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 bool signaled_corruption; 265 266 uint64_t incompatible_features; 267 uint64_t compatible_features; 268 uint64_t autoclear_features; 269 270 size_t unknown_header_fields_size; 271 void* unknown_header_fields; 272 QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext; 273 QTAILQ_HEAD (, Qcow2DiscardRegion) discards; 274 bool cache_discards; 275 } BDRVQcowState; 276 277 /* XXX: use std qcow open function ? */ 278 typedef struct QCowCreateState { 279 int cluster_size; 280 int cluster_bits; 281 uint16_t *refcount_block; 282 uint64_t *refcount_table; 283 int64_t l1_table_offset; 284 int64_t refcount_table_offset; 285 int64_t refcount_block_offset; 286 } QCowCreateState; 287 288 struct QCowAIOCB; 289 290 typedef struct Qcow2COWRegion { 291 /** 292 * Offset of the COW region in bytes from the start of the first cluster 293 * touched by the request. 294 */ 295 uint64_t offset; 296 297 /** Number of sectors to copy */ 298 int nb_sectors; 299 } Qcow2COWRegion; 300 301 /** 302 * Describes an in-flight (part of a) write request that writes to clusters 303 * that are not referenced in their L2 table yet. 304 */ 305 typedef struct QCowL2Meta 306 { 307 /** Guest offset of the first newly allocated cluster */ 308 uint64_t offset; 309 310 /** Host offset of the first newly allocated cluster */ 311 uint64_t alloc_offset; 312 313 /** 314 * Number of sectors from the start of the first allocated cluster to 315 * the end of the (possibly shortened) request 316 */ 317 int nb_available; 318 319 /** Number of newly allocated clusters */ 320 int nb_clusters; 321 322 /** 323 * Requests that overlap with this allocation and wait to be restarted 324 * when the allocating request has completed. 325 */ 326 CoQueue dependent_requests; 327 328 /** 329 * The COW Region between the start of the first allocated cluster and the 330 * area the guest actually writes to. 331 */ 332 Qcow2COWRegion cow_start; 333 334 /** 335 * The COW Region between the area the guest actually writes to and the 336 * end of the last allocated cluster. 337 */ 338 Qcow2COWRegion cow_end; 339 340 /** Pointer to next L2Meta of the same write request */ 341 struct QCowL2Meta *next; 342 343 QLIST_ENTRY(QCowL2Meta) next_in_flight; 344 } QCowL2Meta; 345 346 enum { 347 QCOW2_CLUSTER_UNALLOCATED, 348 QCOW2_CLUSTER_NORMAL, 349 QCOW2_CLUSTER_COMPRESSED, 350 QCOW2_CLUSTER_ZERO 351 }; 352 353 typedef enum QCow2MetadataOverlap { 354 QCOW2_OL_MAIN_HEADER_BITNR = 0, 355 QCOW2_OL_ACTIVE_L1_BITNR = 1, 356 QCOW2_OL_ACTIVE_L2_BITNR = 2, 357 QCOW2_OL_REFCOUNT_TABLE_BITNR = 3, 358 QCOW2_OL_REFCOUNT_BLOCK_BITNR = 4, 359 QCOW2_OL_SNAPSHOT_TABLE_BITNR = 5, 360 QCOW2_OL_INACTIVE_L1_BITNR = 6, 361 QCOW2_OL_INACTIVE_L2_BITNR = 7, 362 363 QCOW2_OL_MAX_BITNR = 8, 364 365 QCOW2_OL_NONE = 0, 366 QCOW2_OL_MAIN_HEADER = (1 << QCOW2_OL_MAIN_HEADER_BITNR), 367 QCOW2_OL_ACTIVE_L1 = (1 << QCOW2_OL_ACTIVE_L1_BITNR), 368 QCOW2_OL_ACTIVE_L2 = (1 << QCOW2_OL_ACTIVE_L2_BITNR), 369 QCOW2_OL_REFCOUNT_TABLE = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR), 370 QCOW2_OL_REFCOUNT_BLOCK = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR), 371 QCOW2_OL_SNAPSHOT_TABLE = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR), 372 QCOW2_OL_INACTIVE_L1 = (1 << QCOW2_OL_INACTIVE_L1_BITNR), 373 /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv 374 * reads. */ 375 QCOW2_OL_INACTIVE_L2 = (1 << QCOW2_OL_INACTIVE_L2_BITNR), 376 } QCow2MetadataOverlap; 377 378 /* Perform all overlap checks which can be done in constant time */ 379 #define QCOW2_OL_CONSTANT \ 380 (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \ 381 QCOW2_OL_SNAPSHOT_TABLE) 382 383 /* Perform all overlap checks which don't require disk access */ 384 #define QCOW2_OL_CACHED \ 385 (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \ 386 QCOW2_OL_INACTIVE_L1) 387 388 /* Perform all overlap checks */ 389 #define QCOW2_OL_ALL \ 390 (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2) 391 392 #define L1E_OFFSET_MASK 0x00fffffffffffe00ULL 393 #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL 394 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL 395 396 #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL 397 398 static inline int64_t start_of_cluster(BDRVQcowState *s, int64_t offset) 399 { 400 return offset & ~(s->cluster_size - 1); 401 } 402 403 static inline int64_t offset_into_cluster(BDRVQcowState *s, int64_t offset) 404 { 405 return offset & (s->cluster_size - 1); 406 } 407 408 static inline int size_to_clusters(BDRVQcowState *s, int64_t size) 409 { 410 return (size + (s->cluster_size - 1)) >> s->cluster_bits; 411 } 412 413 static inline int64_t size_to_l1(BDRVQcowState *s, int64_t size) 414 { 415 int shift = s->cluster_bits + s->l2_bits; 416 return (size + (1ULL << shift) - 1) >> shift; 417 } 418 419 static inline int offset_to_l2_index(BDRVQcowState *s, int64_t offset) 420 { 421 return (offset >> s->cluster_bits) & (s->l2_size - 1); 422 } 423 424 static inline int64_t align_offset(int64_t offset, int n) 425 { 426 offset = (offset + n - 1) & ~(n - 1); 427 return offset; 428 } 429 430 static inline int64_t qcow2_vm_state_offset(BDRVQcowState *s) 431 { 432 return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); 433 } 434 435 static inline uint64_t qcow2_max_refcount_clusters(BDRVQcowState *s) 436 { 437 return QCOW_MAX_REFTABLE_SIZE >> s->cluster_bits; 438 } 439 440 static inline int qcow2_get_cluster_type(uint64_t l2_entry) 441 { 442 if (l2_entry & QCOW_OFLAG_COMPRESSED) { 443 return QCOW2_CLUSTER_COMPRESSED; 444 } else if (l2_entry & QCOW_OFLAG_ZERO) { 445 return QCOW2_CLUSTER_ZERO; 446 } else if (!