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 int refcount_bits; 262 uint64_t refcount_max; 263 264 bool discard_passthrough[QCOW2_DISCARD_MAX]; 265 266 int overlap_check; /* bitmask of Qcow2MetadataOverlap values */ 267 bool signaled_corruption; 268 269 uint64_t incompatible_features; 270 uint64_t compatible_features; 271 uint64_t autoclear_features; 272 273 size_t unknown_header_fields_size; 274 void* unknown_header_fields; 275 QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext; 276 QTAILQ_HEAD (, Qcow2DiscardRegion) discards; 277 bool cache_discards; 278 } BDRVQcowState; 279 280 struct QCowAIOCB; 281 282 typedef struct Qcow2COWRegion { 283 /** 284 * Offset of the COW region in bytes from the start of the first cluster 285 * touched by the request. 286 */ 287 uint64_t offset; 288 289 /** Number of sectors to copy */ 290 int nb_sectors; 291 } Qcow2COWRegion; 292 293 /** 294 * Describes an in-flight (part of a) write request that writes to clusters 295 * that are not referenced in their L2 table yet. 296 */ 297 typedef struct QCowL2Meta 298 { 299 /** Guest offset of the first newly allocated cluster */ 300 uint64_t offset; 301 302 /** Host offset of the first newly allocated cluster */ 303 uint64_t alloc_offset; 304 305 /** 306 * Number of sectors from the start of the first allocated cluster to 307 * the end of the (possibly shortened) request 308 */ 309 int nb_available; 310 311 /** Number of newly allocated clusters */ 312 int nb_clusters; 313 314 /** 315 * Requests that overlap with this allocation and wait to be restarted 316 * when the allocating request has completed. 317 */ 318 CoQueue dependent_requests; 319 320 /** 321 * The COW Region between the start of the first allocated cluster and the 322 * area the guest actually writes to. 323 */ 324 Qcow2COWRegion cow_start; 325 326 /** 327 * The COW Region between the area the guest actually writes to and the 328 * end of the last allocated cluster. 329 */ 330 Qcow2COWRegion cow_end; 331 332 /** Pointer to next L2Meta of the same write request */ 333 struct QCowL2Meta *next; 334 335 QLIST_ENTRY(QCowL2Meta) next_in_flight; 336 } QCowL2Meta; 337 338 enum { 339 QCOW2_CLUSTER_UNALLOCATED, 340 QCOW2_CLUSTER_NORMAL, 341 QCOW2_CLUSTER_COMPRESSED, 342 QCOW2_CLUSTER_ZERO 343 }; 344 345 typedef enum QCow2MetadataOverlap { 346 QCOW2_OL_MAIN_HEADER_BITNR = 0, 347 QCOW2_OL_ACTIVE_L1_BITNR = 1, 348 QCOW2_OL_ACTIVE_L2_BITNR = 2, 349 QCOW2_OL_REFCOUNT_TABLE_BITNR = 3, 350 QCOW2_OL_REFCOUNT_BLOCK_BITNR = 4, 351 QCOW2_OL_SNAPSHOT_TABLE_BITNR = 5, 352 QCOW2_OL_INACTIVE_L1_BITNR = 6, 353 QCOW2_OL_INACTIVE_L2_BITNR = 7, 354 355 QCOW2_OL_MAX_BITNR = 8, 356 357 QCOW2_OL_NONE = 0, 358 QCOW2_OL_MAIN_HEADER = (1 << QCOW2_OL_MAIN_HEADER_BITNR), 359 QCOW2_OL_ACTIVE_L1 = (1 << QCOW2_OL_ACTIVE_L1_BITNR), 360 QCOW2_OL_ACTIVE_L2 = (1 << QCOW2_OL_ACTIVE_L2_BITNR), 361 QCOW2_OL_REFCOUNT_TABLE = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR), 362 QCOW2_OL_REFCOUNT_BLOCK = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR), 363 QCOW2_OL_SNAPSHOT_TABLE = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR), 364 QCOW2_OL_INACTIVE_L1 = (1 << QCOW2_OL_INACTIVE_L1_BITNR), 365 /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv 366 * reads. */ 367 QCOW2_OL_INACTIVE_L2 = (1 << QCOW2_OL_INACTIVE_L2_BITNR), 368 } QCow2MetadataOverlap; 369 370 /* Perform all overlap checks which can be done in constant time */ 371 #define QCOW2_OL_CONSTANT \ 372 (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \ 373 QCOW2_OL_SNAPSHOT_TABLE) 374 375 /* Perform all overlap checks which don't require disk access */ 376 #define QCOW2_OL_CACHED \ 377 (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \ 378 QCOW2_OL_INACTIVE_L1) 379 380 /* Perform all overlap checks */ 381 #define QCOW2_OL_ALL \ 382 (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2) 383 384 #define L1E_OFFSET_MASK 0x00fffffffffffe00ULL 385 #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL 386 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL 387 388 #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL 389 390 static inline int64_t start_of_cluster(BDRVQcowState *s, int64_t offset) 391 { 392 return offset & ~(s->cluster_size - 1); 393 } 394 395 static inline int64_t offset_into_cluster(BDRVQcowState *s, int64_t offset) 396 { 397 return offset & (s->cluster_size - 1); 398 } 399 400 static inline int size_to_clusters(BDRVQcowState *s, int64_t size) 401 { 402 return (size + (s->cluster_size - 1)) >> s->cluster_bits; 403 } 404 405 static inline int64_t