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
  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 /* The cluster reads as all zeros */
  47 #define QCOW_OFLAG_ZERO (1LL << 0)
  48
  49 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
  50
  51 #define MIN_CLUSTER_BITS 9
  52 #define MAX_CLUSTER_BITS 21
  53
  54 #define L2_CACHE_SIZE 16
  55
  56 /* Must be at least 4 to cover all cases of refcount table growth */
  57 #define REFCOUNT_CACHE_SIZE 4
  58
  59 #define DEFAULT_CLUSTER_SIZE 65536
  60
  61 typedef struct QCowHeader {
  62     uint32_t magic;
  63     uint32_t version;
  64     uint64_t backing_file_offset;
  65     uint32_t backing_file_size;
  66     uint32_t cluster_bits;
  67     uint64_t size; /* in bytes */
  68     uint32_t crypt_method;
  69     uint32_t l1_size; /* XXX: save number of clusters instead ? */
  70     uint64_t l1_table_offset;
  71     uint64_t refcount_table_offset;
  72     uint32_t refcount_table_clusters;
  73     uint32_t nb_snapshots;
  74     uint64_t snapshots_offset;
  75
  76     /* The following fields are only valid for version >= 3 */
  77     uint64_t incompatible_features;
  78     uint64_t compatible_features;
  79     uint64_t autoclear_features;
  80
  81     uint32_t refcount_order;
  82     uint32_t header_length;
  83 } QCowHeader;
  84
  85 typedef struct QCowSnapshot {
  86     uint64_t l1_table_offset;
  87     uint32_t l1_size;
  88     char *id_str;
  89     char *name;
  90     uint64_t disk_size;
  91     uint64_t vm_state_size;
  92     uint32_t date_sec;
  93     uint32_t date_nsec;
  94     uint64_t vm_clock_nsec;
  95 } QCowSnapshot;
  96
  97 struct Qcow2Cache;
  98 typedef struct Qcow2Cache Qcow2Cache;
  99
 100 typedef struct Qcow2UnknownHeaderExtension {
 101     uint32_t magic;
 102     uint32_t len;
 103     QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
 104     uint8_t data[];
 105 } Qcow2UnknownHeaderExtension;
 106
 107 enum {
 108     QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,
 109     QCOW2_FEAT_TYPE_COMPATIBLE      = 1,
 110     QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
 111 };
 112
 113 typedef struct Qcow2Feature {
 114     uint8_t type;
 115     uint8_t bit;
 116     char    name[46];
 117 } QEMU_PACKED Qcow2Feature;
 118
 119 typedef struct BDRVQcowState {
 120     int cluster_bits;
 121     int cluster_size;
 122     int cluster_sectors;
 123     int l2_bits;
 124     int l2_size;
 125     int l1_size;
 126     int l1_vm_state_index;
 127     int csize_shift;
 128     int csize_mask;
 129     uint64_t cluster_offset_mask;
 130     uint64_t l1_table_offset;
 131     uint64_t *l1_table;
 132
 133     Qcow2Cache* l2_table_cache;
 134     Qcow2Cache* refcount_block_cache;
 135
 136     uint8_t *cluster_cache;
 137     uint8_t *cluster_data;
 138     uint64_t cluster_cache_offset;
 139     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 140
 141     uint64_t *refcount_table;
 142     uint64_t refcount_table_offset;
 143     uint32_t refcount_table_size;
 144     int64_t free_cluster_index;
 145     int64_t free_byte_offset;
 146
 147     CoMutex lock;
 148
 149     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 150     uint32_t crypt_method_header;
 151     AES_KEY aes_encrypt_key;
 152     AES_KEY aes_decrypt_key;
 153     uint64_t snapshots_offset;
 154     int snapshots_size;
 155     int nb_snapshots;
 156     QCowSnapshot *snapshots;
 157
 158     int flags;
 159     int qcow_version;
 160
 161     uint64_t incompatible_features;
 162     uint64_t compatible_features;
 163     uint64_t autoclear_features;
 164
 165     size_t unknown_header_fields_size;
 166     void* unknown_header_fields;
 167     QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 168 } BDRVQcowState;
 169
 170 /* XXX: use std qcow open function ? */
 171 typedef struct QCowCreateState {
 172     int cluster_size;
 173     int cluster_bits;
 174     uint16_t *refcount_block;
 175     uint64_t *refcount_table;
 176     int64_t l1_table_offset;
 177     int64_t refcount_table_offset;
 178     int64_t refcount_block_offset;
 179 } QCowCreateState;
 180
 181 struct QCowAIOCB;
 182
 183 /* XXX This could be private for qcow2-cluster.c */
 184 typedef struct QCowL2Meta
 185 {
 186     uint64_t offset;
 187     uint64_t cluster_offset;
 188     uint64_t alloc_offset;
 189     int n_start;
 190     int nb_available;
 191     int nb_clusters;
 192     CoQueue dependent_requests;
 193
 194     QLIST_ENTRY(QCowL2Meta) next_in_flight;
 195 } QCowL2Meta;
 196
 197 enum {
 198     QCOW2_CLUSTER_UNALLOCATED,
