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 (1LL << 63) 44 /* indicate that the cluster is compressed (they never have the copied flag) */ 45 #define QCOW_OFLAG_COMPRESSED (1LL << 62) 46 /* The cluster reads as all zeros */ 47 #define QCOW_OFLAG_ZERO (1LL << 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_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR, 123 124 QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY, 125 }; 126 127 /* Compatible feature bits */ 128 enum { 129 QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0, 130 QCOW2_COMPAT_LAZY_REFCOUNTS = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 131 132 QCOW2_COMPAT_FEAT_MASK = QCOW2_COMPAT_LAZY_REFCOUNTS, 133 }; 134 135 enum qcow2_discard_type { 136 QCOW2_DISCARD_NEVER = 0, 137 QCOW2_DISCARD_ALWAYS, 138 QCOW2_DISCARD_REQUEST, 139 QCOW2_DISCARD_SNAPSHOT, 140 QCOW2_DISCARD_OTHER, 141 QCOW2_DISCARD_MAX 142 }; 143 144 typedef struct Qcow2Feature { 145 uint8_t type; 146 uint8_t bit; 147 char name[46]; 148 } QEMU_PACKED Qcow2Feature; 149 150 typedef struct Qcow2DiscardRegion { 151 BlockDriverState *bs; 152 uint64_t offset; 153 uint64_t bytes; 154 QTAILQ_ENTRY(Qcow2DiscardRegion) next; 155 } Qcow2DiscardRegion; 156 157 typedef struct BDRVQcowState { 158 int cluster_bits; 159 int cluster_size; 160 int cluster_sectors; 161 int l2_bits; 162 int l2_size; 163 int l1_size; 164 int l1_vm_state_index; 165 int csize_shift; 166 int csize_mask; 167 uint64_t cluster_offset_mask; 168 uint64_t l1_table_offset; 169 uint64_t *l1_table; 170 171 Qcow2Cache* l2_table_cache; 172 Qcow2Cache* refcount_block_cache; 173 174 uint8_t *cluster_cache; 175 uint8_t *cluster_data; 176 uint64_t cluster_cache_offset; 177 QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs; 178 179 uint64_t *refcount_table; 180 uint64_t refcount_table_offset; 181 uint32_t refcount_table_size; 182 int64_t free_cluster_index; 183 int64_t free_byte_offset; 184 185 CoMutex lock; 186 187 uint32_t crypt_method; /* current crypt method, 0 if no key yet */ 188 uint32_t crypt_method_header; 189 AES_KEY aes_encrypt_key; 190 AES_KEY aes_decrypt_key; 191 uint64_t snapshots_offset; 192 int snapshots_size; 193 int nb_snapshots; 194 QCowSnapshot *snapshots; 195 196 int flags; 197 int qcow_version; 198 bool use_lazy_refcounts; 199 200 bool discard_passthrough[QCOW2_DISCARD_MAX]; 201 202 uint64_t incompatible_features; 203 uint64_t compatible_features; 204 uint64_t autoclear_features; 205 206 size_t unknown_header_fields_size; 207 void* unknown_header_fields; 208 QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext; 209 QTAILQ_HEAD (, Qcow2DiscardRegion) discards; 210 bool cache_discards; 211 } BDRVQcowState; 212 213 /* XXX: use std qcow open function ? */ 214 typedef struct QCowCreateState { 215 int cluster_size; 216 int cluster_bits; 217 uint16_t *refcount_block; 218 uint64_t *refcount_table; 219 int64_t l1_table_offset; 220 int64_t refcount_table_offset; 221 int64_t refcount_block_offset; 222 } QCowCreateState; 223 224 struct QCowAIOCB; 225 226 typedef struct Qcow2COWRegion { 227 /** 228 * Offset of the COW region in bytes from the start of the first cluster 229 * touched by the request. 230 */ 231 uint64_t offset; 232 233 /** Number of sectors to copy */ 234 int nb_sectors; 235 } Qcow2COWRegion; 236 237 /** 238 * Describes an in-flight (part of a) write request that writes to clusters 239 * that are not referenced in their L2 table yet. 240 */ 241 typedef struct QCowL2Meta 242 { 243 /** Guest offset of the first newly allocated cluster */ 244 uint64_t offset; 245 246 /** Host offset of the first newly allocated cluster */ 247 uint64_t alloc_offset; 248 249 /** 250 * Number of sectors from the start of the first allocated cluster to 251 * the end of the (possibly shortened) request 252 */ 253 int nb_available; 254 255 /** Number of newly allocated clusters */ 256 int nb_clusters; 257 258 /** 259 * Requests that overlap with this allocation and wait to be restarted 260 * when the allocating request has completed. 261 */ 262 CoQueue dependent_requests; 263 264 /** 265 * The COW Region between the start of the first allocated cluster and the 266 * area the guest actually writes to. 267 */ 268 Qcow2COWRegion cow_start; 269 270 /** 271 * The COW Region between the area the guest actually writes to and the 272 * end of the last allocated cluster. 