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 QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
  31 #define QCOW_VERSION 2
  32
  33 #define QCOW_CRYPT_NONE 0
  34 #define QCOW_CRYPT_AES  1
  35
  36 #define QCOW_MAX_CRYPT_CLUSTERS 32
  37
  38 /* indicate that the refcount of the referenced cluster is exactly one. */
  39 #define QCOW_OFLAG_COPIED     (1LL << 63)
  40 /* indicate that the cluster is compressed (they never have the copied flag) */
  41 #define QCOW_OFLAG_COMPRESSED (1LL << 62)
  42
  43 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
  44
  45 #define MIN_CLUSTER_BITS 9
  46 #define MAX_CLUSTER_BITS 16
  47
  48 #define L2_CACHE_SIZE 16
  49
  50 typedef struct QCowHeader {
  51     uint32_t magic;
  52     uint32_t version;
  53     uint64_t backing_file_offset;
  54     uint32_t backing_file_size;
  55     uint32_t cluster_bits;
  56     uint64_t size; /* in bytes */
  57     uint32_t crypt_method;
  58     uint32_t l1_size; /* XXX: save number of clusters instead ? */
  59     uint64_t l1_table_offset;
  60     uint64_t refcount_table_offset;
  61     uint32_t refcount_table_clusters;
  62     uint32_t nb_snapshots;
  63     uint64_t snapshots_offset;
  64 } QCowHeader;
  65
  66 typedef struct QCowSnapshot {
  67     uint64_t l1_table_offset;
  68     uint32_t l1_size;
  69     char *id_str;
  70     char *name;
  71     uint32_t vm_state_size;
  72     uint32_t date_sec;
  73     uint32_t date_nsec;
  74     uint64_t vm_clock_nsec;
  75 } QCowSnapshot;
  76
  77 typedef struct BDRVQcowState {
  78     BlockDriverState *hd;
  79     int cluster_bits;
  80     int cluster_size;
  81     int cluster_sectors;
  82     int l2_bits;
  83     int l2_size;
  84     int l1_size;
  85     int l1_vm_state_index;
  86     int csize_shift;
  87     int csize_mask;
  88     uint64_t cluster_offset_mask;
  89     uint64_t l1_table_offset;
  90     uint64_t *l1_table;
  91     uint64_t *l2_cache;
  92     uint64_t l2_cache_offsets[L2_CACHE_SIZE];
  93     uint32_t l2_cache_counts[L2_CACHE_SIZE];
  94     uint8_t *cluster_cache;
  95     uint8_t *cluster_data;
  96     uint64_t cluster_cache_offset;
  97
  98     uint64_t *refcount_table;
  99     uint64_t refcount_table_offset;
 100     uint32_t refcount_table_size;
 101     uint64_t refcount_block_cache_offset;
 102     uint16_t *refcount_block_cache;
 103     int64_t free_cluster_index;
 104     int64_t free_byte_offset;
 105
 106     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 107     uint32_t crypt_method_header;
 108     AES_KEY aes_encrypt_key;
 109     AES_KEY aes_decrypt_key;
 110     uint64_t snapshots_offset;
 111     int snapshots_size;
 112     int nb_snapshots;
 113     QCowSnapshot *snapshots;
 114 } BDRVQcowState;
 115
 116 /* XXX: use std qcow open function ? */
 117 typedef struct QCowCreateState {
 118     int cluster_size;
 119     int cluster_bits;
 120     uint16_t *refcount_block;
 121     uint64_t *refcount_table;
 122     int64_t l1_table_offset;
 123     int64_t refcount_table_offset;
 124     int64_t refcount_block_offset;
 125 } QCowCreateState;
 126
 127 /* XXX This could be private for qcow2-cluster.c */
 128 typedef struct QCowL2Meta
 129 {
 130     uint64_t offset;
 131     int n_start;
 132     int nb_available;
 133     int nb_clusters;
 134 } QCowL2Meta;
 135
 136 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 137 {
 138     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 139 }
 140
 141 // FIXME Need qcow2_ prefix to global functions
 142
 143 /* qcow2.c functions */
 144 void l2_cache_reset(BlockDriverState *bs);
 145 int backing_read1(BlockDriverState *bs,
 146                   int64_t sector_num, uint8_t *buf, int nb_sectors);
 147
 148 /* qcow2-refcount.c functions */
 149 int refcount_init(BlockDriverState *bs);
 150 void refcount_close(BlockDriverState *bs);
 151
 152 int64_t alloc_clusters(BlockDriverState *bs, int64_t size);
 153 int64_t alloc_bytes(BlockDriverState *bs, int size);
 154 void free_clusters(BlockDriverState *bs,
 155     int64_t offset, int64_t size);
 156 void free_any_clusters(BlockDriverState *bs,
 157     uint64_t cluster_offset, int nb_clusters);
 158
 159 void create_refcount_update(QCowCreateState *s, int64_t offset, int64_t size);
 160 int update_snapshot_refcount(BlockDriverState *bs,
 161                              int64_t l1_table_offset,
 162                              int l1_size,
 163                              int addend);
 164
 165 int check_refcounts(BlockDriverState *bs);
 166
 167 /* qcow2-cluster.c functions */
 168 int grow_l1_table(BlockDriverState *bs, int min_size);
 169 int decompress_cluster(BDRVQcowState *s, uint64_t cluster_offset);
 170 void encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 171                      uint8_t *out_buf, const uint8_t *in_buf,
 172                      int nb_sectors, int enc,
 173                      const AES_KEY *key);
 174
 175 uint64_t get_cluster_offset(BlockDriverState *bs, uint64_t offset, int *num);
 176 uint64_t alloc_cluster_offset(BlockDriverState *bs,
 177                               uint64_t offset,
 178                               int n_start, int n_end,
 179                               int *num, QCowL2Meta *m);
 180 uint64_t alloc_compressed_cluster_offset(BlockDriverState *bs,
 181                                          uint64_t offset,
 182                                          int compressed_size);
 183
 184 int alloc_cluster_link_l2(BlockDriverState *bs, uint64_t cluster_offset,
 185     QCowL2Meta *m);
 186
 187 #endif