[mirror_ubuntu-artful-kernel.git] / fs / nilfs2 / bmap.h

/*
 * bmap.h - NILFS block mapping.
 *
 * Copyright (C) 2006-2008 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_BMAP_H
#define _NILFS_BMAP_H

#include <linux/types.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/nilfs2_fs.h>
#include "alloc.h"
#include "dat.h"

#define NILFS_BMAP_INVALID_PTR	0

#define nilfs_bmap_keydiff_abs(diff)	((diff) < 0 ? -(diff) : (diff))


struct nilfs_bmap;

/**
 * union nilfs_bmap_ptr_req - request for bmap ptr
 * @bpr_ptr: bmap pointer
 * @bpr_req: request for persistent allocator
 */
union nilfs_bmap_ptr_req {
	__u64 bpr_ptr;
	struct nilfs_palloc_req bpr_req;
};

/**
 * struct nilfs_bmap_stats - bmap statistics
 * @bs_nblocks: number of blocks created or deleted
 */
struct nilfs_bmap_stats {
	unsigned int bs_nblocks;
};

/**
 * struct nilfs_bmap_operations - bmap operation table
 */
struct nilfs_bmap_operations {
	int (*bop_lookup)(const struct nilfs_bmap *, __u64, int, __u64 *);
	int (*bop_lookup_contig)(const struct nilfs_bmap *, __u64, __u64 *,
				 unsigned);
	int (*bop_insert)(struct nilfs_bmap *, __u64, __u64);
	int (*bop_delete)(struct nilfs_bmap *, __u64);
	void (*bop_clear)(struct nilfs_bmap *);

	int (*bop_propagate)(struct nilfs_bmap *, struct buffer_head *);
	void (*bop_lookup_dirty_buffers)(struct nilfs_bmap *,
					 struct list_head *);

	int (*bop_assign)(struct nilfs_bmap *,
			  struct buffer_head **,
			  sector_t,
			  union nilfs_binfo *);
	int (*bop_mark)(struct nilfs_bmap *, __u64, int);

	/* The following functions are internal use only. */
	int (*bop_last_key)(const struct nilfs_bmap *, __u64 *);
	int (*bop_check_insert)(const struct nilfs_bmap *, __u64);
	int (*bop_check_delete)(struct nilfs_bmap *, __u64);
	int (*bop_gather_data)(struct nilfs_bmap *, __u64 *, __u64 *, int);
};


#define NILFS_BMAP_SIZE		(NILFS_INODE_BMAP_SIZE * sizeof(__le64))
#define NILFS_BMAP_KEY_BIT	(sizeof(unsigned long) * 8 /* CHAR_BIT */)
#define NILFS_BMAP_NEW_PTR_INIT	\
	(1UL << (sizeof(unsigned long) * 8 /* CHAR_BIT */ - 1))

static inline int nilfs_bmap_is_new_ptr(unsigned long ptr)
{
	return !!(ptr & NILFS_BMAP_NEW_PTR_INIT);
}


/**
 * struct nilfs_bmap - bmap structure
 * @b_u: raw data
 * @b_sem: semaphore
 * @b_inode: owner of bmap
 * @b_ops: bmap operation table
 * @b_last_allocated_key: last allocated key for data block
 * @b_last_allocated_ptr: last allocated ptr for data block
 * @b_ptr_type: pointer type
 * @b_state: state
 * @b_nchildren_per_block: maximum number of child nodes for non-root nodes
 */
struct nilfs_bmap {
	union {
		__u8 u_flags;
		__le64 u_data[NILFS_BMAP_SIZE / sizeof(__le64)];
	} b_u;
	struct rw_semaphore b_sem;
	struct inode *b_inode;
	const struct nilfs_bmap_operations *b_ops;
	__u64 b_last_allocated_key;
	__u64 b_last_allocated_ptr;
	int b_ptr_type;
	int b_state;
	__u16 b_nchildren_per_block;
};

/* pointer type */
#define NILFS_BMAP_PTR_P	0	/* physical block number (i.e. LBN) */
#define NILFS_BMAP_PTR_VS	1	/* virtual block number (single
					   version) */
#define NILFS_BMAP_PTR_VM	2	/* virtual block number (has multiple
					   versions) */
#define NILFS_BMAP_PTR_U	(-1)	/* never perform pointer operations */

#define NILFS_BMAP_USE_VBN(bmap)	((bmap)->b_ptr_type > 0)

