block/qcow2.h

   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 "qemu/aes.h"
  29 #include "block/coroutine.h"
  30
  31 //#define DEBUG_ALLOC
  32 //#define DEBUG_ALLOC2
  33 //#define DEBUG_EXT
  34
  35 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  36
  37 #define QCOW_CRYPT_NONE 0
  38 #define QCOW_CRYPT_AES  1
  39
  40 #define QCOW_MAX_CRYPT_CLUSTERS 32
  41 #define QCOW_MAX_SNAPSHOTS 65536
  42
  43 /* 8 MB refcount table is enough for 2 PB images at 64k cluster size
  44  * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
  45 #define QCOW_MAX_REFTABLE_SIZE 0x800000
  46
  47 /* 32 MB L1 table is enough for 2 PB images at 64k cluster size
  48  * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */
  49 #define QCOW_MAX_L1_SIZE 0x2000000
  50
  51 /* Allow for an average of 1k per snapshot table entry, should be plenty of
  52  * space for snapshot names and IDs */
  53 #define QCOW_MAX_SNAPSHOTS_SIZE (1024 * QCOW_MAX_SNAPSHOTS)
  54
  55 /* indicate that the refcount of the referenced cluster is exactly one. */
  56 #define QCOW_OFLAG_COPIED     (1ULL << 63)
  57 /* indicate that the cluster is compressed (they never have the copied flag) */
  58 #define QCOW_OFLAG_COMPRESSED (1ULL << 62)
  59 /* The cluster reads as all zeros */
  60 #define QCOW_OFLAG_ZERO (1ULL << 0)
  61
  62 #define MIN_CLUSTER_BITS 9
  63 #define MAX_CLUSTER_BITS 21
  64
  65 #define MIN_L2_CACHE_SIZE 1 /* cluster */
  66
  67 /* Must be at least 4 to cover all cases of refcount table growth */
  68 #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
  69
  70 #define DEFAULT_L2_CACHE_BYTE_SIZE 1048576 /* bytes */
  71
  72 /* The refblock cache needs only a fourth of the L2 cache size to cover as many
  73  * clusters */
  74 #define DEFAULT_L2_REFCOUNT_SIZE_RATIO 4
  75
  76 #define DEFAULT_CLUSTER_SIZE 65536
  77
  78
  79 #define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts"
  80 #define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request"
  81 #define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot"
  82 #define QCOW2_OPT_DISCARD_OTHER "pass-discard-other"
  83 #define QCOW2_OPT_OVERLAP "overlap-check"
  84 #define QCOW2_OPT_OVERLAP_TEMPLATE "overlap-check.template"
  85 #define QCOW2_OPT_OVERLAP_MAIN_HEADER "overlap-check.main-header"
  86 #define QCOW2_OPT_OVERLAP_ACTIVE_L1 "overlap-check.active-l1"
  87 #define QCOW2_OPT_OVERLAP_ACTIVE_L2 "overlap-check.active-l2"
  88 #define QCOW2_OPT_OVERLAP_REFCOUNT_TABLE "overlap-check.refcount-table"
  89 #define QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK "overlap-check.refcount-block"
  90 #define QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE "overlap-check.snapshot-table"
  91 #define QCOW2_OPT_OVERLAP_INACTIVE_L1 "overlap-check.inactive-l1"
  92 #define QCOW2_OPT_OVERLAP_INACTIVE_L2 "overlap-check.inactive-l2"
  93 #define QCOW2_OPT_CACHE_SIZE "cache-size"
  94 #define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size"
  95 #define QCOW2_OPT_REFCOUNT_CACHE_SIZE "refcount-cache-size"
  96
  97 typedef struct QCowHeader {
  98     uint32_t magic;
  99     uint32_t version;
 100     uint64_t backing_file_offset;
 101     uint32_t backing_file_size;
 102     uint32_t cluster_bits;
 103     uint64_t size; /* in bytes */
 104     uint32_t crypt_method;
 105     uint32_t l1_size; /* XXX: save number of clusters instead ? */
 106     uint64_t l1_table_offset;
 107     uint64_t refcount_table_offset;
 108     uint32_t refcount_table_clusters;
