| Lukas Czerner | bf0449b | 2011-05-18 13:36:53 +0200 | [diff] [blame] | 1 | /* |
| 2 | * qcow2.h --- structures and function prototypes for qcow2.c to generate |
| 3 | * qcow2 formatted disk images. This format is used originally by QEMU |
| 4 | * for virtual machines, and stores the filesystem data on disk in a |
| 5 | * packed format to avoid creating sparse image files that need lots of |
| 6 | * seeking to read and write. |
| 7 | * |
| 8 | * The qcow2 format supports zlib compression, but that is not yet |
| 9 | * implemented. |
| 10 | * |
| 11 | * It is possible to directly mount a qcow2 image using qemu-nbd: |
| 12 | * |
| 13 | * [root]# modprobe nbd max_part=63 |
| 14 | * [root]# qemu-nbd -c /dev/nbd0 image.img |
| 15 | * [root]# mount /dev/nbd0p1 /mnt/qemu |
| 16 | * |
| 17 | * Format details at http://people.gnome.org/~markmc/qcow-image-format.html |
| 18 | * |
| 19 | * Copyright (C) 2010 Red Hat, Inc., Lukas Czerner <lczerner@redhat.com> |
| 20 | * |
| 21 | * %Begin-Header% |
| 22 | * This file may be redistributed under the terms of the GNU Public |
| 23 | * License. |
| 24 | * %End-Header% |
| 25 | */ |
| 26 | |
| 27 | /* Number of l2 tables in memory before writeback */ |
| 28 | #define L2_CACHE_PREALLOC 512 |
| 29 | |
| 30 | |
| 31 | #define QCOW_MAGIC (('Q' << 24) | ('F' << 16) | ('I' << 8) | 0xfb) |
| 32 | #define QCOW_VERSION 2 |
| 33 | #define QCOW_OFLAG_COPIED (1LL << 63) |
| 34 | #define QCOW_OFLAG_COMPRESSED (1LL << 62) |
| 35 | |
| 36 | #define QCOW_COMPRESSED 1 |
| 37 | #define QCOW_ENCRYPTED 2 |
| 38 | |
| 39 | struct ext2_qcow2_hdr { |
| 40 | __u32 magic; |
| 41 | __u32 version; |
| 42 | |
| 43 | __u64 backing_file_offset; |
| 44 | __u32 backing_file_size; |
| 45 | |
| 46 | __u32 cluster_bits; |
| 47 | __u64 size; |
| 48 | __u32 crypt_method; |
| 49 | |
| 50 | __u32 l1_size; |
| 51 | __u64 l1_table_offset; |
| 52 | |
| 53 | __u64 refcount_table_offset; |
| 54 | __u32 refcount_table_clusters; |
| 55 | |
| 56 | __u32 nb_snapshots; |
| 57 | __u64 snapshots_offset; |
| 58 | }; |
| 59 | |
| 60 | typedef struct ext2_qcow2_l2_table L2_CACHE_HEAD; |
| 61 | |
| 62 | struct ext2_qcow2_l2_table { |
| 63 | __u32 l1_index; |
| 64 | __u64 offset; |
| 65 | __u64 *data; |
| 66 | L2_CACHE_HEAD *next; |
| 67 | }; |
| 68 | |
| 69 | struct ext2_qcow2_l2_cache { |
| 70 | L2_CACHE_HEAD *used_head; |
| 71 | L2_CACHE_HEAD *used_tail; |
| 72 | L2_CACHE_HEAD *free_head; |
| 73 | __u32 free; |
| 74 | __u32 count; |
| 75 | __u64 next_offset; |
| 76 | }; |
| 77 | |
| 78 | struct ext2_qcow2_refcount { |
| 79 | __u64 *refcount_table; |
| 80 | __u64 refcount_table_offset; |
| 81 | __u64 refcount_block_offset; |
| 82 | |
| 83 | __u32 refcount_table_clusters; |
| 84 | __u32 refcount_table_index; |
| 85 | __u32 refcount_block_index; |
| 86 | |
| 87 | __u16 *refcount_block; |
| 88 | }; |
| 89 | |
| 90 | struct ext2_qcow2_image { |
| 91 | int fd; |
| 92 | struct ext2_qcow2_hdr *hdr; |
| 93 | struct ext2_qcow2_l2_cache *l2_cache; |
| 94 | struct ext2_qcow2_refcount refcount; |
| 95 | __u32 cluster_size; |
| 96 | __u32 cluster_bits; |
| 97 | __u32 l1_size; |
| 98 | __u32 l2_size; |
| 99 | |
| 100 | __u64 *l1_table; |
| 101 | __u64 l2_offset; |
| 102 | __u64 l1_offset; |
| 103 | __u64 image_size; |
| 104 | }; |
| 105 | |
| 106 | /* Function prototypes */ |
| 107 | |
| 108 | /* qcow2.c */ |
| 109 | |
| 110 | /* Functions for converting qcow2 image into raw image */ |
| 111 | struct ext2_qcow2_hdr *qcow2_read_header(int); |
| 112 | int qcow2_write_raw_image(int, int, struct ext2_qcow2_hdr *); |
| 113 | |