273 */ 274 Qcow2COWRegion cow_end; 275 276 /** Pointer to next L2Meta of the same write request */ 277 struct QCowL2Meta *next; 278 279 QLIST_ENTRY(QCowL2Meta) next_in_flight; 280 } QCowL2Meta; 281 282 enum { 283 QCOW2_CLUSTER_UNALLOCATED, 284 QCOW2_CLUSTER_NORMAL, 285 QCOW2_CLUSTER_COMPRESSED, 286 QCOW2_CLUSTER_ZERO 287 }; 288 289 #define L1E_OFFSET_MASK 0x00ffffffffffff00ULL 290 #define L2E_OFFSET_MASK 0x00ffffffffffff00ULL 291 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL 292 293 #define REFT_OFFSET_MASK 0xffffffffffffff00ULL 294 295 static inline int64_t start_of_cluster(BDRVQcowState *s, int64_t offset) 296 { 297 return offset & ~(s->cluster_size - 1); 298 } 299 300 static inline int64_t offset_into_cluster(BDRVQcowState *s, int64_t offset) 301 { 302 return offset & (s->cluster_size - 1); 303 } 304 305 static inline int size_to_clusters(BDRVQcowState *s, int64_t size) 306 { 307 return (size + (s->cluster_size - 1)) >> s->cluster_bits; 308 } 309 310 static inline int64_t size_to_l1(BDRVQcowState *s, int64_t size) 311 { 312 int shift = s->cluster_bits + s->l2_bits; 313 return (size + (1ULL << shift) - 1) >> shift; 314 } 315 316 static inline int offset_to_l2_index(BDRVQcowState *s, int64_t offset) 317 { 318 return (offset >> s->cluster_bits) & (s->l2_size - 1); 319 } 320 321 static inline int64_t align_offset(int64_t offset, int n) 322 { 323 offset = (offset + n - 1) & ~(n - 1); 324 return offset; 325 } 326 327 static inline int qcow2_get_cluster_type(uint64_t l2_entry) 328 { 329 if (l2_entry & QCOW_OFLAG_COMPRESSED) { 330 return QCOW2_CLUSTER_COMPRESSED; 331 } else if (l2_entry & QCOW_OFLAG_ZERO) { 332 return QCOW2_CLUSTER_ZERO; 333 } else if (!(l2_entry & L2E_OFFSET_MASK)) { 334 return QCOW2_CLUSTER_UNALLOCATED; 335 } else { 336 return QCOW2_CLUSTER_NORMAL; 337 } 338 } 339 340 /* Check whether refcounts are eager or lazy */ 341 static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s) 342 { 343 return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY); 344 } 345 346 static inline uint64_t l2meta_cow_start(QCowL2Meta *m) 347 { 348 return m->offset + m->cow_start.offset; 349 } 350 351 static inline uint64_t l2meta_cow_end(QCowL2Meta *m) 352 { 353 return m->offset + m->cow_end.offset 354 + (m->cow_end.nb_sectors << BDRV_SECTOR_BITS); 355 } 356 357 // FIXME Need qcow2_ prefix to global functions 358 359 /* qcow2.c functions */ 360 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 361 int64_t sector_num, int nb_sectors); 362 363 int qcow2_mark_dirty(BlockDriverState *bs); 364 int qcow2_update_header(BlockDriverState *bs); 365 366 /* qcow2-refcount.c functions */ 367 int qcow2_refcount_init(BlockDriverState *bs); 368 void qcow2_refcount_close(BlockDriverState *bs); 369 370 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size); 371 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, 372 int nb_clusters); 373 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size); 374 void qcow2_free_clusters(BlockDriverState *bs, 375 int64_t offset, int64_t size, 376 enum qcow2_discard_type type); 377 void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry, 378 int nb_clusters, enum qcow2_discard_type type); 379 380 int qcow2_update_snapshot_refcount(BlockDriverState *bs, 381 int64_t l1_table_offset, int l1_size, int addend); 382 383 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, 384 BdrvCheckMode fix); 385 386 void qcow2_process_discards(BlockDriverState *bs, int ret); 387 388 /* qcow2-cluster.c functions */ 389 int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, 390 bool exact_size); 391 void qcow2_l2_cache_reset(BlockDriverState *bs); 392 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 393 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 394 uint8_t *out_buf, const uint8_t *in_buf, 395 int nb_sectors, int enc, 396 const AES_KEY *key); 397 398 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, 399 int *num, uint64_t *cluster_offset); 400 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, 401 int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m); 402 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, 403 uint64_t offset, 404 int compressed_size); 405 406 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m); 407 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset, 408 int nb_sectors); 409 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors); 410 411 /* qcow2-snapshot.c functions */ 412 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info); 413 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id); 414 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id); 415 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab); 416 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); 417 418 void qcow2_free_snapshots(BlockDriverState *bs); 419 int qcow2_read_snapshots(BlockDriverState *bs); 420 421 /* qcow2-cache.c functions */ 422 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables); 423 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c); 424 425 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table); 426 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c); 427 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c, 428 Qcow2Cache *dependency); 429 void qcow2_cache_depends_on_flush(Qcow2Cache *c); 430 431 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, 432 void **table); 433 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, 434 void **table); 435 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table); 436 437 #endif 438