fs/xfs/libxfs/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;

typedef struct xfs_timestamp {
	__be32		t_sec;		/* timestamp seconds */
	__be32		t_nsec;		/* timestamp nanoseconds */
} xfs_timestamp_t;

/*
 * On-disk inode structure.
 *
 * This is just the header or "dinode core", the inode is expanded to fill a
 * variable size the leftover area split into a data and an attribute fork.
 * The format of the data and attribute fork depends on the format of the
 * inode as indicated by di_format and di_aformat.  To access the data and
 * attribute use the XFS_DFORK_DPTR, XFS_DFORK_APTR, and XFS_DFORK_PTR macros
 * below.
 *
 * There is a very similar struct icdinode in xfs_inode which matches the
 * layout of the first 96 bytes of this structure, but is kept in native
 * format instead of big endian.
 *
 * Note: di_flushiter is only used by v1/2 inodes - it's effectively a zeroed
 * padding field for v3 inodes.
 */
#define	XFS_DINODE_MAGIC		0x494e	/* 'IN' */
#define XFS_DINODE_GOOD_VERSION(v)	((v) >= 1 && (v) <= 3)
typedef struct xfs_dinode {
	__be16		di_magic;	/* inode magic # = XFS_DINODE_MAGIC */
	__be16		di_mode;	/* mode and type of file */
	__u8		di_version;	/* inode version */
	__u8		di_format;	/* format of di_c data */
	__be16		di_onlink;	/* old number of links to file */
	__be32		di_uid;		/* owner's user id */
	__be32		di_gid;		/* owner's group id */
	__be32		di_nlink;	/* number of links to file */
	__be16		di_projid_lo;	/* lower part of owner's project id */
	__be16		di_projid_hi;	/* higher part owner's project id */
	__u8		di_pad[6];	/* unused, zeroed space */
	__be16		di_flushiter;	/* incremented on flush */
	xfs_timestamp_t	di_atime;	/* time last accessed */
	xfs_timestamp_t	di_mtime;	/* time last modified */
	xfs_timestamp_t	di_ctime;	/* time created/inode modified */
	__be64		di_size;	/* number of bytes in file */
	__be64		di_nblocks;	/* # of direct & btree blocks used */
	__be32		di_extsize;	/* basic/minimum extent size for file */
	__be32		di_nextents;	/* number of extents in data fork */
	__be16		di_anextents;	/* number of extents in attribute fork*/
	__u8		di_forkoff;	/* attr fork offs, <<3 for 64b align */
	__s8		di_aformat;	/* format of attr fork's data */
	__be32		di_dmevmask;	/* DMIG event mask */
	__be16		di_dmstate;	/* DMIG state info */
	__be16		di_flags;	/* random flags, XFS_DIFLAG_... */
	__be32		di_gen;		/* generation number */

	/* di_next_unlinked is the only non-core field in the old dinode */
	__be32		di_next_unlinked;/* agi unlinked list ptr */

	/* start of the extended dinode, writable fields */
	__le32		di_crc;		/* CRC of the inode */
	__be64		di_changecount;	/* number of attribute changes */
	__be64		di_lsn;		/* flush sequence */
	__be64		di_flags2;	/* more random flags */
	__u8		di_pad2[16];	/* more padding for future expansion */

	/* fields only written to during inode creation */
	xfs_timestamp_t	di_crtime;	/* time created */
	__be64		di_ino;		/* inode number */
	uuid_t		di_uuid;	/* UUID of the filesystem */

	/* structure must be padded to 64 bit alignment */
} xfs_dinode_t;

#define XFS_DINODE_CRC_OFF	offsetof(struct xfs_dinode, di_crc)

#define DI_MAX_FLUSH 0xffff

/*
 * Size of the core inode on disk.  Version 1 and 2 inodes have
 * the same size, but version 3 has grown a few additional fields.
 */
static inline uint xfs_dinode_size(int version)
{
	if (version == 3)
		return sizeof(struct xfs_dinode);
	return offsetof(struct xfs_dinode, di_crc);
}

/*
 * The 32 bit link count in the inode theoretically maxes out at UINT_MAX.
 * Since the pathconf interface is signed, we use 2^31 - 1 instead.
 * The old inode format had a 16 bit link count, so its maximum is USHRT_MAX.
 */
#define	XFS_MAXLINK		((1U << 31) - 1U)
#define	XFS_MAXLINK_1		65535U

