qemu/block/qcow2.h
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   1/*
   2 * Block driver for the QCOW version 2 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#ifndef BLOCK_QCOW2_H
  26#define BLOCK_QCOW2_H
  27
  28#include "crypto/block.h"
  29#include "qemu/coroutine.h"
  30#include "qemu/units.h"
  31#include "block/block_int.h"
  32
  33//#define DEBUG_ALLOC
  34//#define DEBUG_ALLOC2
  35//#define DEBUG_EXT
  36
  37#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  38
  39#define QCOW_CRYPT_NONE 0
  40#define QCOW_CRYPT_AES  1
  41#define QCOW_CRYPT_LUKS 2
  42
  43#define QCOW_MAX_CRYPT_CLUSTERS 32
  44#define QCOW_MAX_SNAPSHOTS 65536
  45
  46/* Field widths in qcow2 mean normal cluster offsets cannot reach
  47 * 64PB; depending on cluster size, compressed clusters can have a
  48 * smaller limit (64PB for up to 16k clusters, then ramps down to
  49 * 512TB for 2M clusters).  */
  50#define QCOW_MAX_CLUSTER_OFFSET ((1ULL << 56) - 1)
  51
  52/* 8 MB refcount table is enough for 2 PB images at 64k cluster size
  53 * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
  54#define QCOW_MAX_REFTABLE_SIZE (8 * MiB)
  55
  56/* 32 MB L1 table is enough for 2 PB images at 64k cluster size
  57 * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
  58#define QCOW_MAX_L1_SIZE (32 * MiB)
  59
  60/* Allow for an average of 1k per snapshot table entry, should be plenty of
  61 * space for snapshot names and IDs */
  62#define QCOW_MAX_SNAPSHOTS_SIZE (1024 * QCOW_MAX_SNAPSHOTS)
  63
  64/* Bitmap header extension constraints */
  65#define QCOW2_MAX_BITMAPS 65535
  66#define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS)
  67
  68/* indicate that the refcount of the referenced cluster is exactly one. */
  69#define QCOW_OFLAG_COPIED     (1ULL << 63)
  70/* indicate that the cluster is compressed (they never have the copied flag) */
  71#define QCOW_OFLAG_COMPRESSED (1ULL << 62)
  72/* The cluster reads as all zeros */
  73#define QCOW_OFLAG_ZERO (1ULL << 0)
  74
  75#define MIN_CLUSTER_BITS 9
  76#define MAX_CLUSTER_BITS 21
  77
  78/* Defined in the qcow2 spec (compressed cluster descriptor) */
  79#define QCOW2_COMPRESSED_SECTOR_SIZE 512U
  80#define QCOW2_COMPRESSED_SECTOR_MASK (~(QCOW2_COMPRESSED_SECTOR_SIZE - 1ULL))
  81
  82/* Must be at least 2 to cover COW */
  83#define MIN_L2_CACHE_SIZE 2 /* cache entries */
  84
  85/* Must be at least 4 to cover all cases of refcount table growth */
  86#define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
  87
  88#ifdef CONFIG_LINUX
  89#define DEFAULT_L2_CACHE_MAX_SIZE (32 * MiB)
  90#define DEFAULT_CACHE_CLEAN_INTERVAL 600  /* seconds */
  91#else
  92#define DEFAULT_L2_CACHE_MAX_SIZE (8 * MiB)
  93/* Cache clean interval is currently available only on Linux, so must be 0 */
  94#define DEFAULT_CACHE_CLEAN_INTERVAL 0
  95#endif
  96
  97#define DEFAULT_CLUSTER_SIZE 65536
  98
  99#define QCOW2_OPT_DATA_FILE "data-file"
 100#define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts"
 101#define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request"
 102#define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot"
 103#define QCOW2_OPT_DISCARD_OTHER "pass-discard-other"
 104#define QCOW2_OPT_OVERLAP "overlap-check"
 105#define QCOW2_OPT_OVERLAP_TEMPLATE "overlap-check.template"