 109     uint32_t nb_snapshots;
 110     uint64_t snapshots_offset;
 111
 112     /* The following fields are only valid for version >= 3 */
 113     uint64_t incompatible_features;
 114     uint64_t compatible_features;
 115     uint64_t autoclear_features;
 116
 117     uint32_t refcount_order;
 118     uint32_t header_length;
 119 } QEMU_PACKED QCowHeader;
 120
 121 typedef struct QEMU_PACKED QCowSnapshotHeader {
 122     /* header is 8 byte aligned */
 123     uint64_t l1_table_offset;
 124
 125     uint32_t l1_size;
 126     uint16_t id_str_size;
 127     uint16_t name_size;
 128
 129     uint32_t date_sec;
 130     uint32_t date_nsec;
 131
 132     uint64_t vm_clock_nsec;
 133
 134     uint32_t vm_state_size;
 135     uint32_t extra_data_size; /* for extension */
 136     /* extra data follows */
 137     /* id_str follows */
 138     /* name follows  */
 139 } QCowSnapshotHeader;
 140
 141 typedef struct QEMU_PACKED QCowSnapshotExtraData {
 142     uint64_t vm_state_size_large;
 143     uint64_t disk_size;
 144 } QCowSnapshotExtraData;
 145
 146
 147 typedef struct QCowSnapshot {
 148     uint64_t l1_table_offset;
 149     uint32_t l1_size;
 150     char *id_str;
 151     char *name;
 152     uint64_t disk_size;
 153     uint64_t vm_state_size;
 154     uint32_t date_sec;
 155     uint32_t date_nsec;
 156     uint64_t vm_clock_nsec;
 157 } QCowSnapshot;
 158
 159 struct Qcow2Cache;
 160 typedef struct Qcow2Cache Qcow2Cache;
 161
 162 typedef struct Qcow2UnknownHeaderExtension {
 163     uint32_t magic;
 164     uint32_t len;
 165     QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
 166     uint8_t data[];
 167 } Qcow2UnknownHeaderExtension;
 168
 169 enum {
 170     QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,
 171     QCOW2_FEAT_TYPE_COMPATIBLE      = 1,
 172     QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
 173 };
 174
 175 /* Incompatible feature bits */
 176 enum {
 177     QCOW2_INCOMPAT_DIRTY_BITNR   = 0,
 178     QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
 179     QCOW2_INCOMPAT_DIRTY         = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
 180     QCOW2_INCOMPAT_CORRUPT       = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR,
 181
 182     QCOW2_INCOMPAT_MASK          = QCOW2_INCOMPAT_DIRTY
 183                                  | QCOW2_INCOMPAT_CORRUPT,
 184 };
 185
 186 /* Compatible feature bits */
 187 enum {
 188     QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
 189     QCOW2_COMPAT_LAZY_REFCOUNTS       = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
 190
 191     QCOW2_COMPAT_FEAT_MASK            = QCOW2_COMPAT_LAZY_REFCOUNTS,
 192 };
 193
 194 enum qcow2_discard_type {
 195     QCOW2_DISCARD_NEVER = 0,
 196     QCOW2_DISCARD_ALWAYS,
 197     QCOW2_DISCARD_REQUEST,
 198     QCOW2_DISCARD_SNAPSHOT,
 199     QCOW2_DISCARD_OTHER,
 200     QCOW2_DISCARD_MAX
 201 };
 202
 203 typedef struct Qcow2Feature {
 204     uint8_t type;
 205     uint8_t bit;
 206     char    name[46];
 207 } QEMU_PACKED Qcow2Feature;
 208
 209 typedef struct Qcow2DiscardRegion {
 210     BlockDriverState *bs;
 211     uint64_t offset;
 212     uint64_t bytes;
 213     QTAILQ_ENTRY(Qcow2DiscardRegion) next;
 214 } Qcow2DiscardRegion;
 215
 216 typedef struct BDRVQcowState {
 217     int cluster_bits;
 218     int cluster_size;
 219     int cluster_sectors;
 220     int l2_bits;
 221     int l2_size;
 222     int l1_size;
 223     int l1_vm_state_index;
 224     int refcount_block_bits;
 225     int refcount_block_size;
