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Diffstat (limited to 'src/block/qcow2.h')
| -rw-r--r-- | src/block/qcow2.h | 594 |
1 files changed, 594 insertions, 0 deletions
diff --git a/src/block/qcow2.h b/src/block/qcow2.h new file mode 100644 index 0000000..b8c500b --- /dev/null +++ b/src/block/qcow2.h @@ -0,0 +1,594 @@ +/* + * 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 "crypto/cipher.h" +#include "qemu/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 +#define QCOW_MAX_SNAPSHOTS 65536 + +/* 8 MB refcount table is enough for 2 PB images at 64k cluster size + * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */ +#define QCOW_MAX_REFTABLE_SIZE 0x800000 + +/* 32 MB L1 table is enough for 2 PB images at 64k cluster size + * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */ +#define QCOW_MAX_L1_SIZE 0x2000000 + +/* Allow for an average of 1k per snapshot table entry, should be plenty of + * space for snapshot names and IDs */ +#define QCOW_MAX_SNAPSHOTS_SIZE (1024 * QCOW_MAX_SNAPSHOTS) + +/* indicate that the refcount of the referenced cluster is exactly one. */ +#define QCOW_OFLAG_COPIED (1ULL << 63) +/* indicate that the cluster is compressed (they never have the copied flag) */ +#define QCOW_OFLAG_COMPRESSED (1ULL << 62) +/* The cluster reads as all zeros */ +#define QCOW_OFLAG_ZERO (1ULL << 0) + +#define MIN_CLUSTER_BITS 9 +#define MAX_CLUSTER_BITS 21 + +/* Must be at least 2 to cover COW */ +#define MIN_L2_CACHE_SIZE 2 /* clusters */ + +/* Must be at least 4 to cover all cases of refcount table growth */ +#define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */ + +/* Whichever is more */ +#define DEFAULT_L2_CACHE_CLUSTERS 8 /* clusters */ +#define DEFAULT_L2_CACHE_BYTE_SIZE 1048576 /* bytes */ + +/* The refblock cache needs only a fourth of the L2 cache size to cover as many + * clusters */ +#define DEFAULT_L2_REFCOUNT_SIZE_RATIO 4 + +#define DEFAULT_CLUSTER_SIZE 65536 + + +#define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts" +#define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request" +#define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot" +#define QCOW2_OPT_DISCARD_OTHER "pass-discard-other" +#define QCOW2_OPT_OVERLAP "overlap-check" +#define QCOW2_OPT_OVERLAP_TEMPLATE "overlap-check.template" +#define QCOW2_OPT_OVERLAP_MAIN_HEADER "overlap-check.main-header" +#define QCOW2_OPT_OVERLAP_ACTIVE_L1 "overlap-check.active-l1" +#define QCOW2_OPT_OVERLAP_ACTIVE_L2 "overlap-check.active-l2" +#define QCOW2_OPT_OVERLAP_REFCOUNT_TABLE "overlap-check.refcount-table" +#define QCOW2_OPT_OVERLAP_REFCOUNT_BLOCK "overlap-check.refcount-block" +#define QCOW2_OPT_OVERLAP_SNAPSHOT_TABLE "overlap-check.snapshot-table" +#define QCOW2_OPT_OVERLAP_INACTIVE_L1 "overlap-check.inactive-l1" +#define QCOW2_OPT_OVERLAP_INACTIVE_L2 "overlap-check.inactive-l2" +#define QCOW2_OPT_CACHE_SIZE "cache-size" +#define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size" +#define QCOW2_OPT_REFCOUNT_CACHE_SIZE "refcount-cache-size" +#define QCOW2_OPT_CACHE_CLEAN_INTERVAL "cache-clean-interval" + +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; +} QEMU_PACKED QCowHeader; + +typedef struct QEMU_PACKED QCowSnapshotHeader { + /* header is 8 byte aligned */ + uint64_t l1_table_offset; + + uint32_t l1_size; + uint16_t id_str_size; + uint16_t name_size; + + uint32_t date_sec; + uint32_t date_nsec; + + uint64_t vm_clock_nsec; + + uint32_t vm_state_size; + uint32_t extra_data_size; /* for extension */ + /* extra data follows */ + /* id_str follows */ + /* name follows */ +} QCowSnapshotHeader; + +typedef struct QEMU_PACKED QCowSnapshotExtraData { + uint64_t vm_state_size_large; + uint64_t disk_size; +} QCowSnapshotExtraData; + + +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_CORRUPT_BITNR = 1, + QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR, + QCOW2_INCOMPAT_CORRUPT = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR, + + QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY + | QCOW2_INCOMPAT_CORRUPT, +}; + +/* 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 Qcow2DiscardRegion { + BlockDriverState *bs; + uint64_t offset; + uint64_t bytes; + QTAILQ_ENTRY(Qcow2DiscardRegion) next; +} Qcow2DiscardRegion; + +typedef uint64_t Qcow2GetRefcountFunc(const void *refcount_array, + uint64_t index); +typedef void Qcow2SetRefcountFunc(void *refcount_array, + uint64_t index, uint64_t value); + +typedef struct BDRVQcow2State { + int cluster_bits; + int cluster_size; + int cluster_sectors; + int l2_bits; + int l2_size; + int l1_size; + int l1_vm_state_index; + int refcount_block_bits; + int refcount_block_size; + 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; + QEMUTimer *cache_clean_timer; + unsigned cache_clean_interval; + + 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; + uint64_t free_cluster_index; + uint64_t free_byte_offset; + + CoMutex lock; + + QCryptoCipher *cipher; /* current cipher, NULL if no key yet */ + uint32_t crypt_method_header; + uint64_t snapshots_offset; + int snapshots_size; + unsigned int nb_snapshots; + QCowSnapshot *snapshots; + + int flags; + int qcow_version; + bool use_lazy_refcounts; + int refcount_order; + int refcount_bits; + uint64_t refcount_max; + + Qcow2GetRefcountFunc *get_refcount; + Qcow2SetRefcountFunc *set_refcount; + + bool discard_passthrough[QCOW2_DISCARD_MAX]; + + int overlap_check; /* bitmask of Qcow2MetadataOverlap values */ + bool signaled_corruption; + + 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; + QTAILQ_HEAD (, Qcow2DiscardRegion) discards; + bool cache_discards; + + /* Backing file path and format as stored in the image (this is not the + * effective path/format, which may be the result of a runtime option + * override) */ + char *image_backing_file; + char *image_backing_format; +} BDRVQcow2State; + +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 +}; + +typedef enum QCow2MetadataOverlap { + QCOW2_OL_MAIN_HEADER_BITNR = 0, + QCOW2_OL_ACTIVE_L1_BITNR = 1, + QCOW2_OL_ACTIVE_L2_BITNR = 2, + QCOW2_OL_REFCOUNT_TABLE_BITNR = 3, + QCOW2_OL_REFCOUNT_BLOCK_BITNR = 4, + QCOW2_OL_SNAPSHOT_TABLE_BITNR = 5, + QCOW2_OL_INACTIVE_L1_BITNR = 6, + QCOW2_OL_INACTIVE_L2_BITNR = 7, + + QCOW2_OL_MAX_BITNR = 8, + + QCOW2_OL_NONE = 0, + QCOW2_OL_MAIN_HEADER = (1 << QCOW2_OL_MAIN_HEADER_BITNR), + QCOW2_OL_ACTIVE_L1 = (1 << QCOW2_OL_ACTIVE_L1_BITNR), + QCOW2_OL_ACTIVE_L2 = (1 << QCOW2_OL_ACTIVE_L2_BITNR), + QCOW2_OL_REFCOUNT_TABLE = (1 << QCOW2_OL_REFCOUNT_TABLE_BITNR), + QCOW2_OL_REFCOUNT_BLOCK = (1 << QCOW2_OL_REFCOUNT_BLOCK_BITNR), + QCOW2_OL_SNAPSHOT_TABLE = (1 << QCOW2_OL_SNAPSHOT_TABLE_BITNR), + QCOW2_OL_INACTIVE_L1 = (1 << QCOW2_OL_INACTIVE_L1_BITNR), + /* NOTE: Checking overlaps with inactive L2 tables will result in bdrv + * reads. */ + QCOW2_OL_INACTIVE_L2 = (1 << QCOW2_OL_INACTIVE_L2_BITNR), +} QCow2MetadataOverlap; + +/* Perform all overlap checks which can be done in constant time */ +#define QCOW2_OL_CONSTANT \ + (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \ + QCOW2_OL_SNAPSHOT_TABLE) + +/* Perform all overlap checks which don't require disk access */ +#define QCOW2_OL_CACHED \ + (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \ + QCOW2_OL_INACTIVE_L1) + +/* Perform all overlap checks */ +#define QCOW2_OL_ALL \ + (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2) + +#define L1E_OFFSET_MASK 0x00fffffffffffe00ULL +#define L2E_OFFSET_MASK 0x00fffffffffffe00ULL +#define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffffffffffffffULL + +#define REFT_OFFSET_MASK 