 106#define QCOW2_OPT_OVERLAP_MAIN_HEADER "overlap-check.main-header"
 107#define QCOW2_OPT_OVERLAP_ACTIVE_L1 "overlap-check.active-l1"
 108#define QCOW2_OPT_OVERLAP_ACTIVE_L2 "overlap-check.active-l2"
 109#define QCOW2_OPT_OVERLAP_REFCOUNT_TABLE "overlap-check.refcount-table"
 110#define QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK "overlap-check.refcount-block"
 111#define QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE "overlap-check.snapshot-table"
 112#define QCOW2_OPT_OVERLAP_INACTIVE_L1 "overlap-check.inactive-l1"
 113#define QCOW2_OPT_OVERLAP_INACTIVE_L2 "overlap-check.inactive-l2"
 114#define QCOW2_OPT_OVERLAP_BITMAP_DIRECTORY "overlap-check.bitmap-directory"
 115#define QCOW2_OPT_CACHE_SIZE "cache-size"
 116#define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size"
 117#define QCOW2_OPT_L2_CACHE_ENTRY_SIZE "l2-cache-entry-size"
 118#define QCOW2_OPT_REFCOUNT_CACHE_SIZE "refcount-cache-size"
 119#define QCOW2_OPT_CACHE_CLEAN_INTERVAL "cache-clean-interval"
 120
 121typedef struct QCowHeader {
 122    uint32_t magic;
 123    uint32_t version;
 124    uint64_t backing_file_offset;
 125    uint32_t backing_file_size;
 126    uint32_t cluster_bits;
 127    uint64_t size; /* in bytes */
 128    uint32_t crypt_method;
 129    uint32_t l1_size; /* XXX: save number of clusters instead ? */
 130    uint64_t l1_table_offset;
 131    uint64_t refcount_table_offset;
 132    uint32_t refcount_table_clusters;
 133    uint32_t nb_snapshots;
 134    uint64_t snapshots_offset;
 135
 136    /* The following fields are only valid for version >= 3 */
 137    uint64_t incompatible_features;
 138    uint64_t compatible_features;
 139    uint64_t autoclear_features;
 140
 141    uint32_t refcount_order;
 142    uint32_t header_length;
 143} QEMU_PACKED QCowHeader;
 144
 145typedef struct QEMU_PACKED QCowSnapshotHeader {
 146    /* header is 8 byte aligned */
 147    uint64_t l1_table_offset;
 148
 149    uint32_t l1_size;
 150    uint16_t id_str_size;
 151    uint16_t name_size;
 152
 153    uint32_t date_sec;
 154    uint32_t date_nsec;
 155
 156    uint64_t vm_clock_nsec;
 157
 158    uint32_t vm_state_size;
 159    uint32_t extra_data_size; /* for extension */
 160    /* extra data follows */
 161    /* id_str follows */
 162    /* name follows  */
 163} QCowSnapshotHeader;
 164
 165typedef struct QEMU_PACKED QCowSnapshotExtraData {
 166    uint64_t vm_state_size_large;
 167    uint64_t disk_size;
 168} QCowSnapshotExtraData;
 169
 170
 171typedef struct QCowSnapshot {
 172    uint64_t l1_table_offset;
 173    uint32_t l1_size;
 174    char *id_str;
 175    char *name;
 176    uint64_t disk_size;
 177    uint64_t vm_state_size;
 178    uint32_t date_sec;
 179    uint32_t date_nsec;
 180    uint64_t vm_clock_nsec;
 181} QCowSnapshot;
 182
 183struct Qcow2Cache;
 184typedef struct Qcow2Cache Qcow2Cache;
 185
 186typedef struct Qcow2CryptoHeaderExtension {
 187    uint64_t offset;
 188    uint64_t length;
 189} QEMU_PACKED Qcow2CryptoHeaderExtension;
 190
 191typedef struct Qcow2UnknownHeaderExtension {
 192    uint32_t magic;
 193    uint32_t len;
 194    QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
 195    uint8_t data[];
 196} Qcow2UnknownHeaderExtension;
 197
 198enum {
 199    QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,
