qemu/block/qcow.c
<<
>>
Prefs
   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
  56typedef 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
  72typedef 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
  93static QemuOptsList qcow_create_opts;
  94
  95static int coroutine_fn GRAPH_RDLOCK
  96decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
  97
  98static 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
 110static 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    error_setg(&s->migration_blocker, "The qcow format used by node '%s' "
 305               "does not support live migration",
 306               bdrv_get_device_or_node_name(bs));
 307    ret = migrate_add_blocker(s->migration_blocker, errp);
 308    if (ret < 0) {
 309        error_free(s->migration_blocker);
 310        goto fail;
 311    }
 312
 313    qobject_unref(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    qobject_unref(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 */
 332static 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-aligned byte offsets 'n_start'
 344 * to 'n_end' within the cluster)
 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 */
 353static int coroutine_fn GRAPH_RDLOCK
 354get_cluster_offset(BlockDriverState *bs, uint64_t offset, int allocate,
 355                   int compressed_size, int n_start, int n_end,
 356                   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_co_pwrite_sync(bs->file,
 384                                  s->l1_table_offset + l1_index * sizeof(tmp),
 385                                  sizeof(tmp), &tmp, 0);
 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_co_pwrite_sync(bs->file, l2_offset,
 417                                  s->l2_size * sizeof(uint64_t), l2_table, 0);
 418        if (ret < 0) {
 419            return ret;
 420        }
 421    } else {
 422        ret = bdrv_co_pread(bs->file, l2_offset,
 423                            s->l2_size * sizeof(uint64_t), l2_table, 0);
 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        assert(QEMU_IS_ALIGNED(n_start | n_end, BDRV_SECTOR_SIZE));
 439        /* allocate a new cluster */
 440        if ((cluster_offset & QCOW_OFLAG_COMPRESSED) &&
 441            (n_end - n_start) < s->cluster_size) {
 442            /* if the cluster is already compressed, we must
 443               decompress it in the case it is not completely
 444               overwritten */
 445            if (decompress_cluster(bs, cluster_offset) < 0) {
 446                return -EIO;
 447            }
 448            cluster_offset = bdrv_getlength(bs->file->bs);
 449            if ((int64_t) cluster_offset < 0) {
 450                return cluster_offset;
 451            }
 452            cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
 453            /* write the cluster content */
 454            BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 455            ret = bdrv_co_pwrite(bs->file, cluster_offset, s->cluster_size,
 456                                 s->cluster_cache, 0);
 457            if (ret < 0) {
 458                return ret;
 459            }
 460        } else {
 461            cluster_offset = bdrv_getlength(bs->file->bs);
 462            if ((int64_t) cluster_offset < 0) {
 463                return cluster_offset;
 464            }
 465            if (allocate == 1) {
 466                /* round to cluster size */
 467                cluster_offset = QEMU_ALIGN_UP(cluster_offset, s->cluster_size);
 468                if (cluster_offset + s->cluster_size > INT64_MAX) {
 469                    return -E2BIG;
 470                }
 471                ret = bdrv_co_truncate(bs->file,
 472                                       cluster_offset + s->cluster_size,
 473                                       false, PREALLOC_MODE_OFF, 0, NULL);
 474                if (ret < 0) {
 475                    return ret;
 476                }
 477                /* if encrypted, we must initialize the cluster
 478                   content which won't be written */
 479                if (bs->encrypted &&
