LXR qemu/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
  61typedef 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
  85typedef 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
  97struct Qcow2Cache;
  98typedef struct Qcow2Cache Qcow2Cache;
  99
 100typedef struct Qcow2UnknownHeaderExtension {
 101    uint32_t magic;
 102    uint32_t len;
 103    QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;
 104    uint8_t data[];
 105} Qcow2UnknownHeaderExtension;
 106
 107enum {
 108    QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,
 109    QCOW2_FEAT_TYPE_COMPATIBLE      = 1,
 110    QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,
 111};
 112
 113/* Incompatible feature bits */
 114enum {
 115    QCOW2_INCOMPAT_DIRTY_BITNR   = 0,
 116    QCOW2_INCOMPAT_DIRTY         = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,
 117
 118    QCOW2_INCOMPAT_MASK          = QCOW2_INCOMPAT_DIRTY,
 119};
 120
 121/* Compatible feature bits */
 122enum {
 123    QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,
 124    QCOW2_COMPAT_LAZY_REFCOUNTS       = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,
 125
 126    QCOW2_COMPAT_FEAT_MASK            = QCOW2_COMPAT_LAZY_REFCOUNTS,
 127};
 128
 129typedef struct Qcow2Feature {
 130    uint8_t type;
 131    uint8_t bit;
 132    char    name[46];
 133} QEMU_PACKED Qcow2Feature;
 134
 135typedef struct BDRVQcowState {
 136    int cluster_bits;
 137    int cluster_size;
 138    int cluster_sectors;
 139    int l2_bits;
 140    int l2_size;
 141    int l1_size;
 142    int l1_vm_state_index;
 143    int csize_shift;
 144    int csize_mask;
 145    uint64_t cluster_offset_mask;
 146    uint64_t l1_table_offset;
 147    uint64_t *l1_table;
 148
 149    Qcow2Cache* l2_table_cache;
 150    Qcow2Cache* refcount_block_cache;
 151
 152    uint8_t *cluster_cache;
 153    uint8_t *cluster_data;
 154    uint64_t cluster_cache_offset;
 155    QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
 156
 157    uint64_t *refcount_table;
 158    uint64_t refcount_table_offset;
 159    uint32_t refcount_table_size;
 160    int64_t free_cluster_index;
 161    int64_t free_byte_offset;
 162
 163    CoMutex lock;
 164
 165    uint32_t crypt_method; /* current crypt method, 0 if no key yet */
 166    uint32_t crypt_method_header;
 167    AES_KEY aes_encrypt_key;
 168    AES_KEY aes_decrypt_key;
 169    uint64_t snapshots_offset;
 170    int snapshots_size;
 171    int nb_snapshots;
 172    QCowSnapshot *snapshots;
 173
 174    int flags;
 175    int qcow_version;
 176
 177    uint64_t incompatible_features;
 178    uint64_t compatible_features;
 179    uint64_t autoclear_features;
 180
 181    size_t unknown_header_fields_size;
 182    void* unknown_header_fields;
 183    QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;
 184} BDRVQcowState;
 185
 186/* XXX: use std qcow open function ? */
 187typedef struct QCowCreateState {
 188    int cluster_size;
 189    int cluster_bits;
 190    uint16_t *refcount_block;
 191    uint64_t *refcount_table;
 192    int64_t l1_table_offset;
 193    int64_t refcount_table_offset;
 194    int64_t refcount_block_offset;
 195} QCowCreateState;
 196
 197struct QCowAIOCB;
 198
 199/* XXX This could be private for qcow2-cluster.c */
 200typedef struct QCowL2Meta
 201{
 202    uint64_t offset;
 203    uint64_t cluster_offset;
 204    uint64_t alloc_offset;
 205    int n_start;
 206    int nb_available;
 207    int nb_clusters;
 208    CoQueue dependent_requests;
 209
 210    QLIST_ENTRY(QCowL2Meta) next_in_flight;
 211} QCowL2Meta;
 212
 213enum {
 214    QCOW2_CLUSTER_UNALLOCATED,
 215    QCOW2_CLUSTER_NORMAL,
 216    QCOW2_CLUSTER_COMPRESSED,
 217    QCOW2_CLUSTER_ZERO
 218};
 219
 220#define L1E_OFFSET_MASK 0x00ffffffffffff00ULL
 221#define L2E_OFFSET_MASK 0x00ffffffffffff00ULL
 222#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL
 223
 224#define REFT_OFFSET_MASK 0xffffffffffffff00ULL
 225
 226static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
 227{
 228    return (size + (s->cluster_size - 1)) >> s->cluster_bits;
 229}
 230
 231static inline int size_to_l1(BDRVQcowState *s, int64_t size)
 232{