 200    QCOW2_FEAT_TYPE_COMPATIBLE      = 1,
 201    QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
 202};
 203
 204/* Incompatible feature bits */
 205enum {
 206    QCOW2_INCOMPAT_DIRTY_BITNR      = 0,
 207    QCOW2_INCOMPAT_CORRUPT_BITNR    = 1,
 208    QCOW2_INCOMPAT_DATA_FILE_BITNR  = 2,
 209    QCOW2_INCOMPAT_DIRTY            = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
 210    QCOW2_INCOMPAT_CORRUPT          = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR,
 211    QCOW2_INCOMPAT_DATA_FILE        = 1 << QCOW2_INCOMPAT_DATA_FILE_BITNR,
 212
 213    QCOW2_INCOMPAT_MASK             = QCOW2_INCOMPAT_DIRTY
 214                                    | QCOW2_INCOMPAT_CORRUPT
 215                                    | QCOW2_INCOMPAT_DATA_FILE,
 216};
 217
 218/* Compatible feature bits */
 219enum {
 220    QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
 221    QCOW2_COMPAT_LAZY_REFCOUNTS       = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
 222
 223    QCOW2_COMPAT_FEAT_MASK            = QCOW2_COMPAT_LAZY_REFCOUNTS,
 224};
 225
 226/* Autoclear feature bits */
 227enum {
 228    QCOW2_AUTOCLEAR_BITMAPS_BITNR       = 0,
 229    QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR = 1,
 230    QCOW2_AUTOCLEAR_BITMAPS             = 1 << QCOW2_AUTOCLEAR_BITMAPS_BITNR,
 231    QCOW2_AUTOCLEAR_DATA_FILE_RAW       = 1 << QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR,
 232
 233    QCOW2_AUTOCLEAR_MASK                = QCOW2_AUTOCLEAR_BITMAPS
 234                                        | QCOW2_AUTOCLEAR_DATA_FILE_RAW,
 235};
 236
 237enum qcow2_discard_type {
 238    QCOW2_DISCARD_NEVER = 0,
 239    QCOW2_DISCARD_ALWAYS,
 240    QCOW2_DISCARD_REQUEST,
 241    QCOW2_DISCARD_SNAPSHOT,
 242    QCOW2_DISCARD_OTHER,
 243    QCOW2_DISCARD_MAX
 244};
 245
 246typedef struct Qcow2Feature {
 247    uint8_t type;
 248    uint8_t bit;
 249    char    name[46];
 250} QEMU_PACKED Qcow2Feature;
 251
 252typedef struct Qcow2DiscardRegion {
 253    BlockDriverState *bs;
 254    uint64_t offset;
 255    uint64_t bytes;
 256    QTAILQ_ENTRY(Qcow2DiscardRegion) next;
 257} Qcow2DiscardRegion;
 258
 259typedef uint64_t Qcow2GetRefcountFunc(const void *refcount_array,
 260                                      uint64_t index);
 261typedef void Qcow2SetRefcountFunc(void *refcount_array,
 262                                  uint64_t index, uint64_t value);
 263
 264typedef struct Qcow2BitmapHeaderExt {
 265    uint32_t nb_bitmaps;
 266    uint32_t reserved32;
 267    uint64_t bitmap_directory_size;
 268    uint64_t bitmap_directory_offset;
 269} QEMU_PACKED Qcow2BitmapHeaderExt;
 270
 271#define QCOW2_MAX_THREADS 4
 272
 273typedef struct BDRVQcow2State {
 274    int cluster_bits;
 275    int cluster_size;
 276    int l2_slice_size;
 277    int l2_bits;
 278    int l2_size;
 279    int l1_size;
 280    int l1_vm_state_index;
 281    int refcount_block_bits;
 282    int refcount_block_size;
 283    int csize_shift;
 284    int csize_mask;
 285    uint64_t cluster_offset_mask;
 286    uint64_t l1_table_offset;
 287    uint64_t *l1_table;
 288
 289    Qcow2Cache* l2_table_cache;
 290    Qcow2Cache* refcount_block_cache;
 291    QEMUTimer *cache_clean_timer;
 292    unsigned cache_clean_interval;
 293
 294    uint8_t *cluster_cache;
 295    uint8_t *cluster_data;