 480                    (n_end - n_start) < s->cluster_size) {
 481                    uint64_t start_offset;
 482                    assert(s->crypto);
 483                    start_offset = offset & ~(s->cluster_size - 1);
 484                    for (i = 0; i < s->cluster_size; i += BDRV_SECTOR_SIZE) {
 485                        if (i < n_start || i >= n_end) {
 486                            memset(s->cluster_data, 0x00, BDRV_SECTOR_SIZE);
 487                            if (qcrypto_block_encrypt(s->crypto,
 488                                                      start_offset + i,
 489                                                      s->cluster_data,
 490                                                      BDRV_SECTOR_SIZE,
 491                                                      NULL) < 0) {
 492                                return -EIO;
 493                            }
 494                            BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 495                            ret = bdrv_co_pwrite(bs->file, cluster_offset + i,
 496                                                 BDRV_SECTOR_SIZE,
 497                                                 s->cluster_data, 0);
 498                            if (ret < 0) {
 499                                return ret;
 500                            }
 501                        }
 502                    }
 503                }
 504            } else if (allocate == 2) {
 505                cluster_offset |= QCOW_OFLAG_COMPRESSED |
 506                    (uint64_t)compressed_size << (63 - s->cluster_bits);
 507            }
 508        }
 509        /* update L2 table */
 510        tmp = cpu_to_be64(cluster_offset);
 511        l2_table[l2_index] = tmp;
 512        if (allocate == 2) {
 513            BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE_COMPRESSED);
 514        } else {
 515            BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE);
 516        }
 517        ret = bdrv_co_pwrite_sync(bs->file, l2_offset + l2_index * sizeof(tmp),
 518                                  sizeof(tmp), &tmp, 0);
 519        if (ret < 0) {
 520            return ret;
 521        }
 522    }
 523    *result = cluster_offset;
 524    return 1;
 525}
 526
 527static int coroutine_fn GRAPH_RDLOCK
 528qcow_co_block_status(BlockDriverState *bs, bool want_zero,
 529                     int64_t offset, int64_t bytes, int64_t *pnum,
 530                     int64_t *map, BlockDriverState **file)
 531{
 532    BDRVQcowState *s = bs->opaque;
 533    int index_in_cluster, ret;
 534    int64_t n;
 535    uint64_t cluster_offset;
 536
 537    qemu_co_mutex_lock(&s->lock);
 538    ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
 539    qemu_co_mutex_unlock(&s->lock);
 540    if (ret < 0) {
 541        return ret;
 542    }
 543    index_in_cluster = offset & (s->cluster_size - 1);
 544    n = s->cluster_size - index_in_cluster;
 545    if (n > bytes) {
 546        n = bytes;
 547    }
 548    *pnum = n;
 549    if (!cluster_offset) {
 550        return 0;
 551    }
 552    if ((cluster_offset & QCOW_OFLAG_COMPRESSED) || s->crypto) {
 553        return BDRV_BLOCK_DATA;
 554    }
 555    *map = cluster_offset | index_in_cluster;
 556    *file = bs->file->bs;
 557    return BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID;
 558}
 559
 560static int decompress_buffer(uint8_t *out_buf, int out_buf_size,
 561                             const uint8_t *buf, int buf_size)
 562{
 563    z_stream strm1, *strm = &strm1;
 564    int ret, out_len;
 565
 566    memset(strm, 0, sizeof(*strm));
 567
 568    strm->next_in = (uint8_t *)buf;
 569    strm->avail_in = buf_size;
 570    strm->next_out = out_buf;
 571    strm->avail_out = out_buf_size;
 572
 573    ret = inflateInit2(strm, -12);
 574    if (ret != Z_OK)
 575        return -1;
 576    ret = inflate(strm, Z_FINISH);
 577    out_len = strm->next_out - out_buf;
 578    if ((ret != Z_STREAM_END && ret != Z_BUF_ERROR) ||
 579        out_len != out_buf_size) {
 580        inflateEnd(strm);
 581        return -1;