 199     QCOW2_CLUSTER_NORMAL,
 200     QCOW2_CLUSTER_COMPRESSED,
 201     QCOW2_CLUSTER_ZERO
 202 };
 203
 204 #define L1E_OFFSET_MASK 0x00ffffffffffff00ULL
 205 #define L2E_OFFSET_MASK 0x00ffffffffffff00ULL
 206 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
 207
 208 #define REFT_OFFSET_MASK 0xffffffffffffff00ULL
 209
 210 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 211 {
 212     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 213 }
 214
 215 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
 216 {
 217     int shift = s->cluster_bits + s->l2_bits;
 218     return (size + (1ULL << shift) - 1) >> shift;
 219 }
 220
 221 static inline int64_t align_offset(int64_t offset, int n)
 222 {
 223     offset = (offset + n - 1) & ~(n - 1);
 224     return offset;
 225 }
 226
 227 static inline int qcow2_get_cluster_type(uint64_t l2_entry)
 228 {
 229     if (l2_entry & QCOW_OFLAG_COMPRESSED) {
 230         return QCOW2_CLUSTER_COMPRESSED;
 231     } else if (l2_entry & QCOW_OFLAG_ZERO) {
 232         return QCOW2_CLUSTER_ZERO;
 233     } else if (!(l2_entry & L2E_OFFSET_MASK)) {
 234         return QCOW2_CLUSTER_UNALLOCATED;
 235     } else {
 236         return QCOW2_CLUSTER_NORMAL;
 237     }
 238 }
 239
 240
 241 // FIXME Need qcow2_ prefix to global functions
 242
 243 /* qcow2.c functions */
 244 int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 245                   int64_t sector_num, int nb_sectors);
 246 int qcow2_update_header(BlockDriverState *bs);
 247
 248 /* qcow2-refcount.c functions */
 249 int qcow2_refcount_init(BlockDriverState *bs);
 250 void qcow2_refcount_close(BlockDriverState *bs);
 251
 252 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
 253 int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 254     int nb_clusters);
 255 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 256 void qcow2_free_clusters(BlockDriverState *bs,
 257     int64_t offset, int64_t size);
 258 void qcow2_free_any_clusters(BlockDriverState *bs,
 259     uint64_t cluster_offset, int nb_clusters);
 260
 261 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 262     int64_t l1_table_offset, int l1_size, int addend);
 263
 264 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res);
 265
 266 /* qcow2-cluster.c functions */
 267 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
 268 void qcow2_l2_cache_reset(BlockDriverState *bs);
 269 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 270 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 271                      uint8_t *out_buf, const uint8_t *in_buf,
 272                      int nb_sectors, int enc,
 273                      const AES_KEY *key);
 274
 275 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 276     int *num, uint64_t *cluster_offset);
 277 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 278     int n_start, int n_end, int *num, QCowL2Meta *m);
 279 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 280                                          uint64_t offset,
 281                                          int compressed_size);
 282
 283 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 284 int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 285     int nb_sectors);
 286 int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
 287
 288 /* qcow2-snapshot.c functions */
 289 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 290 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 291 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 292 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 293 int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 294
 295 void qcow2_free_snapshots(BlockDriverState *bs);
 296 int qcow2_read_snapshots(BlockDriverState *bs);
 297
 298 /* qcow2-cache.c functions */
 299 Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables,
 300     bool writethrough);
 301 int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 302 bool qcow2_cache_set_writethrough(BlockDriverState *bs, Qcow2Cache *c,
 303     bool enable);
 304
 305 void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 306 int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 307 int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 308     Qcow2Cache *dependency);
 309 void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 310
 311 int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 312     void **table);
 313 int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 314     void **table);
 315 int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 316
 317 #endif