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 L2_CACHE_SIZE 16
  68
  69 /* Must be at least 4 to cover all cases of refcount table growth */
  70 #define REFCOUNT_CACHE_SIZE 4
  71
  72 #define DEFAULT_CLUSTER_SIZE 65536
  73
  74
  75 #define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts"
  76 #define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request"
  77 #define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot"
  78 #define QCOW2_OPT_DISCARD_OTHER "pass-discard-other"
  79 #define QCOW2_OPT_OVERLAP "overlap-check"
  80 #define QCOW2_OPT_OVERLAP_MAIN_HEADER "overlap-check.main-header"
  81 #define QCOW2_OPT_OVERLAP_ACTIVE_L1 "overlap-check.active-l1"
  82 #define QCOW2_OPT_OVERLAP_ACTIVE_L2 "overlap-check.active-l2"
  83 #define QCOW2_OPT_OVERLAP_REFCOUNT_TABLE "overlap-check.refcount-table"
  84 #define QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK "overlap-check.refcount-block"
  85 #define QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE "overlap-check.snapshot-table"
  86 #define QCOW2_OPT_OVERLAP_INACTIVE_L1 "overlap-check.inactive-l1"
  87 #define QCOW2_OPT_OVERLAP_INACTIVE_L2 "overlap-check.inactive-l2"
  88
  89 typedef struct QCowHeader {
  90     uint32_t magic;
  91     uint32_t version;
  92     uint64_t backing_file_offset;
  93     uint32_t backing_file_size;
  94     uint32_t cluster_bits;
  95     uint64_t size; /* in bytes */
  96     uint32_t crypt_method;
  97     uint32_t l1_size; /* XXX: save number of clusters instead ? */
  98     uint64_t l1_table_offset;
  99     uint64_t refcount_table_offset;
 100     uint32_t refcount_table_clusters;
 101     uint32_t nb_snapshots;
 102     uint64_t snapshots_offset;
 103
 104     /* The following fields are only valid for version >= 3 */
 105     uint64_t incompatible_features;
 106     uint64_t compatible_features;
 107     uint64_t autoclear_features;
 108
 109     uint32_t refcount_order;
 110     uint32_t header_length;
 111 } QEMU_PACKED QCowHeader;
 112
 113 typedef struct QEMU_PACKED QCowSnapshotHeader {
 114     /* header is 8 byte aligned */
 115     uint64_t l1_table_offset;
 116
 117     uint32_t l1_size;
 118     uint16_t id_str_size;
 119     uint16_t name_size;
 120
 121     uint32_t date_sec;
 122     uint32_t date_nsec;
 123
 124     uint64_t vm_clock_nsec;
 125
 126     uint32_t vm_state_size;
 127     uint32_t extra_data_size; /* for extension */
 128     /* extra data follows */
 129     /* id_str follows */
 130     /* name follows  */
 131 } QCowSnapshotHeader;
 132
 133 typedef struct QEMU_PACKED QCowSnapshotExtraData {
 134     uint64_t vm_state_size_large;
 135     uint64_t disk_size;
 136 } QCowSnapshotExtraData;
 137
 138
 139 typedef struct QCowSnapshot {
 140     uint64_t l1_table_offset;
 141     uint32_t l1_size;
 142     char *id_str;
 143     char *name;
 144     uint64_t disk_size;
 145     uint64_t vm_state_size;
 146     uint32_t date_sec;
 147     uint32_t date_nsec;
 148     uint64_t vm_clock_nsec;
 149 } QCowSnapshot;
 150
 151 struct Qcow2Cache;
 152 typedef struct Qcow2Cache Qcow2Cache;
 153
 154 typedef struct Qcow2UnknownHeaderExtension {
 155     uint32_t magic;
 156     uint32_t len;
 157     QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
 158     uint8_t data[];
 159 } Qcow2UnknownHeaderExtension;
 160
 161 enum {
 162     QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,
 163     QCOW2_FEAT_TYPE_COMPATIBLE      = 1,
 164     QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
 165 };
 166
 167 /* Incompatible feature bits */
 168 enum {
 169     QCOW2_INCOMPAT_DIRTY_BITNR   = 0,
 170     QCOW2_INCOMPAT_CORRUPT_BITNR = 1,
 171     QCOW2_INCOMPAT_DIRTY         = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
 172     QCOW2_INCOMPAT_CORRUPT       = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR,
 173
 174     QCOW2_INCOMPAT_MASK          = QCOW2_INCOMPAT_DIRTY
 175                                  | QCOW2_INCOMPAT_CORRUPT,
 176 };
 177
 178 /* Compatible feature bits */
 179 enum {
 180     QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