 582    }
 583    inflateEnd(strm);
 584    return 0;
 585}
 586
 587static int coroutine_fn GRAPH_RDLOCK
 588decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset)
 589{
 590    BDRVQcowState *s = bs->opaque;
 591    int ret, csize;
 592    uint64_t coffset;
 593
 594    coffset = cluster_offset & s->cluster_offset_mask;
 595    if (s->cluster_cache_offset != coffset) {
 596        csize = cluster_offset >> (63 - s->cluster_bits);
 597        csize &= (s->cluster_size - 1);
 598        BLKDBG_EVENT(bs->file, BLKDBG_READ_COMPRESSED);
 599        ret = bdrv_co_pread(bs->file, coffset, csize, s->cluster_data, 0);
 600        if (ret < 0)
 601            return -1;
 602        if (decompress_buffer(s->cluster_cache, s->cluster_size,
 603                              s->cluster_data, csize) < 0) {
 604            return -1;
 605        }
 606        s->cluster_cache_offset = coffset;
 607    }
 608    return 0;
 609}
 610
 611static void qcow_refresh_limits(BlockDriverState *bs, Error **errp)
 612{
 613    /* At least encrypted images require 512-byte alignment. Apply the
 614     * limit universally, rather than just on encrypted images, as
 615     * it's easier to let the block layer handle rounding than to
 616     * audit this code further. */
 617    bs->bl.request_alignment = BDRV_SECTOR_SIZE;
 618}
 619
 620static int coroutine_fn GRAPH_RDLOCK
 621qcow_co_preadv(BlockDriverState *bs, int64_t offset, int64_t bytes,
 622               QEMUIOVector *qiov, BdrvRequestFlags flags)
 623{
 624    BDRVQcowState *s = bs->opaque;
 625    int offset_in_cluster;
 626    int ret = 0, n;
 627    uint64_t cluster_offset;
 628    uint8_t *buf;
 629    void *orig_buf;
 630
 631    if (qiov->niov > 1) {
 632        buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 633        if (buf == NULL) {
 634            return -ENOMEM;
 635        }
 636    } else {
 637        orig_buf = NULL;
 638        buf = (uint8_t *)qiov->iov->iov_base;
 639    }
 640
 641    qemu_co_mutex_lock(&s->lock);
 642
 643    while (bytes != 0) {
 644        /* prepare next request */
 645        ret = get_cluster_offset(bs, offset, 0, 0, 0, 0, &cluster_offset);
 646        if (ret < 0) {
 647            break;
 648        }
 649        offset_in_cluster = offset & (s->cluster_size - 1);
 650        n = s->cluster_size - offset_in_cluster;
 651        if (n > bytes) {
 652            n = bytes;
 653        }
 654
 655        if (!cluster_offset) {
 656            if (bs->backing) {
 657                /* read from the base image */
 658                qemu_co_mutex_unlock(&s->lock);
 659                /* qcow2 emits this on bs->file instead of bs->backing */
 660                BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO);
 661                ret = bdrv_co_pread(bs->backing, offset, n, buf, 0);
 662                qemu_co_mutex_lock(&s->lock);
 663                if (ret < 0) {
 664                    break;
 665                }
 666            } else {
 667                /* Note: in this case, no need to wait */
 668                memset(buf, 0, n);
 669            }
 670        } else if (cluster_offset & QCOW_OFLAG_COMPRESSED) {
 671            /* add AIO support for compressed blocks ? */
 672            if (decompress_cluster(bs, cluster_offset) < 0) {
 673                ret = -EIO;
 674                break;
 675            }
 676            memcpy(buf, s->cluster_cache + offset_in_cluster, n);
 677        } else {
 678            if ((cluster_offset & 511) != 0) {
 679                ret = -EIO;
 680                break;
 681            }
 682            qemu_co_mutex_unlock(&s->lock);
 683            BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO);
 684            ret = bdrv_co_pread(bs->file, cluster_offset + offset_in_cluster,
 685                                n, buf, 0);
 686            qemu_co_mutex_lock(&s->lock);
 687            if (ret < 0) {
 688                break;
 689            }
 690            if (bs->encrypted) {
 691                assert(s->crypto);
 692                if (qcrypto_block_decrypt(s->crypto,
