Archipelago » qemu

/*

 * Block driver for the QCOW version 2 format

 *

 * Copyright (c) 2004-2006 Fabrice Bellard

 *

 * Permission is hereby granted, free of charge, to any person obtaining a copy

 * of this software and associated documentation files (the "Software"), to deal

 * in the Software without restriction, including without limitation the rights

 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

 * copies of the Software, and to permit persons to whom the Software is

 * furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included in

 * all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

 * THE SOFTWARE.

 */

#ifndef BLOCK_QCOW2_H

#define BLOCK_QCOW2_H

#include "qemu/aes.h"

#include "block/coroutine.h"

//#define DEBUG_ALLOC

//#define DEBUG_ALLOC2

//#define DEBUG_EXT

#define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb)

#define QCOW_CRYPT_NONE 0

#define QCOW_CRYPT_AES  1

#define QCOW_MAX_CRYPT_CLUSTERS 32

/* indicate that the refcount of the referenced cluster is exactly one. */

#define QCOW_OFLAG_COPIED     (1LL << 63)

/* indicate that the cluster is compressed (they never have the copied flag) */

#define QCOW_OFLAG_COMPRESSED (1LL << 62)

/* The cluster reads as all zeros */

#define QCOW_OFLAG_ZERO (1LL << 0)

#define REFCOUNT_SHIFT 1 /* refcount size is 2 bytes */

#define MIN_CLUSTER_BITS 9

#define MAX_CLUSTER_BITS 21

#define L2_CACHE_SIZE 16

/* Must be at least 4 to cover all cases of refcount table growth */

#define REFCOUNT_CACHE_SIZE 4

#define DEFAULT_CLUSTER_SIZE 65536

#define QCOW2_OPT_LAZY_REFCOUNTS "lazy_refcounts"

typedef struct QCowHeader {

    uint32_t magic;

    uint32_t version;

    uint64_t backing_file_offset;

    uint32_t backing_file_size;

    uint32_t cluster_bits;

    uint64_t size; /* in bytes */

    uint32_t crypt_method;

    uint32_t l1_size; /* XXX: save number of clusters instead ? */

    uint64_t l1_table_offset;

    uint64_t refcount_table_offset;

    uint32_t refcount_table_clusters;

    uint32_t nb_snapshots;

    uint64_t snapshots_offset;

    /* The following fields are only valid for version >= 3 */

    uint64_t incompatible_features;

    uint64_t compatible_features;

    uint64_t autoclear_features;

    uint32_t refcount_order;

    uint32_t header_length;

} QCowHeader;

typedef struct QCowSnapshot {

    uint64_t l1_table_offset;

    uint32_t l1_size;

    char *id_str;

    char *name;

    uint64_t disk_size;

    uint64_t vm_state_size;

    uint32_t date_sec;

    uint32_t date_nsec;

    uint64_t vm_clock_nsec;

} QCowSnapshot;

struct Qcow2Cache;

typedef struct Qcow2Cache Qcow2Cache;

typedef struct Qcow2UnknownHeaderExtension {

    uint32_t magic;

    uint32_t len;

    QLIST_ENTRY(Qcow2UnknownHeaderExtension) next;

    uint8_t data[];

} Qcow2UnknownHeaderExtension;

enum {

    QCOW2_FEAT_TYPE_INCOMPATIBLE    = 0,

    QCOW2_FEAT_TYPE_COMPATIBLE      = 1,

    QCOW2_FEAT_TYPE_AUTOCLEAR       = 2,

};

/* Incompatible feature bits */

enum {

    QCOW2_INCOMPAT_DIRTY_BITNR   = 0,

    QCOW2_INCOMPAT_DIRTY         = 1 << QCOW2_INCOMPAT_DIRTY_BITNR,

    QCOW2_INCOMPAT_MASK          = QCOW2_INCOMPAT_DIRTY,

};

/* Compatible feature bits */

enum {

    QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR = 0,

    QCOW2_COMPAT_LAZY_REFCOUNTS       = 1 << QCOW2_COMPAT_LAZY_REFCOUNTS_BITNR,

    QCOW2_COMPAT_FEAT_MASK            = QCOW2_COMPAT_LAZY_REFCOUNTS,

};

enum qcow2_discard_type {

    QCOW2_DISCARD_NEVER = 0,

    QCOW2_DISCARD_ALWAYS,

    QCOW2_DISCARD_REQUEST,

    QCOW2_DISCARD_SNAPSHOT,

    QCOW2_DISCARD_OTHER,

    QCOW2_DISCARD_MAX

};

typedef struct Qcow2Feature {

    uint8_t type;

    uint8_t bit;

    char    name[46];