/* state */
#define NILFS_BMAP_DIRTY	0x00000001

/**
 * struct nilfs_bmap_store - shadow copy of bmap state
 * @data: cached raw block mapping of on-disk inode
 * @last_allocated_key: cached value of last allocated key for data block
 * @last_allocated_ptr: cached value of last allocated ptr for data block
 * @state: cached value of state field of bmap structure
 */
struct nilfs_bmap_store {
	__le64 data[NILFS_BMAP_SIZE / sizeof(__le64)];
	__u64 last_allocated_key;
	__u64 last_allocated_ptr;
	int state;
};

int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
int nilfs_bmap_read(struct nilfs_bmap *, struct nilfs_inode *);
void nilfs_bmap_write(struct nilfs_bmap *, struct nilfs_inode *);
int nilfs_bmap_lookup_contig(struct nilfs_bmap *, __u64, __u64 *, unsigned);
int nilfs_bmap_insert(struct nilfs_bmap *bmap, __u64 key, unsigned long rec);
int nilfs_bmap_delete(struct nilfs_bmap *bmap, __u64 key);
int nilfs_bmap_last_key(struct nilfs_bmap *bmap, __u64 *keyp);
int nilfs_bmap_truncate(struct nilfs_bmap *bmap, __u64 key);
void nilfs_bmap_clear(struct nilfs_bmap *);
int nilfs_bmap_propagate(struct nilfs_bmap *, struct buffer_head *);
void nilfs_bmap_lookup_dirty_buffers(struct nilfs_bmap *, struct list_head *);
int nilfs_bmap_assign(struct nilfs_bmap *, struct buffer_head **,
		      unsigned long, union nilfs_binfo *);
int nilfs_bmap_lookup_at_level(struct nilfs_bmap *, __u64, int, __u64 *);
int nilfs_bmap_mark(struct nilfs_bmap *, __u64, int);

void nilfs_bmap_init_gc(struct nilfs_bmap *);

void nilfs_bmap_save(const struct nilfs_bmap *, struct nilfs_bmap_store *);
void nilfs_bmap_restore(struct nilfs_bmap *, const struct nilfs_bmap_store *);

static inline int nilfs_bmap_lookup(struct nilfs_bmap *bmap, __u64 key,
				    __u64 *ptr)
{
	return nilfs_bmap_lookup_at_level(bmap, key, 1, ptr);
}

/*
 * Internal use only
 */
struct inode *nilfs_bmap_get_dat(const struct nilfs_bmap *);

static inline int nilfs_bmap_prepare_alloc_ptr(struct nilfs_bmap *bmap,
					       union nilfs_bmap_ptr_req *req,
					       struct inode *dat)
{
	if (dat)
		return nilfs_dat_prepare_alloc(dat, &req->bpr_req);
	/* ignore target ptr */
	req->bpr_ptr = bmap->b_last_allocated_ptr++;
	return 0;
}

static inline void nilfs_bmap_commit_alloc_ptr(struct nilfs_bmap *bmap,
					       union nilfs_bmap_ptr_req *req,
					       struct inode *dat)
{
	if (dat)
		nilfs_dat_commit_alloc(dat, &req->bpr_req);
}

static inline void nilfs_bmap_abort_alloc_ptr(struct nilfs_bmap *bmap,
					      union nilfs_bmap_ptr_req *req,
					      struct inode *dat)
{
	if (dat)
		nilfs_dat_abort_alloc(dat, &req->bpr_req);
	else
		bmap->b_last_allocated_ptr--;
}

static inline int nilfs_bmap_prepare_end_ptr(struct nilfs_bmap *bmap,
					     union nilfs_bmap_ptr_req *req,
					     struct inode *dat)
{
	return dat ? nilfs_dat_prepare_end(dat, &req->bpr_req) : 0;
}

static inline void nilfs_bmap_commit_end_ptr(struct nilfs_bmap *bmap,
					     union nilfs_bmap_ptr_req *req,
					     struct inode *dat)
{
	if (dat)
		nilfs_dat_commit_end(dat, &req->bpr_req,
				     bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
}

static inline void nilfs_bmap_abort_end_ptr(struct nilfs_bmap *bmap,
					    union nilfs_bmap_ptr_req *req,
					    struct inode *dat)
{
	if (dat)
		nilfs_dat_abort_end(dat, &req->bpr_req);
}

static inline void nilfs_bmap_set_target_v(struct nilfs_bmap *bmap, __u64 key,
					   __u64 ptr)
{
	bmap->b_last_allocated_key = key;
	bmap->b_last_allocated_ptr = ptr;
}

