block/qcow2.h

   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 typedef struct Qcow2Feature {
 122     uint8_t type;
 123     uint8_t bit;
 124     char    name[46];
 125 } QEMU_PACKED Qcow2Feature;
 126
 127 typedef struct BDRVQcowState {
 128     int cluster_bits;
 129     int cluster_size;
 130     int cluster_sectors;
 131     int l2_bits;
 132     int l2_size;
 133     int l1_size;
 134     int l1_vm_state_index;
 135     int csize_shift;
 136     int csize_mask;
 137     uint64_t cluster_offset_mask;
 138     uint64_t l1_table_offset;
 139     uint64_t *l1_table;
 140
 141     Qcow2Cache* l2_table_cache;
 142     Qcow2Cache* refcount_block_cache;
 143
 144     uint8_t *cluster_cache;
 145     uint8_t *cluster_data;
 146     uint64_t cluster_cache_offset;
 147     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 148
 149     uint64_t *refcount_table;
 150     uint64_t refcount_table_offset;
 151     uint32_t refcount_table_size;
 152     int64_t free_cluster_index;
 153     int64_t free_byte_offset;
 154
 155     CoMutex lock;
 156
 157     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 158     uint32_t crypt_method_header;
 159     AES_KEY aes_encrypt_key;
 160     AES_KEY aes_decrypt_key;
 161     uint64_t snapshots_offset;
 162     int snapshots_size;
 163     int nb_snapshots;
 164     QCowSnapshot *snapshots;
 165
 166     int flags;
 167     int qcow_version;
 168
 169     uint64_t incompatible_features;
 170     uint64_t compatible_features;
 171     uint64_t autoclear_features;
 172
 173     size_t unknown_header_fields_size;
 174     void* unknown_header_fields;
 175     QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 176 } BDRVQcowState;
 177
 178 /* XXX: use std qcow open function ? */
 179 typedef struct QCowCreateState {
 180     int cluster_size;
 181     int cluster_bits;
 182     uint16_t *refcount_block;
 183     uint64_t *refcount_table;
 184     int64_t l1_table_offset;
 185     int64_t refcount_table_offset;
 186     int64_t refcount_block_offset;
 187 } QCowCreateState;
 188
 189 struct QCowAIOCB;
 190
 191 /* XXX This could be private for qcow2-cluster.c */
 192 typedef struct QCowL2Meta
 193 {
 194     uint64_t offset;
 195     uint64_t cluster_offset;
 196     uint64_t alloc_offset;
 197     int n_start;
 198     int nb_available;
 199     int nb_clusters;
 200     CoQueue dependent_requests;
 201
 202     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 203 } QCowL2Meta;
 204
 205 enum {
 206     QCOW2_CLUSTER_UNALLOCATED,
 207     QCOW2_CLUSTER_NORMAL,
 208     QCOW2_CLUSTER_COMPRESSED,
 209     QCOW2_CLUSTER_ZERO
 210 };
 211
 212 #define L1E_OFFSET_MASK 0x00ffffffffffff00ULL
 213 #define L2E_OFFSET_MASK 0x00ffffffffffff00ULL
 214 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
 215
 216 #define REFT_OFFSET_MASK 0xffffffffffffff00ULL
 217
 218 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 219 {
 220     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 221 }
 222
 223 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
 224 {
 225     int shift = s->cluster_bits + s->l2_bits;
 226     return (size + (1ULL << shift) - 1) >> shift;
 227 }
 228
 229 static inline int64_t align_offset(int64_t offset, int n)
 230 {
 231     offset = (offset + n - 1) & ~(n - 1);
 232     return offset;
 233 }
 234
 235 static inline int qcow2_get_cluster_type(uint64_t l2_entry)
 236 {
 237     if (l2_entry & QCOW_OFLAG_COMPRESSED) {
 238         return QCOW2_CLUSTER_COMPRESSED;
 239     } else if (l2_entry & QCOW_OFLAG_ZERO) {
 240         return QCOW2_CLUSTER_ZERO;
 241     } else if (!(l2_entry & L2E_OFFSET_MASK)) {
 242         return QCOW2_CLUSTER_UNALLOCATED;
 243     } else {
 244         return QCOW2_CLUSTER_NORMAL;
 245     }
 246 }
 247
 248
 249 // FIXME Need qcow2_ prefix to global functions
 250
 251 /* qcow2.c functions */
 252 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 253                   int64_t sector_num, int nb_sectors);
 254 int qcow2_update_header(BlockDriverState *bs);
 255
 256 /* qcow2-refcount.c functions */
 257 int qcow2_refcount_init(BlockDriverState *bs);
 258 void qcow2_refcount_close(BlockDriverState *bs);
 259
 260 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
 261 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 262     int nb_clusters);
 263 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 264 void qcow2_free_clusters(BlockDriverState *bs,
 265     int64_t offset, int64_t size);
 266 void qcow2_free_any_clusters(BlockDriverState *bs,
 267     uint64_t cluster_offset, int nb_clusters);
 268
 269 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 270     int64_t l1_table_offset, int l1_size, int addend);
 271
 272 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 273                           BdrvCheckMode fix);
 274
 275 /* qcow2-cluster.c functions */
 276 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
 277 void qcow2_l2_cache_reset(BlockDriverState *bs);
 278 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 279 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 280                      uint8_t *out_buf, const uint8_t *in_buf,
 281                      int nb_sectors, int enc,
 282                      const AES_KEY *key);
 283
 284 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 285     int *num, uint64_t *cluster_offset);
 286 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 287     int n_start, int n_end, int *num, QCowL2Meta *m);
 288 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 289                                          uint64_t offset,
 290                                          int compressed_size);
 291
 292 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 293 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 294     int nb_sectors);
 295 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
 296
 297 /* qcow2-snapshot.c functions */
 298 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 299 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 300 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 301 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 302 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 303
 304 void qcow2_free_snapshots(BlockDriverState *bs);
 305 int qcow2_read_snapshots(BlockDriverState *bs);
 306
 307 /* qcow2-cache.c functions */
 308 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
 309 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 310
 311 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 312 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 313 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 314     Qcow2Cache *dependency);
 315 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 316
 317 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 318     void **table);
 319 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 320     void **table);
 321 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 322
 323 #endif