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 42 /* indicate that the refcount of the referenced cluster is exactly one. */ 43 #define QCOW_OFLAG_COPIED (1ULL << 63) 44 /* indicate that the cluster is compressed (they never have the copied flag) */ 45 #define QCOW_OFLAG_COMPRESSED (1ULL << 62) 46 /* The cluster reads as all zeros */ 47 #define QCOW_OFLAG_ZERO (1ULL << 0) 48 49 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */ 50 51 #define MIN_CLUSTER_BITS 9 52 #define MAX_CLUSTER_BITS 21 53 54 #define L2_CACHE_SIZE 16 55 56 /* Must be at least 4 to cover all cases of refcount table growth */ 57 #define REFCOUNT_CACHE_SIZE 4 58 59 #define DEFAULT_CLUSTER_SIZE 65536 60 61 62 #define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts" 63 #define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request" 64 #define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot" 65 #define QCOW2_OPT_DISCARD_OTHER "pass-discard-other" 66 67 typedef struct QCowHeader { 68 uint32_t magic; 69 uint32_t version; 70 uint64_t backing_file_offset; 71 uint32_t backing_file_size; 72 uint32_t cluster_bits; 73 uint64_t size; /* in bytes */ 74 uint32_t crypt_method; 75 uint32_t l1_size; /* XXX: save number of clusters instead ? */ 76 uint64_t l1_table_offset; 77 uint64_t refcount_table_offset; 78 uint32_t refcount_table_clusters; 79 uint32_t nb_snapshots; 80 uint64_t snapshots_offset; 81 82 /* The following fields are only valid for version >= 3 */ 83 uint64_t incompatible_features; 84 uint64_t compatible_features; 85 uint64_t autoclear_features; 86 87 uint32_t refcount_order; 88 uint32_t header_length; 89 } QCowHeader; 90 91 typedef struct QCowSnapshot { 92 uint64_t l1_table_offset; 93 uint32_t l1_size; 94 char *id_str; 95 char *name; 96 uint64_t disk_size; 97 uint64_t vm_state_size; 98 uint32_t date_sec; 99 uint32_t date_nsec; 100 uint64_t vm_clock_nsec; 101 } QCowSnapshot; 102 103 struct Qcow2Cache; 104 typedef struct Qcow2Cache Qcow2Cache; 105 106 typedef struct Qcow2UnknownHeaderExtension { 107 uint32_t magic; 108 uint32_t len; 109 QLIST_ENTRY(Qcow2UnknownHeaderExtension) next; 110 uint8_t data[]; 111 } Qcow2UnknownHeaderExtension; 112 113 enum { 114 QCOW2_FEAT_TYPE_INCOMPATIBLE = 0, 115 QCOW2_FEAT_TYPE_COMPATIBLE = 1, 116 QCOW2_FEAT_TYPE_AUTOCLEAR = 2, 117 }; 118 119 /* Incompatible feature bits */ 120 enum { 121 QCOW2_INCOMPAT_DIRTY_BITNR = 0, 122 QCOW2_INCOMPAT_CORRUPT_BITNR = 1, 123 QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR, 124 QCOW2_INCOMPAT_CORRUPT = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR, 125 126 QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY 127 | QCOW2_INCOMPAT_CORRUPT, 128 }; 129 130 /* Compatible feature bits */ 131 enum { 132 QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0, 133 QCOW2_COMPAT_LAZY_REFCOUNTS = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 134 135 QCOW2_COMPAT_FEAT_MASK = QCOW2_COMPAT_LAZY_REFCOUNTS, 136 }; 137 138 enum qcow2_discard_type { 139 QCOW2_DISCARD_NEVER = 0, 140 QCOW2_DISCARD_ALWAYS, 141 QCOW2_DISCARD_REQUEST, 142 QCOW2_DISCARD_SNAPSHOT, 143 QCOW2_DISCARD_OTHER, 144 QCOW2_DISCARD_MAX 145 }; 146 147 typedef struct Qcow2Feature { 148 uint8_t type; 149 uint8_t bit; 150 char name[46]; 151 } QEMU_PACKED Qcow2Feature; 152 153 typedef struct Qcow2DiscardRegion { 154 BlockDriverState *bs; 155 uint64_t offset; 156 uint64_t bytes; 157 QTAILQ_ENTRY(Qcow2DiscardRegion) next; 158 } Qcow2DiscardRegion; 159 160 typedef struct BDRVQcowState { 161 int cluster_bits; 162 int cluster_size; 163 int cluster_sectors; 164 int l2_bits; 165 int l2_size; 166 int l1_size; 167 int