 693                                          offset, buf, n, NULL) < 0) {
 694                    ret = -EIO;
 695                    break;
 696                }
 697            }
 698        }
 699        ret = 0;
 700
 701        bytes -= n;
 702        offset += n;
 703        buf += n;
 704    }
 705
 706    qemu_co_mutex_unlock(&s->lock);
 707
 708    if (qiov->niov > 1) {
 709        qemu_iovec_from_buf(qiov, 0, orig_buf, qiov->size);
 710        qemu_vfree(orig_buf);
 711    }
 712
 713    return ret;
 714}
 715
 716static int coroutine_fn GRAPH_RDLOCK
 717qcow_co_pwritev(BlockDriverState *bs, int64_t offset, int64_t bytes,
 718                QEMUIOVector *qiov, BdrvRequestFlags flags)
 719{
 720    BDRVQcowState *s = bs->opaque;
 721    int offset_in_cluster;
 722    uint64_t cluster_offset;
 723    int ret = 0, n;
 724    uint8_t *buf;
 725    void *orig_buf;
 726
 727    s->cluster_cache_offset = -1; /* disable compressed cache */
 728
 729    /* We must always copy the iov when encrypting, so we
 730     * don't modify the original data buffer during encryption */
 731    if (bs->encrypted || qiov->niov > 1) {
 732        buf = orig_buf = qemu_try_blockalign(bs, qiov->size);
 733        if (buf == NULL) {
 734            return -ENOMEM;
 735        }
 736        qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
 737    } else {
 738        orig_buf = NULL;
 739        buf = (uint8_t *)qiov->iov->iov_base;
 740    }
 741
 742    qemu_co_mutex_lock(&s->lock);
 743
 744    while (bytes != 0) {
 745        offset_in_cluster = offset & (s->cluster_size - 1);
 746        n = s->cluster_size - offset_in_cluster;
 747        if (n > bytes) {
 748            n = bytes;
 749        }
 750        ret = get_cluster_offset(bs, offset, 1, 0, offset_in_cluster,
 751                                 offset_in_cluster + n, &cluster_offset);
 752        if (ret < 0) {
 753            break;
 754        }
 755        if (!cluster_offset || (cluster_offset & 511) != 0) {
 756            ret = -EIO;
 757            break;
 758        }
 759        if (bs->encrypted) {
 760            assert(s->crypto);
 761            if (qcrypto_block_encrypt(s->crypto, offset, buf, n, NULL) < 0) {
 762                ret = -EIO;
 763                break;
 764            }
 765        }
 766
 767        qemu_co_mutex_unlock(&s->lock);
 768        BLKDBG_EVENT(bs->file, BLKDBG_WRITE_AIO);
 769        ret = bdrv_co_pwrite(bs->file, cluster_offset + offset_in_cluster,
 770                             n, buf, 0);
 771        qemu_co_mutex_lock(&s->lock);
 772        if (ret < 0) {
 773            break;
 774        }
 775        ret = 0;
 776
 777        bytes -= n;
 778        offset += n;
 779        buf += n;
 780    }
 781    qemu_co_mutex_unlock(&s->lock);
 782
 783    qemu_vfree(orig_buf);
 784
 785    return ret;
 786}
 787
 788static void qcow_close(BlockDriverState *bs)
 789{
 790    BDRVQcowState *s = bs->opaque;
 791
 792    qcrypto_block_free(s->crypto);
 793    s->crypto = NULL;
 794    g_free(s->l1_table);
 795    qemu_vfree(s->l2_cache);
 796    g_free(s->cluster_cache);
 797    g_free(s->cluster_data);
 798
 799    migrate_del_blocker(s->migration_blocker);
 800    error_free(s->migration_blocker);
 801}
 802
 803static int coroutine_fn qcow_co_create(BlockdevCreateOptions *opts,
 804                                       Error **errp)
 805{
 806    BlockdevCreateOptionsQcow *qcow_opts;
 807    int header_size, backing_filename_len, l1_size, shift, i;
 808    QCowHeader header;
 809    uint8_t *tmp;
 810    int64_t total_size = 0;
 811    int ret;
 812    BlockDriverState *bs;
 813    BlockBackend *qcow_blk;
 814    QCryptoBlock *crypto = NULL;
 815
 816    assert(opts->driver == BLOCKDEV_DRIVER_QCOW);
 817    qcow_opts = &opts->u.qcow;
 818
 819    /* Sanity checks */
 820    total_size = qcow_opts->size;
 821    if (total_size == 0) {
 822        error_setg(errp, "Image size is too small, cannot be zero length");
 823        return -EINVAL;
 824    }
 825
 826    if (qcow_opts->encrypt &&
 827        qcow_opts->encrypt->format != Q_CRYPTO_BLOCK_FORMAT_QCOW)
