xfs_btree.h

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/*
 * Copyright (c) 2000-2001 Silicon Graphics, Inc.  All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 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.
 *
 * Further, this software is distributed without any warranty that it is
 * free of the rightful claim of any third person regarding infringement
 * or the like.  Any license provided herein, whether implied or
 * otherwise, applies only to this software file.  Patent licenses, if
 * any, provided herein do not apply to combinations of this program with
 * other software, or any other product whatsoever.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write the Free Software Foundation, Inc., 59
 * Temple Place - Suite 330, Boston MA 02111-1307, USA.
 *
 * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
 * Mountain View, CA  94043, or:
 *
 * http://www.sgi.com
 *
 * For further information regarding this notice, see:
 *
 * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
 */
#ifndef __XFS_BTREE_H__
#define	__XFS_BTREE_H__

struct xfs_buf;
struct xfs_bmap_free;
struct xfs_inode;
struct xfs_mount;
struct xfs_trans;

/*
 * This nonsense is to make -wlint happy.
 */
#define	XFS_LOOKUP_EQ	((xfs_lookup_t)XFS_LOOKUP_EQi)
#define	XFS_LOOKUP_LE	((xfs_lookup_t)XFS_LOOKUP_LEi)
#define	XFS_LOOKUP_GE	((xfs_lookup_t)XFS_LOOKUP_GEi)

#define	XFS_BTNUM_BNO	((xfs_btnum_t)XFS_BTNUM_BNOi)
#define	XFS_BTNUM_CNT	((xfs_btnum_t)XFS_BTNUM_CNTi)
#define	XFS_BTNUM_BMAP	((xfs_btnum_t)XFS_BTNUM_BMAPi)
#define	XFS_BTNUM_INO	((xfs_btnum_t)XFS_BTNUM_INOi)

/*
 * Short form header: space allocation btrees.
 */
typedef struct xfs_btree_sblock
{
	__uint32_t	bb_magic;	/* magic number for block type */
	__uint16_t	bb_level;	/* 0 is a leaf */
	__uint16_t	bb_numrecs;	/* current # of data records */
	xfs_agblock_t	bb_leftsib;	/* left sibling block or NULLAGBLOCK */
	xfs_agblock_t	bb_rightsib;	/* right sibling block or NULLAGBLOCK */
} xfs_btree_sblock_t;

/*
 * Long form header: bmap btrees.
 */
typedef struct xfs_btree_lblock
{
	__uint32_t	bb_magic;	/* magic number for block type */
	__uint16_t	bb_level;	/* 0 is a leaf */
	__uint16_t	bb_numrecs;	/* current # of data records */
	xfs_dfsbno_t	bb_leftsib;	/* left sibling block or NULLDFSBNO */
	xfs_dfsbno_t	bb_rightsib;	/* right sibling block or NULLDFSBNO */
} xfs_btree_lblock_t;

/*
 * Combined header and structure, used by common code.
 */
typedef struct xfs_btree_hdr
{
	__uint32_t	bb_magic;	/* magic number for block type */
	__uint16_t	bb_level;	/* 0 is a leaf */
	__uint16_t	bb_numrecs;	/* current # of data records */
} xfs_btree_hdr_t;

typedef struct xfs_btree_block
{
	xfs_btree_hdr_t	bb_h;		/* header */
	union		{
		struct	{
			xfs_agblock_t	bb_leftsib;
			xfs_agblock_t	bb_rightsib;
		}	s;		/* short form pointers */
		struct	{
			xfs_dfsbno_t	bb_leftsib;
			xfs_dfsbno_t	bb_rightsib;
		}	l;		/* long form pointers */
	}		bb_u;		/* rest */
} xfs_btree_block_t;

/*
 * For logging record fields.
 */
#define	XFS_BB_MAGIC		0x01
#define	XFS_BB_LEVEL		0x02
#define	XFS_BB_NUMRECS		0x04
#define	XFS_BB_LEFTSIB		0x08
#define	XFS_BB_RIGHTSIB		0x10
#define	XFS_BB_NUM_BITS		5
#define	XFS_BB_ALL_BITS		((1 << XFS_BB_NUM_BITS) - 1)