l1_vm_state_index; 168 int csize_shift; 169 int csize_mask; 170 uint64_t cluster_offset_mask; 171 uint64_t l1_table_offset; 172 uint64_t *l1_table; 173 174 Qcow2Cache* l2_table_cache; 175 Qcow2Cache* refcount_block_cache; 176 177 uint8_t *cluster_cache; 178 uint8_t *cluster_data; 179 uint64_t cluster_cache_offset; 180 QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs; 181 182 uint64_t *refcount_table; 183 uint64_t refcount_table_offset; 184 uint32_t refcount_table_size; 185 int64_t free_cluster_index; 186 int64_t free_byte_offset; 187 188 CoMutex lock; 189 190 uint32_t crypt_method; /* current crypt method, 0 if no key yet */ 191 uint32_t crypt_method_header; 192 AES_KEY aes_encrypt_key; 193 AES_KEY aes_decrypt_key; 194 uint64_t snapshots_offset; 195 int snapshots_size; 196 int nb_snapshots; 197 QCowSnapshot *snapshots; 198 199 int flags; 200 int qcow_version; 201 bool use_lazy_refcounts; 202 int refcount_order; 203 204 bool discard_passthrough[QCOW2_DISCARD_MAX]; 205 206 uint64_t incompatible_features; 207 uint64_t compatible_features; 208 uint64_t autoclear_features; 209 210 size_t unknown_header_fields_size; 211 void* unknown_header_fields; 212 QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext; 213 QTAILQ_HEAD (, Qcow2DiscardRegion) discards; 214 bool cache_discards; 215 } BDRVQcowState; 216 217 /* XXX: use std qcow open function ? */ 218 typedef struct QCowCreateState { 219 int cluster_size; 220 int cluster_bits; 221 uint16_t *refcount_block; 222 uint64_t *refcount_table; 223 int64_t l1_table_offset; 224 int64_t refcount_table_offset; 225 int64_t refcount_block_offset; 226 } QCowCreateState; 227 228 struct QCowAIOCB; 229 230 typedef struct Qcow2COWRegion { 231 /** 232 * Offset of the COW region in bytes from the start of the first cluster 233 * touched by the request. 234 */ 235 uint64_t offset; 236 237 /** Number of sectors to copy */ 238 int nb_sectors; 239 } Qcow2COWRegion; 240 241 /** 242 * Describes an in-flight (part of a) write request that writes to clusters 243 * that are not referenced in their L2 table yet. 244 */ 245 typedef struct QCowL2Meta 246 { 247 /** Guest offset of the first newly allocated cluster */ 248 uint64_t offset; 249 250 /** Host offset of the first newly allocated cluster */ 251 uint64_t alloc_offset; 252 253 /** 254 * Number of sectors from the start of the first allocated cluster to 255 * the end of the (possibly shortened) request 256 */ 257 int nb_available; 258 259 /** Number of newly allocated clusters */ 260 int nb_clusters; 261 262 /** 263 * Requests that overlap with this allocation and wait to be restarted 264 * when the allocating request has completed. 265 */ 266 CoQueue dependent_requests; 267 268 /** 269 * The COW Region between the start of the first allocated cluster and the 270 * area the guest actually writes to. 271 */ 272 Qcow2COWRegion cow_start; 273 274 /** 275 * The COW Region between the area the guest actually writes to and the 276 * end of the last allocated cluster. 277 */ 278 Qcow2COWRegion cow_end; 279 280 /** Pointer to next L2Meta of the same write request */ 281 struct QCowL2Meta *next; 282 283 QLIST_ENTRY(QCowL2Meta) next_in_flight; 284 } QCowL2Meta; 285 286 enum { 287 QCOW2_CLUSTER_UNALLOCATED, 288 QCOW2_CLUSTER_NORMAL, 289 QCOW2_CLUSTER_COMPRESSED, 290 QCOW2_CLUSTER_ZERO 291 }; 292 293 typedef enum QCow2MetadataOverlap { 294 QCOW2_OL_MAIN_HEADER_BITNR = 0, 295 QCOW2_OL_ACTIVE_L1_BITNR = 1, 296 QCOW2_OL_ACTIVE_L2_BITNR = 2, 297 QCOW2_OL_REFCOUNT_TABLE_BITNR = 3, 298 QCOW2_OL_REFCOUNT_BLOCK_BITNR = 4, 299 QCOW2_OL_SNAPSHOT_TABLE_BITNR = 5, 300 QCOW2_OL_INACTIVE_L1_BITNR = 6, 301 QCOW2_OL_INACTIVE_L2_BITNR = 7, 302 303 QCOW2_OL_MAX_BITNR = 8, 304 305 QCOW2_OL_NONE = 0, 306 QCOW2_OL_MAIN_HEADER = (1 << QCOW2_OL_MAIN_HEADER_BITNR), 307 QCOW2_OL_ACTIVE_L1 = (1 << QCOW2_OL_ACTIVE_L1_BITNR), 308 QCOW2_OL_ACTIVE_L2 = (1 << QCOW2_OL_ACTIVE_L2_BITNR), 309 QCOW2_OL_REFCOUNT_TABLE = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR), 310 QCOW2_OL_REFCOUNT_BLOCK = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR), 311 QCOW2_OL_SNAPSHOT_TABLE = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR), 312 QCOW2_OL_INACTIVE_L1 = (1 << QCOW2_OL_INACTIVE_L1_BITNR), 313 /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv 314 * reads. */ 315 QCOW2_OL_INACTIVE_L2 = (1 << QCOW2_OL_INACTIVE_L2_BITNR), 316 } QCow2MetadataOverlap; 317 318 /* Perform all overlap checks which don't require disk access */ 319 #define QCOW2_OL_CACHED \ 320 (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_ACTIVE_L2 | \ 321 QCOW2_OL_REFCOUNT_TABLE | QCOW2_OL_REFCOUNT_BLOCK | \ 322 QCOW2_OL_SNAPSHOT_TABLE | QCOW2_OL_INACTIVE_L1) 323 324 /* The default checks to perform */ 325 #define QCOW2_OL_DEFAULT QCOW2_OL_CACHED 326 327 #define L1E_OFFSET_MASK 0x00ffffffffffff00ULL 328 #define L2E_OFFSET_MASK 0x00ffffffffffff00ULL 329 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL 330 331 #define REFT_OFFSET_MASK 0xffffffffffffff00ULL 332 333 static inline int64_t start_of_cluster(BDRVQcowState *s, int64_t offset) 334 { 335 return offset & ~(s->cluster_size - 1); 336 } 337 338 static inline int64_t offset_into_cluster(BDRVQcowState *s, int64_t offset) 339 { 340 return offset & (s->cluster_size - 1); 341 } 342 343 static inline int size_to_clusters(BDRVQcowState *s, int64_t size) 344 { 345 return (size + (s->cluster_size - 1)) >> s->cluster_bits; 346 } 347 348 static inline int64_t size_to_l1(BDRVQcowState *s, int64_t size) 349 { 350 int shift = s->cluster_bits + s->l2_bits; 351 return (size + (1ULL << shift) - 1) >> shift; 352 } 353 354 static inline int offset_to_l2_index(BDRVQcowState *s, int64_t offset) 355 { 356 return (offset >> s->cluster_bits) & (s->l2_size - 1); 357 } 358 359 static inline int64_t align_offset(int64_t offset, int n) 360 { 361 offset = (offset + n - 1) & ~(n - 1); 362 return offset; 363 } 364 365 static inline int64_t qcow2_vm_state_offset(BDRVQcowState *s) 366 { 367 return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); 368 } 369 370 static inline int qcow2_get_cluster_type(uint64_t l2_entry) 371 { 372 if (l2_entry & QCOW_OFLAG_COMPRESSED) { 373 return QCOW2_CLUSTER_COMPRESSED; 374 } else if (l2_entry & QCOW_OFLAG_ZERO) { 375 return QCOW2_CLUSTER_ZERO; 376 } else if (!(l2_entry & L2E_OFFSET_MASK)) { 377 return QCOW2_CLUSTER_UNALLOCATED; 378 } else { 379 return QCOW2_CLUSTER_NORMAL; 380 } 381 } 382 383 /* Check whether refcounts are eager or lazy */ 384 static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s) 385 { 386 return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY); 387 } 388 389 static inline uint64_t l2meta_cow_start(QCowL2Meta *m) 390 { 391 return m->offset + m->cow_start.offset; 392 } 393 394 static inline uint64_t l2meta_cow_end(QCowL2Meta *m) 395 { 396 return m->offset + m->cow_end.offset 397 + (m->cow_end.nb_sectors << BDRV_SECTOR_BITS); 398 } 399 400 // FIXME Need qcow2_ prefix to global functions 401 402 /* qcow2.c functions */ 403 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 404 int64_t sector_num, int nb_sectors); 405 406 int qcow2_mark_dirty(BlockDriverState *bs); 407 int qcow2_mark_corrupt(BlockDriverState *bs); 408 int qcow2_mark_consistent(BlockDriverState *bs); 