/*
   * btree.h - NILFS B-tree.
   *
   * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   *
   * 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; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will 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 to the Free Software
   * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
   *
   * Written by Koji Sato <koji@osrg.net>.
   */
  
  #ifndef _NILFS_BTREE_H
  #define _NILFS_BTREE_H
  
  #include <linux/types.h>
  #include <linux/buffer_head.h>
  #include <linux/list.h>
  #include <linux/nilfs2_fs.h>
  #include "btnode.h"
  #include "bmap.h"

  /**

   * struct nilfs_btree_path - A path on which B-tree operations are executed
   * @bp_bh: buffer head of node block
   * @bp_sib_bh: buffer head of sibling node block
   * @bp_index: index of child node
   * @bp_oldreq: ptr end request for old ptr
   * @bp_newreq: ptr alloc request for new ptr
   * @bp_op: rebalance operation
   */
  struct nilfs_btree_path {
  	struct buffer_head *bp_bh;
  	struct buffer_head *bp_sib_bh;
  	int bp_index;
  	union nilfs_bmap_ptr_req bp_oldreq;
  	union nilfs_bmap_ptr_req bp_newreq;
  	struct nilfs_btnode_chkey_ctxt bp_ctxt;

  	void (*bp_op)(struct nilfs_bmap *, struct nilfs_btree_path *,

  		      int, __u64 *, __u64 *);
  };

  
  #define NILFS_BTREE_ROOT_SIZE		NILFS_BMAP_SIZE
  #define NILFS_BTREE_ROOT_NCHILDREN_MAX					\
  	((NILFS_BTREE_ROOT_SIZE - sizeof(struct nilfs_btree_node)) /	\
  	 (sizeof(__le64 /* dkey */) + sizeof(__le64 /* dptr */)))
  #define NILFS_BTREE_ROOT_NCHILDREN_MIN	0
  #define NILFS_BTREE_NODE_EXTRA_PAD_SIZE	(sizeof(__le64))
  #define NILFS_BTREE_NODE_NCHILDREN_MAX(nodesize)			\
  	(((nodesize) - sizeof(struct nilfs_btree_node) -		\
  		NILFS_BTREE_NODE_EXTRA_PAD_SIZE) /			\
  	 (sizeof(__le64 /* dkey */) + sizeof(__le64 /* dptr */)))
  #define NILFS_BTREE_NODE_NCHILDREN_MIN(nodesize)			\
  	((NILFS_BTREE_NODE_NCHILDREN_MAX(nodesize) - 1) / 2 + 1)
  #define NILFS_BTREE_KEY_MIN	((__u64)0)
  #define NILFS_BTREE_KEY_MAX	(~(__u64)0)

  extern struct kmem_cache *nilfs_btree_path_cache;

  int nilfs_btree_init(struct nilfs_bmap *);

  int nilfs_btree_convert_and_insert(struct nilfs_bmap *, __u64, __u64,

  				   const __u64 *, const __u64 *, int);

  void nilfs_btree_init_gc(struct nilfs_bmap *);

  int nilfs_btree_broken_node_block(struct buffer_head *bh);

  #endif	/* _NILFS_BTREE_H */