 296    uint64_t cluster_cache_offset;
 297    QLIST_HEAD(, QCowL2Meta) cluster_allocs;
 298
 299    uint64_t *refcount_table;
 300    uint64_t refcount_table_offset;
 301    uint32_t refcount_table_size;
 302    uint32_t max_refcount_table_index; /* Last used entry in refcount_table */
 303    uint64_t free_cluster_index;
 304    uint64_t free_byte_offset;
 305
 306    CoMutex lock;
 307
 308    Qcow2CryptoHeaderExtension crypto_header; /* QCow2 header extension */
 309    QCryptoBlockOpenOptions *crypto_opts; /* Disk encryption runtime options */
 310    QCryptoBlock *crypto; /* Disk encryption format driver */
 311    bool crypt_physical_offset; /* Whether to use virtual or physical offset
 312                                   for encryption initialization vector tweak */
 313    uint32_t crypt_method_header;
 314    uint64_t snapshots_offset;
 315    int snapshots_size;
 316    unsigned int nb_snapshots;
 317    QCowSnapshot *snapshots;
 318
 319    uint32_t nb_bitmaps;
 320    uint64_t bitmap_directory_size;
 321    uint64_t bitmap_directory_offset;
 322
 323    int flags;
 324    int qcow_version;
 325    bool use_lazy_refcounts;
 326    int refcount_order;
 327    int refcount_bits;
 328    uint64_t refcount_max;
 329
 330    Qcow2GetRefcountFunc *get_refcount;
 331    Qcow2SetRefcountFunc *set_refcount;
 332
 333    bool discard_passthrough[QCOW2_DISCARD_MAX];
 334
 335    int overlap_check; /* bitmask of Qcow2MetadataOverlap values */
 336    bool signaled_corruption;
 337
 338    uint64_t incompatible_features;
 339    uint64_t compatible_features;
 340    uint64_t autoclear_features;
 341
 342    size_t unknown_header_fields_size;
 343    void* unknown_header_fields;
 344    QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 345    QTAILQ_HEAD (, Qcow2DiscardRegion) discards;
 346    bool cache_discards;
 347
 348    /* Backing file path and format as stored in the image (this is not the
 349     * effective path/format, which may be the result of a runtime option
 350     * override) */
 351    char *image_backing_file;
 352    char *image_backing_format;
 353    char *image_data_file;
 354
 355    CoQueue thread_task_queue;
 356    int nb_threads;
 357
 358    BdrvChild *data_file;
 359
 360    bool metadata_preallocation_checked;
 361    bool metadata_preallocation;
 362} BDRVQcow2State;
 363
 364typedef struct Qcow2COWRegion {
 365    /**
 366     * Offset of the COW region in bytes from the start of the first cluster
 367     * touched by the request.
 368     */
 369    unsigned    offset;
 370
 371    /** Number of bytes to copy */
 372    unsigned    nb_bytes;
 373} Qcow2COWRegion;
 374
 375/**
 376 * Describes an in-flight (part of a) write request that writes to clusters
 377 * that are not referenced in their L2 table yet.
 378 */
 379typedef struct QCowL2Meta
 380{
 381    /** Guest offset of the first newly allocated cluster */
 382    uint64_t offset;
 383
 384    /** Host offset of the first newly allocated cluster */
 385    uint64_t alloc_offset;
 386
 387    /** Number of newly allocated clusters */
 388    int nb_clusters;
 389
 390    /** Do not free the old clusters */
 391    bool keep_old_clusters;
 392
 393    /**
 394     * Requests that overlap with this allocation and wait to be restarted
 395     * when the allocating request has completed.
