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 "aes.h" 29 #include "qemu-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 typedef struct QCowHeader { 62 uint32_t magic; 63 uint32_t version; 64 uint64_t backing_file_offset; 65 uint32_t backing_file_size; 66 uint32_t cluster_bits; 67 uint64_t size; /* in bytes */ 68 uint32_t crypt_method; 69 uint32_t l1_size; /* XXX: save number of clusters instead ? */ 70 uint64_t l1_table_offset; 71 uint64_t refcount_table_offset; 72 uint32_t refcount_table_clusters; 73 uint32_t nb_snapshots; 74 uint64_t snapshots_offset; 75 76 /* The following fields are only valid for version >= 3 */ 77 uint64_t incompatible_features; 78 uint64_t compatible_features; 79 uint64_t autoclear_features; 80 81 uint32_t refcount_order; 82 uint32_t header_length; 83 } QCowHeader; 84 85 typedef struct QCowSnapshot { 86 uint64_t l1_table_offset; 87 uint32_t l1_size; 88 char *id_str; 89 char *name; 90 uint64_t disk_size; 91 uint64_t vm_state_size; 92 uint32_t date_sec; 93 uint32_t date_nsec; 94 uint64_t vm_clock_nsec; 95 } QCowSnapshot; 96 97 struct Qcow2Cache; 98 typedef struct Qcow2Cache Qcow2Cache; 99 100 typedef struct Qcow2UnknownHeaderExtension { 101 uint32_t magic; 102 uint32_t len; 103 QLIST_ENTRY(Qcow2UnknownHeaderExtension) next; 104 uint8_t data[]; 105 } Qcow2UnknownHeaderExtension; 106 107 enum { 108 QCOW2_FEAT_TYPE_INCOMPATIBLE = 0, 109 QCOW2_FEAT_TYPE_COMPATIBLE = 1, 110 QCOW2_FEAT_TYPE_AUTOCLEAR = 2, 111 }; 112 113 /* Incompatible feature bits */ 114 enum { 115 QCOW2_INCOMPAT_DIRTY_BITNR = 0, 116 QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR, 117 118 QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY, 119 }; 120 121 /* Compatible feature bits */ 122 enum { 123 QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0, 124 QCOW2_COMPAT_LAZY_REFCOUNTS = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR, 125 126 QCOW2_COMPAT_FEAT_MASK = QCOW2_COMPAT_LAZY_REFCOUNTS, 127 }; 128 129 typedef struct Qcow2Feature { 130 uint8_t type; 131 uint8_t bit; 132 char name[46]; 133 } QEMU_PACKED Qcow2Feature; 134 135 typedef struct BDRVQcowState { 136 int cluster_bits; 137 int cluster_size; 138 int cluster_sectors; 139 int l2_bits; 140 int l2_size; 141 int l1_size; 142 int l1_vm_state_index; 143 int csize_shift; 144 int csize_mask; 145 uint64_t cluster_offset_mask; 146 uint64_t l1_table_offset; 147 uint64_t *l1_table; 148 149 Qcow2Cache* l2_table_cache; 150 Qcow2Cache* refcount_block_cache; 151 152 uint8_t *cluster_cache; 153 uint8_t *cluster_data; 154 uint64_t cluster_cache_offset; 155 QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs; 156 157 uint64_t *refcount_table; 158 uint64_t refcount_table_offset; 159 uint32_t refcount_table_size; 160 int64_t free_cluster_index; 161 int64_t free_byte_offset; 162 163 CoMutex lock; 164 165 uint32_t crypt_method; /* current crypt method, 0 if no key yet */ 166 uint32_t crypt_method_header; 167 AES_KEY aes_encrypt_key; 168 AES_KEY aes_decrypt_key; 169 uint64_t snapshots_offset; 170 int snapshots_size; 171 int nb_snapshots; 172 QCowSnapshot *snapshots; 173 174 int flags; 175 int qcow_version; 176 177 uint64_t incompatible_features; 178 uint64_t compatible_features; 179 uint64_t autoclear_features; 180 181 size_t unknown_header_fields_size; 182 void* unknown_header_fields; 183 QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext; 184 } BDRVQcowState; 185 186 /* XXX: use std qcow open function ? */ 187 typedef struct QCowCreateState { 188 int cluster_size; 189 int cluster_bits; 190 uint16_t *refcount_block; 191 uint64_t *refcount_table; 192 int64_t l1_table_offset; 193 int64_t refcount_table_offset; 194 int64_t refcount_block_offset; 195 } QCowCreateState; 196 197 struct QCowAIOCB; 198 199 typedef struct Qcow2COWRegion { 200 /** 201 * Offset of the COW region in bytes from the start of the first cluster 202 * touched by the request. 203 */ 204 uint64_t offset; 205 206 /** Number of sectors to copy */ 207 int nb_sectors; 208 } Qcow2COWRegion; 209 210 /** 211 * Describes an in-flight (part of a) write request that writes to clusters 212 * that are not referenced in their L2 table yet. 213 */ 214 typedef struct QCowL2Meta 215 { 216 /** Guest offset of the first newly allocated cluster */ 217 uint64_t offset; 218 219 /** Host offset of the first newly allocated cluster */ 220 uint64_t alloc_offset; 221 222 /** 223 * Number of sectors from the start of the first allocated cluster to 224 * the end of the (possibly shortened) request 225 */ 226 int nb_available; 227 228 /** Number of newly allocated clusters */ 229 int nb_clusters; 230 231 /** 232 * Requests that overlap with this allocation and wait to be restarted 233 * when the allocating request has completed. 