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