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     uint64_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 Qcow2UnknownHeaderExtension {
  91     uint32_t magic;
  92     uint32_t len;
  93     QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
  94     uint8_t data[];
  95 } Qcow2UnknownHeaderExtension;
  96
  97 typedef struct BDRVQcowState {
  98     int cluster_bits;
  99     int cluster_size;
 100     int cluster_sectors;
 101     int l2_bits;
 102     int l2_size;
 103     int l1_size;
 104     int l1_vm_state_index;
 105     int csize_shift;
 106     int csize_mask;
 107     uint64_t cluster_offset_mask;
 108     uint64_t l1_table_offset;
 109     uint64_t *l1_table;
 110
 111     Qcow2Cache* l2_table_cache;
 112     Qcow2Cache* refcount_block_cache;
 113
 114     uint8_t *cluster_cache;
 115     uint8_t *cluster_data;
 116     uint64_t cluster_cache_offset;
 117     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 118
 119     uint64_t *refcount_table;
 120     uint64_t refcount_table_offset;
 121     uint32_t refcount_table_size;
 122     int64_t free_cluster_index;
 123     int64_t free_byte_offset;
 124
 125     CoMutex lock;
 126
 127     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 128     uint32_t crypt_method_header;
 129     AES_KEY aes_encrypt_key;
 130     AES_KEY aes_decrypt_key;
 131     uint64_t snapshots_offset;
 132     int snapshots_size;
 133     int nb_snapshots;
 134     QCowSnapshot *snapshots;
 135
 136     int flags;
 137     QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 138 } BDRVQcowState;
 139
 140 /* XXX: use std qcow open function ? */
 141 typedef struct QCowCreateState {
 142     int cluster_size;
 143     int cluster_bits;
 144     uint16_t *refcount_block;
 145     uint64_t *refcount_table;
 146     int64_t l1_table_offset;
 147     int64_t refcount_table_offset;
 148     int64_t refcount_block_offset;
 149 } QCowCreateState;
 150
 151 struct QCowAIOCB;
 152
 153 /* XXX This could be private for qcow2-cluster.c */
 154 typedef struct QCowL2Meta
 155 {
 156     uint64_t offset;
 157     uint64_t cluster_offset;
 158     uint64_t alloc_offset;
 159     int n_start;
 160     int nb_available;
 161     int nb_clusters;
 162     CoQueue dependent_requests;
 163
 164     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 165 } QCowL2Meta;
 166
 167 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 168 {
 169     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 170 }
 171
 172 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
 173 {
 174     int shift = s->cluster_bits + s->l2_bits;
 175     return (size + (1ULL << shift) - 1) >> shift;
 176 }
 177
 178 static inline int64_t align_offset(int64_t offset, int n)
 179 {
 180     offset = (offset + n - 1) & ~(n - 1);
 181     return offset;
 182 }
 183
 184
 185 // FIXME Need qcow2_ prefix to global functions
 186
 187 /* qcow2.c functions */
 188 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 189                   int64_t sector_num, int nb_sectors);
 190 int qcow2_update_header(BlockDriverState *bs);
 191
 192 /* qcow2-refcount.c functions */
 193 int qcow2_refcount_init(BlockDriverState *bs);
 194 void qcow2_refcount_close(BlockDriverState *bs);
 195
 196 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
 197 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 198     int nb_clusters);
 199 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 200 void qcow2_free_clusters(BlockDriverState *bs,
 201     int64_t offset, int64_t size);
 202 void qcow2_free_any_clusters(BlockDriverState *bs,
 203     uint64_t cluster_offset, int nb_clusters);
 204
 205 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 206     int64_t l1_table_offset, int l1_size, int addend);
 207
 208 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res);
 209
 210 /* qcow2-cluster.c functions */
 211 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
 212 void qcow2_l2_cache_reset(BlockDriverState *bs);
 213 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 214 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 215                      uint8_t *out_buf, const uint8_t *in_buf,
 216                      int nb_sectors, int enc,
 217                      const AES_KEY *key);
 218
 219 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 220     int *num, uint64_t *cluster_offset);
 221 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 222     int n_start, int n_end, int *num, QCowL2Meta *m);
 223 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 224                                          uint64_t offset,
 225                                          int compressed_size);
 226
 227 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 228 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 229     int nb_sectors);
 230
 231 /* qcow2-snapshot.c functions */
 232 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 233 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 234 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 235 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 236 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 237
 238 void qcow2_free_snapshots(BlockDriverState *bs);
 239 int qcow2_read_snapshots(BlockDriverState *bs);
 240
 241 /* qcow2-cache.c functions */
 242 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
 243     bool writethrough);
 244 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 245 bool qcow2_cache_set_writethrough(BlockDriverState *bs, Qcow2Cache *c,
 246     bool enable);
 247
 248 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 249 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 250 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 251     Qcow2Cache *dependency);
 252 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 253
 254 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 255     void **table);
 256 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 257     void **table);
 258 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 259
 260 #endif