 233    int shift = s->cluster_bits + s->l2_bits;
 234    return (size + (1ULL << shift) - 1) >> shift;
 235}
 236
 237static inline int64_t align_offset(int64_t offset, int n)
 238{
 239    offset = (offset + n - 1) & ~(n - 1);
 240    return offset;
 241}
 242
 243static inline int qcow2_get_cluster_type(uint64_t l2_entry)
 244{
 245    if (l2_entry & QCOW_OFLAG_COMPRESSED) {
 246        return QCOW2_CLUSTER_COMPRESSED;
 247    } else if (l2_entry & QCOW_OFLAG_ZERO) {
 248        return QCOW2_CLUSTER_ZERO;
 249    } else if (!(l2_entry & L2E_OFFSET_MASK)) {
 250        return QCOW2_CLUSTER_UNALLOCATED;
 251    } else {
 252        return QCOW2_CLUSTER_NORMAL;
 253    }
 254}
 255
 256/* Check whether refcounts are eager or lazy */
 257static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s)
 258{
 259    return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);
 260}
 261
 262// FIXME Need qcow2_ prefix to global functions
 263
 264/* qcow2.c functions */
 265int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,
 266                  int64_t sector_num, int nb_sectors);
 267int qcow2_update_header(BlockDriverState *bs);
 268
 269/* qcow2-refcount.c functions */
 270int qcow2_refcount_init(BlockDriverState *bs);
 271void qcow2_refcount_close(BlockDriverState *bs);
 272
 273int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
 274int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,
 275    int nb_clusters);
 276int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
 277void qcow2_free_clusters(BlockDriverState *bs,
 278    int64_t offset, int64_t size);
 279void qcow2_free_any_clusters(BlockDriverState *bs,
 280    uint64_t cluster_offset, int nb_clusters);
 281
 282int qcow2_update_snapshot_refcount(BlockDriverState *bs,
 283    int64_t l1_table_offset, int l1_size, int addend);
 284
 285int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,
 286                          BdrvCheckMode fix);
 287
 288/* qcow2-cluster.c functions */
 289int qcow2_grow_l1_table(BlockDriverState *bs, int min_size, bool exact_size);
 290void qcow2_l2_cache_reset(BlockDriverState *bs);
 291int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
 292void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
 293                     uint8_t *out_buf, const uint8_t *in_buf,
 294                     int nb_sectors, int enc,
 295                     const AES_KEY *key);
 296
 297int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
 298    int *num, uint64_t *cluster_offset);
 299int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
 300    int n_start, int n_end, int *num, QCowL2Meta *m);
 301uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
 302                                         uint64_t offset,
 303                                         int compressed_size);
 304
 305int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
 306int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,
 307    int nb_sectors);
 308int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);
 309
 310/* qcow2-snapshot.c functions */
 311int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
 312int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
 313int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
 314int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
 315int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);
 316
 317void qcow2_free_snapshots(BlockDriverState *bs);
 318int qcow2_read_snapshots(BlockDriverState *bs);
 319
 320/* qcow2-cache.c functions */
 321Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);
 322int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);
 323
 324void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);
 325int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);
 326int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
 327    Qcow2Cache *dependency);
 328void qcow2_cache_depends_on_flush(Qcow2Cache *c);
 329
 330int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 331    void **table);
 332int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,
 333    void **table);
 334int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);
 335
 336#endif
 337