 226     int csize_shift;
 227     int csize_mask;
 228     uint64_t cluster_offset_mask;
 229     uint64_t l1_table_offset;
 230     uint64_t *l1_table;
 231
 232     Qcow2Cache* l2_table_cache;
 233     Qcow2Cache* refcount_block_cache;
 234
 235     uint8_t *cluster_cache;
 236     uint8_t *cluster_data;
 237     uint64_t cluster_cache_offset;
 238     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 239
 240     uint64_t *refcount_table;
 241     uint64_t refcount_table_offset;
 242     uint32_t refcount_table_size;
 243     uint64_t free_cluster_index;
 244     uint64_t free_byte_offset;
 245
 246     CoMutex lock;
 247
 248     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 249     uint32_t crypt_method_header;
 250     AES_KEY aes_encrypt_key;
 251     AES_KEY aes_decrypt_key;
 252     uint64_t snapshots_offset;
 253     int snapshots_size;
 254     unsigned int nb_snapshots;
 255     QCowSnapshot *snapshots;
 256
 257     int flags;
 258     int qcow_version;
 259     bool use_lazy_refcounts;
 260     int refcount_order;
 261
 262     bool discard_passthrough[QCOW2_DISCARD_MAX];
 263
 264     int overlap_check; /* bitmask of Qcow2MetadataOverlap values */
 265     bool signaled_corruption;
 266
 267     uint64_t incompatible_features;
 268     uint64_t compatible_features;
 269     uint64_t autoclear_features;
 270
 271     size_t unknown_header_fields_size;
 272     void* unknown_header_fields;
 273     QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 274     QTAILQ_HEAD (, Qcow2DiscardRegion) discards;
 275     bool cache_discards;
 276 } BDRVQcowState;
 277
 278 /* XXX: use std qcow open function ? */
 279 typedef struct QCowCreateState {
 280     int cluster_size;
 281     int cluster_bits;
 282     uint16_t *refcount_block;
 283     uint64_t *refcount_table;
 284     int64_t l1_table_offset;
 285     int64_t refcount_table_offset;
 286     int64_t refcount_block_offset;
 287 } QCowCreateState;
 288
 289 struct QCowAIOCB;
 290
 291 typedef struct Qcow2COWRegion {
 292     /**
 293      * Offset of the COW region in bytes from the start of the first cluster
 294      * touched by the request.
 295      */
 296     uint64_t    offset;
 297
 298     /** Number of sectors to copy */
 299     int         nb_sectors;
 300 } Qcow2COWRegion;
 301
 302 /**
 303  * Describes an in-flight (part of a) write request that writes to clusters
 304  * that are not referenced in their L2 table yet.
 305  */
 306 typedef struct QCowL2Meta
 307 {
 308     /** Guest offset of the first newly allocated cluster */
 309     uint64_t offset;
 310
 311     /** Host offset of the first newly allocated cluster */
 312     uint64_t alloc_offset;
 313
 314     /**
 315      * Number of sectors from the start of the first allocated cluster to
 316      * the end of the (possibly shortened) request
 317      */
 318     int nb_available;
 319
 320     /** Number of newly allocated clusters */
 321     int nb_clusters;
 322
 323     /**
 324      * Requests that overlap with this allocation and wait to be restarted
 325      * when the allocating request has completed.
 326      */
 327     CoQueue dependent_requests;
 328
 329     /**
 330      * The COW Region between the start of the first allocated cluster and the
 331      * area the guest actually writes to.
 332      */
 333     Qcow2COWRegion cow_start;
 334
 335     /**
 336      * The COW Region between the area the guest actually writes to and the
 337      * end of the last allocated cluster.