409 int qcow2_update_header(BlockDriverState *bs); 410 411 /* qcow2-refcount.c functions */ 412 int qcow2_refcount_init(BlockDriverState *bs); 413 void qcow2_refcount_close(BlockDriverState *bs); 414 415 int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index, 416 int addend, enum qcow2_discard_type type); 417 418 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size); 419 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, 420 int nb_clusters); 421 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size); 422 void qcow2_free_clusters(BlockDriverState *bs, 423 int64_t offset, int64_t size, 424 enum qcow2_discard_type type); 425 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry, 426 int nb_clusters, enum qcow2_discard_type type); 427 428 int qcow2_update_snapshot_refcount(BlockDriverState *bs, 429 int64_t l1_table_offset, int l1_size, int addend); 430 431 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, 432 BdrvCheckMode fix); 433 434 void qcow2_process_discards(BlockDriverState *bs, int ret); 435 436 int qcow2_check_metadata_overlap(BlockDriverState *bs, int chk, int64_t offset, 437 int64_t size); 438 int qcow2_pre_write_overlap_check(BlockDriverState *bs, int chk, int64_t offset, 439 int64_t size); 440 441 /* qcow2-cluster.c functions */ 442 int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, 443 bool exact_size); 444 int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index); 445 void qcow2_l2_cache_reset(BlockDriverState *bs); 446 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 447 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 448 uint8_t *out_buf, const uint8_t *in_buf, 449 int nb_sectors, int enc, 450 const AES_KEY *key); 451 452 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, 453 int *num, uint64_t *cluster_offset); 454 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, 455 int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m); 456 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, 457 uint64_t offset, 458 int compressed_size); 459 460 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m); 461 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset, 462 int nb_sectors, enum qcow2_discard_type type); 463 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors); 464 465 int qcow2_expand_zero_clusters(BlockDriverState *bs); 466 467 /* qcow2-snapshot.c functions */ 468 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info); 469 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id); 470 int qcow2_snapshot_delete(BlockDriverState *bs, 471 const char *snapshot_id, 472 const char *name, 473 Error **errp); 474 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab); 475 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); 476 477 void qcow2_free_snapshots(BlockDriverState *bs); 478 int qcow2_read_snapshots(BlockDriverState *bs); 479 480 /* qcow2-cache.c functions */ 481 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables); 482 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c); 483 484 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table); 485 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c); 486 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c, 487 Qcow2Cache *dependency); 488 void qcow2_cache_depends_on_flush(Qcow2Cache *c); 489 490 int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c); 491 492 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, 493 void **table); 494 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, 495 void **table); 496 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table); 497 498 #endif 499