ~(s->cluster_size - 1);
 487                     for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) {
 488                         if (i < n_start || i >= n_end) {
 489                             memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE);
 490                             if (qcrypto_block_encrypt(s->crypto,
 491                                                       start_offset + i,
 492                                                       s->cluster_data,
 493                                                       BDRV_SECTOR_SIZE,
 494                                                       NULL) < 0) {
 495                                 return -EIO;
 496                             }
 497                             BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
 498                             ret = bdrv_co_pwrite(bs->file, cluster_offset + i,
 499                                                  BDRV_SECTOR_SIZE,
 500                                                  s->cluster_data, 0);
 501                             if (ret < 0) {
 502                                 return ret;
 503                             }
 504                         }
 505                     }
 506                 }
 507             } else if (allocate == 2) {
 508                 cluster_offset |= QCOW_OFLAG_COMPRESSED |
 509                     (uint64_t)compressed_size << (63 - s->cluster_bits);
 510             }
 511         }
 512         /* update L2 table */
 513         tmp = cpu_to_be64(cluster_offset);
 514         l2_table[l2_index] = tmp;
 515         if (allocate == 2) {
 516             BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
 517         } else {
 518             BLKDBG_CO_EVENT(bs->file, BLKDBG_L2_UPDATE);
 519         }
 520         ret = bdrv_co_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
 521                                   sizeof(tmp), &tmp, 0);
 522         if (ret < 0) {
 523             return ret;
 524         }
 525     }
 526     *result = cluster_offset;
 527     return 1;
 528 }
 529
 530 static int coroutine_fn GRAPH_RDLOCK
 531 qcow_co_block_status(BlockDriverState *bs, bool want_zero,
 532                      int64_t offset, int64_t bytes, int64_t *pnum,
 533                      int64_t *map, BlockDriverState **file)
 534 {
 535     BDRVQcowState *s = bs->opaque;
 536     int index_in_cluster, ret;
 537     int64_t n;
 538     uint64_t cluster_offset;
 539
 540     qemu_co_mutex_lock(&s->lock);
 541     ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
 542     qemu_co_mutex_unlock(&s->lock);
 543     if (ret < 0) {
 544         return ret;
 545     }
 546     index_in_cluster = offset & (s->cluster_size - 1);
 547     n = s->cluster_size - index_in_cluster;
 548     if (n > bytes) {
 549         n = bytes;
 550     }
 551     *pnum = n;
 552     if (!cluster_offset) {
 553         return 0;
 554     }
 555     if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
 556         return BDRV_BLOCK_DATA | BDRV_BLOCK_COMPRESSED;
 557     }
 558     if (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 coroutine_fn GRAPH_RDLOCK
 594 decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 595 {
 596     BDRVQcowState *s = bs->opaque;
 597     int ret, csize;
 598     uint64_t coffset;
 599
 600     coffset = cluster_offset & s->cluster_offset_mask;
 601     if (s->cluster_cache_offset != coffset) {
 602         csize = cluster_offset >> (63 - s->cluster_bits);
 603         csize &= (s->cluster_size - 1);
 604         BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
 605         ret = bdrv_co_pread(bs->file, coffset, csize, s->cluster_data, 0);
 606         if (ret < 0)
 607             return -1;
 608         if (decompress_buffer(s->cluster_cache, s->cluster_size,
 609                               s->cluster_data, csize) < 0) {
 610             return -1;
 611         }
 612         s->cluster_cache_offset = coffset;
 613     }
 614     return 0;
 615 }
 616
 617 static void qcow_refresh_limits(BlockDriverState *bs, Error **errp)
 618 {
 619     /* At least encrypted images require 512-byte alignment. Apply the
 620      * limit universally, rather than just on encrypted images, as
 621      * it's easier to let the block layer handle rounding than to
 622      * audit this code further. */
 623     bs->bl.request_alignment = BDRV_SECTOR_SIZE;
 624 }
 625
 626 static int coroutine_fn GRAPH_RDLOCK
 627 qcow_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
 628                QEMUIOVector *qiov, BdrvRequestFlags flags)
 629 {
 630     BDRVQcowState *s = bs->opaque;
 631     int offset_in_cluster;
 632     int ret = 0, n;
 633     uint64_t cluster_offset;
 634     uint8_t *buf;
 635     void *orig_buf;
 636
 637     if (qiov->niov > 1) {
 638         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 639         if (buf == NULL) {
 640             return -ENOMEM;
 641         }
 642     } else {
 643         orig_buf = NULL;
 644         buf = (uint8_t *)qiov->iov->iov_base;
 645     }
 646
 647     qemu_co_mutex_lock(&s->lock);
 648
 649     while (bytes != 0) {