 828    {
 829        error_setg(errp, "Unsupported encryption format");
 830        return -EINVAL;
 831    }
 832
 833    /* Create BlockBackend to write to the image */
 834    bs = bdrv_co_open_blockdev_ref(qcow_opts->file, errp);
 835    if (bs == NULL) {
 836        return -EIO;
 837    }
 838
 839    qcow_blk = blk_co_new_with_bs(bs, BLK_PERM_WRITE | BLK_PERM_RESIZE,
 840                                  BLK_PERM_ALL, errp);
 841    if (!qcow_blk) {
 842        ret = -EPERM;
 843        goto exit;
 844    }
 845    blk_set_allow_write_beyond_eof(qcow_blk, true);
 846
 847    /* Create image format */
 848    memset(&header, 0, sizeof(header));
 849    header.magic = cpu_to_be32(QCOW_MAGIC);
 850    header.version = cpu_to_be32(QCOW_VERSION);
 851    header.size = cpu_to_be64(total_size);
 852    header_size = sizeof(header);
 853    backing_filename_len = 0;
 854    if (qcow_opts->backing_file) {
 855        if (strcmp(qcow_opts->backing_file, "fat:")) {
 856            header.backing_file_offset = cpu_to_be64(header_size);
 857            backing_filename_len = strlen(qcow_opts->backing_file);
 858            header.backing_file_size = cpu_to_be32(backing_filename_len);
 859            header_size += backing_filename_len;
 860        } else {
 861            /* special backing file for vvfat */
 862            qcow_opts->backing_file = NULL;
 863        }
 864        header.cluster_bits = 9; /* 512 byte cluster to avoid copying
 865                                    unmodified sectors */
 866        header.l2_bits = 12; /* 32 KB L2 tables */
 867    } else {
 868        header.cluster_bits = 12; /* 4 KB clusters */
 869        header.l2_bits = 9; /* 4 KB L2 tables */
 870    }
 871    header_size = (header_size + 7) & ~7;
 872    shift = header.cluster_bits + header.l2_bits;
 873    l1_size = (total_size + (1LL << shift) - 1) >> shift;
 874
 875    header.l1_table_offset = cpu_to_be64(header_size);
 876
 877    if (qcow_opts->encrypt) {
 878        header.crypt_method = cpu_to_be32(QCOW_CRYPT_AES);
 879
 880        crypto = qcrypto_block_create(qcow_opts->encrypt, "encrypt.",
 881                                      NULL, NULL, NULL, errp);
 882        if (!crypto) {
 883            ret = -EINVAL;
 884            goto exit;
 885        }
 886    } else {
 887        header.crypt_method = cpu_to_be32(QCOW_CRYPT_NONE);
 888    }
 889
 890    /* write all the data */
 891    ret = blk_co_pwrite(qcow_blk, 0, sizeof(header), &header, 0);
 892    if (ret < 0) {
 893        goto exit;
 894    }
 895
 896    if (qcow_opts->backing_file) {
 897        ret = blk_co_pwrite(qcow_blk, sizeof(header), backing_filename_len,
 898                            qcow_opts->backing_file, 0);
 899        if (ret < 0) {
 900            goto exit;
 901        }
 902    }
 903
 904    tmp = g_malloc0(BDRV_SECTOR_SIZE);
 905    for (i = 0; i < DIV_ROUND_UP(sizeof(uint64_t) * l1_size, BDRV_SECTOR_SIZE);
 906         i++) {
 907        ret = blk_co_pwrite(qcow_blk, header_size + BDRV_SECTOR_SIZE * i,
 908                            BDRV_SECTOR_SIZE, tmp, 0);
 909        if (ret < 0) {
 910            g_free(tmp);
 911            goto exit;
 912        }
 913    }
 914
 915    g_free(tmp);
 916    ret = 0;
 917exit:
 918    blk_co_unref(qcow_blk);
 919    bdrv_co_unref(bs);
 920    qcrypto_block_free(crypto);
 921    return ret;
 922}
 923
 924static int coroutine_fn GRAPH_RDLOCK
 925qcow_co_create_opts(BlockDriver *drv, const char *filename,
 926                    QemuOpts *opts, Error **errp)
 927{
 928    BlockdevCreateOptions *create_options = NULL;
 929    BlockDriverState *bs = NULL;
 930    QDict *qdict = NULL;
 931    Visitor *v;
 932    const char *val;
 933    int ret;
 934    char *backing_fmt;
 935
 936    static const QDictRenames opt_renames[] = {
 937        { BLOCK_OPT_BACKING_FILE,       "backing-file" },
 938        { BLOCK_OPT_ENCRYPT,            BLOCK_OPT_ENCRYPT_FORMAT },
 939        { NULL, NULL },
 940    };
 941
 942    /*
 943     * We can't actually store a backing format, but can check that
 944     * the user's request made sense.
