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
  30 //#define DEBUG_ALLOC
  31 //#define DEBUG_ALLOC2
  32 //#define DEBUG_EXT
  33
  34 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  35 #define QCOW_VERSION 2
  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
  47 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
  48
  49 #define MIN_CLUSTER_BITS 9
  50 #define MAX_CLUSTER_BITS 21
  51
  52 #define L2_CACHE_SIZE 16
  53
  54 /* Must be at least 4 to cover all cases of refcount table growth */
  55 #define REFCOUNT_CACHE_SIZE 4
  56
  57 #define DEFAULT_CLUSTER_SIZE 65536
  58
  59 typedef struct QCowHeader {
  60     uint32_t magic;
  61     uint32_t version;
  62     uint64_t backing_file_offset;
  63     uint32_t backing_file_size;
  64     uint32_t cluster_bits;
  65     uint64_t size; /* in bytes */
  66     uint32_t crypt_method;
  67     uint32_t l1_size; /* XXX: save number of clusters instead ? */
  68     uint64_t l1_table_offset;
  69     uint64_t refcount_table_offset;
  70     uint32_t refcount_table_clusters;
  71     uint32_t nb_snapshots;
  72     uint64_t snapshots_offset;
  73 } QCowHeader;
  74
  75 typedef struct QCowSnapshot {
  76     uint64_t l1_table_offset;
  77     uint32_t l1_size;
  78     char *id_str;
  79     char *name;
  80     uint32_t vm_state_size;
  81     uint32_t date_sec;
  82     uint32_t date_nsec;
  83     uint64_t vm_clock_nsec;
  84 } QCowSnapshot;
  85
  86 struct Qcow2Cache;
  87 typedef struct Qcow2Cache Qcow2Cache;
  88
  89 typedef struct BDRVQcowState {
  90     int cluster_bits;
  91     int cluster_size;
  92     int cluster_sectors;
  93     int l2_bits;
  94     int l2_size;
  95     int l1_size;
  96     int l1_vm_state_index;
  97     int csize_shift;
  98     int csize_mask;
  99     uint64_t cluster_offset_mask;
 100     uint64_t l1_table_offset;
 101     uint64_t *l1_table;
 102
 103     Qcow2Cache* l2_table_cache;
 104     Qcow2Cache* refcount_block_cache;
 105
 106     uint8_t *cluster_cache;
 107     uint8_t *cluster_data;
 108     uint64_t cluster_cache_offset;
 109     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 110
 111     uint64_t *refcount_table;
 112     uint64_t refcount_table_offset;
 113     uint32_t refcount_table_size;
 114     int64_t free_cluster_index;
 115     int64_t free_byte_offset;
 116
 117     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 118     uint32_t crypt_method_header;
 119     AES_KEY aes_encrypt_key;
 120     AES_KEY aes_decrypt_key;
 121     uint64_t snapshots_offset;
 122     int snapshots_size;
 123     int nb_snapshots;
 124     QCowSnapshot *snapshots;
 125 } BDRVQcowState;
 126
 127 /* XXX: use std qcow open function ? */
 128 typedef struct QCowCreateState {
 129     int cluster_size;
 130     int cluster_bits;
 131     uint16_t *refcount_block;
 132     uint64_t *refcount_table;
 133     int64_t l1_table_offset;
 134     int64_t refcount_table_offset;
 135     int64_t refcount_block_offset;
 136 } QCowCreateState;
 137
 138 struct QCowAIOCB;
 139
 140 /* XXX This could be private for qcow2-cluster.c */
 141 typedef struct QCowL2Meta
 142 {
 143     uint64_t offset;
 144     uint64_t cluster_offset;
 145     int n_start;
 146     int nb_available;
 147     int nb_clusters;
 148     struct QCowL2Meta *depends_on;
 149     QLIST_HEAD(QCowAioDependencies, QCowAIOCB) dependent_requests;
 150
 151     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 152 } QCowL2Meta;
 153
 154 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 155 {
 156     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 157 }
 158
 159 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
 160 {
 161     int shift = s->cluster_bits + s->l2_bits;
 162     return (size + (1ULL << shift) - 1) >> shift;
 163 }
 164
 165 static inline int64_t align_offset(int64_t offset, int n)
 166 {
 167     offset = (offset + n - 1) & ~(n - 1);
 168     return offset;
 169 }
 170
 171
 172 // FIXME Need qcow2_ prefix to global functions
 173
 174 /* qcow2.c functions */
 175 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 176                   int64_t sector_num, int nb_sectors);
 177
 178 /* qcow2-refcount.c functions */
 179 int qcow2_refcount_init(BlockDriverState *bs);
 180 void qcow2_refcount_close(BlockDriverState *bs);
 181
 182 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
 183 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 184 void qcow2_free_clusters(BlockDriverState *bs,
 185     int64_t offset, int64_t size);
 186 void qcow2_free_any_clusters(BlockDriverState *bs,
 187     uint64_t cluster_offset, int nb_clusters);
 188
 189 void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset,
 190     int64_t size);
 191 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 192     int64_t l1_table_offset, int l1_size, int addend);
 193
 194 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res);
 195
 196 /* qcow2-cluster.c functions */
 197 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
 198 void qcow2_l2_cache_reset(BlockDriverState *bs);
 199 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 200 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 201                      uint8_t *out_buf, const uint8_t *in_buf,
 202                      int nb_sectors, int enc,
 203                      const AES_KEY *key);
 204
 205 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 206     int *num, uint64_t *cluster_offset);
 207 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 208     int n_start, int n_end, int *num, QCowL2Meta *m);
 209 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 210                                          uint64_t offset,
 211                                          int compressed_size);
 212
 213 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 214 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 215     int nb_sectors);
 216
 217 /* qcow2-snapshot.c functions */
 218 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 219 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 220 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 221 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 222 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 223
 224 void qcow2_free_snapshots(BlockDriverState *bs);
 225 int qcow2_read_snapshots(BlockDriverState *bs);
 226
 227 /* qcow2-cache.c functions */
 228 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
 229     bool writethrough);
 230 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 231 bool qcow2_cache_set_writethrough(BlockDriverState *bs, Qcow2Cache *c,
 232     bool enable);
 233
 234 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 235 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 236 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 237     Qcow2Cache *dependency);
 238 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 239
 240 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 241     void **table);
 242 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 243     void **table);
 244 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 245
 246 #endif