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Commit 17c76b01 authored by Koji Sato's avatar Koji Sato Committed by Linus Torvalds
Browse files

nilfs2: B-tree based block mapping 



This adds declarations and functions of NILFS2 B-tree.

Two variants are integrated in the NILFS2 B-tree.  The B-tree for the most
files points to the child nodes or data blocks with virtual block
addresses, whereas the B-tree of the DAT uses actual block addresses.

Signed-off-by: default avatarKoji Sato <sato.koji@lab.ntt.co.jp>
Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bdb265ea

fs/nilfs2/btree.c

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+2276 −0

File added.

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fs/nilfs2/btree.h

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/*

 * 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;

struct nilfs_btree_path;



/**

 * struct nilfs_btree_operations - B-tree operation table

 */

struct nilfs_btree_operations {

	__u64 (*btop_find_target)(const struct nilfs_btree *,

				  const struct nilfs_btree_path *, __u64);

	void (*btop_set_target)(struct nilfs_btree *, __u64, __u64);



	struct the_nilfs *(*btop_get_nilfs)(struct nilfs_btree *);



	int (*btop_propagate)(struct nilfs_btree *,

			      struct nilfs_btree_path *,

			      int,

			      struct buffer_head *);

	int (*btop_assign)(struct nilfs_btree *,

			   struct nilfs_btree_path *,

			   int,

			   struct buffer_head **,

			   sector_t,

			   union nilfs_binfo *);

};



/**

 * struct nilfs_btree_node - B-tree node

 * @bn_flags: flags

 * @bn_level: level

 * @bn_nchildren: number of children

 * @bn_pad: padding

 */

struct nilfs_btree_node {

	__u8 bn_flags;

	__u8 bn_level;

	__le16 bn_nchildren;

	__le32 bn_pad;

};



/* flags */

#define NILFS_BTREE_NODE_ROOT	0x01



/* level */

#define NILFS_BTREE_LEVEL_DATA		0

#define NILFS_BTREE_LEVEL_NODE_MIN	(NILFS_BTREE_LEVEL_DATA + 1)

#define NILFS_BTREE_LEVEL_MAX		14



/**

 * struct nilfs_btree - B-tree structure

 * @bt_bmap: bmap base structure

 * @bt_ops: B-tree operation table

 */

struct nilfs_btree {

	struct nilfs_bmap bt_bmap;



	/* B-tree-specific members */

	const struct nilfs_btree_operations *bt_ops;

};





#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)





int nilfs_btree_path_cache_init(void);

void nilfs_btree_path_cache_destroy(void);

int nilfs_btree_init(struct nilfs_bmap *, __u64, __u64);

int nilfs_btree_convert_and_insert(struct nilfs_bmap *, __u64, __u64,

				   const __u64 *, const __u64 *,

				   int, __u64, __u64);

void nilfs_btree_init_gc(struct nilfs_bmap *);



#endif	/* _NILFS_BTREE_H */