/*
 * Values for di_format
 */
typedef enum xfs_dinode_fmt {
	XFS_DINODE_FMT_DEV,		/* xfs_dev_t */
	XFS_DINODE_FMT_LOCAL,		/* bulk data */
	XFS_DINODE_FMT_EXTENTS,		/* struct xfs_bmbt_rec */
	XFS_DINODE_FMT_BTREE,		/* struct xfs_bmdr_block */
	XFS_DINODE_FMT_UUID		/* uuid_t */
} xfs_dinode_fmt_t;

/*
 * Inode minimum and maximum sizes.
 */
#define	XFS_DINODE_MIN_LOG	8
#define	XFS_DINODE_MAX_LOG	11
#define	XFS_DINODE_MIN_SIZE	(1 << XFS_DINODE_MIN_LOG)
#define	XFS_DINODE_MAX_SIZE	(1 << XFS_DINODE_MAX_LOG)

/*
 * Inode size for given fs.
 */
#define XFS_LITINO(mp, version) \
	((int)(((mp)->m_sb.sb_inodesize) - xfs_dinode_size(version)))

/*
 * Inode data & attribute fork sizes, per inode.
 */
#define XFS_DFORK_Q(dip)		((dip)->di_forkoff != 0)
#define XFS_DFORK_BOFF(dip)		((int)((dip)->di_forkoff << 3))

#define XFS_DFORK_DSIZE(dip,mp) \
	(XFS_DFORK_Q(dip) ? \
		XFS_DFORK_BOFF(dip) : \
		XFS_LITINO(mp, (dip)->di_version))
#define XFS_DFORK_ASIZE(dip,mp) \
	(XFS_DFORK_Q(dip) ? \
		XFS_LITINO(mp, (dip)->di_version) - XFS_DFORK_BOFF(dip) : \
		0)
#define XFS_DFORK_SIZE(dip,mp,w) \
	((w) == XFS_DATA_FORK ? \
		XFS_DFORK_DSIZE(dip, mp) : \
		XFS_DFORK_ASIZE(dip, mp))

/*
 * Return pointers to the data or attribute forks.
 */
#define XFS_DFORK_DPTR(dip) \
	((char *)dip + xfs_dinode_size(dip->di_version))
#define XFS_DFORK_APTR(dip)	\
	(XFS_DFORK_DPTR(dip) + XFS_DFORK_BOFF(dip))
#define XFS_DFORK_PTR(dip,w)	\
	((w) == XFS_DATA_FORK ? XFS_DFORK_DPTR(dip) : XFS_DFORK_APTR(dip))

#define XFS_DFORK_FORMAT(dip,w) \
	((w) == XFS_DATA_FORK ? \
		(dip)->di_format : \
		(dip)->di_aformat)
#define XFS_DFORK_NEXTENTS(dip,w) \
	((w) == XFS_DATA_FORK ? \
		be32_to_cpu((dip)->di_nextents) : \
		be16_to_cpu((dip)->di_anextents))

/*
 * For block and character special files the 32bit dev_t is stored at the
 * beginning of the data fork.
 */
static inline xfs_dev_t xfs_dinode_get_rdev(struct xfs_dinode *dip)
{
	return be32_to_cpu(*(__be32 *)XFS_DFORK_DPTR(dip));
}

static inline void xfs_dinode_put_rdev(struct xfs_dinode *dip, xfs_dev_t rdev)
{
	*(__be32 *)XFS_DFORK_DPTR(dip) = cpu_to_be32(rdev);
}