 945     */
 946    backing_fmt = qemu_opt_get_del(opts, BLOCK_OPT_BACKING_FMT);
 947    if (backing_fmt && !bdrv_find_format(backing_fmt)) {
 948        error_setg(errp, "unrecognized backing format '%s'", backing_fmt);
 949        ret = -EINVAL;
 950        goto fail;
 951    }
 952
 953    /* Parse options and convert legacy syntax */
 954    qdict = qemu_opts_to_qdict_filtered(opts, NULL, &qcow_create_opts, true);
 955
 956    val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT);
 957    if (val && !strcmp(val, "on")) {
 958        qdict_put_str(qdict, BLOCK_OPT_ENCRYPT, "qcow");
 959    } else if (val && !strcmp(val, "off")) {
 960        qdict_del(qdict, BLOCK_OPT_ENCRYPT);
 961    }
 962
 963    val = qdict_get_try_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT);
 964    if (val && !strcmp(val, "aes")) {
 965        qdict_put_str(qdict, BLOCK_OPT_ENCRYPT_FORMAT, "qcow");
 966    }
 967
 968    if (!qdict_rename_keys(qdict, opt_renames, errp)) {
 969        ret = -EINVAL;
 970        goto fail;
 971    }
 972
 973    /* Create and open the file (protocol layer) */
 974    ret = bdrv_co_create_file(filename, opts, errp);
 975    if (ret < 0) {
 976        goto fail;
 977    }
 978
 979    bs = bdrv_co_open(filename, NULL, NULL,
 980                      BDRV_O_RDWR | BDRV_O_RESIZE | BDRV_O_PROTOCOL, errp);
 981    if (bs == NULL) {
 982        ret = -EIO;
 983        goto fail;
 984    }
 985
 986    /* Now get the QAPI type BlockdevCreateOptions */
 987    qdict_put_str(qdict, "driver", "qcow");
 988    qdict_put_str(qdict, "file", bs->node_name);
 989
 990    v = qobject_input_visitor_new_flat_confused(qdict, errp);
 991    if (!v) {
 992        ret = -EINVAL;
 993        goto fail;
 994    }
 995
 996    visit_type_BlockdevCreateOptions(v, NULL, &create_options, errp);
 997    visit_free(v);
 998    if (!create_options) {
 999        ret = -EINVAL;
1000        goto fail;
1001    }
1002
1003    /* Silently round up size */
1004    assert(create_options->driver == BLOCKDEV_DRIVER_QCOW);
1005    create_options->u.qcow.size =
1006        ROUND_UP(create_options->u.qcow.size, BDRV_SECTOR_SIZE);
1007
1008    /* Create the qcow image (format layer) */
1009    ret = qcow_co_create(create_options, errp);
1010    if (ret < 0) {
1011        goto fail;
1012    }
1013
1014    ret = 0;
1015fail:
1016    g_free(backing_fmt);
1017    qobject_unref(qdict);
1018    bdrv_co_unref(bs);
1019    qapi_free_BlockdevCreateOptions(create_options);
1020    return ret;
1021}
1022
1023static int qcow_make_empty(BlockDriverState *bs)
1024{
1025    BDRVQcowState *s = bs->opaque;
1026    uint32_t l1_length = s->l1_size * sizeof(uint64_t);
1027    int ret;
1028
1029    memset(s->l1_table, 0, l1_length);
1030    if (bdrv_pwrite_sync(bs->file, s->l1_table_offset, l1_length, s->l1_table,
1031                         0) < 0)
1032        return -1;
1033    ret = bdrv_truncate(bs->file, s->l1_table_offset + l1_length, false,
