jfs.h

open source bios with linux platform, very good and can be reused.

/* jfs.h - an extractions from linux/include/linux/jfs/jfs* into one file */
/*   
 *  GRUB  --  GRand Unified Bootloader
 *  Copyright (C) 2000  International Business Machines  Corp.
 *  Copyright (C) 2001  Free Software Foundation, Inc.
 *
 *  This program is free software;  you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or 
 *  (at your option) any later version.
 * 
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY;  without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *  the GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program;  if not, write to the Free Software 
 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, 
 *  MA 02110-1301, USA.
 */

#ifndef _JFS_H_
#define _JFS_H_

/* those are from jfs_filsys.h */

/*
 *	 file system option (superblock flag)
 */
/* platform option (conditional compilation) */
#define JFS_AIX		0x80000000	/* AIX support */
/*	POSIX name/directory  support */

#define JFS_OS2		0x40000000	/* OS/2 support */
/*	case-insensitive name/directory support */

#define JFS_LINUX      	0x10000000	/* Linux support */
/*	case-sensitive name/directory support */

/* directory option */
#define JFS_UNICODE	0x00000001	/* unicode name */

/* bba */
#define	JFS_SWAP_BYTES		0x00100000	/* running on big endian computer */


/*
 *	buffer cache configuration
 */
/* page size */
#ifdef PSIZE
#undef PSIZE
#endif
#define	PSIZE		4096	/* page size (in byte) */

/*
 *	fs fundamental size
 *
 * PSIZE >= file system block size >= PBSIZE >= DISIZE
 */
#define	PBSIZE		512	/* physical block size (in byte) */
#define DISIZE		512	/* on-disk inode size (in byte) */
#define L2DISIZE	9
#define	INOSPERIAG	4096	/* number of disk inodes per iag */
#define	L2INOSPERIAG	12
#define INOSPEREXT	32	/* number of disk inode per extent */
#define L2INOSPEREXT	5

/* Minimum number of bytes supported for a JFS partition */
#define MINJFS			(0x1000000)

/*
 * fixed byte offset address
 */
#define SUPER1_OFF	0x8000	/* primary superblock */

#define AITBL_OFF	(SUPER1_OFF + PSIZE + (PSIZE << 1))

/*
 *	fixed reserved inode number
 */
/* aggregate inode */
#define	AGGREGATE_I	1	/* aggregate inode map inode */
#define	FILESYSTEM_I	16	/* 1st/only fileset inode in ait:
				 * fileset inode map inode
				 */

/* per fileset inode */
#define	ROOT_I		2	/* fileset root inode */

/*
 *	directory configuration
 */
#define JFS_NAME_MAX	255
#define JFS_PATH_MAX	PSIZE

#if 0
typedef unsigned char u8;
typedef char s8;
typedef unsigned short u16;
typedef short s16;
typedef unsigned int u32;
typedef int s32;
typedef unsigned long long u64;
typedef long long s64;
#endif

typedef u16 UniChar;

/* these from jfs_btree.h */

/* btpaget_t flag */
#define BT_TYPE		0x07	/* B+-tree index */
#define	BT_ROOT		0x01	/* root page */
#define	BT_LEAF		0x02	/* leaf page */
#define	BT_INTERNAL	0x04	/* internal page */
#define	BT_RIGHTMOST	0x10	/* rightmost page */
#define	BT_LEFTMOST	0x20	/* leftmost page */

/* those are from jfs_types.h */

struct timestruc_t {
	u32 tv_sec;
	u32 tv_nsec;
};

/*
 *	physical xd (pxd)
 */
typedef struct {
	unsigned len:24;
	unsigned addr1:8;
	u32 addr2;
} pxd_t;

/* xd_t field extraction */
#define	lengthPXD(pxd)	((pxd)->len)
#define	addressPXD(pxd)	(((s64)((pxd)->addr1)) << 32 | ((pxd)->addr2))

/*
 *	data extent descriptor (dxd)
 */
typedef struct {
	unsigned flag:8;	/* 1: flags */
	unsigned rsrvd:24;	/* 3: */
	u32 size;		/* 4: size in byte */
	unsigned len:24;	/* 3: length in unit of fsblksize */
	unsigned addr1:8;	/* 1: address in unit of fsblksize */
	u32 addr2;		/* 4: address in unit of fsblksize */
} dxd_t;			/* - 16 - */

/*
 *	DASD limit information - stored in directory inode
 */
typedef struct dasd {
	u8 thresh;		/* Alert Threshold (in percent) */
	u8 delta;		/* Alert Threshold delta (in percent)   */
	u8 rsrvd1;
	u8 limit_hi;		/* DASD limit (in logical blocks)       */
	u32 limit_lo;		/* DASD limit (in logical blocks)       */
	u8 rsrvd2[3];
	u8 used_hi;		/* DASD usage (in logical blocks)       */
	u32 used_lo;		/* DASD usage (in logical blocks)       */
} dasd_t;


