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
  33 struct nilfs_btree;
  34 struct 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  */
  43 struct 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  */
  62 struct 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
  83 int nilfs_btree_path_cache_init(void);
  84 void nilfs_btree_path_cache_destroy(void);
  85 int nilfs_btree_init(struct nilfs_bmap *);
  86 int nilfs_btree_convert_and_insert(struct nilfs_bmap *, __u64, __u64,
  87                                    const __u64 *, const __u64 *, int);
  88 void nilfs_btree_init_gc(struct nilfs_bmap *);
  89
  90 #endif  /* _NILFS_BTREE_H */