(l2_entry & L2E_OFFSET_MASK)) { 447 return QCOW2_CLUSTER_UNALLOCATED; 448 } else { 449 return QCOW2_CLUSTER_NORMAL; 450 } 451 } 452 453 /* Check whether refcounts are eager or lazy */ 454 static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s) 455 { 456 return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY); 457 } 458 459 static inline uint64_t l2meta_cow_start(QCowL2Meta *m) 460 { 461 return m->offset + m->cow_start.offset; 462 } 463 464 static inline uint64_t l2meta_cow_end(QCowL2Meta *m) 465 { 466 return m->offset + m->cow_end.offset 467 + (m->cow_end.nb_sectors << BDRV_SECTOR_BITS); 468 } 469 470 // FIXME Need qcow2_ prefix to global functions 471 472 /* qcow2.c functions */ 473 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 474 int64_t sector_num, int nb_sectors); 475 476 int qcow2_mark_dirty(BlockDriverState *bs); 477 int qcow2_mark_corrupt(BlockDriverState *bs); 478 int qcow2_mark_consistent(BlockDriverState *bs); 479 int qcow2_update_header(BlockDriverState *bs); 480 481 void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, 482 int64_t size, const char *message_format, ...) 483 GCC_FMT_ATTR(5, 6); 484 485 /* qcow2-refcount.c functions */ 486 int qcow2_refcount_init(BlockDriverState *bs); 487 void qcow2_refcount_close(BlockDriverState *bs); 488 489 int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index, 490 int addend, enum qcow2_discard_type type); 491 492 int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size); 493 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, 494 int nb_clusters); 495 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size); 496 void qcow2_free_clusters(BlockDriverState *bs, 497 int64_t offset, int64_t size, 498 enum qcow2_discard_type type); 499 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry, 500 int nb_clusters, enum qcow2_discard_type type); 501 502 int qcow2_update_snapshot_refcount(BlockDriverState *bs, 503 int64_t l1_table_offset, int l1_size, int addend); 504 505 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, 506 BdrvCheckMode fix); 507 508 void qcow2_process_discards(BlockDriverState *bs, int ret); 509 510 int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset, 511 int64_t size); 512 int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset, 513 int64_t size); 514 515 /* qcow2-cluster.c functions */ 516 int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, 517 bool exact_size); 518 int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index); 519 void qcow2_l2_cache_reset(BlockDriverState *bs); 520 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 521 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 522 uint8_t *out_buf, const uint8_t *in_buf, 523 int nb_sectors, int enc, 524 const AES_KEY *key); 525 526 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, 527 int *num, uint64_t *cluster_offset); 528 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, 529 int *num, uint64_t *host_offset, QCowL2Meta **m); 530 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, 531 uint64_t offset, 532 int compressed_size); 533 534 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m); 535 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset, 536 int nb_sectors, enum qcow2_discard_type type); 537 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors); 538 539 int qcow2_expand_zero_clusters(BlockDriverState *bs); 540 541 /* qcow2-snapshot.c functions */ 542 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info); 543 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id); 544 int qcow2_snapshot_delete(BlockDriverState *bs, 545 const char *snapshot_id, 546 const char *name, 547 Error **errp); 548 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab); 549 int qcow2_snapshot_load_tmp(BlockDriverState *bs, 550 const char *snapshot_id, 551 const char *name, 552 Error **errp); 553 554 void qcow2_free_snapshots(BlockDriverState *bs); 555 int qcow2_read_snapshots(BlockDriverState *bs); 556 557 /* qcow2-cache.c functions */ 558 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables); 559 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c); 560 561 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table); 562 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c); 563 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c, 564 Qcow2Cache *dependency); 565 void qcow2_cache_depends_on_flush(Qcow2Cache *c); 566 567 int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c); 568 569 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, 570 void **table); 571 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, 572 void **table); 573 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table); 574 575 #endif 576