source: bootcd/isolinux/syslinux-6.03/core/fs/btrfs/btrfs.h

#ifndef _BTRFS_H_
#define _BTRFS_H_

#include <stdint.h>
#include <zconf.h>

typedef uint8_t u8;
typedef uint16_t u16;
typedef uint32_t u32;
typedef uint64_t u64;
/* type that store on disk, but it is same as cpu type for i386 arch */
typedef u16 __le16;
typedef u32 __le32;
typedef u64 __le64;

#include "crc32c.h"
#define btrfs_crc32c crc32c_le

#define BTRFS_SUPER_INFO_OFFSET (64 * 1024)
#define BTRFS_SUPER_INFO_SIZE 4096
#define BTRFS_MAX_LEAF_SIZE 4096
#define BTRFS_BLOCK_SHIFT 12
#define BTRFS_BLOCK_SIZE  (1 << BTRFS_BLOCK_SHIFT)

#define BTRFS_SUPER_MIRROR_MAX   3
#define BTRFS_SUPER_MIRROR_SHIFT 12
#define BTRFS_CSUM_SIZE 32
#define BTRFS_FSID_SIZE 16
#define BTRFS_LABEL_SIZE 256
#define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048
#define BTRFS_UUID_SIZE 16

#define BTRFS_MAGIC "_BHRfS_M"
#define BTRFS_MAGIC_L 8
#define BTRFS_MAGIC_N 0x4d5f53665248425f

#define BTRFS_SUPER_FLAG_METADUMP       (1ULL << 33)

#define BTRFS_DEV_ITEM_KEY      216
#define BTRFS_CHUNK_ITEM_KEY    228
#define BTRFS_ROOT_REF_KEY      156
#define BTRFS_ROOT_ITEM_KEY     132
#define BTRFS_EXTENT_DATA_KEY   108
#define BTRFS_DIR_ITEM_KEY      84
#define BTRFS_INODE_ITEM_KEY    1

#define BTRFS_EXTENT_TREE_OBJECTID 2ULL
#define BTRFS_FS_TREE_OBJECTID 5ULL

#define BTRFS_FIRST_CHUNK_TREE_OBJECTID 256ULL

#define BTRFS_FILE_EXTENT_INLINE 0
#define BTRFS_FILE_EXTENT_REG 1
#define BTRFS_FILE_EXTENT_PREALLOC 2

#define BTRFS_MAX_LEVEL 8
#define BTRFS_MAX_CHUNK_ENTRIES 256

#define BTRFS_FT_REG_FILE       1
#define BTRFS_FT_DIR            2
#define BTRFS_FT_SYMLINK        7

#define ROOT_DIR_WORD 0x002f

struct btrfs_dev_item {
        __le64 devid;
        __le64 total_bytes;
        __le64 bytes_used;
        __le32 io_align;
        __le32 io_width;
        __le32 sector_size;
        __le64 type;
        __le64 generation;
        __le64 start_offset;
        __le32 dev_group;
        u8 seek_speed;
        u8 bandwidth;
        u8 uuid[BTRFS_UUID_SIZE];
        u8 fsid[BTRFS_UUID_SIZE];
} __attribute__ ((__packed__));

struct btrfs_super_block {
        u8 csum[BTRFS_CSUM_SIZE];
        /* the first 3 fields must match struct btrfs_header */
        u8 fsid[BTRFS_FSID_SIZE];    /* FS specific uuid */
        __le64 bytenr; /* this block number */
        __le64 flags;

        /* allowed to be different from the btrfs_header from here own down */
        __le64 magic;
        __le64 generation;
        __le64 root;
        __le64 chunk_root;
        __le64 log_root;

        /* this will help find the new super based on the log root */
        __le64 log_root_transid;
        __le64 total_bytes;
        __le64 bytes_used;
        __le64 root_dir_objectid;
        __le64 num_devices;
        __le32 sectorsize;
        __le32 nodesize;
        __le32 leafsize;
        __le32 stripesize;
        __le32 sys_chunk_array_size;
        __le64 chunk_root_generation;
        __le64 compat_flags;
        __le64 compat_ro_flags;
        __le64 incompat_flags;
        __le16 csum_type;
        u8 root_level;
        u8 chunk_root_level;
        u8 log_root_level;
        struct btrfs_dev_item dev_item;

        char label[BTRFS_LABEL_SIZE];

