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 disk_size;
  82     uint64_t vm_state_size;
  83     uint32_t date_sec;
  84     uint32_t date_nsec;
  85     uint64_t vm_clock_nsec;
  86 } QCowSnapshot;
  87
  88 struct Qcow2Cache;
  89 typedef struct Qcow2Cache Qcow2Cache;
  90
  91 typedef struct Qcow2UnknownHeaderExtension {
  92     uint32_t magic;
  93     uint32_t len;
  94     QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
  95     uint8_t data[];
  96 } Qcow2UnknownHeaderExtension;
  97
  98 typedef struct BDRVQcowState {
  99     int cluster_bits;
 100     int cluster_size;
 101     int cluster_sectors;
 102     int l2_bits;
 103     int l2_size;
 104     int l1_size;
 105     int l1_vm_state_index;
 106     int csize_shift;
 107     int csize_mask;
 108     uint64_t cluster_offset_mask;
 109     uint64_t l1_table_offset;
 110     uint64_t *l1_table;
 111
 112     Qcow2Cache* l2_table_cache;
 113     Qcow2Cache* refcount_block_cache;
 114
 115     uint8_t *cluster_cache;
 116     uint8_t *cluster_data;
 117     uint64_t cluster_cache_offset;
 118     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 119
 120     uint64_t *refcount_table;
 121     uint64_t refcount_table_offset;
 122     uint32_t refcount_table_size;
 123     int64_t free_cluster_index;
 124     int64_t free_byte_offset;
 125
 126     CoMutex lock;
 127
 128     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 129     uint32_t crypt_method_header;
 130     AES_KEY aes_encrypt_key;
 131     AES_KEY aes_decrypt_key;
 132     uint64_t snapshots_offset;
 133     int snapshots_size;
 134     int nb_snapshots;
 135     QCowSnapshot *snapshots;
 136
 137     int flags;
 138     QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 139 } BDRVQcowState;
 140
 141 /* XXX: use std qcow open function ? */
 142 typedef struct QCowCreateState {
 143     int cluster_size;
 144     int cluster_bits;
 145     uint16_t *refcount_block;
 146     uint64_t *refcount_table;
 147     int64_t l1_table_offset;
 148     int64_t refcount_table_offset;
 149     int64_t refcount_block_offset;
 150 } QCowCreateState;
 151
 152 struct QCowAIOCB;
 153
 154 /* XXX This could be private for qcow2-cluster.c */
 155 typedef struct QCowL2Meta
 156 {
 157     uint64_t offset;
 158     uint64_t cluster_offset;
 159     uint64_t alloc_offset;
 160     int n_start;
 161     int nb_available;
 162     int nb_clusters;
 163     CoQueue dependent_requests;
 164
 165     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 166 } QCowL2Meta;
 167
 168 enum {
 169     QCOW2_CLUSTER_UNALLOCATED,
 170     QCOW2_CLUSTER_NORMAL,
 171     QCOW2_CLUSTER_COMPRESSED,
 172 };
 173
 174 #define L1E_OFFSET_MASK 0x00ffffffffffff00ULL
 175 #define L2E_OFFSET_MASK 0x00ffffffffffff00ULL
 176 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
 177
 178 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 179 {
 180     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 181 }
 182
 183 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
 184 {
 185     int shift = s->cluster_bits + s->l2_bits;
 186     return (size + (1ULL << shift) - 1) >> shift;
 187 }
 188
 189 static inline int64_t align_offset(int64_t offset, int n)
 190 {
 191     offset = (offset + n - 1) & ~(n - 1);
 192     return offset;
 193 }
 194
 195 static inline int qcow2_get_cluster_type(uint64_t l2_entry)
 196 {
 197     if (l2_entry & QCOW_OFLAG_COMPRESSED) {
 198         return QCOW2_CLUSTER_COMPRESSED;
 199     } else if (!(l2_entry & L2E_OFFSET_MASK)) {
 200         return QCOW2_CLUSTER_UNALLOCATED;
 201     } else {
 202         return QCOW2_CLUSTER_NORMAL;
 203     }
 204 }
 205
 206
 207 // FIXME Need qcow2_ prefix to global functions
 208
 209 /* qcow2.c functions */
 210 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 211                   int64_t sector_num, int nb_sectors);
 212 int qcow2_update_header(BlockDriverState *bs);
 213
 214 /* qcow2-refcount.c functions */
 215 int qcow2_refcount_init(BlockDriverState *bs);
 216 void qcow2_refcount_close(BlockDriverState *bs);
 217
 218 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
 219 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 220     int nb_clusters);
 221 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 222 void qcow2_free_clusters(BlockDriverState *bs,
 223     int64_t offset, int64_t size);
 224 void qcow2_free_any_clusters(BlockDriverState *bs,
 225     uint64_t cluster_offset, int nb_clusters);
 226
 227 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 228     int64_t l1_table_offset, int l1_size, int addend);
 229
 230 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res);
 231
 232 /* qcow2-cluster.c functions */
 233 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
 234 void qcow2_l2_cache_reset(BlockDriverState *bs);
 235 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 236 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 237                      uint8_t *out_buf, const uint8_t *in_buf,
 238                      int nb_sectors, int enc,
 239                      const AES_KEY *key);
 240
 241 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 242     int *num, uint64_t *cluster_offset);
 243 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 244     int n_start, int n_end, int *num, QCowL2Meta *m);
 245 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 246                                          uint64_t offset,
 247                                          int compressed_size);
 248
 249 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 250 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 251     int nb_sectors);
 252
 253 /* qcow2-snapshot.c functions */
 254 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 255 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 256 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 257 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 258 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 259
 260 void qcow2_free_snapshots(BlockDriverState *bs);
 261 int qcow2_read_snapshots(BlockDriverState *bs);
 262
 263 /* qcow2-cache.c functions */
 264 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
 265     bool writethrough);
 266 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 267 bool qcow2_cache_set_writethrough(BlockDriverState *bs, Qcow2Cache *c,
 268     bool enable);
 269
 270 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 271 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 272 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 273     Qcow2Cache *dependency);
 274 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 275
 276 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 277     void **table);
 278 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 279     void **table);
 280 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 281
 282 #endif