 396     */
 397    CoQueue dependent_requests;
 398
 399    /**
 400     * The COW Region between the start of the first allocated cluster and the
 401     * area the guest actually writes to.
 402     */
 403    Qcow2COWRegion cow_start;
 404
 405    /**
 406     * The COW Region between the area the guest actually writes to and the
 407     * end of the last allocated cluster.
 408     */
 409    Qcow2COWRegion cow_end;
 410
 411    /*
 412     * Indicates that COW regions are already handled and do not require
 413     * any more processing.
 414     */
 415    bool skip_cow;
 416
 417    /**
 418     * The I/O vector with the data from the actual guest write request.
 419     * If non-NULL, this is meant to be merged together with the data
 420     * from @cow_start and @cow_end into one single write operation.
 421     */
 422    QEMUIOVector *data_qiov;
 423
 424    /** Pointer to next L2Meta of the same write request */
 425    struct QCowL2Meta *next;
 426
 427    QLIST_ENTRY(QCowL2Meta) next_in_flight;
 428} QCowL2Meta;
 429
 430typedef enum QCow2ClusterType {
 431    QCOW2_CLUSTER_UNALLOCATED,
 432    QCOW2_CLUSTER_ZERO_PLAIN,
 433    QCOW2_CLUSTER_ZERO_ALLOC,
 434    QCOW2_CLUSTER_NORMAL,
 435    QCOW2_CLUSTER_COMPRESSED,
 436} QCow2ClusterType;
 437
 438typedef enum QCow2MetadataOverlap {
 439    QCOW2_OL_MAIN_HEADER_BITNR      = 0,
 440    QCOW2_OL_ACTIVE_L1_BITNR        = 1,
 441    QCOW2_OL_ACTIVE_L2_BITNR        = 2,
 442    QCOW2_OL_REFCOUNT_TABLE_BITNR   = 3,
 443    QCOW2_OL_REFCOUNT_BLOCK_BITNR   = 4,
 444    QCOW2_OL_SNAPSHOT_TABLE_BITNR   = 5,
 445    QCOW2_OL_INACTIVE_L1_BITNR      = 6,
 446    QCOW2_OL_INACTIVE_L2_BITNR      = 7,
 447    QCOW2_OL_BITMAP_DIRECTORY_BITNR = 8,
 448
 449    QCOW2_OL_MAX_BITNR              = 9,
 450
 451    QCOW2_OL_NONE             = 0,
 452    QCOW2_OL_MAIN_HEADER      = (1 << QCOW2_OL_MAIN_HEADER_BITNR),
 453    QCOW2_OL_ACTIVE_L1        = (1 << QCOW2_OL_ACTIVE_L1_BITNR),
 454    QCOW2_OL_ACTIVE_L2        = (1 << QCOW2_OL_ACTIVE_L2_BITNR),
 455    QCOW2_OL_REFCOUNT_TABLE   = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR),
 456    QCOW2_OL_REFCOUNT_BLOCK   = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR),
 457    QCOW2_OL_SNAPSHOT_TABLE   = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR),
 458    QCOW2_OL_INACTIVE_L1      = (1 << QCOW2_OL_INACTIVE_L1_BITNR),
 459    /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv
 460     * reads. */
 461    QCOW2_OL_INACTIVE_L2      = (1 << QCOW2_OL_INACTIVE_L2_BITNR),
 462    QCOW2_OL_BITMAP_DIRECTORY = (1 << QCOW2_OL_BITMAP_DIRECTORY_BITNR),
 463} QCow2MetadataOverlap;
 464
 465/* Perform all overlap checks which can be done in constant time */
 466#define QCOW2_OL_CONSTANT \
 467    (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \
 468     QCOW2_OL_SNAPSHOT_TABLE | QCOW2_OL_BITMAP_DIRECTORY)
 469
 470/* Perform all overlap checks which don't require disk access */
 471#define QCOW2_OL_CACHED \
 472    (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \
 473     QCOW2_OL_INACTIVE_L1)
 474
 475/* Perform all overlap checks */
 476#define QCOW2_OL_ALL \
 477    (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2)
 478
 479#define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
 480#define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
 481#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
 482
 483#define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
 484
 485#define INV_OFFSET (-1ULL)
 486
 487static inline bool has_data_file(BlockDriverState *bs)
 488{
 489    BDRVQcow2State *s = bs->opaque;
 490    return (s->data_file != bs->file);
 491}
 492
 493static inline bool data_file_is_raw(BlockDriverState *bs)
 494{
 495    BDRVQcow2State *s = bs->opaque;
