LXR linux/fs/nilfs2/btree.h

   1/*
   2 * btree.h - NILFS B-tree.
   3 *
   4 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, write to the Free Software
  18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19 *
  20 * Written by Koji Sato <koji@osrg.net>.
  21 */
  22
  23#ifndef _NILFS_BTREE_H
  24#define _NILFS_BTREE_H
  25
  26#include <linux/types.h>
  27#include <linux/buffer_head.h>
  28#include <linux/list.h>
  29#include <linux/nilfs2_fs.h>
  30#include "btnode.h"
  31#include "bmap.h"
  32
  33struct nilfs_btree;
  34struct nilfs_btree_path;
  35
  36/**
  37 * struct nilfs_btree_node - B-tree node
  38 * @bn_flags: flags
  39 * @bn_level: level
  40 * @bn_nchildren: number of children
  41 * @bn_pad: padding
  42 */
  43struct nilfs_btree_node {
  44        __u8 bn_flags;
  45        __u8 bn_level;
  46        __le16 bn_nchildren;
  47        __le32 bn_pad;
  48};
  49
  50/* flags */
  51#define NILFS_BTREE_NODE_ROOT   0x01
  52
  53/* level */
  54#define NILFS_BTREE_LEVEL_DATA          0
  55#define NILFS_BTREE_LEVEL_NODE_MIN      (NILFS_BTREE_LEVEL_DATA + 1)
  56#define NILFS_BTREE_LEVEL_MAX           14
  57
  58/**
  59 * struct nilfs_btree - B-tree structure
  60 * @bt_bmap: bmap base structure
  61 */
  62struct nilfs_btree {
  63        struct nilfs_bmap bt_bmap;
  64};
  65
  66
  67#define NILFS_BTREE_ROOT_SIZE           NILFS_BMAP_SIZE
  68#define NILFS_BTREE_ROOT_NCHILDREN_MAX                                  \
  69        ((NILFS_BTREE_ROOT_SIZE - sizeof(struct nilfs_btree_node)) /    \
  70         (sizeof(__le64 /* dkey */) + sizeof(__le64 /* dptr */)))
  71#define NILFS_BTREE_ROOT_NCHILDREN_MIN  0
  72#define NILFS_BTREE_NODE_EXTRA_PAD_SIZE (sizeof(__le64))
  73#define NILFS_BTREE_NODE_NCHILDREN_MAX(nodesize)                        \
  74        (((nodesize) - sizeof(struct nilfs_btree_node) -                \
  75                NILFS_BTREE_NODE_EXTRA_PAD_SIZE) /                      \
  76         (sizeof(__le64 /* dkey */) + sizeof(__le64 /* dptr */)))
  77#define NILFS_BTREE_NODE_NCHILDREN_MIN(nodesize)                        \
  78        ((NILFS_BTREE_NODE_NCHILDREN_MAX(nodesize) - 1) / 2 + 1)
  79#define NILFS_BTREE_KEY_MIN     ((__u64)0)
  80#define NILFS_BTREE_KEY_MAX     (~(__u64)0)
  81
  82
  83int nilfs_btree_path_cache_init(void);
  84void nilfs_btree_path_cache_destroy(void);
  85int nilfs_btree_init(struct nilfs_bmap *);
  86int nilfs_btree_convert_and_insert(struct nilfs_bmap *, __u64, __u64,
  87                                   const __u64 *, const __u64 *, int);
  88void nilfs_btree_init_gc(struct nilfs_bmap *);
  89
  90#endif  /* _NILFS_BTREE_H */
  91