text: /*
   * Copyright (c) 2000-2001,2005 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_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 {
  	__be32		bb_magic;	/* magic number for block type */
  	__be16		bb_level;	/* 0 is a leaf */
  	__be16		bb_numrecs;	/* current # of data records */
  	__be32		bb_leftsib;	/* left sibling block or NULLAGBLOCK */
  	__be32		bb_rightsib;	/* right sibling block or NULLAGBLOCK */
  } xfs_btree_sblock_t;
  
  /*
   * Long form header: bmap btrees.
   */
  typedef struct xfs_btree_lblock {
  	__be32		bb_magic;	/* magic number for block type */
  	__be16		bb_level;	/* 0 is a leaf */
  	__be16		bb_numrecs;	/* current # of data records */
  	__be64		bb_leftsib;	/* left sibling block or NULLDFSBNO */
  	__be64		bb_rightsib;	/* right sibling block or NULLDFSBNO */
  } xfs_btree_lblock_t;
  
  /*
   * Combined header and structure, used by common code.
   */
  typedef struct xfs_btree_hdr
  {
  	__be32		bb_magic;	/* magic number for block type */
  	__be16		bb_level;	/* 0 is a leaf */
  	__be16		bb_numrecs;	/* current # of data records */
  } xfs_btree_hdr_t;
  
  typedef struct xfs_btree_block {
  	xfs_btree_hdr_t	bb_h;		/* header */
  	union {
  		struct {
  			__be32		bb_leftsib;
  			__be32		bb_rightsib;
  		} s;			/* short form pointers */
  		struct	{
  			__be64		bb_leftsib;
  			__be64		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.
   */
  #define	XFS_BTREE_LONG_PTRS(btnum)	((btnum) == XFS_BTNUM_BMAP)
  
  /*
   * 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_incore_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.
   */
  #define	XFS_BUF_TO_BLOCK(bp)	((xfs_btree_block_t *)XFS_BUF_PTR(bp))
  #define	XFS_BUF_TO_LBLOCK(bp)	((xfs_btree_lblock_t *)XFS_BUF_PTR(bp))
  #define	XFS_BUF_TO_SBLOCK(bp)	((xfs_btree_sblock_t *)XFS_BUF_PTR(bp))
  
  
  #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 */
  	xfs_agblock_t		ptr,	/* btree block disk address */
  	int			level);	/* btree block level */
  
  /*
   * Delete the btree cursor.
   */
  void
  xfs_btree_del_cursor(
  	xfs_btree_cur_t		*cur,	/* btree cursor */
  	int			error);	/* del because of error */
  
  /*
   * Duplicate the btree cursor.
   * Allocate a new one, copy the record, re-get the buffers.
   */
  int					/* error */
  xfs_btree_dup_cursor(
  	xfs_btree_cur_t		*cur,	/* input cursor */
  	xfs_btree_cur_t		**ncur);/* output cursor */
  
  /*
   * Change the cursor to point to the first record in the current block
   * at the given level.  Other levels are unaffected.
   */
  int					/* success=1, failure=0 */
  xfs_btree_firstrec(
  	xfs_btree_cur_t		*cur,	/* btree cursor */
  	int			level);	/* level to change */
  
  /*
   * Get a buffer for the block, return it with no data read.
   * Long-form addressing.
   */
  struct xfs_buf *				/* buffer for fsbno */
  xfs_btree_get_bufl(
  	struct xfs_mount	*mp,	/* file system mount point */
  	struct xfs_trans	*tp,	/* transaction pointer */
  	xfs_fsblock_t		fsbno,	/* file system block number */
  	uint			lock);	/* lock flags for get_buf */
  
  /*
   * Get a buffer for the block, return it with no data read.
   * Short-form addressing.
   */
  struct xfs_buf *				/* buffer for agno/agbno */
  xfs_btree_get_bufs(
  	struct xfs_mount	*mp,	/* file system mount point */
  	struct xfs_trans	*tp,	/* transaction pointer */
  	xfs_agnumber_t		agno,	/* allocation group number */
  	xfs_agblock_t		agbno,	/* allocation group block number */
  	uint			lock);	/* lock flags for get_buf */
  
  /*
   * Allocate a new btree cursor.
   * The cursor is either for allocation (A) or bmap (B).
   */
  xfs_btree_cur_t *			/* new btree cursor */
  xfs_btree_init_cursor(
  	struct xfs_mount	*mp,	/* file system mount point */
  	struct xfs_trans	*tp,	/* transaction pointer */
  	struct xfs_buf		*agbp,	/* (A only) buffer for agf structure */
  	xfs_agnumber_t		agno,	/* (A only) allocation group number */
  	xfs_btnum_t		btnum,	/* btree identifier */
  	struct xfs_inode	*ip,	/* (B only) inode owning the btree */
  	int			whichfork); /* (B only) data/attr fork */
  
  /*
   * Check for the cursor referring to the last block at the given level.
   */
  int					/* 1=is last block, 0=not last block */
  xfs_btree_islastblock(
  	xfs_btree_cur_t		*cur,	/* btree cursor */
  	int			level);	/* level to check */
  
  /*
   * Change the cursor to point to the last record in the current block
   * at the given level.  Other levels are unaffected.
   */
  int					/* success=1, failure=0 */
  xfs_btree_lastrec(
  	xfs_btree_cur_t		*cur,	/* btree cursor */
  	int			level);	/* level to change */
  
  /*
   * Compute first and last byte offsets for the fields given.
   * Interprets the offsets table, which contains struct field offsets.
   */
  void
  xfs_btree_offsets(
  	__int64_t		fields,	/* bitmask of fields */
  	const short		*offsets,/* table of field offsets */
  	int			nbits,	/* number of bits to inspect */
  	int			*first,	/* output: first byte offset */
  	int			*last);	/* output: last byte offset */
  