 496    return !!(s->autoclear_features & QCOW2_AUTOCLEAR_DATA_FILE_RAW);
 497}
 498
 499static inline int64_t start_of_cluster(BDRVQcow2State *s, int64_t offset)
 500{
 501    return offset & ~(s->cluster_size - 1);
 502}
 503
 504static inline int64_t offset_into_cluster(BDRVQcow2State *s, int64_t offset)
 505{
 506    return offset & (s->cluster_size - 1);
 507}
 508
 509static inline uint64_t size_to_clusters(BDRVQcow2State *s, uint64_t size)
 510{
 511    return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 512}
 513
 514static inline int64_t size_to_l1(BDRVQcow2State *s, int64_t size)
 515{
 516    int shift = s->cluster_bits + s->l2_bits;
 517    return (size + (1ULL << shift) - 1) >> shift;
 518}
 519
 520static inline int offset_to_l1_index(BDRVQcow2State *s, uint64_t offset)
 521{
 522    return offset >> (s->l2_bits + s->cluster_bits);
 523}
 524
 525static inline int offset_to_l2_index(BDRVQcow2State *s, int64_t offset)
 526{
 527    return (offset >> s->cluster_bits) & (s->l2_size - 1);
 528}
 529
 530static inline int offset_to_l2_slice_index(BDRVQcow2State *s, int64_t offset)
 531{
 532    return (offset >> s->cluster_bits) & (s->l2_slice_size - 1);
 533}
 534
 535static inline int64_t qcow2_vm_state_offset(BDRVQcow2State *s)
 536{
 537    return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
 538}
 539
 540static inline QCow2ClusterType qcow2_get_cluster_type(BlockDriverState *bs,
 541                                                      uint64_t l2_entry)
 542{
 543    if (l2_entry & QCOW_OFLAG_COMPRESSED) {
 544        return QCOW2_CLUSTER_COMPRESSED;
 545    } else if (l2_entry & QCOW_OFLAG_ZERO) {
 546        if (l2_entry & L2E_OFFSET_MASK) {
 547            return QCOW2_CLUSTER_ZERO_ALLOC;
 548        }
 549        return QCOW2_CLUSTER_ZERO_PLAIN;
 550    } else if (!(l2_entry & L2E_OFFSET_MASK)) {
 551        /* Offset 0 generally means unallocated, but it is ambiguous with
 552         * external data files because 0 is a valid offset there. However, all
 553         * clusters in external data files always have refcount 1, so we can
 554         * rely on QCOW_OFLAG_COPIED to disambiguate. */
 555        if (has_data_file(bs) && (l2_entry & QCOW_OFLAG_COPIED)) {
 556            return QCOW2_CLUSTER_NORMAL;
 557        } else {
 558            return QCOW2_CLUSTER_UNALLOCATED;
 559        }
 560    } else {
 561        return QCOW2_CLUSTER_NORMAL;
 562    }
 563}
 564
 565/* Check whether refcounts are eager or lazy */
 566static inline bool qcow2_need_accurate_refcounts(BDRVQcow2State *s)
 567{
 568    return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
 569}
 570
 571static inline uint64_t l2meta_cow_start(QCowL2Meta *m)
 572{
 573    return m->offset + m->cow_start.offset;
 574}
 575
 576static inline uint64_t l2meta_cow_end(QCowL2Meta *m)
 577{
 578    return m->offset + m->cow_end.offset + m->cow_end.nb_bytes;
 579}
 580
 581static inline uint64_t refcount_diff(uint64_t r1, uint64_t r2)
 582{
 583    return r1 > r2 ? r1 - r2 : r2 - r1;
 584}
 585
 586static inline
 587uint32_t offset_to_reftable_index(BDRVQcow2State *s, uint64_t offset)
 588{
 589    return offset >> (s->refcount_block_bits + s->cluster_bits);
 590}
 591
 592/* qcow2.c functions */
 593int64_t qcow2_refcount_metadata_size(int64_t clusters, size_t cluster_size,
 594                                     int refcount_order, bool generous_increase,
 595                                     uint64_t *refblock_count);
 596
 597int qcow2_mark_dirty(BlockDriverState *bs);
 598int qcow2_mark_corrupt(BlockDriverState *bs);
 599int qcow2_mark_consistent(BlockDriverState *bs);
 600int qcow2_update_header(BlockDriverState *bs);
 601
 602void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
 603                             int64_t size, const char *message_format, ...)