/*
 * Values for di_flags
 * There should be a one-to-one correspondence between these flags and the
 * XFS_XFLAG_s.
 */
#define XFS_DIFLAG_REALTIME_BIT  0	/* file's blocks come from rt area */
#define XFS_DIFLAG_PREALLOC_BIT  1	/* file space has been preallocated */
#define XFS_DIFLAG_NEWRTBM_BIT   2	/* for rtbitmap inode, new format */
#define XFS_DIFLAG_IMMUTABLE_BIT 3	/* inode is immutable */
#define XFS_DIFLAG_APPEND_BIT    4	/* inode is append-only */
#define XFS_DIFLAG_SYNC_BIT      5	/* inode is written synchronously */
#define XFS_DIFLAG_NOATIME_BIT   6	/* do not update atime */
#define XFS_DIFLAG_NODUMP_BIT    7	/* do not dump */
#define XFS_DIFLAG_RTINHERIT_BIT 8	/* create with realtime bit set */
#define XFS_DIFLAG_PROJINHERIT_BIT   9	/* create with parents projid */
#define XFS_DIFLAG_NOSYMLINKS_BIT   10	/* disallow symlink creation */
#define XFS_DIFLAG_EXTSIZE_BIT      11	/* inode extent size allocator hint */
#define XFS_DIFLAG_EXTSZINHERIT_BIT 12	/* inherit inode extent size */
#define XFS_DIFLAG_NODEFRAG_BIT     13	/* do not reorganize/defragment */
#define XFS_DIFLAG_FILESTREAM_BIT   14  /* use filestream allocator */
#define XFS_DIFLAG_REALTIME      (1 << XFS_DIFLAG_REALTIME_BIT)
#define XFS_DIFLAG_PREALLOC      (1 << XFS_DIFLAG_PREALLOC_BIT)
#define XFS_DIFLAG_NEWRTBM       (1 << XFS_DIFLAG_NEWRTBM_BIT)
#define XFS_DIFLAG_IMMUTABLE     (1 << XFS_DIFLAG_IMMUTABLE_BIT)
#define XFS_DIFLAG_APPEND        (1 << XFS_DIFLAG_APPEND_BIT)
#define XFS_DIFLAG_SYNC          (1 << XFS_DIFLAG_SYNC_BIT)
#define XFS_DIFLAG_NOATIME       (1 << XFS_DIFLAG_NOATIME_BIT)
#define XFS_DIFLAG_NODUMP        (1 << XFS_DIFLAG_NODUMP_BIT)
#define XFS_DIFLAG_RTINHERIT     (1 << XFS_DIFLAG_RTINHERIT_BIT)
#define XFS_DIFLAG_PROJINHERIT   (1 << XFS_DIFLAG_PROJINHERIT_BIT)
#define XFS_DIFLAG_NOSYMLINKS    (1 << XFS_DIFLAG_NOSYMLINKS_BIT)
#define XFS_DIFLAG_EXTSIZE       (1 << XFS_DIFLAG_EXTSIZE_BIT)
#define XFS_DIFLAG_EXTSZINHERIT  (1 << XFS_DIFLAG_EXTSZINHERIT_BIT)
#define XFS_DIFLAG_NODEFRAG      (1 << XFS_DIFLAG_NODEFRAG_BIT)
#define XFS_DIFLAG_FILESTREAM    (1 << XFS_DIFLAG_FILESTREAM_BIT)

#define XFS_DIFLAG_ANY \
	(XFS_DIFLAG_REALTIME | XFS_DIFLAG_PREALLOC | XFS_DIFLAG_NEWRTBM | \
	 XFS_DIFLAG_IMMUTABLE | XFS_DIFLAG_APPEND | XFS_DIFLAG_SYNC | \
	 XFS_DIFLAG_NOATIME | XFS_DIFLAG_NODUMP | XFS_DIFLAG_RTINHERIT | \
	 XFS_DIFLAG_PROJINHERIT | XFS_DIFLAG_NOSYMLINKS | XFS_DIFLAG_EXTSIZE | \
	 XFS_DIFLAG_EXTSZINHERIT | XFS_DIFLAG_NODEFRAG | XFS_DIFLAG_FILESTREAM)


/*
 * 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)

#define	XFS_RTBLOCKLOG(b)	xfs_highbit64(b)

/*
 * 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;
};

#define XFS_SYMLINK_CRC_OFF	offsetof(struct xfs_dsymlink_hdr, sl_crc)

/*
 * 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))


/*
 * Allocation Btree format definitions
 *
 * There are two on-disk btrees, one sorted by blockno and one sorted
 * by blockcount and blockno.  All blocks look the same to make the code
 * simpler; if we have time later, we'll make the optimizations.
 */
#define	XFS_ABTB_MAGIC		0x41425442	/* 'ABTB' for bno tree */
#define	XFS_ABTB_CRC_MAGIC	0x41423342	/* 'AB3B' */
#define	XFS_ABTC_MAGIC		0x41425443	/* 'ABTC' for cnt tree */
#define	XFS_ABTC_CRC_MAGIC	0x41423343	/* 'AB3C' */

/*
 * Data record/key structure
 */
typedef struct xfs_alloc_rec {
	__be32		ar_startblock;	/* starting block number */
	__be32		ar_blockcount;	/* count of free blocks */
} xfs_alloc_rec_t, xfs_alloc_key_t;

typedef struct xfs_alloc_rec_incore {
	xfs_agblock_t	ar_startblock;	/* starting block number */
	xfs_extlen_t	ar_blockcount;	/* count of free blocks */
} xfs_alloc_rec_incore_t;

