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qcow2.h
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/* * qcow2.h --- structures and function prototypes for qcow2.c to generate * qcow2 formatted disk images. This format is used originally by QEMU * for virtual machines, and stores the filesystem data on disk in a * packed format to avoid creating sparse image files that need lots of * seeking to read and write. * * The qcow2 format supports zlib compression, but that is not yet * implemented. * * It is possible to directly mount a qcow2 image using qemu-nbd: * * [root]# modprobe nbd max_part=63 * [root]# qemu-nbd -c /dev/nbd0 image.img * [root]# mount /dev/nbd0p1 /mnt/qemu * * Format details at http://people.gnome.org/~markmc/qcow-image-format.html * * Copyright (C) 2010 Red Hat, Inc., Lukas Czerner <lczerner@redhat.com> * * %Begin-Header% * This file may be redistributed under the terms of the GNU Public * License. * %End-Header% */ /* Number of l2 tables in memory before writeback */ #define L2_CACHE_PREALLOC 512 #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) #define QCOW_VERSION 2 #define QCOW_OFLAG_COPIED (1LL << 63) #define QCOW_OFLAG_COMPRESSED (1LL << 62) #define QCOW_COMPRESSED 1 #define QCOW_ENCRYPTED 2 struct ext2_qcow2_hdr { __u32 magic; __u32 version; __u64 backing_file_offset; __u32 backing_file_size; __u32 cluster_bits; __u64 size; __u32 crypt_method; __u32 l1_size; __u64 l1_table_offset; __u64 refcount_table_offset; __u32 refcount_table_clusters; __u32 nb_snapshots; __u64 snapshots_offset; }; typedef struct ext2_qcow2_l2_table L2_CACHE_HEAD; struct ext2_qcow2_l2_table { __u32 l1_index; __u64 offset; __u64 *data; L2_CACHE_HEAD *next; }; struct ext2_qcow2_l2_cache { L2_CACHE_HEAD *used_head; L2_CACHE_HEAD *used_tail; L2_CACHE_HEAD *free_head; __u32 free; __u32 count; __u64 next_offset; }; struct ext2_qcow2_refcount { __u64 *refcount_table; __u64 refcount_table_offset; __u64 refcount_block_offset; __u32 refcount_table_clusters; __u32 refcount_table_index; __u32 refcount_block_index; __u16 *refcount_block; }; struct ext2_qcow2_image { int fd; struct ext2_qcow2_hdr *hdr; struct ext2_qcow2_l2_cache *l2_cache; struct ext2_qcow2_refcount refcount; __u32 cluster_size; __u32 cluster_bits; __u32 l1_size; __u32 l2_size; __u64 *l1_table; __u64 l2_offset; __u64 l1_offset; __u64 image_size; }; /* Function prototypes */ /* qcow2.c */ /* Functions for converting qcow2 image into raw image */ struct ext2_qcow2_hdr *qcow2_read_header(int); int qcow2_write_raw_image(int, int, struct ext2_qcow2_hdr *);