 604                             GCC_FMT_ATTR(5, 6);
 605
 606int qcow2_validate_table(BlockDriverState *bs, uint64_t offset,
 607                         uint64_t entries, size_t entry_len,
 608                         int64_t max_size_bytes, const char *table_name,
 609                         Error **errp);
 610
 611/* qcow2-refcount.c functions */
 612int qcow2_refcount_init(BlockDriverState *bs);
 613void qcow2_refcount_close(BlockDriverState *bs);
 614
 615int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index,
 616                       uint64_t *refcount);
 617
 618int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index,
 619                                  uint64_t addend, bool decrease,
 620                                  enum qcow2_discard_type type);
 621
 622int64_t qcow2_refcount_area(BlockDriverState *bs, uint64_t offset,
 623                            uint64_t additional_clusters, bool exact_size,
 624                            int new_refblock_index,
 625                            uint64_t new_refblock_offset);
 626
 627int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size);
 628int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 629                                int64_t nb_clusters);
 630int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 631void qcow2_free_clusters(BlockDriverState *bs,
 632                          int64_t offset, int64_t size,
 633                          enum qcow2_discard_type type);
 634void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
 635                             int nb_clusters, enum qcow2_discard_type type);
 636
 637int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 638    int64_t l1_table_offset, int l1_size, int addend);
 639
 640int coroutine_fn qcow2_flush_caches(BlockDriverState *bs);
 641int coroutine_fn qcow2_write_caches(BlockDriverState *bs);
 642int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 643                          BdrvCheckMode fix);
 644
 645void qcow2_process_discards(BlockDriverState *bs, int ret);
 646
 647int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
 648                                 int64_t size);
 649int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
 650                                  int64_t size, bool data_file);
 651int qcow2_inc_refcounts_imrt(BlockDriverState *bs, BdrvCheckResult *res,
 652                             void **refcount_table,
 653                             int64_t *refcount_table_size,
 654                             int64_t offset, int64_t size);
 655
 656int qcow2_change_refcount_order(BlockDriverState *bs, int refcount_order,
 657                                BlockDriverAmendStatusCB *status_cb,
 658                                void *cb_opaque, Error **errp);
 659int qcow2_shrink_reftable(BlockDriverState *bs);
 660int64_t qcow2_get_last_cluster(BlockDriverState *bs, int64_t size);
 661int qcow2_detect_metadata_preallocation(BlockDriverState *bs);
 662
 663/* qcow2-cluster.c functions */
 664int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
 665                        bool exact_size);
 666int qcow2_shrink_l1_table(BlockDriverState *bs, uint64_t max_size);
 667int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
 668int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num,
 669                          uint8_t *buf, int nb_sectors, bool enc, Error **errp);
 670
 671int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 672                             unsigned int *bytes, uint64_t *cluster_offset);
 673int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 674                               unsigned int *bytes, uint64_t *host_offset,
 675                               QCowL2Meta **m);
 676int qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 677                                          uint64_t offset,
 678                                          int compressed_size,
 679                                          uint64_t *host_offset);
 680
 681int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 682void qcow2_alloc_cluster_abort(BlockDriverState *bs, QCowL2Meta *m);
 683int qcow2_cluster_discard(BlockDriverState *bs, uint64_t offset,
