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 #define QCOW_VERSION 2
  37
  38 #define QCOW_CRYPT_NONE 0
  39 #define QCOW_CRYPT_AES  1
  40
  41 #define QCOW_MAX_CRYPT_CLUSTERS 32
  42
  43 /* indicate that the refcount of the referenced cluster is exactly one. */
  44 #define QCOW_OFLAG_COPIED     (1LL << 63)
  45 /* indicate that the cluster is compressed (they never have the copied flag) */
  46 #define QCOW_OFLAG_COMPRESSED (1LL << 62)
  47
  48 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
  49
  50 #define MIN_CLUSTER_BITS 9
  51 #define MAX_CLUSTER_BITS 21
  52
  53 #define L2_CACHE_SIZE 16
  54
  55 /* Must be at least 4 to cover all cases of refcount table growth */
  56 #define REFCOUNT_CACHE_SIZE 4
  57
  58 #define DEFAULT_CLUSTER_SIZE 65536
  59
  60 typedef struct QCowHeader {
  61     uint32_t magic;
  62     uint32_t version;
  63     uint64_t backing_file_offset;
  64     uint32_t backing_file_size;
  65     uint32_t cluster_bits;
  66     uint64_t size; /* in bytes */
  67     uint32_t crypt_method;
  68     uint32_t l1_size; /* XXX: save number of clusters instead ? */
  69     uint64_t l1_table_offset;
  70     uint64_t refcount_table_offset;
  71     uint32_t refcount_table_clusters;
  72     uint32_t nb_snapshots;
  73     uint64_t snapshots_offset;
  74 } QCowHeader;
  75
  76 typedef struct QCowSnapshot {
  77     uint64_t l1_table_offset;
  78     uint32_t l1_size;
  79     char *id_str;
  80     char *name;
  81     uint32_t vm_state_size;
  82     uint32_t date_sec;
  83     uint32_t date_nsec;
  84     uint64_t vm_clock_nsec;
  85 } QCowSnapshot;
  86
  87 struct Qcow2Cache;
  88 typedef struct Qcow2Cache Qcow2Cache;
  89
  90 typedef struct BDRVQcowState {
  91     int cluster_bits;
  92     int cluster_size;
  93     int cluster_sectors;
  94     int l2_bits;
  95     int l2_size;
  96     int l1_size;
  97     int l1_vm_state_index;
  98     int csize_shift;
  99     int csize_mask;
 100     uint64_t cluster_offset_mask;
 101     uint64_t l1_table_offset;
 102     uint64_t *l1_table;
 103
 104     Qcow2Cache* l2_table_cache;
 105     Qcow2Cache* refcount_block_cache;
 106
 107     uint8_t *cluster_cache;
 108     uint8_t *cluster_data;
 109     uint64_t cluster_cache_offset;
 110     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 111
 112     uint64_t *refcount_table;
 113     uint64_t refcount_table_offset;
 114     uint32_t refcount_table_size;
 115     int64_t free_cluster_index;
 116     int64_t free_byte_offset;
 117
 118     CoMutex lock;
 119
 120     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 121     uint32_t crypt_method_header;
 122     AES_KEY aes_encrypt_key;
 123     AES_KEY aes_decrypt_key;
 124     uint64_t snapshots_offset;
 125     int snapshots_size;
 126     int nb_snapshots;
 127     QCowSnapshot *snapshots;
 128 } BDRVQcowState;
 129
 130 /* XXX: use std qcow open function ? */
 131 typedef struct QCowCreateState {
 132     int cluster_size;
 133     int cluster_bits;
 134     uint16_t *refcount_block;
 135     uint64_t *refcount_table;
 136     int64_t l1_table_offset;
 137     int64_t refcount_table_offset;
 138     int64_t refcount_block_offset;
 139 } QCowCreateState;
 140
 141 struct QCowAIOCB;
 142
 143 /* XXX This could be private for qcow2-cluster.c */
 144 typedef struct QCowL2Meta
 145 {
 146     uint64_t offset;
 147     uint64_t cluster_offset;
 148     int n_start;
 149     int nb_available;
 150     int nb_clusters;
 151     struct QCowL2Meta *depends_on;
 152     CoQueue dependent_requests;
 153
 154     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 155 } QCowL2Meta;
 156
 157 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 158 {
 159     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 160 }
 161
 162 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
 163 {
 164     int shift = s->cluster_bits + s->l2_bits;
 165     return (size + (1ULL << shift) - 1) >> shift;
 166 }
 167
 168 static inline int64_t align_offset(int64_t offset, int n)
 169 {
 170     offset = (offset + n - 1) & ~(n - 1);
 171     return offset;
 172 }
 173
 174
 175 // FIXME Need qcow2_ prefix to global functions
 176
 177 /* qcow2.c functions */
 178 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 179                   int64_t sector_num, int nb_sectors);
 180
 181 /* qcow2-refcount.c functions */
 182 int qcow2_refcount_init(BlockDriverState *bs);
 183 void qcow2_refcount_close(BlockDriverState *bs);
 184
 185 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
 186 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 187 void qcow2_free_clusters(BlockDriverState *bs,
 188     int64_t offset, int64_t size);
 189 void qcow2_free_any_clusters(BlockDriverState *bs,
 190     uint64_t cluster_offset, int nb_clusters);
 191
 192 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 193     int64_t l1_table_offset, int l1_size, int addend);
 194
 195 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res);
 196
 197 /* qcow2-cluster.c functions */
 198 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
 199 void qcow2_l2_cache_reset(BlockDriverState *bs);
 200 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 201 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 202                      uint8_t *out_buf, const uint8_t *in_buf,
 203                      int nb_sectors, int enc,
 204                      const AES_KEY *key);
 205
 206 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 207     int *num, uint64_t *cluster_offset);
 208 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 209     int n_start, int n_end, int *num, QCowL2Meta *m);
 210 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 211                                          uint64_t offset,
 212                                          int compressed_size);
 213
 214 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 215 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 216     int nb_sectors);
 217
 218 /* qcow2-snapshot.c functions */
 219 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 220 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 221 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 222 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 223 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 224
 225 void qcow2_free_snapshots(BlockDriverState *bs);
 226 int qcow2_read_snapshots(BlockDriverState *bs);
 227
 228 /* qcow2-cache.c functions */
 229 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
 230     bool writethrough);
 231 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 232 bool qcow2_cache_set_writethrough(BlockDriverState *bs, Qcow2Cache *c,
 233     bool enable);
 234
 235 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 236 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 237 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 238     Qcow2Cache *dependency);
 239 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 240
 241 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 242     void **table);
 243 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 244     void **table);
 245 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 246
 247 #endif