size_to_l1(BDRVQcowState *s, int64_t size) 406 { 407 int shift = s->cluster_bits + s->l2_bits; 408 return (size + (1ULL << shift) - 1) >> shift; 409 } 410 411 static inline int offset_to_l2_index(BDRVQcowState *s, int64_t offset) 412 { 413 return (offset >> s->cluster_bits) & (s->l2_size - 1); 414 } 415 416 static inline int64_t align_offset(int64_t offset, int n) 417 { 418 offset = (offset + n - 1) & ~(n - 1); 419 return offset; 420 } 421 422 static inline int64_t qcow2_vm_state_offset(BDRVQcowState *s) 423 { 424 return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); 425 } 426 427 static inline uint64_t qcow2_max_refcount_clusters(BDRVQcowState *s) 428 { 429 return QCOW_MAX_REFTABLE_SIZE >> s->cluster_bits; 430 } 431 432 static inline int qcow2_get_cluster_type(uint64_t l2_entry) 433 { 434 if (l2_entry & QCOW_OFLAG_COMPRESSED) { 435 return QCOW2_CLUSTER_COMPRESSED; 436 } else if (l2_entry & QCOW_OFLAG_ZERO) { 437 return QCOW2_CLUSTER_ZERO; 438 } else if (!(l2_entry & L2E_OFFSET_MASK)) { 439 return QCOW2_CLUSTER_UNALLOCATED; 440 } else { 441 return QCOW2_CLUSTER_NORMAL; 442 } 443 } 444 445 /* Check whether refcounts are eager or lazy */ 446 static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s) 447 { 448 return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY); 449 } 450 451 static inline uint64_t l2meta_cow_start(QCowL2Meta *m) 452 { 453 return m->offset + m->cow_start.offset; 454 } 455 456 static inline uint64_t l2meta_cow_end(QCowL2Meta *m) 457 { 458 return m->offset + m->cow_end.offset 459 + (m->cow_end.nb_sectors << BDRV_SECTOR_BITS); 460 } 461 462 // FIXME Need qcow2_ prefix to global functions 463 464 /* qcow2.c functions */ 465 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 466 int64_t sector_num, int nb_sectors); 467 468 int qcow2_mark_dirty(BlockDriverState *bs); 469 int qcow2_mark_corrupt(BlockDriverState *bs); 470 int qcow2_mark_consistent(BlockDriverState *bs); 471 int qcow2_update_header(BlockDriverState *bs); 472 473 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 474 int64_t size, const char *message_format, ...) 475 GCC_FMT_ATTR(5, 6); 476 477 /* qcow2-refcount.c functions */ 478 int qcow2_refcount_init(BlockDriverState *bs); 479 void qcow2_refcount_close(BlockDriverState *bs); 480 481 int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index); 482 483 int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index, 484 int addend, enum qcow2_discard_type type); 485 486 int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size); 487 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, 488 int nb_clusters); 489 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size); 490 void qcow2_free_clusters(BlockDriverState *bs, 491 int64_t offset, int64_t size, 492 enum qcow2_discard_type type); 493 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry, 494 int nb_clusters, enum qcow2_discard_type type); 495 496 int qcow2_update_snapshot_refcount(BlockDriverState *bs, 497 int64_t l1_table_offset, int l1_size, int addend); 498 499 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, 500 BdrvCheckMode fix); 501 502 void qcow2_process_discards(BlockDriverState *bs, int ret); 503 504 int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset, 505 int64_t size); 506 int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset, 507 int64_t size); 508 509 /* qcow2-cluster.c functions */ 510 int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, 511 bool exact_size); 512 int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index); 513 void qcow2_l2_cache_reset(BlockDriverState *bs); 514 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 515 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 516 uint8_t *out_buf, const uint8_t *in_buf, 517 int nb_sectors, int enc, 518 const AES_KEY *key); 519 520 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, 521 int *num, uint64_t *cluster_offset); 522 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, 523 int *num, uint64_t *host_offset, QCowL2Meta **m); 524 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, 525 uint64_t offset, 526 int compressed_size); 527 528 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m); 529 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset, 530 int nb_sectors, enum qcow2_discard_type type, bool full_discard); 531 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors); 532 533 int qcow2_expand_zero_clusters(BlockDriverState *bs, 534 BlockDriverAmendStatusCB *status_cb); 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 571