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 typedef struct QCowHeader {
  55     uint32_t magic;
  56     uint32_t version;
  57     uint64_t backing_file_offset;
  58     uint32_t backing_file_size;
  59     uint32_t cluster_bits;
  60     uint64_t size; /* in bytes */
  61     uint32_t crypt_method;
  62     uint32_t l1_size; /* XXX: save number of clusters instead ? */
  63     uint64_t l1_table_offset;
  64     uint64_t refcount_table_offset;
  65     uint32_t refcount_table_clusters;
  66     uint32_t nb_snapshots;
  67     uint64_t snapshots_offset;
  68 } QCowHeader;
  69
  70 typedef struct QCowSnapshot {
  71     uint64_t l1_table_offset;
  72     uint32_t l1_size;
  73     char *id_str;
  74     char *name;
  75     uint32_t vm_state_size;
  76     uint32_t date_sec;
  77     uint32_t date_nsec;
  78     uint64_t vm_clock_nsec;
  79 } QCowSnapshot;
  80
  81 typedef struct BDRVQcowState {
  82     BlockDriverState *hd;
  83     int cluster_bits;
  84     int cluster_size;
  85     int cluster_sectors;
  86     int l2_bits;
  87     int l2_size;
  88     int l1_size;
  89     int l1_vm_state_index;
  90     int csize_shift;
  91     int csize_mask;
  92     uint64_t cluster_offset_mask;
  93     uint64_t l1_table_offset;
  94     uint64_t *l1_table;
  95     uint64_t *l2_cache;
  96     uint64_t l2_cache_offsets[L2_CACHE_SIZE];
  97     uint32_t l2_cache_counts[L2_CACHE_SIZE];
  98     uint8_t *cluster_cache;
  99     uint8_t *cluster_data;
 100     uint64_t cluster_cache_offset;
 101     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 102
 103     uint64_t *refcount_table;
 104     uint64_t refcount_table_offset;
 105     uint32_t refcount_table_size;
 106     uint64_t refcount_block_cache_offset;
 107     uint16_t *refcount_block_cache;
 108     int64_t free_cluster_index;
 109     int64_t free_byte_offset;
 110
 111     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 112     uint32_t crypt_method_header;
 113     AES_KEY aes_encrypt_key;
 114     AES_KEY aes_decrypt_key;
 115     uint64_t snapshots_offset;
 116     int snapshots_size;
 117     int nb_snapshots;
 118     QCowSnapshot *snapshots;
 119 } BDRVQcowState;
 120
 121 /* XXX: use std qcow open function ? */
 122 typedef struct QCowCreateState {
 123     int cluster_size;
 124     int cluster_bits;
 125     uint16_t *refcount_block;
 126     uint64_t *refcount_table;
 127     int64_t l1_table_offset;
 128     int64_t refcount_table_offset;
 129     int64_t refcount_block_offset;
 130 } QCowCreateState;
 131
 132 struct QCowAIOCB;
 133
 134 /* XXX This could be private for qcow2-cluster.c */
 135 typedef struct QCowL2Meta
 136 {
 137     uint64_t offset;
 138     uint64_t cluster_offset;
 139     int n_start;
 140     int nb_available;
 141     int nb_clusters;
 142     struct QCowL2Meta *depends_on;
 143     QLIST_HEAD(QCowAioDependencies, QCowAIOCB) dependent_requests;
 144
 145     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 146 } QCowL2Meta;
 147
 148 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 149 {
 150     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 151 }
 152
 153 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
 154 {
 155     int shift = s->cluster_bits + s->l2_bits;
 156     return (size + (1ULL << shift) - 1) >> shift;
 157 }
 158
 159 static inline int64_t align_offset(int64_t offset, int n)
 160 {
 161     offset = (offset + n - 1) & ~(n - 1);
 162     return offset;
 163 }
 164
 165
 166 // FIXME Need qcow2_ prefix to global functions
 167
 168 /* qcow2.c functions */
 169 int qcow2_backing_read1(BlockDriverState *bs,
 170                   int64_t sector_num, uint8_t *buf, int nb_sectors);
 171
 172 /* qcow2-refcount.c functions */
 173 int qcow2_refcount_init(BlockDriverState *bs);
 174 void qcow2_refcount_close(BlockDriverState *bs);
 175
 176 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
 177 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 178 void qcow2_free_clusters(BlockDriverState *bs,
 179     int64_t offset, int64_t size);
 180 void qcow2_free_any_clusters(BlockDriverState *bs,
 181     uint64_t cluster_offset, int nb_clusters);
 182
 183 void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset,
 184     int64_t size);
 185 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 186     int64_t l1_table_offset, int l1_size, int addend);
 187
 188 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res);
 189
 190 /* qcow2-cluster.c functions */
 191 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size);
 192 void qcow2_l2_cache_reset(BlockDriverState *bs);
 193 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 194 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 195                      uint8_t *out_buf, const uint8_t *in_buf,
 196                      int nb_sectors, int enc,
 197                      const AES_KEY *key);
 198
 199 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 200     int *num, uint64_t *cluster_offset);
 201 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 202     int n_start, int n_end, int *num, QCowL2Meta *m);
 203 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 204                                          uint64_t offset,
 205                                          int compressed_size);
 206
 207 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 208
 209 /* qcow2-snapshot.c functions */
 210 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 211 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 212 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 213 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 214
 215 void qcow2_free_snapshots(BlockDriverState *bs);
 216 int qcow2_read_snapshots(BlockDriverState *bs);
 217
 218 #endif