 650         /* prepare next request */
 651         ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
 652         if (ret < 0) {
 653             break;
 654         }
 655         offset_in_cluster = offset & (s->cluster_size - 1);
 656         n = s->cluster_size - offset_in_cluster;
 657         if (n > bytes) {
 658             n = bytes;
 659         }
 660
 661         if (!cluster_offset) {
 662             if (bs->backing) {
 663                 /* read from the base image */
 664                 qemu_co_mutex_unlock(&s->lock);
 665                 /* qcow2 emits this on bs->file instead of bs->backing */
 666                 BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
 667                 ret = bdrv_co_pread(bs->backing, offset, n, buf, 0);
 668                 qemu_co_mutex_lock(&s->lock);
 669                 if (ret < 0) {
 670                     break;
 671                 }
 672             } else {
 673                 /* Note: in this case, no need to wait */
 674                 memset(buf, 0, n);
 675             }
 676         } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
 677             /* add AIO support for compressed blocks ? */
 678             if (decompress_cluster(bs, cluster_offset) < 0) {
 679                 ret = -EIO;
 680                 break;
 681             }
 682             memcpy(buf, s->cluster_cache + offset_in_cluster, n);
 683         } else {
 684             if ((cluster_offset & 511) != 0) {
 685                 ret = -EIO;
 686                 break;
 687             }
 688             qemu_co_mutex_unlock(&s->lock);
 689             BLKDBG_CO_EVENT(bs->file, BLKDBG_READ_AIO);
 690             ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster,
 691                                 n, buf, 0);
 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                                           offset, buf, n, NULL) < 0) {
 700                     ret = -EIO;
 701                     break;
 702                 }
 703             }
 704         }
 705         ret = 0;
 706
 707         bytes -= n;
 708         offset += n;
 709         buf += n;
 710     }
 711
 712     qemu_co_mutex_unlock(&s->lock);
 713
 714     if (qiov->niov > 1) {
 715         qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
 716         qemu_vfree(orig_buf);
 717     }
 718
 719     return ret;
 720 }
 721
 722 static int coroutine_fn GRAPH_RDLOCK
 723 qcow_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
 724                 QEMUIOVector *qiov, BdrvRequestFlags flags)
 725 {
 726     BDRVQcowState *s = bs->opaque;
 727     int offset_in_cluster;
 728     uint64_t cluster_offset;
 729     int ret = 0, n;
 730     uint8_t *buf;
 731     void *orig_buf;
 732
 733     s->cluster_cache_offset = -1; /* disable compressed cache */
 734
 735     /* We must always copy the iov when encrypting, so we
 736      * don't modify the original data buffer during encryption */
 737     if (bs->encrypted || qiov->niov > 1) {
 738         buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 739         if (buf == NULL) {
 740             return -ENOMEM;
 741         }
 742         qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
 743     } else {
 744         orig_buf = NULL;
 745         buf = (uint8_t *)qiov->iov->iov_base;
 746     }
 747
 748     qemu_co_mutex_lock(&s->lock);
 749
 750     while (bytes != 0) {
 751         offset_in_cluster = offset & (s->cluster_size - 1);
 752         n = s->cluster_size - offset_in_cluster;
 753         if (n > bytes) {
 754             n = bytes;
 755         }
 756         ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster,
 757                                  offset_in_cluster + n, &cluster_offset);
 758         if (ret < 0) {
 759             break;
 760         }
 761         if (!cluster_offset || (cluster_offset & 511) != 0) {
 762             ret = -EIO;
 763             break;
 764         }
 765         if (bs->encrypted) {
 766             assert(s->crypto);
 767             if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) {
 768                 ret = -EIO;
 769                 break;
 770             }
 771         }
 772
 773         qemu_co_mutex_unlock(&s->lock);
 774         BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_AIO);
 775         ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster,
 776                              n, buf, 0);
 777         qemu_co_mutex_lock(&s->lock);
 778         if (ret < 0) {
 779             break;
 780         }
 781         ret = 0;
 782
 783         bytes -= n;
 784         offset += n;
 785         buf += n;
 786     }
 787     qemu_co_mutex_unlock(&s->lock);
 788
 789     qemu_vfree(orig_buf);
 790
 791     return ret;
 792 }
 793
 794 static void qcow_close(BlockDriverState *bs)
 795 {
 796     BDRVQcowState *s = bs->opaque;
 797
 798     qcrypto_block_free(s->crypto);
 799     s->crypto = NULL;
 800     g_free(s->l1_table);
 801     qemu_vfree(s->l2_cache);
 802     g_free(s->cluster_cache);
 803     g_free(s->cluster_data);
 804
 805     migrate_del_blocker(s->migration_blocker);