 181     QCOW2_COMPAT_LAZY_REFCOUNTS       = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
 182
 183     QCOW2_COMPAT_FEAT_MASK            = QCOW2_COMPAT_LAZY_REFCOUNTS,
 184 };
 185
 186 enum qcow2_discard_type {
 187     QCOW2_DISCARD_NEVER = 0,
 188     QCOW2_DISCARD_ALWAYS,
 189     QCOW2_DISCARD_REQUEST,
 190     QCOW2_DISCARD_SNAPSHOT,
 191     QCOW2_DISCARD_OTHER,
 192     QCOW2_DISCARD_MAX
 193 };
 194
 195 typedef struct Qcow2Feature {
 196     uint8_t type;
 197     uint8_t bit;
 198     char    name[46];
 199 } QEMU_PACKED Qcow2Feature;
 200
 201 typedef struct Qcow2DiscardRegion {
 202     BlockDriverState *bs;
 203     uint64_t offset;
 204     uint64_t bytes;
 205     QTAILQ_ENTRY(Qcow2DiscardRegion) next;
 206 } Qcow2DiscardRegion;
 207
 208 typedef struct BDRVQcowState {
 209     int cluster_bits;
 210     int cluster_size;
 211     int cluster_sectors;
 212     int l2_bits;
 213     int l2_size;
 214     int l1_size;
 215     int l1_vm_state_index;
 216     int csize_shift;
 217     int csize_mask;
 218     uint64_t cluster_offset_mask;
 219     uint64_t l1_table_offset;
 220     uint64_t *l1_table;
 221
 222     Qcow2Cache* l2_table_cache;
 223     Qcow2Cache* refcount_block_cache;
 224
 225     uint8_t *cluster_cache;
 226     uint8_t *cluster_data;
 227     uint64_t cluster_cache_offset;
 228     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 229
 230     uint64_t *refcount_table;
 231     uint64_t refcount_table_offset;
 232     uint32_t refcount_table_size;
 233     uint64_t free_cluster_index;
 234     uint64_t free_byte_offset;
 235
 236     CoMutex lock;
 237
 238     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 239     uint32_t crypt_method_header;
 240     AES_KEY aes_encrypt_key;
 241     AES_KEY aes_decrypt_key;
 242     uint64_t snapshots_offset;
 243     int snapshots_size;
 244     unsigned int nb_snapshots;
 245     QCowSnapshot *snapshots;
 246
 247     int flags;
 248     int qcow_version;
 249     bool use_lazy_refcounts;
 250     int refcount_order;
 251
 252     bool discard_passthrough[QCOW2_DISCARD_MAX];
 253
 254     int overlap_check; /* bitmask of Qcow2MetadataOverlap values */
 255
 256     uint64_t incompatible_features;
 257     uint64_t compatible_features;
 258     uint64_t autoclear_features;
 259
 260     size_t unknown_header_fields_size;
 261     void* unknown_header_fields;
 262     QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 263     QTAILQ_HEAD (, Qcow2DiscardRegion) discards;
 264     bool cache_discards;
 265 } BDRVQcowState;
 266
 267 /* XXX: use std qcow open function ? */
 268 typedef struct QCowCreateState {
 269     int cluster_size;
 270     int cluster_bits;
 271     uint16_t *refcount_block;
 272     uint64_t *refcount_table;
 273     int64_t l1_table_offset;
 274     int64_t refcount_table_offset;
 275     int64_t refcount_block_offset;
 276 } QCowCreateState;
 277
 278 struct QCowAIOCB;
 279
 280 typedef struct Qcow2COWRegion {
 281     /**
 282      * Offset of the COW region in bytes from the start of the first cluster
 283      * touched by the request.
 284      */
 285     uint64_t    offset;
 286
 287     /** Number of sectors to copy */
 288     int         nb_sectors;
 289 } Qcow2COWRegion;
 290
 291 /**
 292  * Describes an in-flight (part of a) write request that writes to clusters
 293  * that are not referenced in their L2 table yet.
 294  */
 295 typedef struct QCowL2Meta
 296 {
 297     /** Guest offset of the first newly allocated cluster */
 298     uint64_t offset;
 299
 300     /** Host offset of the first newly allocated cluster */
 301     uint64_t alloc_offset;
 302
 303     /**
 304      * Number of sectors from the start of the first allocated cluster to
 305      * the end of the (possibly shortened) request
 306      */
 307     int nb_available;
 308
 309     /** Number of newly allocated clusters */
 310     int nb_clusters;
 311
 312     /**
 313      * Requests that overlap with this allocation and wait to be restarted
 314      * when the allocating request has completed.