} QEMU_PACKED Qcow2Feature;

typedef struct BDRVQcowState {

    int cluster_bits;

    int cluster_size;

    int cluster_sectors;

    int l2_bits;

    int l2_size;

    int l1_size;

    int l1_vm_state_index;

    int csize_shift;

    int csize_mask;

    uint64_t cluster_offset_mask;

    uint64_t l1_table_offset;

    uint64_t *l1_table;

    Qcow2Cache* l2_table_cache;

    Qcow2Cache* refcount_block_cache;

    uint8_t *cluster_cache;

    uint8_t *cluster_data;

    uint64_t cluster_cache_offset;

    QLIST_HEAD(QCowClusterAlloc, QCowL2Meta) cluster_allocs;

    uint64_t *refcount_table;

    uint64_t refcount_table_offset;

    uint32_t refcount_table_size;

    int64_t free_cluster_index;

    int64_t free_byte_offset;

    CoMutex lock;

    uint32_t crypt_method; /* current crypt method, 0 if no key yet */

    uint32_t crypt_method_header;

    AES_KEY aes_encrypt_key;

    AES_KEY aes_decrypt_key;

    uint64_t snapshots_offset;

    int snapshots_size;

    int nb_snapshots;

    QCowSnapshot *snapshots;

    int flags;

    int qcow_version;

    bool use_lazy_refcounts;

    uint64_t incompatible_features;

    uint64_t compatible_features;

    uint64_t autoclear_features;

    size_t unknown_header_fields_size;

    void* unknown_header_fields;

    QLIST_HEAD(, Qcow2UnknownHeaderExtension) unknown_header_ext;

} BDRVQcowState;

/* XXX: use std qcow open function ? */

typedef struct QCowCreateState {

    int cluster_size;

    int cluster_bits;

    uint16_t *refcount_block;

    uint64_t *refcount_table;

    int64_t l1_table_offset;

    int64_t refcount_table_offset;

    int64_t refcount_block_offset;

} QCowCreateState;

struct QCowAIOCB;

typedef struct Qcow2COWRegion {

    /**

     * Offset of the COW region in bytes from the start of the first cluster

     * touched by the request.

     */

    uint64_t    offset;

    /** Number of sectors to copy */

    int         nb_sectors;

} Qcow2COWRegion;

/**

 * Describes an in-flight (part of a) write request that writes to clusters

 * that are not referenced in their L2 table yet.

 */

typedef struct QCowL2Meta

{

    /** Guest offset of the first newly allocated cluster */

    uint64_t offset;

    /** Host offset of the first newly allocated cluster */

    uint64_t alloc_offset;

    /**

     * Number of sectors from the start of the first allocated cluster to

     * the end of the (possibly shortened) request

     */

    int nb_available;

    /** Number of newly allocated clusters */

    int nb_clusters;

    /**

     * Requests that overlap with this allocation and wait to be restarted

     * when the allocating request has completed.

     */

    CoQueue dependent_requests;

    /**

     * The COW Region between the start of the first allocated cluster and the

     * area the guest actually writes to.

     */

    Qcow2COWRegion cow_start;

    /**

     * The COW Region between the area the guest actually writes to and the

     * end of the last allocated cluster.

     */

    Qcow2COWRegion cow_end;

    /** Pointer to next L2Meta of the same write request */

    struct QCowL2Meta *next;

    QLIST_ENTRY(QCowL2Meta) next_in_flight;

} QCowL2Meta;

enum {

    QCOW2_CLUSTER_UNALLOCATED,

    QCOW2_CLUSTER_NORMAL,

    QCOW2_CLUSTER_COMPRESSED,

    QCOW2_CLUSTER_ZERO

};

#define L1E_OFFSET_MASK 0x00ffffffffffff00ULL

#define L2E_OFFSET_MASK 0x00ffffffffffff00ULL

#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL

#define REFT_OFFSET_MASK 0xffffffffffffff00ULL

static inline int64_t start_of_cluster(BDRVQcowState *s, int64_t offset)

{

    return offset & ~(s->cluster_size - 1);

}

static inline int64_t offset_into_cluster(BDRVQcowState *s, int64_t offset)

{

    return offset & (s->cluster_size - 1);

}

static inline int size_to_clusters(BDRVQcowState *s, int64_t size)

{

    return (size + (s->cluster_size - 1)) >> s->cluster_bits;

}

static inline int64_t size_to_l1(BDRVQcowState *s, int64_t size)

{

    int shift = s->cluster_bits + s->l2_bits;

    return (size + (1ULL << shift) - 1) >> shift;