1034                        PREALLOC_MODE_OFF, 0, NULL);
1035    if (ret < 0)
1036        return ret;
1037
1038    memset(s->l2_cache, 0, s->l2_size * L2_CACHE_SIZE * sizeof(uint64_t));
1039    memset(s->l2_cache_offsets, 0, L2_CACHE_SIZE * sizeof(uint64_t));
1040    memset(s->l2_cache_counts, 0, L2_CACHE_SIZE * sizeof(uint32_t));
1041
1042    return 0;
1043}
1044
1045/* XXX: put compressed sectors first, then all the cluster aligned
1046   tables to avoid losing bytes in alignment */
1047static int coroutine_fn GRAPH_RDLOCK
1048qcow_co_pwritev_compressed(BlockDriverState *bs, int64_t offset, int64_t bytes,
1049                           QEMUIOVector *qiov)
1050{
1051    BDRVQcowState *s = bs->opaque;
1052    z_stream strm;
1053    int ret, out_len;
1054    uint8_t *buf, *out_buf;
1055    uint64_t cluster_offset;
1056
1057    buf = qemu_blockalign(bs, s->cluster_size);
1058    if (bytes != s->cluster_size) {
1059        if (bytes > s->cluster_size ||
1060            offset + bytes != bs->total_sectors << BDRV_SECTOR_BITS)
1061        {
1062            qemu_vfree(buf);
1063            return -EINVAL;
1064        }
1065        /* Zero-pad last write if image size is not cluster aligned */
1066        memset(buf + bytes, 0, s->cluster_size - bytes);
1067    }
1068    qemu_iovec_to_buf(qiov, 0, buf, qiov->size);
1069
1070    out_buf = g_malloc(s->cluster_size);
1071
1072    /* best compression, small window, no zlib header */
1073    memset(&strm, 0, sizeof(strm));
1074    ret = deflateInit2(&strm, Z_DEFAULT_COMPRESSION,
1075                       Z_DEFLATED, -12,
1076                       9, Z_DEFAULT_STRATEGY);
1077    if (ret != 0) {
1078        ret = -EINVAL;
1079        goto fail;
1080    }
1081
1082    strm.avail_in = s->cluster_size;
1083    strm.next_in = (uint8_t *)buf;
1084    strm.avail_out = s->cluster_size;
1085    strm.next_out = out_buf;
1086
1087    ret = deflate(&strm, Z_FINISH);
1088    if (ret != Z_STREAM_END && ret != Z_OK) {
1089        deflateEnd(&strm);
1090        ret = -EINVAL;
1091        goto fail;
1092    }
1093    out_len = strm.next_out - out_buf;
1094
1095    deflateEnd(&strm);
1096
1097    if (ret != Z_STREAM_END || out_len >= s->cluster_size) {
1098        /* could not compress: write normal cluster */
1099        ret = qcow_co_pwritev(bs, offset, bytes, qiov, 0);
1100        if (ret < 0) {
1101            goto fail;
1102        }
1103        goto success;
1104    }
1105    qemu_co_mutex_lock(&s->lock);
1106    ret = get_cluster_offset(bs, offset, 2, out_len, 0, 0, &cluster_offset);
1107    qemu_co_mutex_unlock(&s->lock);
1108    if (ret < 0) {
1109        goto fail;
1110    }
1111    if (cluster_offset == 0) {
1112        ret = -EIO;
1113        goto fail;
1114    }
1115    cluster_offset &= s->cluster_offset_mask;
1116
1117    BLKDBG_EVENT(bs->file, BLKDBG_WRITE_COMPRESSED);
1118    ret = bdrv_co_pwrite(bs->file, cluster_offset, out_len, out_buf, 0);
1119    if (ret < 0) {
1120        goto fail;