 338      */
 339     Qcow2COWRegion cow_end;
 340
 341     /** Pointer to next L2Meta of the same write request */
 342     struct QCowL2Meta *next;
 343
 344     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 345 } QCowL2Meta;
 346
 347 enum {
 348     QCOW2_CLUSTER_UNALLOCATED,
 349     QCOW2_CLUSTER_NORMAL,
 350     QCOW2_CLUSTER_COMPRESSED,
 351     QCOW2_CLUSTER_ZERO
 352 };
 353
 354 typedef enum QCow2MetadataOverlap {
 355     QCOW2_OL_MAIN_HEADER_BITNR    = 0,
 356     QCOW2_OL_ACTIVE_L1_BITNR      = 1,
 357     QCOW2_OL_ACTIVE_L2_BITNR      = 2,
 358     QCOW2_OL_REFCOUNT_TABLE_BITNR = 3,
 359     QCOW2_OL_REFCOUNT_BLOCK_BITNR = 4,
 360     QCOW2_OL_SNAPSHOT_TABLE_BITNR = 5,
 361     QCOW2_OL_INACTIVE_L1_BITNR    = 6,
 362     QCOW2_OL_INACTIVE_L2_BITNR    = 7,
 363
 364     QCOW2_OL_MAX_BITNR            = 8,
 365
 366     QCOW2_OL_NONE           = 0,
 367     QCOW2_OL_MAIN_HEADER    = (1 << QCOW2_OL_MAIN_HEADER_BITNR),
 368     QCOW2_OL_ACTIVE_L1      = (1 << QCOW2_OL_ACTIVE_L1_BITNR),
 369     QCOW2_OL_ACTIVE_L2      = (1 << QCOW2_OL_ACTIVE_L2_BITNR),
 370     QCOW2_OL_REFCOUNT_TABLE = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR),
 371     QCOW2_OL_REFCOUNT_BLOCK = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR),
 372     QCOW2_OL_SNAPSHOT_TABLE = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR),
 373     QCOW2_OL_INACTIVE_L1    = (1 << QCOW2_OL_INACTIVE_L1_BITNR),
 374     /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv
 375      * reads. */
 376     QCOW2_OL_INACTIVE_L2    = (1 << QCOW2_OL_INACTIVE_L2_BITNR),
 377 } QCow2MetadataOverlap;
 378
 379 /* Perform all overlap checks which can be done in constant time */
 380 #define QCOW2_OL_CONSTANT \
 381     (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \
 382      QCOW2_OL_SNAPSHOT_TABLE)
 383
 384 /* Perform all overlap checks which don't require disk access */
 385 #define QCOW2_OL_CACHED \
 386     (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \
 387      QCOW2_OL_INACTIVE_L1)
 388
 389 /* Perform all overlap checks */
 390 #define QCOW2_OL_ALL \
 391     (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2)
 392
 393 #define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
 394 #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
 395 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
 396
 397 #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
 398
 399 static inline int64_t start_of_cluster(BDRVQcowState *s, int64_t offset)
 400 {
 401     return offset & ~(s->cluster_size - 1);
 402 }
 403
 404 static inline int64_t offset_into_cluster(BDRVQcowState *s, int64_t offset)
 405 {
 406     return offset & (s->cluster_size - 1);
 407 }
 408
 409 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 410 {
 411     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 412 }
 413
 414 static inline int64_t size_to_l1(BDRVQcowState *s, int64_t size)
 415 {
 416     int shift = s->cluster_bits + s->l2_bits;
 417     return (size + (1ULL << shift) - 1) >> shift;
 418 }
 419
 420 static inline int offset_to_l2_index(BDRVQcowState *s, int64_t offset)
 421 {
 422     return (offset >> s->cluster_bits) & (s->l2_size - 1);
 423 }
 424
 425 static inline int64_t align_offset(int64_t offset, int n)
 426 {
 427     offset = (offset + n - 1) & ~(n - 1);
 428     return offset;
 429 }
 430
 431 static inline int64_t qcow2_vm_state_offset(BDRVQcowState *s)
 432 {
 433     return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
 434 }
 435
 436 static inline uint64_t qcow2_max_refcount_clusters(BDRVQcowState *s)
 437 {
 438     return QCOW_MAX_REFTABLE_SIZE >> s->cluster_bits;
 439 }
 440
 441 static inline int qcow2_get_cluster_type(uint64_t l2_entry)
 442 {
 443     if (l2_entry & QCOW_OFLAG_COMPRESSED) {
 444         return QCOW2_CLUSTER_COMPRESSED;
 445     } else if (l2_entry & QCOW_OFLAG_ZERO) {
 446         return QCOW2_CLUSTER_ZERO;
 447     } else if (!(l2_entry & L2E_OFFSET_MASK)) {
 448         return QCOW2_CLUSTER_UNALLOCATED;
 449     } else {
 450         return QCOW2_CLUSTER_NORMAL;
 451     }
 452 }
 453
 454 /* Check whether refcounts are eager or lazy */
 455 static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s)
 456 {
 457     return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
 458 }
 459
 460 static inline uint64_t l2meta_cow_start(QCowL2Meta *m)
 461 {
 462     return m->offset + m->cow_start.offset;
 463 }
 464
 465 static inline uint64_t l2meta_cow_end(QCowL2Meta *m)
 466 {
 467     return m->offset + m->cow_end.offset
 468         + (m->cow_end.nb_sectors << BDRV_SECTOR_BITS);
 469 }
 470
 471 // FIXME Need qcow2_ prefix to global functions
 472