/*
 * Boolean to select which form of xfs_btree_block_t.bb_u to use.
 */
#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_BTREE_LONG_PTRS)
int xfs_btree_long_ptrs(xfs_btnum_t btnum);
#define	XFS_BTREE_LONG_PTRS(btnum)	((btnum) == XFS_BTNUM_BMAP)
#else
#define	XFS_BTREE_LONG_PTRS(btnum)	((btnum) == XFS_BTNUM_BMAP)
#endif

/*
 * Magic numbers for btree blocks.
 */
extern const __uint32_t	xfs_magics[];

/*
 * Maximum and minimum records in a btree block.
 * Given block size, type prefix, and leaf flag (0 or 1).
 * The divisor below is equivalent to lf ? (e1) : (e2) but that produces
 * compiler warnings.
 */
#define	XFS_BTREE_BLOCK_MAXRECS(bsz,t,lf)	\
	((int)(((bsz) - (uint)sizeof(t ## _block_t)) / \
	 (((lf) * (uint)sizeof(t ## _rec_t)) + \
	  ((1 - (lf)) * \
	   ((uint)sizeof(t ## _key_t) + (uint)sizeof(t ## _ptr_t))))))
#define	XFS_BTREE_BLOCK_MINRECS(bsz,t,lf)	\
	(XFS_BTREE_BLOCK_MAXRECS(bsz,t,lf) / 2)

/*
 * Record, key, and pointer address calculation macros.
 * Given block size, type prefix, block pointer, and index of requested entry
 * (first entry numbered 1).
 */
#define	XFS_BTREE_REC_ADDR(bsz,t,bb,i,mxr)	\
	((t ## _rec_t *)((char *)(bb) + sizeof(t ## _block_t) + \
	 ((i) - 1) * sizeof(t ## _rec_t)))
#define	XFS_BTREE_KEY_ADDR(bsz,t,bb,i,mxr)	\
	((t ## _key_t *)((char *)(bb) + sizeof(t ## _block_t) + \
	 ((i) - 1) * sizeof(t ## _key_t)))
#define	XFS_BTREE_PTR_ADDR(bsz,t,bb,i,mxr)	\
	((t ## _ptr_t *)((char *)(bb) + sizeof(t ## _block_t) + \
	 (mxr) * sizeof(t ## _key_t) + ((i) - 1) * sizeof(t ## _ptr_t)))

#define	XFS_BTREE_MAXLEVELS	8	/* max of all btrees */

/*
 * Btree cursor structure.
 * This collects all information needed by the btree code in one place.
 */
typedef struct xfs_btree_cur
{
	struct xfs_trans	*bc_tp;	/* transaction we're in, if any */
	struct xfs_mount	*bc_mp;	/* file system mount struct */
	union {
		xfs_alloc_rec_t		a;
		xfs_bmbt_irec_t		b;
		xfs_inobt_rec_t		i;
	}		bc_rec;		/* current insert/search record value */
	struct xfs_buf	*bc_bufs[XFS_BTREE_MAXLEVELS];	/* buf ptr per level */
	int		bc_ptrs[XFS_BTREE_MAXLEVELS];	/* key/record # */
	__uint8_t	bc_ra[XFS_BTREE_MAXLEVELS];	/* readahead bits */
#define	XFS_BTCUR_LEFTRA	1	/* left sibling has been read-ahead */
#define	XFS_BTCUR_RIGHTRA	2	/* right sibling has been read-ahead */
	__uint8_t	bc_nlevels;	/* number of levels in the tree */
	__uint8_t	bc_blocklog;	/* log2(blocksize) of btree blocks */
	xfs_btnum_t	bc_btnum;	/* identifies which btree type */
	union {
		struct {			/* needed for BNO, CNT */
			struct xfs_buf	*agbp;	/* agf buffer pointer */
			xfs_agnumber_t	agno;	/* ag number */
		} a;
		struct {			/* needed for BMAP */
			struct xfs_inode *ip;	/* pointer to our inode */
			struct xfs_bmap_free *flist;	/* list to free after */
			xfs_fsblock_t	firstblock;	/* 1st blk allocated */
			int		allocated;	/* count of alloced */
			short		forksize;	/* fork's inode space */
			char		whichfork;	/* data or attr fork */
			char		flags;		/* flags */
#define	XFS_BTCUR_BPRV_WASDEL	1			/* was delayed */
		} b;
		struct {			/* needed for INO */
			struct xfs_buf	*agbp;	/* agi buffer pointer */
			xfs_agnumber_t	agno;	/* ag number */
		} i;
	}		bc_private;	/* per-btree type data */
} xfs_btree_cur_t;