  /*
   * Get a buffer for the block, return it read in.
   * Long-form addressing.
   */
  int					/* error */
  xfs_btree_read_bufl(
  	struct xfs_mount	*mp,	/* file system mount point */
  	struct xfs_trans	*tp,	/* transaction pointer */
  	xfs_fsblock_t		fsbno,	/* file system block number */
  	uint			lock,	/* lock flags for read_buf */
  	struct xfs_buf		**bpp,	/* buffer for fsbno */
  	int			refval);/* ref count value for buffer */
  
  /*
   * Get a buffer for the block, return it read in.
   * Short-form addressing.
   */
  int					/* error */
  xfs_btree_read_bufs(
  	struct xfs_mount	*mp,	/* file system mount point */
  	struct xfs_trans	*tp,	/* transaction pointer */
  	xfs_agnumber_t		agno,	/* allocation group number */
  	xfs_agblock_t		agbno,	/* allocation group block number */
  	uint			lock,	/* lock flags for read_buf */
  	struct xfs_buf		**bpp,	/* buffer for agno/agbno */
  	int			refval);/* ref count value for buffer */
  
  /*
   * Read-ahead the block, don't wait for it, don't return a buffer.
   * Long-form addressing.
   */
  void					/* error */
  xfs_btree_reada_bufl(
  	struct xfs_mount	*mp,	/* file system mount point */
  	xfs_fsblock_t		fsbno,	/* file system block number */
  	xfs_extlen_t		count);	/* count of filesystem blocks */
  
  /*
   * Read-ahead the block, don't wait for it, don't return a buffer.
   * Short-form addressing.
   */
  void					/* error */
  xfs_btree_reada_bufs(
  	struct xfs_mount	*mp,	/* file system mount point */
  	xfs_agnumber_t		agno,	/* allocation group number */
  	xfs_agblock_t		agbno,	/* allocation group block number */
  	xfs_extlen_t		count);	/* count of filesystem blocks */
  
  /*
   * Read-ahead btree blocks, at the given level.
   * Bits in lr are set from XFS_BTCUR_{LEFT,RIGHT}RA.
   */
  int					/* readahead block count */
  xfs_btree_readahead_core(
  	xfs_btree_cur_t		*cur,	/* btree cursor */
  	int			lev,	/* level in btree */
  	int			lr);	/* left/right bits */
  
  static inline int			/* readahead block count */
  xfs_btree_readahead(
  	xfs_btree_cur_t		*cur,	/* btree cursor */
  	int			lev,	/* level in btree */
  	int			lr)	/* left/right bits */
  {
  	if ((cur->bc_ra[lev] | lr) == cur->bc_ra[lev])
  		return 0;
  
  	return xfs_btree_readahead_core(cur, lev, lr);
  }
  
  
  /*
   * Set the buffer for level "lev" in the cursor to bp, releasing
   * any previous buffer.
   */
  void
  xfs_btree_setbuf(
  	xfs_btree_cur_t		*cur,	/* btree cursor */
  	int			lev,	/* level in btree */
  	struct xfs_buf		*bp);	/* new buffer to set */
  
  #endif	/* __KERNEL__ */
  
  
  /*
   * Min and max functions for extlen, agblock, fileoff, and filblks types.
   */
  #define	XFS_EXTLEN_MIN(a,b)	\
  	((xfs_extlen_t)(a) < (xfs_extlen_t)(b) ? \
  		(xfs_extlen_t)(a) : (xfs_extlen_t)(b))
  #define	XFS_EXTLEN_MAX(a,b)	\
  	((xfs_extlen_t)(a) > (xfs_extlen_t)(b) ? \
  		(xfs_extlen_t)(a) : (xfs_extlen_t)(b))
  #define	XFS_AGBLOCK_MIN(a,b)	\
  	((xfs_agblock_t)(a) < (xfs_agblock_t)(b) ? \
  		(xfs_agblock_t)(a) : (xfs_agblock_t)(b))
  #define	XFS_AGBLOCK_MAX(a,b)	\
  	((xfs_agblock_t)(a) > (xfs_agblock_t)(b) ? \
  		(xfs_agblock_t)(a) : (xfs_agblock_t)(b))
  #define	XFS_FILEOFF_MIN(a,b)	\
  	((xfs_fileoff_t)(a) < (xfs_fileoff_t)(b) ? \
  		(xfs_fileoff_t)(a) : (xfs_fileoff_t)(b))
  #define	XFS_FILEOFF_MAX(a,b)	\
  	((xfs_fileoff_t)(a) > (xfs_fileoff_t)(b) ? \
  		(xfs_fileoff_t)(a) : (xfs_fileoff_t)(b))
  #define	XFS_FILBLKS_MIN(a,b)	\
  	((xfs_filblks_t)(a) < (xfs_filblks_t)(b) ? \
  		(xfs_filblks_t)(a) : (xfs_filblks_t)(b))
  #define	XFS_FILBLKS_MAX(a,b)	\
  	((xfs_filblks_t)(a) > (xfs_filblks_t)(b) ? \
  		(xfs_filblks_t)(a) : (xfs_filblks_t)(b))
  
  #define	XFS_FSB_SANITY_CHECK(mp,fsb)	\
  	(XFS_FSB_TO_AGNO(mp, fsb) < mp->m_sb.sb_agcount && \
  		XFS_FSB_TO_AGBNO(mp, fsb) < mp->m_sb.sb_agblocks)
  
  #endif	/* __XFS_BTREE_H__ */
  