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 /**
  34  * struct nilfs_btree - B-tree structure
  35  * @bt_bmap: bmap base structure
  36  */
  37 struct nilfs_btree {
  38         struct nilfs_bmap bt_bmap;
  39 };
  40
  41 /**
  42  * struct nilfs_btree_path - A path on which B-tree operations are executed
  43  * @bp_bh: buffer head of node block
  44  * @bp_sib_bh: buffer head of sibling node block
  45  * @bp_index: index of child node
  46  * @bp_oldreq: ptr end request for old ptr
  47  * @bp_newreq: ptr alloc request for new ptr
  48  * @bp_op: rebalance operation
  49  */
  50 struct nilfs_btree_path {
  51         struct buffer_head *bp_bh;
  52         struct buffer_head *bp_sib_bh;
  53         int bp_index;
  54         union nilfs_bmap_ptr_req bp_oldreq;
  55         union nilfs_bmap_ptr_req bp_newreq;
  56         struct nilfs_btnode_chkey_ctxt bp_ctxt;
  57         void (*bp_op)(struct nilfs_btree *, struct nilfs_btree_path *,
  58                       int, __u64 *, __u64 *);
  59 };
  60
  61 #define NILFS_BTREE_ROOT_SIZE           NILFS_BMAP_SIZE
  62 #define NILFS_BTREE_ROOT_NCHILDREN_MAX                                  \
  63         ((NILFS_BTREE_ROOT_SIZE - sizeof(struct nilfs_btree_node)) /    \
  64          (sizeof(__le64 /* dkey */) + sizeof(__le64 /* dptr */)))
  65 #define NILFS_BTREE_ROOT_NCHILDREN_MIN  0
  66 #define NILFS_BTREE_NODE_EXTRA_PAD_SIZE (sizeof(__le64))
  67 #define NILFS_BTREE_NODE_NCHILDREN_MAX(nodesize)                        \
  68         (((nodesize) - sizeof(struct nilfs_btree_node) -                \
  69                 NILFS_BTREE_NODE_EXTRA_PAD_SIZE) /                      \
  70          (sizeof(__le64 /* dkey */) + sizeof(__le64 /* dptr */)))
  71 #define NILFS_BTREE_NODE_NCHILDREN_MIN(nodesize)                        \
  72         ((NILFS_BTREE_NODE_NCHILDREN_MAX(nodesize) - 1) / 2 + 1)
  73 #define NILFS_BTREE_KEY_MIN     ((__u64)0)
  74 #define NILFS_BTREE_KEY_MAX     (~(__u64)0)
  75
  76 extern struct kmem_cache *nilfs_btree_path_cache;
  77
  78 int nilfs_btree_init(struct nilfs_bmap *);
  79 int nilfs_btree_convert_and_insert(struct nilfs_bmap *, __u64, __u64,
  80                                    const __u64 *, const __u64 *, int);
  81 void nilfs_btree_init_gc(struct nilfs_bmap *);
  82
  83 #endif  /* _NILFS_BTREE_H */