#define	XFS_BTREE_NOERROR	0
#define	XFS_BTREE_ERROR		1

/*
 * Convert from buffer to btree block header.
 */
#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_BUF_TO_BLOCK)
xfs_btree_block_t *xfs_buf_to_block(struct xfs_buf *bp);
#define	XFS_BUF_TO_BLOCK(bp)	xfs_buf_to_block(bp)
#else
#define	XFS_BUF_TO_BLOCK(bp)	((xfs_btree_block_t *)(XFS_BUF_PTR(bp)))
#endif
#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_BUF_TO_LBLOCK)
xfs_btree_lblock_t *xfs_buf_to_lblock(struct xfs_buf *bp);
#define	XFS_BUF_TO_LBLOCK(bp)	xfs_buf_to_lblock(bp)
#else
#define	XFS_BUF_TO_LBLOCK(bp)	((xfs_btree_lblock_t *)(XFS_BUF_PTR(bp)))
#endif
#if XFS_WANT_FUNCS || (XFS_WANT_SPACE && XFSSO_XFS_BUF_TO_SBLOCK)
xfs_btree_sblock_t *xfs_buf_to_sblock(struct xfs_buf *bp);
#define	XFS_BUF_TO_SBLOCK(bp)	xfs_buf_to_sblock(bp)
#else
#define	XFS_BUF_TO_SBLOCK(bp)	((xfs_btree_sblock_t *)(XFS_BUF_PTR(bp)))
#endif

#ifdef __KERNEL__

#ifdef DEBUG
/*
 * Debug routine: check that block header is ok.
 */
void
xfs_btree_check_block(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_btree_block_t	*block,	/* generic btree block pointer */
	int			level,	/* level of the btree block */
	struct xfs_buf		*bp);	/* buffer containing block, if any */

/*
 * Debug routine: check that keys are in the right order.
 */
void
xfs_btree_check_key(
	xfs_btnum_t		btnum,	/* btree identifier */
	void			*ak1,	/* pointer to left (lower) key */
	void			*ak2);	/* pointer to right (higher) key */

/*
 * Debug routine: check that records are in the right order.
 */
void
xfs_btree_check_rec(
	xfs_btnum_t		btnum,	/* btree identifier */
	void			*ar1,	/* pointer to left (lower) record */
	void			*ar2);	/* pointer to right (higher) record */
#else
#define	xfs_btree_check_block(a,b,c,d)
#define	xfs_btree_check_key(a,b,c)
#define	xfs_btree_check_rec(a,b,c)
#endif	/* DEBUG */

/*
 * Checking routine: check that long form block header is ok.
 */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_lblock(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_btree_lblock_t	*block,	/* btree long form block pointer */
	int			level,	/* level of the btree block */
	struct xfs_buf		*bp);	/* buffer containing block, if any */

/*
 * Checking routine: check that (long) pointer is ok.
 */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_lptr(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_dfsbno_t		ptr,	/* btree block disk address */
	int			level);	/* btree block level */

/*
 * Checking routine: check that short form block header is ok.
 */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_sblock(
	xfs_btree_cur_t		*cur,	/* btree cursor */
	xfs_btree_sblock_t	*block,	/* btree short form block pointer */
	int			level,	/* level of the btree block */
	struct xfs_buf		*bp);	/* buffer containing block */

/*
 * Checking routine: check that (short) pointer is ok.
 */
int					/* error (0 or EFSCORRUPTED) */
xfs_btree_check_sptr(
	xfs_btree_cur_t		*cur,	/* btree cursor */