/* * 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 #ifdef __cplusplus extern "C" { #endif #include "qemu_dep.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_CRYPT_LUKS 2 #define QCOW_MAX_CRYPT_CLUSTERS 32 #define QCOW_MAX_SNAPSHOTS 65536 /* Field widths in qcow2 mean normal cluster offsets cannot reach * 64PB; depending on cluster size, compressed clusters can have a * smaller limit (64PB for up to 16k clusters, then ramps down to * 512TB for 2M clusters). */ #define QCOW_MAX_CLUSTER_OFFSET ((1ULL << 56) - 1) /* 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 (8 * MiB) /* 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 (32 * MiB) /* 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) /* Maximum amount of extra data per snapshot table entry to accept */ #define QCOW_MAX_SNAPSHOT_EXTRA_DATA 1024 /* Bitmap header extension constraints */ #define QCOW2_MAX_BITMAPS 65535 #define QCOW2_MAX_BITMAP_DIRECTORY_SIZE (1024 * QCOW2_MAX_BITMAPS) /* 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 QCOW_EXTL2_SUBCLUSTERS_PER_CLUSTER 32 /* The subcluster X [0..31] is allocated */ #define QCOW_OFLAG_SUB_ALLOC(X) (1ULL << (X)) /* The subcluster X [0..31] reads as zeroes */ #define QCOW_OFLAG_SUB_ZERO(X) (QCOW_OFLAG_SUB_ALLOC(X) << 32) /* Subclusters [X, Y) (0 <= X <= Y <= 32) are allocated */ #define QCOW_OFLAG_SUB_ALLOC_RANGE(X, Y) \ (QCOW_OFLAG_SUB_ALLOC(Y) - QCOW_OFLAG_SUB_ALLOC(X)) /* Subclusters [X, Y) (0 <= X <= Y <= 32) read as zeroes */ #define QCOW_OFLAG_SUB_ZERO_RANGE(X, Y) \ (QCOW_OFLAG_SUB_ALLOC_RANGE(X, Y) << 32) /* L2 entry bitmap with all allocation bits set */ #define QCOW_L2_BITMAP_ALL_ALLOC (QCOW_OFLAG_SUB_ALLOC_RANGE(0, 32)) /* L2 entry bitmap with all "read as zeroes" bits set */ #define QCOW_L2_BITMAP_ALL_ZEROES (QCOW_OFLAG_SUB_ZERO_RANGE(0, 32)) /* Size of normal and extended L2 entries */ #define L2E_SIZE_NORMAL (sizeof(uint64_t)) #define L2E_SIZE_EXTENDED (sizeof(uint64_t) * 2) /* Size of L1 table entries */ #define L1E_SIZE (sizeof(uint64_t)) /* Size of reftable entries */ #define REFTABLE_ENTRY_SIZE (sizeof(uint64_t)) #define MIN_CLUSTER_BITS 9 #define MAX_CLUSTER_BITS 21 /* Defined in the qcow2 spec (compressed cluster descriptor) */ #define QCOW2_COMPRESSED_SECTOR_SIZE 512U /* Must be at least 2 to cover COW */ #define MIN_L2_CACHE_SIZE 2 /* cache entries */ /* Must be at least 4 to cover all cases of refcount table growth */ #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */ #define DEFAULT_L2_CACHE_MAX_SIZE (32 * MiB) #define DEFAULT_CACHE_CLEAN_INTERVAL 600 /* seconds */ #define DEFAULT_CLUSTER_SIZE 65536 #define QCOW2_OPT_DATA_FILE "data-file" #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_OVERLAP_BITMAP_DIRECTORY "overlap-check.bitmap-directory" #define QCOW2_OPT_CACHE_SIZE "cache-size" #define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size" #define QCOW2_OPT_L2_CACHE_ENTRY_SIZE "l2-cache-entry-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; /* Additional fields */ uint8_t compression_type; /* header must be a multiple of 8 */ uint8_t padding[7]; } QEMU_PACKED QCowHeader; //QEMU_BUILD_BUG_ON(!QEMU_IS_ALIGNED(sizeof(QCowHeader), 8)); 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; uint64_t icount; } QCowSnapshotExtraData; typedef struct Qcow2CryptoHeaderExtension { uint64_t offset; uint64_t length; } QEMU_PACKED Qcow2CryptoHeaderExtension; 