/* btree pointer type */
typedef __be32 xfs_alloc_ptr_t;

/*
 * Block numbers in the AG:
 * SB is sector 0, AGF is sector 1, AGI is sector 2, AGFL is sector 3.
 */
#define	XFS_BNO_BLOCK(mp)	((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
#define	XFS_CNT_BLOCK(mp)	((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))


/*
 * Inode Allocation Btree format definitions
 *
 * There is a btree for the inode map per allocation group.
 */
#define	XFS_IBT_MAGIC		0x49414254	/* 'IABT' */
#define	XFS_IBT_CRC_MAGIC	0x49414233	/* 'IAB3' */
#define	XFS_FIBT_MAGIC		0x46494254	/* 'FIBT' */
#define	XFS_FIBT_CRC_MAGIC	0x46494233	/* 'FIB3' */

typedef	__uint64_t	xfs_inofree_t;
#define	XFS_INODES_PER_CHUNK		(NBBY * sizeof(xfs_inofree_t))
#define	XFS_INODES_PER_CHUNK_LOG	(XFS_NBBYLOG + 3)
#define	XFS_INOBT_ALL_FREE		((xfs_inofree_t)-1)
#define	XFS_INOBT_MASK(i)		((xfs_inofree_t)1 << (i))

static inline xfs_inofree_t xfs_inobt_maskn(int i, int n)
{
	return ((n >= XFS_INODES_PER_CHUNK ? 0 : XFS_INOBT_MASK(n)) - 1) << i;
}

/*
 * Data record structure
 */
typedef struct xfs_inobt_rec {
	__be32		ir_startino;	/* starting inode number */
	__be32		ir_freecount;	/* count of free inodes (set bits) */
	__be64		ir_free;	/* free inode mask */
} xfs_inobt_rec_t;

typedef struct xfs_inobt_rec_incore {
	xfs_agino_t	ir_startino;	/* starting inode number */
	__int32_t	ir_freecount;	/* count of free inodes (set bits) */
	xfs_inofree_t	ir_free;	/* free inode mask */
} xfs_inobt_rec_incore_t;


/*
 * Key structure
 */
typedef struct xfs_inobt_key {
	__be32		ir_startino;	/* starting inode number */
} xfs_inobt_key_t;

/* btree pointer type */
typedef __be32 xfs_inobt_ptr_t;

/*
 * block numbers in the AG.
 */
#define	XFS_IBT_BLOCK(mp)		((xfs_agblock_t)(XFS_CNT_BLOCK(mp) + 1))
#define	XFS_FIBT_BLOCK(mp)		((xfs_agblock_t)(XFS_IBT_BLOCK(mp) + 1))

/*
 * The first data block of an AG depends on whether the filesystem was formatted
 * with the finobt feature. If so, account for the finobt reserved root btree
 * block.
 */
#define XFS_PREALLOC_BLOCKS(mp) \
	(xfs_sb_version_hasfinobt(&((mp)->m_sb)) ? \
	 XFS_FIBT_BLOCK(mp) + 1 : \
	 XFS_IBT_BLOCK(mp) + 1)



/*
 * BMAP Btree format definitions
 *
 * This includes both the root block definition that sits inside an inode fork
 * and the record/pointer formats for the leaf/node in the blocks.
 */
#define XFS_BMAP_MAGIC		0x424d4150	/* 'BMAP' */
#define XFS_BMAP_CRC_MAGIC	0x424d4133	/* 'BMA3' */

/*
 * Bmap root header, on-disk form only.
 */
typedef struct xfs_bmdr_block {
	__be16		bb_level;	/* 0 is a leaf */
	__be16		bb_numrecs;	/* current # of data records */
} xfs_bmdr_block_t;

/*
 * Bmap btree record and extent descriptor.
 *  l0:63 is an extent flag (value 1 indicates non-normal).
 *  l0:9-62 are startoff.
 *  l0:0-8 and l1:21-63 are startblock.
 *  l1:0-20 are blockcount.
 */
#define BMBT_EXNTFLAG_BITLEN	1
#define BMBT_STARTOFF_BITLEN	54
#define BMBT_STARTBLOCK_BITLEN	52
#define BMBT_BLOCKCOUNT_BITLEN	21

typedef struct xfs_bmbt_rec {
	__be64			l0, l1;
} xfs_bmbt_rec_t;

typedef __uint64_t	xfs_bmbt_rec_base_t;	/* use this for casts */
typedef xfs_bmbt_rec_t xfs_bmdr_rec_t;

typedef struct xfs_bmbt_rec_host {
	__uint64_t		l0, l1;
} xfs_bmbt_rec_host_t;