0xfffffffffffffe00ULL + +static inline int64_t start_of_cluster(BDRVQcow2State *s, int64_t offset) +{ + return offset & ~(s->cluster_size - 1); +} + +static inline int64_t offset_into_cluster(BDRVQcow2State *s, int64_t offset) +{ + return offset & (s->cluster_size - 1); +} + +static inline uint64_t size_to_clusters(BDRVQcow2State *s, uint64_t size) +{ + return (size + (s->cluster_size - 1)) >> s->cluster_bits; +} + +static inline int64_t size_to_l1(BDRVQcow2State *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(BDRVQcow2State *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 int64_t qcow2_vm_state_offset(BDRVQcow2State *s) +{ + return (int64_t)s->l1_vm_state_index << (s->cluster_bits + s->l2_bits); +} + +static inline uint64_t qcow2_max_refcount_clusters(BDRVQcow2State *s) +{ + return QCOW_MAX_REFTABLE_SIZE >> s->cluster_bits; +} + +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(BDRVQcow2State *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); +} + +static inline uint64_t refcount_diff(uint64_t r1, uint64_t r2) +{ + return r1 > r2 ? r1 - r2 : r2 - r1; +} + +// 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_mark_corrupt(BlockDriverState *bs); +int qcow2_mark_consistent(BlockDriverState *bs); +int qcow2_update_header(BlockDriverState *bs); + +void qcow2_signal_corruption(BlockDriverState *bs, bool fatal, int64_t offset, + int64_t size, const char *message_format, ...) + GCC_FMT_ATTR(5, 6); + +/* qcow2-refcount.c functions */ +int qcow2_refcount_init(BlockDriverState *bs); +void qcow2_refcount_close(BlockDriverState *bs); + +int qcow2_get_refcount(BlockDriverState *bs, int64_t cluster_index, + uint64_t *refcount); + +int qcow2_update_cluster_refcount(BlockDriverState *bs, int64_t cluster_index, + uint64_t addend, bool decrease, + enum qcow2_discard_type type); + +int64_t qcow2_alloc_clusters(BlockDriverState *bs, uint64_t size); +int64_t qcow2_alloc_clusters_at(BlockDriverState *bs, uint64_t offset, + int64_t 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); + +void qcow2_process_discards(BlockDriverState *bs, int ret); + +int qcow2_check_metadata_overlap(BlockDriverState *bs, int ign, int64_t offset, + int64_t size); +int qcow2_pre_write_overlap_check(BlockDriverState *bs, int ign, int64_t offset, + int64_t size); + +/* qcow2-cluster.c functions */ +int qcow2_grow_l1_table(BlockDriverState *bs, uint64_t min_size, + bool exact_size); +int qcow2_write_l1_entry(BlockDriverState *bs, int l1_index); +void qcow2_l2_cache_reset(BlockDriverState *bs); +int qcow2_decompress_cluster(BlockDriverState *bs, uint64_t cluster_offset); +int qcow2_encrypt_sectors(BDRVQcow2State *s, int64_t sector_num, + uint8_t *out_buf, const uint8_t *in_buf, + int nb_sectors, bool enc, Error **errp); + +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 *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, enum qcow2_discard_type type, bool full_discard); +int qcow2_zero_clusters(BlockDriverState *bs, uint64_t offset, int nb_sectors); + +int qcow2_expand_zero_clusters(BlockDriverState *bs, + BlockDriverAmendStatusCB *status_cb); + +/* 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, + const char *name, + Error **errp); +int qcow2_snapshot_list(BlockDriverState *bs, QEMUSnapshotInfo **psn_tab); +int qcow2_snapshot_load_tmp(BlockDriverState *bs, + const char *snapshot_id, + const char *name, + Error **errp); + +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(BlockDriverState *bs, 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); + +void qcow2_cache_clean_unused(BlockDriverState *bs, Qcow2Cache *c); +int qcow2_cache_empty(BlockDriverState *bs, 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); +void qcow2_cache_put(BlockDriverState *bs, Qcow2Cache *c, void **table); + +#endif |
