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      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 
     30 //#define DEBUG_ALLOC
     31 //#define DEBUG_ALLOC2
     32 //#define DEBUG_EXT
     33 
     34 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)
     35 #define QCOW_VERSION 2
     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 
     47 #define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */
     48 
     49 #define MIN_CLUSTER_BITS 9
     50 #define MAX_CLUSTER_BITS 21
     51 
     52 #define L2_CACHE_SIZE 16
     53 
     54 typedef struct QCowHeader {
     55     uint32_t magic;
     56     uint32_t version;
     57     uint64_t backing_file_offset;
     58     uint32_t backing_file_size;
     59     uint32_t cluster_bits;
     60     uint64_t size; /* in bytes */
     61     uint32_t crypt_method;
     62     uint32_t l1_size; /* XXX: save number of clusters instead ? */
     63     uint64_t l1_table_offset;
     64     uint64_t refcount_table_offset;
     65     uint32_t refcount_table_clusters;
     66     uint32_t nb_snapshots;
     67     uint64_t snapshots_offset;
     68 } QCowHeader;
     69 
     70 typedef struct QCowSnapshot {
     71     uint64_t l1_table_offset;
     72     uint32_t l1_size;
     73     char *id_str;
     74     char *name;
     75     uint32_t vm_state_size;
     76     uint32_t date_sec;
     77     uint32_t date_nsec;
     78     uint64_t vm_clock_nsec;
     79 } QCowSnapshot;
     80 
     81 typedef struct BDRVQcowState {
     82     BlockDriverState *hd;
     83     int cluster_bits;
     84     int cluster_size;
     85     int cluster_sectors;
     86     int l2_bits;
     87     int l2_size;
     88     int l1_size;
     89     int l1_vm_state_index;
     90     int csize_shift;
     91     int csize_mask;
     92     uint64_t cluster_offset_mask;
     93     uint64_t l1_table_offset;
     94     uint64_t *l1_table;
     95     uint64_t *l2_cache;
     96     uint64_t l2_cache_offsets[L2_CACHE_SIZE];
     97     uint32_t l2_cache_counts[L2_CACHE_SIZE];
     98     uint8_t *cluster_cache;
     99     uint8_t *cluster_data;
    100     uint64_t cluster_cache_offset;
    101     QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;
    102 
    103     uint64_t *refcount_table;
    104     uint64_t refcount_table_offset;
    105     uint32_t refcount_table_size;
    106     uint64_t refcount_block_cache_offset;
    107     uint16_t *refcount_block_cache;
    108     int64_t free_cluster_index;
    109     int64_t free_byte_offset;
    110 
    111     uint32_t crypt_method; /* current crypt method, 0 if no key yet */
    112     uint32_t crypt_method_header;
    113     AES_KEY aes_encrypt_key;
    114     AES_KEY aes_decrypt_key;
    115     uint64_t snapshots_offset;
    116     int snapshots_size;
    117     int nb_snapshots;
    118     QCowSnapshot *snapshots;
    119 } BDRVQcowState;
    120 
    121 /* XXX: use std qcow open function ? */
    122 typedef struct QCowCreateState {
    123     int cluster_size;
    124     int cluster_bits;
    125     uint16_t *refcount_block;
    126     uint64_t *refcount_table;
    127     int64_t l1_table_offset;
    128     int64_t refcount_table_offset;
    129     int64_t refcount_block_offset;
    130 } QCowCreateState;
    131 
    132 struct QCowAIOCB;
    133 
    134 /* XXX This could be private for qcow2-cluster.c */
    135 typedef struct QCowL2Meta
    136 {
    137     uint64_t offset;
    138     uint64_t cluster_offset;
    139     int n_start;
    140     int nb_available;
    141     int nb_clusters;
    142     struct QCowL2Meta *depends_on;
    143     QLIST_HEAD(QCowAioDependencies, QCowAIOCB) dependent_requests;
    144 
    145     QLIST_ENTRY(QCowL2Meta) next_in_flight;
    146 } QCowL2Meta;
    147 
    148 static inline int size_to_clusters(BDRVQcowState *s, int64_t size)
    149 {
    150     return (size + (s->cluster_size - 1)) >> s->cluster_bits;
    151 }
    152 
    153 static inline int size_to_l1(BDRVQcowState *s, int64_t size)
    154 {
    155     int shift = s->cluster_bits + s->l2_bits;
    156     return (size + (1ULL << shift) - 1) >> shift;
    157 }
    158 
    159 static inline int64_t align_offset(int64_t offset, int n)
    160 {
    161     offset = (offset + n - 1) & ~(n - 1);
    162     return offset;
    163 }
    164 
    165 
    166 // FIXME Need qcow2_ prefix to global functions
    167 
    168 /* qcow2.c functions */
    169 int qcow2_backing_read1(BlockDriverState *bs,
    170                   int64_t sector_num, uint8_t *buf, int nb_sectors);
    171 
    172 /* qcow2-refcount.c functions */
    173 int qcow2_refcount_init(BlockDriverState *bs);
    174 void qcow2_refcount_close(BlockDriverState *bs);
    175 
    176 int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);
    177 int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);
    178 void qcow2_free_clusters(BlockDriverState *bs,
    179     int64_t offset, int64_t size);
    180 void qcow2_free_any_clusters(BlockDriverState *bs,
    181     uint64_t cluster_offset, int nb_clusters);
    182 
    183 void qcow2_create_refcount_update(QCowCreateState *s, int64_t offset,
    184     int64_t size);
    185 int qcow2_update_snapshot_refcount(BlockDriverState *bs,
    186     int64_t l1_table_offset, int l1_size, int addend);
    187 
    188 int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res);
    189 
    190 /* qcow2-cluster.c functions */
    191 int qcow2_grow_l1_table(BlockDriverState *bs, int min_size);
    192 void qcow2_l2_cache_reset(BlockDriverState *bs);
    193 int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);
    194 void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,
    195                      uint8_t *out_buf, const uint8_t *in_buf,
    196                      int nb_sectors, int enc,
    197                      const AES_KEY *key);
    198 
    199 int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,
    200     int *num, uint64_t *cluster_offset);
    201 int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,
    202     int n_start, int n_end, int *num, QCowL2Meta *m);
    203 uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,
    204                                          uint64_t offset,
    205                                          int compressed_size);
    206 
    207 int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);
    208 
    209 /* qcow2-snapshot.c functions */
    210 int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);
    211 int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);
    212 int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);
    213 int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);
    214 
    215 void qcow2_free_snapshots(BlockDriverState *bs);
    216 int qcow2_read_snapshots(BlockDriverState *bs);
    217 
    218 #endif
    219