 315      */
 316     CoQueue dependent_requests;
 317
 318     /**
 319      * The COW Region between the start of the first allocated cluster and the
 320      * area the guest actually writes to.
 321      */
 322     Qcow2COWRegion cow_start;
 323
 324     /**
 325      * The COW Region between the area the guest actually writes to and the
 326      * end of the last allocated cluster.
 327      */
 328     Qcow2COWRegion cow_end;
 329
 330     /** Pointer to next L2Meta of the same write request */
 331     struct QCowL2Meta *next;
 332
 333     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 334 } QCowL2Meta;
 335
 336 enum {
 337     QCOW2_CLUSTER_UNALLOCATED,
 338     QCOW2_CLUSTER_NORMAL,
 339     QCOW2_CLUSTER_COMPRESSED,
 340     QCOW2_CLUSTER_ZERO
 341 };
 342
 343 typedef enum QCow2MetadataOverlap {
 344     QCOW2_OL_MAIN_HEADER_BITNR    = 0,
 345     QCOW2_OL_ACTIVE_L1_BITNR      = 1,
 346     QCOW2_OL_ACTIVE_L2_BITNR      = 2,
 347     QCOW2_OL_REFCOUNT_TABLE_BITNR = 3,
 348     QCOW2_OL_REFCOUNT_BLOCK_BITNR = 4,
 349     QCOW2_OL_SNAPSHOT_TABLE_BITNR = 5,
 350     QCOW2_OL_INACTIVE_L1_BITNR    = 6,
 351     QCOW2_OL_INACTIVE_L2_BITNR    = 7,
 352
 353     QCOW2_OL_MAX_BITNR            = 8,
 354
 355     QCOW2_OL_NONE           = 0,
 356     QCOW2_OL_MAIN_HEADER    = (1 << QCOW2_OL_MAIN_HEADER_BITNR),
 357     QCOW2_OL_ACTIVE_L1      = (1 << QCOW2_OL_ACTIVE_L1_BITNR),
 358     QCOW2_OL_ACTIVE_L2      = (1 << QCOW2_OL_ACTIVE_L2_BITNR),
 359     QCOW2_OL_REFCOUNT_TABLE = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR),
 360     QCOW2_OL_REFCOUNT_BLOCK = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR),
 361     QCOW2_OL_SNAPSHOT_TABLE = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR),
 362     QCOW2_OL_INACTIVE_L1    = (1 << QCOW2_OL_INACTIVE_L1_BITNR),
 363     /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv
 364      * reads. */
 365     QCOW2_OL_INACTIVE_L2    = (1 << QCOW2_OL_INACTIVE_L2_BITNR),
 366 } QCow2MetadataOverlap;
 367
 368 /* Perform all overlap checks which can be done in constant time */
 369 #define QCOW2_OL_CONSTANT \
 370     (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \
 371      QCOW2_OL_SNAPSHOT_TABLE)
 372
 373 /* Perform all overlap checks which don't require disk access */
 374 #define QCOW2_OL_CACHED \
 375     (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \
 376      QCOW2_OL_INACTIVE_L1)
 377
 378 /* Perform all overlap checks */
 379 #define QCOW2_OL_ALL \
 380     (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2)
 381
 382 #define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
 383 #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
 384 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
 385
 386 #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL
 387
 388 static inline int64_t start_of_cluster(BDRVQcowState *s, int64_t offset)
 389 {
 390     return offset & ~(s->cluster_size - 1);
 391 }
 392
 393 static inline int64_t offset_into_cluster(BDRVQcowState *s, int64_t offset)
 394 {
 395     return offset & (s->cluster_size - 1);
 396 }
 397
 398 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 399 {
 400     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 401 }
 402
 403 static inline int64_t size_to_l1(BDRVQcowState *s, int64_t size)
 404 {
 405     int shift = s->cluster_bits + s->l2_bits;
 406     return (size + (1ULL << shift) - 1) >> shift;
 407 }
 408
 409 static inline int offset_to_l2_index(BDRVQcowState *s, int64_t offset)
 410 {
 411     return (offset >> s->cluster_bits) & (s->l2_size - 1);
 412 }
 413
 414 static inline int64_t align_offset(int64_t offset, int n)
 415 {
 416     offset = (offset + n - 1) & ~(n - 1);
 417     return offset;
 418 }
 419
 420 static inline int64_t qcow2_vm_state_offset(BDRVQcowState *s)
 421 {
 422     return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits);
 423 }
 424
 425 static inline uint64_t qcow2_max_refcount_clusters(BDRVQcowState *s)
 426 {
 427     return QCOW_MAX_REFTABLE_SIZE >> s->cluster_bits;
 428 }
 429
 430 static inline int qcow2_get_cluster_type(uint64_t l2_entry)
 431 {
 432     if (l2_entry & QCOW_OFLAG_COMPRESSED) {
 433         return QCOW2_CLUSTER_COMPRESSED;
 434     } else if (l2_entry & QCOW_OFLAG_ZERO) {
 435         return QCOW2_CLUSTER_ZERO;
 436     } else if (!(l2_entry & L2E_OFFSET_MASK)) {
 437         return QCOW2_CLUSTER_UNALLOCATED;
 438     } else {
 439         return QCOW2_CLUSTER_NORMAL;
 440     }
 441 }
 442
 443 /* Check whether refcounts are eager or lazy */
 444 static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s)
 445 {
 446     return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
 447 }
 448
 449 static inline uint64_t l2meta_cow_start(QCowL2Meta *m)
 450 {
