/*

   * 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_ALLOC_BTREE_H__
  #define	__XFS_ALLOC_BTREE_H__
  
  /*
   * Freespace on-disk structures
   */
  
  struct xfs_buf;
  struct xfs_btree_cur;

  struct xfs_mount;
  
  /*
   * 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_ABTC_MAGIC	0x41425443	/* 'ABTC' for cnt tree */
  
  /*
   * 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;

  
  /*

   * Minimum and maximum blocksize and sectorsize.
   * The blocksize upper limit is pretty much arbitrary.
   * The sectorsize upper limit is due to sizeof(sb_sectsize).
   */
  #define XFS_MIN_BLOCKSIZE_LOG	9	/* i.e. 512 bytes */
  #define XFS_MAX_BLOCKSIZE_LOG	16	/* i.e. 65536 bytes */
  #define XFS_MIN_BLOCKSIZE	(1 << XFS_MIN_BLOCKSIZE_LOG)
  #define XFS_MAX_BLOCKSIZE	(1 << XFS_MAX_BLOCKSIZE_LOG)
  #define XFS_MIN_SECTORSIZE_LOG	9	/* i.e. 512 bytes */
  #define XFS_MAX_SECTORSIZE_LOG	15	/* i.e. 32768 bytes */
  #define XFS_MIN_SECTORSIZE	(1 << XFS_MIN_SECTORSIZE_LOG)
  #define XFS_MAX_SECTORSIZE	(1 << XFS_MAX_SECTORSIZE_LOG)
  
  /*
   * 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))

  
  /*

   * Btree block header size depends on a superblock flag.
   *
   * (not quite yet, but soon)
   */
  #define XFS_ALLOC_BLOCK_LEN(mp)	XFS_BTREE_SBLOCK_LEN
  
  /*

   * Record, key, and pointer address macros for btree blocks.

   *
   * (note that some of these may appear unused, but they are used in userspace)

   */

  #define XFS_ALLOC_REC_ADDR(mp, block, index) \
  	((xfs_alloc_rec_t *) \
  		((char *)(block) + \

  		 XFS_ALLOC_BLOCK_LEN(mp) + \

  		 (((index) - 1) * sizeof(xfs_alloc_rec_t))))

  #define XFS_ALLOC_KEY_ADDR(mp, block, index) \
  	((xfs_alloc_key_t *) \
  		((char *)(block) + \

  		 XFS_ALLOC_BLOCK_LEN(mp) + \

  		 ((index) - 1) * sizeof(xfs_alloc_key_t)))

  #define XFS_ALLOC_PTR_ADDR(mp, block, index, maxrecs) \
  	((xfs_alloc_ptr_t *) \
  		((char *)(block) + \

  		 XFS_ALLOC_BLOCK_LEN(mp) + \

  		 (maxrecs) * sizeof(xfs_alloc_key_t) + \
  		 ((index) - 1) * sizeof(xfs_alloc_ptr_t)))

  
  extern struct xfs_btree_cur *xfs_allocbt_init_cursor(struct xfs_mount *,
  		struct xfs_trans *, struct xfs_buf *,
  		xfs_agnumber_t, xfs_btnum_t);

  extern int xfs_allocbt_maxrecs(struct xfs_mount *, int, int);

  #endif	/* __XFS_ALLOC_BTREE_H__ */