}

static inline int offset_to_l2_index(BDRVQcowState *s, int64_t offset)

{

    return (offset >> s->cluster_bits) & (s->l2_size - 1);

}

static inline int64_t align_offset(int64_t offset, int n)

{

    offset = (offset + n - 1) & ~(n - 1);

    return offset;

}

static inline int qcow2_get_cluster_type(uint64_t l2_entry)

{

    if (l2_entry & QCOW_OFLAG_COMPRESSED) {

        return QCOW2_CLUSTER_COMPRESSED;

    } else if (l2_entry & QCOW_OFLAG_ZERO) {

        return QCOW2_CLUSTER_ZERO;

    } else if (!(l2_entry & L2E_OFFSET_MASK)) {

        return QCOW2_CLUSTER_UNALLOCATED;

    } else {

        return QCOW2_CLUSTER_NORMAL;

    }

}

/* Check whether refcounts are eager or lazy */

static inline bool qcow2_need_accurate_refcounts(BDRVQcowState *s)

{

    return !(s->incompatible_features & QCOW2_INCOMPAT_DIRTY);

}

static inline uint64_t l2meta_cow_start(QCowL2Meta *m)

{

    return m->offset + m->cow_start.offset;

}

static inline uint64_t l2meta_cow_end(QCowL2Meta *m)

{

    return m->offset + m->cow_end.offset

        + (m->cow_end.nb_sectors << BDRV_SECTOR_BITS);

}

// FIXME Need qcow2_ prefix to global functions

/* qcow2.c functions */

int qcow2_backing_read1(BlockDriverState *bs, QEMUIOVector *qiov,

                  int64_t sector_num, int nb_sectors);

int qcow2_mark_dirty(BlockDriverState *bs);

int qcow2_update_header(BlockDriverState *bs);

/* qcow2-refcount.c functions */

int qcow2_refcount_init(BlockDriverState *bs);

void qcow2_refcount_close(BlockDriverState *bs);

int64_t qcow2_alloc_clusters(BlockDriverState *bs, int64_t size);

int qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset,

    int nb_clusters);

int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size);

void qcow2_free_clusters(BlockDriverState *bs,

                          int64_t offset, int64_t size,

                          enum qcow2_discard_type type);

void qcow2_free_any_clusters(BlockDriverState *bs, uint64_t l2_entry,

                             int nb_clusters, enum qcow2_discard_type type);

int qcow2_update_snapshot_refcount(BlockDriverState *bs,

    int64_t l1_table_offset, int l1_size, int addend);

int qcow2_check_refcounts(BlockDriverState *bs, BdrvCheckResult *res,

                          BdrvCheckMode fix);

/* qcow2-cluster.c functions */

int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size,

                        bool exact_size);

void qcow2_l2_cache_reset(BlockDriverState *bs);

int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset);

void qcow2_encrypt_sectors(BDRVQcowState *s, int64_t sector_num,

                     uint8_t *out_buf, const uint8_t *in_buf,

                     int nb_sectors, int enc,

                     const AES_KEY *key);

int qcow2_get_cluster_offset(BlockDriverState *bs, uint64_t offset,

    int *num, uint64_t *cluster_offset);

int qcow2_alloc_cluster_offset(BlockDriverState *bs, uint64_t offset,

    int n_start, int n_end, int *num, uint64_t *host_offset, QCowL2Meta **m);

uint64_t qcow2_alloc_compressed_cluster_offset(BlockDriverState *bs,

                                         uint64_t offset,

                                         int compressed_size);

int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m);

int qcow2_discard_clusters(BlockDriverState *bs, uint64_t offset,

    int nb_sectors);

int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors);

/* qcow2-snapshot.c functions */

int qcow2_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info);

int qcow2_snapshot_goto(BlockDriverState *bs, const char *snapshot_id);

int qcow2_snapshot_delete(BlockDriverState *bs, const char *snapshot_id);

int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab);

int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name);

void qcow2_free_snapshots(BlockDriverState *bs);

int qcow2_read_snapshots(BlockDriverState *bs);

/* qcow2-cache.c functions */

Qcow2Cache *qcow2_cache_create(BlockDriverState *bs, int num_tables);

int qcow2_cache_destroy(BlockDriverState* bs, Qcow2Cache *c);

void qcow2_cache_entry_mark_dirty(Qcow2Cache *c, void *table);

int qcow2_cache_flush(BlockDriverState *bs, Qcow2Cache *c);

int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,

    Qcow2Cache *dependency);

void qcow2_cache_depends_on_flush(Qcow2Cache *c);

int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,

    void **table);

int qcow2_cache_get_empty(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,

    void **table);

int qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table);

#endif