 806     error_free(s->migration_blocker);
 807 }
 808
 809 static int coroutine_fn GRAPH_UNLOCKED
 810 qcow_co_create(BlockdevCreateOptions *opts, Error **errp)
 811 {
 812     BlockdevCreateOptionsQcow *qcow_opts;
 813     int header_size, backing_filename_len, l1_size, shift, i;
 814     QCowHeader header;
 815     uint8_t *tmp;
 816     int64_t total_size = 0;
 817     int ret;
 818     BlockDriverState *bs;
 819     BlockBackend *qcow_blk;
 820     QCryptoBlock *crypto = NULL;
 821
 822     assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
 823     qcow_opts = &opts->u.qcow;
 824
 825     /* Sanity checks */
 826     total_size = qcow_opts->size;
 827     if (total_size == 0) {
 828         error_setg(errp, "Image size is too small, cannot be zero length");
 829         return -EINVAL;
 830     }
 831
 832     if (qcow_opts->encrypt &&
 833         qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW)
 834     {
 835         error_setg(errp, "Unsupported encryption format");
 836         return -EINVAL;
 837     }
 838
 839     /* Create BlockBackend to write to the image */
 840     bs = bdrv_co_open_blockdev_ref(qcow_opts->file, errp);
 841     if (bs == NULL) {
 842         return -EIO;
 843     }
 844
 845     qcow_blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE,
 846                                   BLK_PERM_ALL, errp);
 847     if (!qcow_blk) {
 848         ret = -EPERM;
 849         goto exit;
 850     }
 851     blk_set_allow_write_beyond_eof(qcow_blk, true);
 852
 853     /* Create image format */
 854     memset(&header, 0, sizeof(header));
 855     header.magic = cpu_to_be32(QCOW_MAGIC);
 856     header.version = cpu_to_be32(QCOW_VERSION);
 857     header.size = cpu_to_be64(total_size);
 858     header_size = sizeof(header);
 859     backing_filename_len = 0;
 860     if (qcow_opts->backing_file) {
 861         if (strcmp(qcow_opts->backing_file, "fat:")) {
 862             header.backing_file_offset = cpu_to_be64(header_size);
 863             backing_filename_len = strlen(qcow_opts->backing_file);
 864             header.backing_file_size = cpu_to_be32(backing_filename_len);
 865             header_size += backing_filename_len;
 866         } else {
 867             /* special backing file for vvfat */
 868             qcow_opts->backing_file = NULL;
 869         }
 870         header.cluster_bits = 9; /* 512 byte cluster to avoid copying
 871                                     unmodified sectors */
 872         header.l2_bits = 12; /* 32 KB L2 tables */
 873     } else {
 874         header.cluster_bits = 12; /* 4 KB clusters */
 875         header.l2_bits = 9; /* 4 KB L2 tables */
 876     }
 877     header_size = (header_size + 7) & ~7;
 878     shift = header.cluster_bits + header.l2_bits;
 879     l1_size = (total_size + (1LL << shift) - 1) >> shift;
 880
 881     header.l1_table_offset = cpu_to_be64(header_size);
 882
 883     if (qcow_opts->encrypt) {
 884         header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
 885
 886         crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
 887                                       NULL, NULL, NULL, errp);
 888         if (!crypto) {
 889             ret = -EINVAL;
 890             goto exit;
 891         }
 892     } else {
 893         header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
 894     }
 895
 896     /* write all the data */
 897     ret = blk_co_pwrite(qcow_blk, 0, sizeof(header), &header, 0);
 898     if (ret < 0) {
 899         goto exit;
 900     }
 901
 902     if (qcow_opts->backing_file) {
 903         ret = blk_co_pwrite(qcow_blk, sizeof(header), backing_filename_len,
 904                             qcow_opts->backing_file, 0);
 905         if (ret < 0) {
 906             goto exit;
 907         }
 908     }
 909
 910     tmp = g_malloc0(BDRV_SECTOR_SIZE);
 911     for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
 912          i++) {
 913         ret = blk_co_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
 914                             BDRV_SECTOR_SIZE, tmp, 0);
 915         if (ret < 0) {
 916             g_free(tmp);
 917             goto exit;
 918         }
 919     }
 920
 921     g_free(tmp);
 922     ret = 0;
 923 exit:
 924     blk_co_unref(qcow_blk);
 925     bdrv_co_unref(bs);
 926     qcrypto_block_free(crypto);
 927     return ret;
 928 }
 929
 930 static int coroutine_fn GRAPH_UNLOCKED
 931 qcow_co_create_opts(BlockDriver *drv, const char *filename,
 932                     QemuOpts *opts, Error **errp)
 933 {
 934     BlockdevCreateOptions *create_options = NULL;
 935     BlockDriverState *bs = NULL;
 936     QDict *qdict = NULL;
 937     Visitor *v;
 938     const char *val;
 939     int ret;
 940     char *backing_fmt;
 941
 942     static const QDictRenames opt_renames[] = {
 943         { BLOCK_OPT_BACKING_FILE,       "backing-file" },
 944         { BLOCK_OPT_ENCRYPT,            BLOCK_OPT_ENCRYPT_FORMAT },
 945         { NULL, NULL },
 946     };
 947
 948     /*
 949      * We can't actually store a backing format, but can check that
 950      * the user's request made sense.