 473 /* qcow2.c functions */
 474 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 475                   int64_t sector_num, int nb_sectors);
 476
 477 int qcow2_mark_dirty(BlockDriverState *bs);
 478 int qcow2_mark_corrupt(BlockDriverState *bs);
 479 int qcow2_mark_consistent(BlockDriverState *bs);
 480 int qcow2_update_header(BlockDriverState *bs);
 481
 482 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset,
 483                              int64_t size, const char *message_format, ...)
 484                              GCC_FMT_ATTR(5, 6);
 485
 486 /* qcow2-refcount.c functions */
 487 int qcow2_refcount_init(BlockDriverState *bs);
 488 void qcow2_refcount_close(BlockDriverState *bs);
 489
 490 int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index,
 491                                   int addend, enum qcow2_discard_type type);
 492
 493 int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size);
 494 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 495     int nb_clusters);
 496 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 497 void qcow2_free_clusters(BlockDriverState *bs,
 498                           int64_t offset, int64_t size,
 499                           enum qcow2_discard_type type);
 500 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
 501                              int nb_clusters, enum qcow2_discard_type type);
 502
 503 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 504     int64_t l1_table_offset, int l1_size, int addend);
 505
 506 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 507                           BdrvCheckMode fix);
 508
 509 void qcow2_process_discards(BlockDriverState *bs, int ret);
 510
 511 int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
 512                                  int64_t size);
 513 int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
 514                                   int64_t size);
 515
 516 /* qcow2-cluster.c functions */
 517 int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
 518                         bool exact_size);
 519 int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
 520 void qcow2_l2_cache_reset(BlockDriverState *bs);
 521 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 522 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 523                      uint8_t *out_buf, const uint8_t *in_buf,
 524                      int nb_sectors, int enc,
 525                      const AES_KEY *key);
 526
 527 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 528     int *num, uint64_t *cluster_offset);
 529 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 530     int *num, uint64_t *host_offset, QCowL2Meta **m);
 531 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 532                                          uint64_t offset,
 533                                          int compressed_size);
 534
 535 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 536 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 537     int nb_sectors, enum qcow2_discard_type type);
 538 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
 539
 540 int qcow2_expand_zero_clusters(BlockDriverState *bs);
 541
 542 /* qcow2-snapshot.c functions */
 543 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 544 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 545 int qcow2_snapshot_delete(BlockDriverState *bs,
 546                           const char *snapshot_id,
 547                           const char *name,
 548                           Error **errp);
 549 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 550 int qcow2_snapshot_load_tmp(BlockDriverState *bs,
 551                             const char *snapshot_id,
 552                             const char *name,
 553                             Error **errp);
 554
 555 void qcow2_free_snapshots(BlockDriverState *bs);
 556 int qcow2_read_snapshots(BlockDriverState *bs);
 557
 558 /* qcow2-cache.c functions */
 559 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
 560 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 561
 562 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 563 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 564 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 565     Qcow2Cache *dependency);
 566 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 567
 568 int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c);
 569
 570 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 571     void **table);
 572 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 573     void **table);
 574 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 575
 576 #endif