 451     return m->offset + m->cow_start.offset;
 452 }
 453
 454 static inline uint64_t l2meta_cow_end(QCowL2Meta *m)
 455 {
 456     return m->offset + m->cow_end.offset
 457         + (m->cow_end.nb_sectors << BDRV_SECTOR_BITS);
 458 }
 459
 460 // FIXME Need qcow2_ prefix to global functions
 461
 462 /* qcow2.c functions */
 463 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 464                   int64_t sector_num, int nb_sectors);
 465
 466 int qcow2_mark_dirty(BlockDriverState *bs);
 467 int qcow2_mark_corrupt(BlockDriverState *bs);
 468 int qcow2_mark_consistent(BlockDriverState *bs);
 469 int qcow2_update_header(BlockDriverState *bs);
 470
 471 /* qcow2-refcount.c functions */
 472 int qcow2_refcount_init(BlockDriverState *bs);
 473 void qcow2_refcount_close(BlockDriverState *bs);
 474
 475 int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index,
 476                                   int addend, enum qcow2_discard_type type);
 477
 478 int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size);
 479 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 480     int nb_clusters);
 481 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 482 void qcow2_free_clusters(BlockDriverState *bs,
 483                           int64_t offset, int64_t size,
 484                           enum qcow2_discard_type type);
 485 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,
 486                              int nb_clusters, enum qcow2_discard_type type);
 487
 488 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 489     int64_t l1_table_offset, int l1_size, int addend);
 490
 491 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 492                           BdrvCheckMode fix);
 493
 494 void qcow2_process_discards(BlockDriverState *bs, int ret);
 495
 496 int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset,
 497                                  int64_t size);
 498 int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset,
 499                                   int64_t size);
 500
 501 /* qcow2-cluster.c functions */
 502 int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,
 503                         bool exact_size);
 504 int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index);
 505 void qcow2_l2_cache_reset(BlockDriverState *bs);
 506 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 507 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 508                      uint8_t *out_buf, const uint8_t *in_buf,
 509                      int nb_sectors, int enc,
 510                      const AES_KEY *key);
 511
 512 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 513     int *num, uint64_t *cluster_offset);
 514 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 515     int *num, uint64_t *host_offset, QCowL2Meta **m);
 516 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 517                                          uint64_t offset,
 518                                          int compressed_size);
 519
 520 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 521 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 522     int nb_sectors, enum qcow2_discard_type type);
 523 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
 524
 525 int qcow2_expand_zero_clusters(BlockDriverState *bs);
 526
 527 /* qcow2-snapshot.c functions */
 528 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 529 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 530 int qcow2_snapshot_delete(BlockDriverState *bs,
 531                           const char *snapshot_id,
 532                           const char *name,
 533                           Error **errp);
 534 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 535 int qcow2_snapshot_load_tmp(BlockDriverState *bs,
 536                             const char *snapshot_id,
 537                             const char *name,
 538                             Error **errp);
 539
 540 void qcow2_free_snapshots(BlockDriverState *bs);
 541 int qcow2_read_snapshots(BlockDriverState *bs);
 542
 543 /* qcow2-cache.c functions */
 544 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
 545 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 546
 547 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 548 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 549 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 550     Qcow2Cache *dependency);
 551 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 552
 553 int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c);
 554
 555 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 556     void **table);
 557 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 558     void **table);
 559 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 560
 561 #endif