 684                          uint64_t bytes, enum qcow2_discard_type type,
 685                          bool full_discard);
 686int qcow2_cluster_zeroize(BlockDriverState *bs, uint64_t offset,
 687                          uint64_t bytes, int flags);
 688
 689int qcow2_expand_zero_clusters(BlockDriverState *bs,
 690                               BlockDriverAmendStatusCB *status_cb,
 691                               void *cb_opaque);
 692
 693/* qcow2-snapshot.c functions */
 694int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 695int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 696int qcow2_snapshot_delete(BlockDriverState *bs,
 697                          const char *snapshot_id,
 698                          const char *name,
 699                          Error **errp);
 700int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 701int qcow2_snapshot_load_tmp(BlockDriverState *bs,
 702                            const char *snapshot_id,
 703                            const char *name,
 704                            Error **errp);
 705
 706void qcow2_free_snapshots(BlockDriverState *bs);
 707int qcow2_read_snapshots(BlockDriverState *bs);
 708
 709/* qcow2-cache.c functions */
 710Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
 711                               unsigned table_size);
 712int qcow2_cache_destroy(Qcow2Cache *c);
 713
 714void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 715int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 716int qcow2_cache_write(BlockDriverState *bs, Qcow2Cache *c);
 717int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 718    Qcow2Cache *dependency);
 719void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 720
 721void qcow2_cache_clean_unused(Qcow2Cache *c);
 722int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c);
 723
 724int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 725    void **table);
 726int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 727    void **table);
 728void qcow2_cache_put(Qcow2Cache *c, void **table);
 729void *qcow2_cache_is_table_offset(Qcow2Cache *c, uint64_t offset);
 730void qcow2_cache_discard(Qcow2Cache *c, void *table);
 731
 732/* qcow2-bitmap.c functions */
 733int qcow2_check_bitmaps_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 734                                  void **refcount_table,
 735                                  int64_t *refcount_table_size);
 736bool qcow2_load_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 737Qcow2BitmapInfoList *qcow2_get_bitmap_info_list(BlockDriverState *bs,
 738                                                Error **errp);
 739int qcow2_reopen_bitmaps_rw_hint(BlockDriverState *bs, bool *header_updated,
 740                                 Error **errp);
 741int qcow2_reopen_bitmaps_rw(BlockDriverState *bs, Error **errp);
 742int qcow2_truncate_bitmaps_check(BlockDriverState *bs, Error **errp);
 743void qcow2_store_persistent_dirty_bitmaps(BlockDriverState *bs, Error **errp);
 744int qcow2_reopen_bitmaps_ro(BlockDriverState *bs, Error **errp);
 745bool qcow2_can_store_new_dirty_bitmap(BlockDriverState *bs,
 746                                      const char *name,
 747                                      uint32_t granularity,
 748                                      Error **errp);
 749void qcow2_remove_persistent_dirty_bitmap(BlockDriverState *bs,
 750                                          const char *name,
 751                                          Error **errp);
 752
 753ssize_t coroutine_fn
 754qcow2_co_compress(BlockDriverState *bs, void *dest, size_t dest_size,
 755                  const void *src, size_t src_size);
 756ssize_t coroutine_fn
 757qcow2_co_decompress(BlockDriverState *bs, void *dest, size_t dest_size,
 758                    const void *src, size_t src_size);
 759int coroutine_fn
 760qcow2_co_encrypt(BlockDriverState *bs, uint64_t file_cluster_offset,
 761                 uint64_t offset, void *buf, size_t len);
 762int coroutine_fn
 763qcow2_co_decrypt(BlockDriverState *bs, uint64_t file_cluster_offset,
 764                 uint64_t offset, void *buf, size_t len);
 765
 766#endif
 767