 951      */
 952     backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
 953     if (backing_fmt && !bdrv_find_format(backing_fmt)) {
 954         error_setg(errp, "unrecognized backing format '%s'", backing_fmt);
 955         ret = -EINVAL;
 956         goto fail;
 957     }
 958
 959     /* Parse options and convert legacy syntax */
 960     qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
 961
 962     val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
 963     if (val && !strcmp(val, "on")) {
 964         qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
 965     } else if (val && !strcmp(val, "off")) {
 966         qdict_del(qdict, BLOCK_OPT_ENCRYPT);
 967     }
 968
 969     val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
 970     if (val && !strcmp(val, "aes")) {
 971         qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
 972     }
 973
 974     if (!qdict_rename_keys(qdict, opt_renames, errp)) {
 975         ret = -EINVAL;
 976         goto fail;
 977     }
 978
 979     /* Create and open the file (protocol layer) */
 980     ret = bdrv_co_create_file(filename, opts, errp);
 981     if (ret < 0) {
 982         goto fail;
 983     }
 984
 985     bs = bdrv_co_open(filename, NULL, NULL,
 986                       BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
 987     if (bs == NULL) {
 988         ret = -EIO;
 989         goto fail;
 990     }
 991
 992     /* Now get the QAPI type BlockdevCreateOptions */
 993     qdict_put_str(qdict, "driver", "qcow");
 994     qdict_put_str(qdict, "file", bs->node_name);
 995
 996     v = qobject_input_visitor_new_flat_confused(qdict, errp);
 997     if (!v) {
 998         ret = -EINVAL;
 999         goto fail;
1000     }
1001
1002     visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
1003     visit_free(v);
1004     if (!create_options) {
1005         ret = -EINVAL;
1006         goto fail;
1007     }
1008
1009     /* Silently round up size */
1010     assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
1011     create_options->u.qcow.size =
1012         ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
1013
1014     /* Create the qcow image (format layer) */
1015     ret = qcow_co_create(create_options, errp);
1016     if (ret < 0) {
1017         goto fail;
1018     }
1019
1020     ret = 0;
1021 fail:
1022     g_free(backing_fmt);
1023     qobject_unref(qdict);
1024     bdrv_co_unref(bs);
1025     qapi_free_BlockdevCreateOptions(create_options);
1026     return ret;
1027 }
1028
1029 static int qcow_make_empty(BlockDriverState *bs)
1030 {
1031     BDRVQcowState *s = bs->opaque;
1032     uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1033     int ret;
1034
1035     memset(s->l1_table, 0, l1_length);
1036     if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, l1_length, s->l1_table,
1037                          0) < 0)
1038         return -1;
1039     ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false,
1040                         PREALLOC_MODE_OFF, 0, NULL);
1041     if (ret < 0)
1042         return ret;
1043
1044     memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
1045     memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
1046     memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
1047
1048     return 0;
1049 }
1050
1051 /* XXX: put compressed sectors first, then all the cluster aligned
1052    tables to avoid losing bytes in alignment */
1053 static int coroutine_fn GRAPH_RDLOCK
1054 qcow_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes,
1055                            QEMUIOVector *qiov)
1056 {
1057     BDRVQcowState *s = bs->opaque;
1058     z_stream strm;
1059     int ret, out_len;
1060     uint8_t *buf, *out_buf;
1061     uint64_t cluster_offset;
1062
1063     buf = qemu_blockalign(bs, s->cluster_size);
1064     if (bytes != s->cluster_size) {
1065         if (bytes > s->cluster_size ||
1066             offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1067         {
1068             qemu_vfree(buf);
1069             return -EINVAL;
1070         }
1071         /* Zero-pad last write if image size is not cluster aligned */
1072         memset(buf + bytes, 0, s->cluster_size - bytes);
1073     }
1074     qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1075