/* from jfs_superblock.h */

#define JFS_MAGIC 	0x3153464A	/* "JFS1" */

struct jfs_superblock
{
	u32 s_magic;		/* 4: magic number */
	u32 s_version;		/* 4: version number */

	s64 s_size;		/* 8: aggregate size in hardware/LVM blocks;
				 * VFS: number of blocks
				 */
	s32 s_bsize;		/* 4: aggregate block size in bytes; 
				 * VFS: fragment size
				 */
	s16 s_l2bsize;		/* 2: log2 of s_bsize */
	s16 s_l2bfactor;	/* 2: log2(s_bsize/hardware block size) */
	s32 s_pbsize;		/* 4: hardware/LVM block size in bytes */
	s16 s_l2pbsize;		/* 2: log2 of s_pbsize */
	s16 pad;		/* 2: padding necessary for alignment */

	u32 s_agsize;		/* 4: allocation group size in aggr. blocks */

	u32 s_flag;		/* 4: aggregate attributes:
				 *    see jfs_filsys.h
				 */
	u32 s_state;		/* 4: mount/unmount/recovery state: 
				 *    see jfs_filsys.h
				 */
	s32 s_compress;		/* 4: > 0 if data compression */

	pxd_t s_ait2;		/* 8: first extent of secondary
				 *    aggregate inode table
				 */

	pxd_t s_aim2;		/* 8: first extent of secondary
				 *    aggregate inode map
				 */
	u32 s_logdev;		/* 4: device address of log */
	s32 s_logserial;	/* 4: log serial number at aggregate mount */
	pxd_t s_logpxd;		/* 8: inline log extent */

	pxd_t s_fsckpxd;	/* 8: inline fsck work space extent */

	struct timestruc_t s_time;	/* 8: time last updated */

	s32 s_fsckloglen;	/* 4: Number of filesystem blocks reserved for
				 *    the fsck service log.  
				 *    N.B. These blocks are divided among the
				 *         versions kept.  This is not a per
				 *         version size.
				 *    N.B. These blocks are included in the 
				 *         length field of s_fsckpxd.
				 */
	s8 s_fscklog;		/* 1: which fsck service log is most recent
				 *    0 => no service log data yet
				 *    1 => the first one
				 *    2 => the 2nd one
				 */
	char s_fpack[11];	/* 11: file system volume name 
				 *     N.B. This must be 11 bytes to
				 *          conform with the OS/2 BootSector
				 *          requirements
				 */

	/* extendfs() parameter under s_state & FM_EXTENDFS */
	s64 s_xsize;		/* 8: extendfs s_size */
	pxd_t s_xfsckpxd;	/* 8: extendfs fsckpxd */
	pxd_t s_xlogpxd;	/* 8: extendfs logpxd */
	/* - 128 byte boundary - */

	/*
	 *      DFS VFS support (preliminary) 
	 */
	char s_attach;		/* 1: VFS: flag: set when aggregate is attached
				 */
	u8 rsrvd4[7];		/* 7: reserved - set to 0 */

	u64 totalUsable;	/* 8: VFS: total of 1K blocks which are
				 * available to "normal" (non-root) users.
				 */
	u64 minFree;		/* 8: VFS: # of 1K blocks held in reserve for 
				 * exclusive use of root.  This value can be 0,
				 * and if it is then totalUsable will be equal 
				 * to # of blocks in aggregate.  I believe this
				 * means that minFree + totalUsable = # blocks.
				 * In that case, we don't need to store both 
				 * totalUsable and minFree since we can compute
				 * one from the other.  I would guess minFree 
				 * would be the one we should store, and 
				 * totalUsable would be the one we should 
				 * compute.  (Just a guess...)
				 */

	u64 realFree;		/* 8: VFS: # of free 1K blocks can be used by 
				 * "normal" users.  It may be this is something
				 * we should compute when asked for instead of 
				 * storing in the superblock.  I don't know how
				 * often this information is needed.
				 */
	/*
	 *      graffiti area
	 */
};

/* from jfs_dtree.h */

/*
 *      entry segment/slot
 *
 * an entry consists of type dependent head/only segment/slot and
 * additional segments/slots linked vi next field;
 * N.B. last/only segment of entry is terminated by next = -1;
 */
/*
 *	directory page slot
 */
typedef struct {
	s8 next;		/* 1: */
	s8 cnt;			/* 1: */
	UniChar name[15];	/* 30: */
} dtslot_t;			/* (32) */

#define DTSLOTDATALEN	15

/*
 *	 internal node entry head/only segment
 */
typedef struct {
	pxd_t xd;		/* 8: child extent descriptor */

	s8 next;		/* 1: */
	u8 namlen;		/* 1: */
	UniChar name[11];	/* 22: 2-byte aligned */
} idtentry_t;			/* (32) */