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_DATA_FILE_BITNR = 2, QCOW2_INCOMPAT_COMPRESSION_BITNR = 3, QCOW2_INCOMPAT_EXTL2_BITNR = 4, QCOW2_INCOMPAT_DIRTY = 1 << QCOW2_INCOMPAT_DIRTY_BITNR, QCOW2_INCOMPAT_CORRUPT = 1 << QCOW2_INCOMPAT_CORRUPT_BITNR, QCOW2_INCOMPAT_DATA_FILE = 1 << QCOW2_INCOMPAT_DATA_FILE_BITNR, QCOW2_INCOMPAT_COMPRESSION = 1 << QCOW2_INCOMPAT_COMPRESSION_BITNR, QCOW2_INCOMPAT_EXTL2 = 1 << QCOW2_INCOMPAT_EXTL2_BITNR, QCOW2_INCOMPAT_MASK = QCOW2_INCOMPAT_DIRTY | QCOW2_INCOMPAT_CORRUPT | QCOW2_INCOMPAT_DATA_FILE | QCOW2_INCOMPAT_COMPRESSION | QCOW2_INCOMPAT_EXTL2, }; /* 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, }; /* Autoclear feature bits */ enum { QCOW2_AUTOCLEAR_BITMAPS_BITNR = 0, QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR = 1, QCOW2_AUTOCLEAR_BITMAPS = 1 << QCOW2_AUTOCLEAR_BITMAPS_BITNR, QCOW2_AUTOCLEAR_DATA_FILE_RAW = 1 << QCOW2_AUTOCLEAR_DATA_FILE_RAW_BITNR, QCOW2_AUTOCLEAR_MASK = QCOW2_AUTOCLEAR_BITMAPS | QCOW2_AUTOCLEAR_DATA_FILE_RAW, }; 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 Qcow2BitmapHeaderExt { uint32_t nb_bitmaps; uint32_t reserved32; uint64_t bitmap_directory_size; uint64_t bitmap_directory_offset; } QEMU_PACKED Qcow2BitmapHeaderExt; /* * In images with standard L2 entries all clusters are treated as if * they had one subcluster so QCow2ClusterType and QCow2SubclusterType * can be mapped to each other and have the exact same meaning * (QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC cannot happen in these images). * * In images with extended L2 entries QCow2ClusterType refers to the * complete cluster and QCow2SubclusterType to each of the individual * subclusters, so there are several possible combinations: * * |--------------+---------------------------| * | Cluster type | Possible subcluster types | * |--------------+---------------------------| * | UNALLOCATED | UNALLOCATED_PLAIN | * | | ZERO_PLAIN | * |--------------+---------------------------| * | NORMAL | UNALLOCATED_ALLOC | * | | ZERO_ALLOC | * | | NORMAL | * |--------------+---------------------------| * | COMPRESSED | COMPRESSED | * |--------------+---------------------------| * * QCOW2_SUBCLUSTER_INVALID means that the L2 entry is incorrect and * the image should be marked corrupt. */ typedef enum QCow2ClusterType { QCOW2_CLUSTER_UNALLOCATED, QCOW2_CLUSTER_ZERO_PLAIN, QCOW2_CLUSTER_ZERO_ALLOC, QCOW2_CLUSTER_NORMAL, QCOW2_CLUSTER_COMPRESSED, } QCow2ClusterType; typedef enum QCow2SubclusterType { QCOW2_SUBCLUSTER_UNALLOCATED_PLAIN, QCOW2_SUBCLUSTER_UNALLOCATED_ALLOC, QCOW2_SUBCLUSTER_ZERO_PLAIN, QCOW2_SUBCLUSTER_ZERO_ALLOC, QCOW2_SUBCLUSTER_NORMAL, QCOW2_SUBCLUSTER_COMPRESSED, QCOW2_SUBCLUSTER_INVALID, } QCow2SubclusterType; 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_BITMAP_DIRECTORY_BITNR = 8, QCOW2_OL_MAX_BITNR = 9, 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), QCOW2_OL_BITMAP_DIRECTORY = (1 << QCOW2_OL_BITMAP_DIRECTORY_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 | QCOW2_OL_BITMAP_DIRECTORY) /* 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 L1E_RESERVED_MASK 0x7f000000000001ffULL #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL #define L2E_STD_RESERVED_MASK 0x3f000000000001feULL #define REFT_OFFSET_MASK 0xfffffffffffffe00ULL #define REFT_RESERVED_MASK 0x1ffULL #define INV_OFFSET (-1ULL) #ifdef __cplusplus } #endif #endif