1076     out_buf = g_malloc(s->cluster_size);
1077
1078     /* best compression, small window, no zlib header */
1079     memset(&strm, 0, sizeof(strm));
1080     ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1081                        Z_DEFLATED, -12,
1082                        9, Z_DEFAULT_STRATEGY);
1083     if (ret != 0) {
1084         ret = -EINVAL;
1085         goto fail;
1086     }
1087
1088     strm.avail_in = s->cluster_size;
1089     strm.next_in = (uint8_t *)buf;
1090     strm.avail_out = s->cluster_size;
1091     strm.next_out = out_buf;
1092
1093     ret = deflate(&strm, Z_FINISH);
1094     if (ret != Z_STREAM_END && ret != Z_OK) {
1095         deflateEnd(&strm);
1096         ret = -EINVAL;
1097         goto fail;
1098     }
1099     out_len = strm.next_out - out_buf;
1100
1101     deflateEnd(&strm);
1102
1103     if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1104         /* could not compress: write normal cluster */
1105         ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0);
1106         if (ret < 0) {
1107             goto fail;
1108         }
1109         goto success;
1110     }
1111     qemu_co_mutex_lock(&s->lock);
1112     ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1113     qemu_co_mutex_unlock(&s->lock);
1114     if (ret < 0) {
1115         goto fail;
1116     }
1117     if (cluster_offset == 0) {
1118         ret = -EIO;
1119         goto fail;
1120     }
1121     cluster_offset &= s->cluster_offset_mask;
1122
1123     BLKDBG_CO_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1124     ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0);
1125     if (ret < 0) {
1126         goto fail;
1127     }
1128 success:
1129     ret = 0;
1130 fail:
1131     qemu_vfree(buf);
1132     g_free(out_buf);
1133     return ret;
1134 }
1135
1136 static int coroutine_fn
1137 qcow_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1138 {
1139     BDRVQcowState *s = bs->opaque;
1140     bdi->cluster_size = s->cluster_size;
1141     return 0;
1142 }
1143
1144 static QemuOptsList qcow_create_opts = {
1145     .name = "qcow-create-opts",
1146     .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1147     .desc = {
1148         {
1149             .name = BLOCK_OPT_SIZE,
1150             .type = QEMU_OPT_SIZE,
1151             .help = "Virtual disk size"
1152         },
1153         {
1154             .name = BLOCK_OPT_BACKING_FILE,
1155             .type = QEMU_OPT_STRING,
1156             .help = "File name of a base image"
1157         },
1158         {
1159             .name = BLOCK_OPT_BACKING_FMT,
1160             .type = QEMU_OPT_STRING,
1161             .help = "Format of the backing image",
1162         },
1163         {
1164             .name = BLOCK_OPT_ENCRYPT,
1165             .type = QEMU_OPT_BOOL,
1166             .help = "Encrypt the image with format 'aes'. (Deprecated "
1167                     "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1168         },
1169         {
1170             .name = BLOCK_OPT_ENCRYPT_FORMAT,
1171             .type = QEMU_OPT_STRING,
1172             .help = "Encrypt the image, format choices: 'aes'",
1173         },
1174         BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1175         { /* end of list */ }
1176     }
1177 };
1178
1179 static const char *const qcow_strong_runtime_opts[] = {
1180     "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
1181
1182     NULL
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_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     .is_format              = true,
1197     .supports_backing       = true,
1198     .bdrv_refresh_limits    = qcow_refresh_limits,
1199
1200     .bdrv_co_preadv         = qcow_co_preadv,
1201     .bdrv_co_pwritev        = qcow_co_pwritev,
1202     .bdrv_co_block_status   = qcow_co_block_status,
1203
1204     .bdrv_make_empty        = qcow_make_empty,
1205     .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1206     .bdrv_co_get_info       = qcow_co_get_info,
1207
1208     .create_opts            = &qcow_create_opts,
1209     .strong_runtime_opts    = qcow_strong_runtime_opts,
1210 };
1211
1212 static void bdrv_qcow_init(void)
1213 {
1214     bdrv_register(&bdrv_qcow);
1215 }
1216
1217 block_init(bdrv_qcow_init);