linux/fs/xfs/xfs_format.h

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it would 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 the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_FORMAT_H__
#define __XFS_FORMAT_H__

/*
 * XFS On Disk Format Definitions
 *
 * This header file defines all the on-disk format definitions for 
 * general XFS objects. Directory and attribute related objects are defined in
 * xfs_da_format.h, which log and log item formats are defined in
 * xfs_log_format.h. Everything else goes here.
 */

struct xfs_mount;
struct xfs_trans;
struct xfs_inode;
struct xfs_buf;
struct xfs_ifork;

/*
 * RealTime Device format definitions
 */

/* Min and max rt extent sizes, specified in bytes */
#define	XFS_MAX_RTEXTSIZE	(1024 * 1024 * 1024)	/* 1GB */
#define	XFS_DFL_RTEXTSIZE	(64 * 1024)	        /* 64kB */
#define	XFS_MIN_RTEXTSIZE	(4 * 1024)		/* 4kB */

#define	XFS_BLOCKSIZE(mp)	((mp)->m_sb.sb_blocksize)
#define	XFS_BLOCKMASK(mp)	((mp)->m_blockmask)
#define	XFS_BLOCKWSIZE(mp)	((mp)->m_blockwsize)
#define	XFS_BLOCKWMASK(mp)	((mp)->m_blockwmask)

/*
 * RT Summary and bit manipulation macros.
 */
#define	XFS_SUMOFFS(mp,ls,bb)	((int)((ls) * (mp)->m_sb.sb_rbmblocks + (bb)))
#define	XFS_SUMOFFSTOBLOCK(mp,s)	\
	(((s) * (uint)sizeof(xfs_suminfo_t)) >> (mp)->m_sb.sb_blocklog)
#define	XFS_SUMPTR(mp,bp,so)	\
	((xfs_suminfo_t *)((bp)->b_addr + \
		(((so) * (uint)sizeof(xfs_suminfo_t)) & XFS_BLOCKMASK(mp))))

#define	XFS_BITTOBLOCK(mp,bi)	((bi) >> (mp)->m_blkbit_log)
#define	XFS_BLOCKTOBIT(mp,bb)	((bb) << (mp)->m_blkbit_log)
#define	XFS_BITTOWORD(mp,bi)	\
	((int)(((bi) >> XFS_NBWORDLOG) & XFS_BLOCKWMASK(mp)))

#define	XFS_RTMIN(a,b)	((a) < (b) ? (a) : (b))
#define	XFS_RTMAX(a,b)	((a) > (b) ? (a) : (b))

#define	XFS_RTLOBIT(w)	xfs_lowbit32(w)
#define	XFS_RTHIBIT(w)	xfs_highbit32(w)

#if XFS_BIG_BLKNOS
#define	XFS_RTBLOCKLOG(b)	xfs_highbit64(b)
#else
#define	XFS_RTBLOCKLOG(b)	xfs_highbit32(b)
#endif

/*
 * Dquot and dquot block format definitions
 */
#define XFS_DQUOT_MAGIC		0x4451		/* 'DQ' */
#define XFS_DQUOT_VERSION	(u_int8_t)0x01	/* latest version number */

/*
 * This is the main portion of the on-disk representation of quota
 * information for a user. This is the q_core of the xfs_dquot_t that
 * is kept in kernel memory. We pad this with some more expansion room
 * to construct the on disk structure.
 */
typedef struct	xfs_disk_dquot {
	__be16		d_magic;	/* dquot magic = XFS_DQUOT_MAGIC */
	__u8		d_version;	/* dquot version */
	__u8		d_flags;	/* XFS_DQ_USER/PROJ/GROUP */
	__be32		d_id;		/* user,project,group id */
	__be64		d_blk_hardlimit;/* absolute limit on disk blks */
	__be64		d_blk_softlimit;/* preferred limit on disk blks */
	__be64		d_ino_hardlimit;/* maximum # allocated inodes */
	__be64		d_ino_softlimit;/* preferred inode limit */
	__be64		d_bcount;	/* disk blocks owned by the user */
	__be64		d_icount;	/* inodes owned by the user */
	__be32		d_itimer;	/* zero if within inode limits if not,
					   this is when we refuse service */
	__be32		d_btimer;	/* similar to above; for disk blocks */
	__be16		d_iwarns;	/* warnings issued wrt num inodes */
	__be16		d_bwarns;	/* warnings issued wrt disk blocks */
	__be32		d_pad0;		/* 64 bit align */
	__be64		d_rtb_hardlimit;/* absolute limit on realtime blks */
	__be64		d_rtb_softlimit;/* preferred limit on RT disk blks */
	__be64		d_rtbcount;	/* realtime blocks owned */
	__be32		d_rtbtimer;	/* similar to above; for RT disk blocks */
	__be16		d_rtbwarns;	/* warnings issued wrt RT disk blocks */
	__be16		d_pad;
} xfs_disk_dquot_t;

/*
 * This is what goes on disk. This is separated from the xfs_disk_dquot because
 * carrying the unnecessary padding would be a waste of memory.
 */
typedef struct xfs_dqblk {
	xfs_disk_dquot_t  dd_diskdq;	/* portion that lives incore as well */
	char		  dd_fill[4];	/* filling for posterity */

	/*
	 * These two are only present on filesystems with the CRC bits set.
	 */
	__be32		  dd_crc;	/* checksum */
	__be64		  dd_lsn;	/* last modification in log */
	uuid_t		  dd_uuid;	/* location information */
} xfs_dqblk_t;

#define XFS_DQUOT_CRC_OFF	offsetof(struct xfs_dqblk, dd_crc)

/*
 * Remote symlink format and access functions.
 */
#define XFS_SYMLINK_MAGIC	0x58534c4d	/* XSLM */

struct xfs_dsymlink_hdr {
	__be32	sl_magic;
	__be32	sl_offset;
	__be32	sl_bytes;
	__be32	sl_crc;
	uuid_t	sl_uuid;
	__be64	sl_owner;
	__be64	sl_blkno;
	__be64	sl_lsn;
};

/*
 * The maximum pathlen is 1024 bytes. Since the minimum file system
 * blocksize is 512 bytes, we can get a max of 3 extents back from
 * bmapi when crc headers are taken into account.
 */
#define XFS_SYMLINK_MAPS 3

#define XFS_SYMLINK_BUF_SPACE(mp, bufsize)	\
	((bufsize) - (xfs_sb_version_hascrc(&(mp)->m_sb) ? \
			sizeof(struct xfs_dsymlink_hdr) : 0))

int xfs_symlink_blocks(struct xfs_mount *mp, int pathlen);
int xfs_symlink_hdr_set(struct xfs_mount *mp, xfs_ino_t ino, uint32_t offset,
			uint32_t size, struct xfs_buf *bp);
bool xfs_symlink_hdr_ok(struct xfs_mount *mp, xfs_ino_t ino, uint32_t offset,
			uint32_t size, struct xfs_buf *bp);
void xfs_symlink_local_to_remote(struct xfs_trans *tp, struct xfs_buf *bp,
				 struct xfs_inode *ip, struct xfs_ifork *ifp);

extern const struct xfs_buf_ops xfs_symlink_buf_ops;

#endif /* __XFS_FORMAT_H__ */