1121    }
1122success:
1123    ret = 0;
1124fail:
1125    qemu_vfree(buf);
1126    g_free(out_buf);
1127    return ret;
1128}
1129
1130static int coroutine_fn
1131qcow_co_get_info(BlockDriverState *bs, BlockDriverInfo *bdi)
1132{
1133    BDRVQcowState *s = bs->opaque;
1134    bdi->cluster_size = s->cluster_size;
1135    return 0;
1136}
1137
1138static QemuOptsList qcow_create_opts = {
1139    .name = "qcow-create-opts",
1140    .head = QTAILQ_HEAD_INITIALIZER(qcow_create_opts.head),
1141    .desc = {
1142        {
1143            .name = BLOCK_OPT_SIZE,
1144            .type = QEMU_OPT_SIZE,
1145            .help = "Virtual disk size"
1146        },
1147        {
1148            .name = BLOCK_OPT_BACKING_FILE,
1149            .type = QEMU_OPT_STRING,
1150            .help = "File name of a base image"
1151        },
1152        {
1153            .name = BLOCK_OPT_BACKING_FMT,
1154            .type = QEMU_OPT_STRING,
1155            .help = "Format of the backing image",
1156        },
1157        {
1158            .name = BLOCK_OPT_ENCRYPT,
1159            .type = QEMU_OPT_BOOL,
1160            .help = "Encrypt the image with format 'aes'. (Deprecated "
1161                    "in favor of " BLOCK_OPT_ENCRYPT_FORMAT "=aes)",
1162        },
1163        {
1164            .name = BLOCK_OPT_ENCRYPT_FORMAT,
1165            .type = QEMU_OPT_STRING,
1166            .help = "Encrypt the image, format choices: 'aes'",
1167        },
1168        BLOCK_CRYPTO_OPT_DEF_QCOW_KEY_SECRET("encrypt."),
1169        { /* end of list */ }
1170    }
1171};
1172
1173static const char *const qcow_strong_runtime_opts[] = {
1174    "encrypt." BLOCK_CRYPTO_OPT_QCOW_KEY_SECRET,
1175
1176    NULL
1177};
1178
1179static BlockDriver bdrv_qcow = {
1180    .format_name        = "qcow",
1181    .instance_size      = sizeof(BDRVQcowState),
1182    .bdrv_probe         = qcow_probe,
1183    .bdrv_open          = qcow_open,
1184    .bdrv_close         = qcow_close,
1185    .bdrv_child_perm        = bdrv_default_perms,
1186    .bdrv_reopen_prepare    = qcow_reopen_prepare,
1187    .bdrv_co_create         = qcow_co_create,
1188    .bdrv_co_create_opts    = qcow_co_create_opts,
1189    .bdrv_has_zero_init     = bdrv_has_zero_init_1,
1190    .is_format              = true,
1191    .supports_backing       = true,
1192    .bdrv_refresh_limits    = qcow_refresh_limits,
1193
1194    .bdrv_co_preadv         = qcow_co_preadv,
1195    .bdrv_co_pwritev        = qcow_co_pwritev,
1196    .bdrv_co_block_status   = qcow_co_block_status,
1197
1198    .bdrv_make_empty        = qcow_make_empty,
1199    .bdrv_co_pwritev_compressed = qcow_co_pwritev_compressed,
1200    .bdrv_co_get_info       = qcow_co_get_info,
1201
1202    .create_opts            = &qcow_create_opts,
1203    .strong_runtime_opts    = qcow_strong_runtime_opts,
1204};
1205
1206static void bdrv_qcow_init(void)
1207{
1208    bdrv_register(&bdrv_qcow);
1209}
1210
1211block_init(bdrv_qcow_init);
1212