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_TEMPLATE "overlap-check.template" 87 #define QCOW2_OPT_OVERLAP_MAIN_HEADER "overlap-check.main-header" 88 #define QCOW2_OPT_OVERLAP_ACTIVE_L1 "overlap-check.active-l1" 89 #define QCOW2_OPT_OVERLAP_ACTIVE_L2 "overlap-check.active-l2" 90 #define QCOW2_OPT_OVERLAP_REFCOUNT_TABLE "overlap-check.refcount-table" 91 #define QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK "overlap-check.refcount-block" 92 #define QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE "overlap-check.snapshot-table" 93 #define QCOW2_OPT_OVERLAP_INACTIVE_L1 "overlap-check.inactive-l1" 94 #define QCOW2_OPT_OVERLAP_INACTIVE_L2 "overlap-check.inactive-l2" 95 #define QCOW2_OPT_CACHE_SIZE "cache-size" 96 #define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size" 97 #define QCOW2_OPT_REFCOUNT_CACHE_SIZE "refcount-cache-size" 98 99 typedef struct QCowHeader { 100 uint32_t magic; 101 uint32_t version; 102 uint64_t backing_file_offset; 103 uint32_t backing_file_size; 104 uint32_t cluster_bits; 105 uint64_t size; /* in bytes */ 106 uint32_t crypt_method; 107 uint32_t l1_size; /* XXX: save number of clusters instead ? */ 108 uint64_t l1_table_offset; 109 uint64_t refcount_table_offset; 110 uint32_t refcount_table_clusters; 111 uint32_t nb_snapshots; 112 uint64_t snapshots_offset; 113 114 /* The following fields are only valid for version >= 3 */ 115 uint64_t incompatible_features; 116 uint64_t compatible_features; 117 uint64_t autoclear_features; 118 119 uint32_t refcount_order; 120 uint32_t header_length; 121 } QEMU_PACKED QCowHeader; 122 123 typedef struct QEMU_PACKED QCowSnapshotHeader { 124 /* header is 8 byte aligned */ 125 uint64_t l1_table_offset; 126 127 uint32_t l1_size; 128 uint16_t id_str_size; 129 uint16_t name_size; 130 131 uint32_t date_sec; 132 uint32_t date_nsec; 133 134 uint64_t vm_clock_nsec; 135 136 uint32_t vm_state_size; 137 uint32_t extra_data_size; /* for extension */ 138 /* extra data follows */ 139 /* id_str follows */ 140 /* name follows */ 141 } QCowSnapshotHeader; 142 143 typedef struct QEMU_PACKED QCowSnapshotExtraData { 144 uint64_t vm_state_size_large; 145 uint64_t disk_size; 146 } QCowSnapshotExtraData; 147 148 149 typedef struct QCowSnapshot { 150 uint64_t l1_table_offset; 151 uint32_t l1_size; 152 char *id_str; 153 char *name; 154 uint64_t disk_size; 155 uint64_t vm_state_size; 156 uint32_t date_sec; 157 uint32_t date_nsec; 158 uint64_t vm_clock_nsec; 159 } QCowSnapshot; 160 161 struct Qcow2Cache; 162 typedef struct Qcow2Cache Qcow2Cache; 163 164 typedef struct Qcow2UnknownHeaderExtension { 165 uint32_t magic; 166 uint32_t len; 167 QLIST_ENTRY(Qcow2UnknownHeaderExtension) next; 168 uint8_t data[]; 169 } Qcow2UnknownHeaderExtension; 170 171 enum { 172 QCOW2_FEAT_TYPE_INCOMPATIBLE = 0, 173 QCOW2_FEAT_TYPE_COMPATIBLE = 1, 174 QCOW2_FEAT_TYPE_AUTOCLEAR = 2, 175 }; 176 177 /* Incompatible feature bits */ 178 enum { 179 QCOW2_INCOMPAT_DIRTY_BITNR = 0, 180 QCOW2_INCOMPAT_CORRUPT_BITNR = 1, 181 QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR, 182 QCOW2_INCOMPAT_CORRUPT = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR, 183 184 QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY 185 | QCOW2_INCOMPAT_CORRUPT, 186 }; 187 188 /* Compatible feature bits */ 189 enum { 190 QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0, 191 QCOW2_COMPAT_LAZY_REFCOUNTS = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 192 193 QCOW2_COMPAT_FEAT_MASK = QCOW2_COMPAT_LAZY_REFCOUNTS, 194 }; 195 196 enum qcow2_discard_type { 197 QCOW2_DISCARD_NEVER = 0, 198 QCOW2_DISCARD_ALWAYS, 199 QCOW2_DISCARD_REQUEST, 200 QCOW2_DISCARD_SNAPSHOT, 201 QCOW2_DISCARD_OTHER, 202 QCOW2_DISCARD_MAX 203 }; 204 205 typedef struct Qcow2Feature { 206 uint8_t type; 207 uint8_t bit; 208 char name[46]; 209 } QEMU_PACKED Qcow2Feature; 210 211 typedef struct Qcow2DiscardRegion { 212 BlockDriverState *bs; 213 uint64_t offset; 214 uint64_t bytes; 215 QTAILQ_ENTRY(Qcow2DiscardRegion) next; 216 } Qcow2DiscardRegion; 217 218 typedef struct BDRVQcowState { 219 int cluster_bits; 220 int cluster_size; 221 int cluster_sectors; 222 int l2_bits; 223 int l2_size; 224 int l1_size; 225 int l1_vm_state_index; 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 577