234 */ 235 CoQueue dependent_requests; 236 237 /** 238 * The COW Region between the start of the first allocated cluster and the 239 * area the guest actually writes to. 240 */ 241 Qcow2COWRegion cow_start; 242 243 /** 244 * The COW Region between the area the guest actually writes to and the 245 * end of the last allocated cluster. 246 */ 247 Qcow2COWRegion cow_end; 248 249 QLIST_ENTRY(QCowL2Meta) next_in_flight; 250 } QCowL2Meta; 251 252 enum { 253 QCOW2_CLUSTER_UNALLOCATED, 254 QCOW2_CLUSTER_NORMAL, 255 QCOW2_CLUSTER_COMPRESSED, 256 QCOW2_CLUSTER_ZERO 257 }; 258 259 #define L1E_OFFSET_MASK 0x00ffffffffffff00ULL 260 #define L2E_OFFSET_MASK 0x00ffffffffffff00ULL 261 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL 262 263 #define REFT_OFFSET_MASK 0xffffffffffffff00ULL 264 265 static inline int size_to_clusters(BDRVQcowState *s, int64_t size) 266 { 267 return (size + (s->cluster_size - 1)) >> s->cluster_bits; 268 } 269 270 static inline int size_to_l1(BDRVQcowState *s, int64_t size) 271 { 272 int shift = s->cluster_bits + s->l2_bits; 273 return (size + (1ULL << shift) - 1) >> shift; 274 } 275 276 static inline int64_t align_offset(int64_t offset, int n) 277 { 278 offset = (offset + n - 1) & ~(n - 1); 279 return offset; 280 } 281 282 static inline int qcow2_get_cluster_type(uint64_t l2_entry) 283 { 284 if (l2_entry & QCOW_OFLAG_COMPRESSED) { 285 return QCOW2_CLUSTER_COMPRESSED; 286 } else if (l2_entry & QCOW_OFLAG_ZERO) { 287 return QCOW2_CLUSTER_ZERO; 288 } else if (!(l2_entry & L2E_OFFSET_MASK)) { 289 return QCOW2_CLUSTER_UNALLOCATED; 290 } else { 291 return QCOW2_CLUSTER_NORMAL; 292 } 293 } 294 295 /* Check whether refcounts are eager or lazy */ 296 static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s) 297 { 298 return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY); 299 } 300 301 // FIXME Need qcow2_ prefix to global functions 302 303 /* qcow2.c functions */ 304 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov, 305 int64_t sector_num, int nb_sectors); 306 307 int qcow2_mark_dirty(BlockDriverState *bs); 308 int qcow2_update_header(BlockDriverState *bs); 309 310 /* qcow2-refcount.c functions */ 311 int qcow2_refcount_init(BlockDriverState *bs); 312 void qcow2_refcount_close(BlockDriverState *bs); 313 314 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size); 315 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, 316 int nb_clusters); 317 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size); 318 void qcow2_free_clusters(BlockDriverState *bs, 319 int64_t offset, int64_t size); 320 void qcow2_free_any_clusters(BlockDriverState *bs, 321 uint64_t cluster_offset, int nb_clusters); 322 323 int qcow2_update_snapshot_refcount(BlockDriverState *bs, 324 int64_t l1_table_offset, int l1_size, int addend); 325 326 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res, 327 BdrvCheckMode fix); 328 329 /* qcow2-cluster.c functions */ 330 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size); 331 void qcow2_l2_cache_reset(BlockDriverState *bs); 332 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); 333 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num, 334 uint8_t *out_buf, const uint8_t *in_buf, 335 int nb_sectors, int enc, 336 const AES_KEY *key); 337 338 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset, 339 int *num, uint64_t *cluster_offset); 340 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset, 341 int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m); 342 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs, 343 uint64_t offset, 344 int compressed_size); 345 346 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m); 347 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset, 348 int nb_sectors); 349 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors); 350 351 /* qcow2-snapshot.c functions */ 352 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info); 353 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id); 354 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id); 355 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab); 356 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name); 357 358 void qcow2_free_snapshots(BlockDriverState *bs); 359 int qcow2_read_snapshots(BlockDriverState *bs); 360 361 /* qcow2-cache.c functions */ 362 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables); 363 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c); 364 365 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table); 366 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c); 367 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c, 368 Qcow2Cache *dependency); 369 void qcow2_cache_depends_on_flush(Qcow2Cache *c); 370 371 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, 372 void **table); 373 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset, 374 void **table); 375 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table); 376 377 #endif 378