/*
 * Values and macros for delayed-allocation startblock fields.
 */
#define STARTBLOCKVALBITS	17
#define STARTBLOCKMASKBITS	(15 + 20)
#define STARTBLOCKMASK		\
	(((((xfs_fsblock_t)1) << STARTBLOCKMASKBITS) - 1) << STARTBLOCKVALBITS)

static inline int isnullstartblock(xfs_fsblock_t x)
{
	return ((x) & STARTBLOCKMASK) == STARTBLOCKMASK;
}

static inline xfs_fsblock_t nullstartblock(int k)
{
	ASSERT(k < (1 << STARTBLOCKVALBITS));
	return STARTBLOCKMASK | (k);
}

static inline xfs_filblks_t startblockval(xfs_fsblock_t x)
{
	return (xfs_filblks_t)((x) & ~STARTBLOCKMASK);
}

/*
 * Possible extent formats.
 */
typedef enum {
	XFS_EXTFMT_NOSTATE = 0,
	XFS_EXTFMT_HASSTATE
} xfs_exntfmt_t;

/*
 * Possible extent states.
 */
typedef enum {
	XFS_EXT_NORM, XFS_EXT_UNWRITTEN,
	XFS_EXT_DMAPI_OFFLINE, XFS_EXT_INVALID
} xfs_exntst_t;

/*
 * Incore version of above.
 */
typedef struct xfs_bmbt_irec
{
	xfs_fileoff_t	br_startoff;	/* starting file offset */
	xfs_fsblock_t	br_startblock;	/* starting block number */
	xfs_filblks_t	br_blockcount;	/* number of blocks */
	xfs_exntst_t	br_state;	/* extent state */
} xfs_bmbt_irec_t;

/*
 * Key structure for non-leaf levels of the tree.
 */
typedef struct xfs_bmbt_key {
	__be64		br_startoff;	/* starting file offset */
} xfs_bmbt_key_t, xfs_bmdr_key_t;

/* btree pointer type */
typedef __be64 xfs_bmbt_ptr_t, xfs_bmdr_ptr_t;


/*
 * Generic Btree block format definitions
 *
 * This is a combination of the actual format used on disk for short and long
 * format btrees.  The first three fields are shared by both format, but the
 * pointers are different and should be used with care.
 *
 * To get the size of the actual short or long form headers please use the size
 * macros below.  Never use sizeof(xfs_btree_block).
 *
 * The blkno, crc, lsn, owner and uuid fields are only available in filesystems
 * with the crc feature bit, and all accesses to them must be conditional on
 * that flag.
 */
struct xfs_btree_block {
	__be32		bb_magic;	/* magic number for block type */
	__be16		bb_level;	/* 0 is a leaf */
	__be16		bb_numrecs;	/* current # of data records */
	union {
		struct {
			__be32		bb_leftsib;
			__be32		bb_rightsib;

			__be64		bb_blkno;
			__be64		bb_lsn;
			uuid_t		bb_uuid;
			__be32		bb_owner;
			__le32		bb_crc;
		} s;			/* short form pointers */
		struct	{
			__be64		bb_leftsib;
			__be64		bb_rightsib;

			__be64		bb_blkno;
			__be64		bb_lsn;
			uuid_t		bb_uuid;
			__be64		bb_owner;
			__le32		bb_crc;
			__be32		bb_pad; /* padding for alignment */
		} l;			/* long form pointers */
	} bb_u;				/* rest */
};

#define XFS_BTREE_SBLOCK_LEN	16	/* size of a short form block */
#define XFS_BTREE_LBLOCK_LEN	24	/* size of a long form block */

/* sizes of CRC enabled btree blocks */
#define XFS_BTREE_SBLOCK_CRC_LEN	(XFS_BTREE_SBLOCK_LEN + 40)
#define XFS_BTREE_LBLOCK_CRC_LEN	(XFS_BTREE_LBLOCK_LEN + 48)

#define XFS_BTREE_SBLOCK_CRC_OFF \
	offsetof(struct xfs_btree_block, bb_u.s.bb_crc)
#define XFS_BTREE_LBLOCK_CRC_OFF \
	offsetof(struct xfs_btree_block, bb_u.l.bb_crc)

#endif /* __XFS_FORMAT_H__ */