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_operations - B-tree operation table
  38  */
  39 struct nilfs_btree_operations {
  40         __u64 (*btop_find_target)(const struct nilfs_btree *,
  41                                   const struct nilfs_btree_path *, __u64);
  42         void (*btop_set_target)(struct nilfs_btree *, __u64, __u64);
  43
  44         struct the_nilfs *(*btop_get_nilfs)(struct nilfs_btree *);
  45
  46         int (*btop_propagate)(struct nilfs_btree *,
  47                               struct nilfs_btree_path *,
  48                               int,
  49                               struct buffer_head *);
  50         int (*btop_assign)(struct nilfs_btree *,
  51                            struct nilfs_btree_path *,
  52                            int,
  53                            struct buffer_head **,
  54                            sector_t,
  55                            union nilfs_binfo *);
  56 };
  57
  58 /**
  59  * struct nilfs_btree_node - B-tree node
  60  * @bn_flags: flags
  61  * @bn_level: level
  62  * @bn_nchildren: number of children
  63  * @bn_pad: padding
  64  */
  65 struct nilfs_btree_node {
  66         __u8 bn_flags;
  67         __u8 bn_level;
  68         __le16 bn_nchildren;
  69         __le32 bn_pad;
  70 };
  71
  72 /* flags */
  73 #define NILFS_BTREE_NODE_ROOT   0x01
  74
  75 /* level */
  76 #define NILFS_BTREE_LEVEL_DATA          0
  77 #define NILFS_BTREE_LEVEL_NODE_MIN      (NILFS_BTREE_LEVEL_DATA + 1)
  78 #define NILFS_BTREE_LEVEL_MAX           14
  79
  80 /**
  81  * struct nilfs_btree - B-tree structure
  82  * @bt_bmap: bmap base structure
  83  * @bt_ops: B-tree operation table
  84  */
  85 struct nilfs_btree {
  86         struct nilfs_bmap bt_bmap;
  87
  88         /* B-tree-specific members */
  89         const struct nilfs_btree_operations *bt_ops;
  90 };
  91
  92
  93 #define NILFS_BTREE_ROOT_SIZE           NILFS_BMAP_SIZE
  94 #define NILFS_BTREE_ROOT_NCHILDREN_MAX                                  \
  95         ((NILFS_BTREE_ROOT_SIZE - sizeof(struct nilfs_btree_node)) /    \
  96          (sizeof(__le64 /* dkey */) + sizeof(__le64 /* dptr */)))
  97 #define NILFS_BTREE_ROOT_NCHILDREN_MIN  0
  98 #define NILFS_BTREE_NODE_EXTRA_PAD_SIZE (sizeof(__le64))
  99 #define NILFS_BTREE_NODE_NCHILDREN_MAX(nodesize)                        \
 100         (((nodesize) - sizeof(struct nilfs_btree_node) -                \
 101                 NILFS_BTREE_NODE_EXTRA_PAD_SIZE) /                      \
 102          (sizeof(__le64 /* dkey */) + sizeof(__le64 /* dptr */)))
 103 #define NILFS_BTREE_NODE_NCHILDREN_MIN(nodesize)                        \
 104         ((NILFS_BTREE_NODE_NCHILDREN_MAX(nodesize) - 1) / 2 + 1)
 105 #define NILFS_BTREE_KEY_MIN     ((__u64)0)
 106 #define NILFS_BTREE_KEY_MAX     (~(__u64)0)
 107
 108
 109 int nilfs_btree_path_cache_init(void);
 110 void nilfs_btree_path_cache_destroy(void);
 111 int nilfs_btree_init(struct nilfs_bmap *, __u64, __u64);
 112 int nilfs_btree_convert_and_insert(struct nilfs_bmap *, __u64, __u64,
 113                                    const __u64 *, const __u64 *,
 114                                    int, __u64, __u64);
 115 void nilfs_btree_init_gc(struct nilfs_bmap *);
 116
 117 #endif  /* _NILFS_BTREE_H */