        /* future expansion */
        __le64 reserved[32];
        u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE];
} __attribute__ ((__packed__));

struct btrfs_disk_key {
        __le64 objectid;
        u8 type;
        __le64 offset;
} __attribute__ ((__packed__));

struct btrfs_stripe {
        __le64 devid;
        __le64 offset;
        u8 dev_uuid[BTRFS_UUID_SIZE];
} __attribute__ ((__packed__));

struct btrfs_chunk {
        __le64 length;
        __le64 owner;
        __le64 stripe_len;
        __le64 type;
        __le32 io_align;
        __le32 io_width;
        __le32 sector_size;
        __le16 num_stripes;
        __le16 sub_stripes;
        struct btrfs_stripe stripe;
} __attribute__ ((__packed__));

struct btrfs_header {
        /* these first four must match the super block */
        u8 csum[BTRFS_CSUM_SIZE];
        u8 fsid[BTRFS_FSID_SIZE]; /* FS specific uuid */
        __le64 bytenr; /* which block this node is supposed to live in */
        __le64 flags;

        /* allowed to be different from the super from here on down */
        u8 chunk_tree_uuid[BTRFS_UUID_SIZE];
        __le64 generation;
        __le64 owner;
        __le32 nritems;
        u8 level;
} __attribute__ ((__packed__));

struct btrfs_item {
        struct btrfs_disk_key key;
        __le32 offset;
        __le32 size;
} __attribute__ ((__packed__));

struct btrfs_leaf {
        struct btrfs_header header;
        struct btrfs_item items[];
} __attribute__ ((__packed__));

struct btrfs_key_ptr {
        struct btrfs_disk_key key;
        __le64 blockptr;
        __le64 generation;
} __attribute__ ((__packed__));

struct btrfs_node {
        struct btrfs_header header;
        struct btrfs_key_ptr ptrs[];
} __attribute__ ((__packed__));

/* remember how we get to a node/leaf */
struct btrfs_path {
        u64 offsets[BTRFS_MAX_LEVEL];
        int itemsnr[BTRFS_MAX_LEVEL];
        int slots[BTRFS_MAX_LEVEL];
        /* remember last slot's item and data */
        struct btrfs_item item;
        u8 data[BTRFS_MAX_LEAF_SIZE];
};

/* store logical offset to physical offset mapping */
struct btrfs_chunk_map_item {
        u64 logical;
        u64 length;
        u64 devid;
        u64 physical;
};

struct btrfs_chunk_map {
        struct btrfs_chunk_map_item *map;
        u32 map_length;
        u32 cur_length;
};

struct btrfs_timespec {
        __le64 sec;
        __le32 nsec;
} __attribute__ ((__packed__));

struct btrfs_inode_item {
        /* nfs style generation number */
        __le64 generation;
        /* transid that last touched this inode */
        __le64 transid;
        __le64 size;
        __le64 nbytes;
        __le64 block_group;
        __le32 nlink;
        __le32 uid;
        __le32 gid;
        __le32 mode;
        __le64 rdev;
        __le64 flags;

        /* modification sequence number for NFS */
        __le64 sequence;

        /*
         * a little future expansion, for more than this we can
         * just grow the inode item and version it
         */
        __le64 reserved[4];
        struct btrfs_timespec atime;
        struct btrfs_timespec ctime;
        struct btrfs_timespec mtime;
        struct btrfs_timespec otime;
} __attribute__ ((__packed__));

struct btrfs_root_item {
        struct btrfs_inode_item inode;
        __le64 generation;
        __le64 root_dirid;
        __le64 bytenr;
        __le64 byte_limit;
        __le64 bytes_used;
        __le64 last_snapshot;
        __le64 flags;
        __le32 refs;
        struct btrfs_disk_key drop_progress;
        u8 drop_level;
        u8 level;
} __attribute__ ((__packed__));

struct btrfs_dir_item {
        struct btrfs_disk_key location;
        __le64 transid;
        __le16 data_len;
        __le16 name_len;
        u8 type;
} __attribute__ ((__packed__));

struct btrfs_file_extent_item {
        __le64 generation;
        __le64 ram_bytes;
        u8 compression;
        u8 encryption;
        __le16 other_encoding; /* spare for later use */
        u8 type;
        __le64 disk_bytenr;
        __le64 disk_num_bytes;
        __le64 offset;
        __le64 num_bytes;
} __attribute__ ((__packed__));

struct btrfs_root_ref {
        __le64 dirid;
        __le64 sequence;
        __le16 name_len;
} __attribute__ ((__packed__));

/*
 * btrfs private inode information
 */
struct btrfs_pvt_inode {
    uint64_t offset;
};

#define PVT(i) ((struct btrfs_pvt_inode *)((i)->pvt))

#endif