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