__u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *,
			      const struct buffer_head *);

__u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *, __u64);
__u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *);


/* Assume that bmap semaphore is locked. */
static inline int nilfs_bmap_dirty(const struct nilfs_bmap *bmap)
{
	return !!(bmap->b_state & NILFS_BMAP_DIRTY);
}

/* Assume that bmap semaphore is locked. */
static inline void nilfs_bmap_set_dirty(struct nilfs_bmap *bmap)
{
	bmap->b_state |= NILFS_BMAP_DIRTY;
}

/* Assume that bmap semaphore is locked. */
static inline void nilfs_bmap_clear_dirty(struct nilfs_bmap *bmap)
{
	bmap->b_state &= ~NILFS_BMAP_DIRTY;
}


#define NILFS_BMAP_LARGE	0x1

#define NILFS_BMAP_SMALL_LOW	NILFS_DIRECT_KEY_MIN
#define NILFS_BMAP_SMALL_HIGH	NILFS_DIRECT_KEY_MAX
#define NILFS_BMAP_LARGE_LOW	NILFS_BTREE_ROOT_NCHILDREN_MAX
#define NILFS_BMAP_LARGE_HIGH	NILFS_BTREE_KEY_MAX

#endif	/* _NILFS_BMAP_H */
Commit	Line	Data
bdb265ea KS	1	/*
	2	* bmap.h - NILFS block mapping.
	3	*
	4	* Copyright (C) 2006-2008 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_BMAP_H
	24	#define _NILFS_BMAP_H
	25
	26	#include <linux/types.h>
	27	#include <linux/fs.h>
	28	#include <linux/buffer_head.h>
	29	#include <linux/nilfs2_fs.h>
	30	#include "alloc.h"
2e0c2c73	31	#include "dat.h"
bdb265ea KS	32
	33	#define NILFS_BMAP_INVALID_PTR 0
	34
bdb265ea KS	35	#define nilfs_bmap_keydiff_abs(diff) ((diff) < 0 ? -(diff) : (diff))
	36
	37
	38	struct nilfs_bmap;
	39
	40	/**
	41	* union nilfs_bmap_ptr_req - request for bmap ptr
	42	* @bpr_ptr: bmap pointer
	43	* @bpr_req: request for persistent allocator
	44	*/
	45	union nilfs_bmap_ptr_req {
	46	__u64 bpr_ptr;
	47	struct nilfs_palloc_req bpr_req;
	48	};
	49
	50	/**
	51	* struct nilfs_bmap_stats - bmap statistics
	52	* @bs_nblocks: number of blocks created or deleted
	53	*/
	54	struct nilfs_bmap_stats {
	55	unsigned int bs_nblocks;
	56	};
	57
	58	/**
	59	* struct nilfs_bmap_operations - bmap operation table
	60	*/
	61	struct nilfs_bmap_operations {
	62	int (bop_lookup)(const struct nilfs_bmap , __u64, int, __u64 *);
c3a7abf0 RK	63	int (bop_lookup_contig)(const struct nilfs_bmap , __u64, __u64 *,
c3a7abf0 RK	64	unsigned);
bdb265ea KS	65	int (bop_insert)(struct nilfs_bmap , __u64, __u64);
	66	int (bop_delete)(struct nilfs_bmap , __u64);
	67	void (bop_clear)(struct nilfs_bmap );
	68
583ada47	69	int (bop_propagate)(struct nilfs_bmap , struct buffer_head *);
bdb265ea KS	70	void (bop_lookup_dirty_buffers)(struct nilfs_bmap ,
	71	struct list_head *);
	72
	73	int (bop_assign)(struct nilfs_bmap ,
	74	struct buffer_head **,
	75	sector_t,
	76	union nilfs_binfo *);
	77	int (bop_mark)(struct nilfs_bmap , __u64, int);
	78
	79	/* The following functions are internal use only. */
	80	int (bop_last_key)(const struct nilfs_bmap , __u64 *);
	81	int (bop_check_insert)(const struct nilfs_bmap , __u64);
	82	int (bop_check_delete)(struct nilfs_bmap , __u64);
	83	int (bop_gather_data)(struct nilfs_bmap , __u64 , __u64 , int);
	84	};
	85
	86
bdb265ea KS	87	#define NILFS_BMAP_SIZE (NILFS_INODE_BMAP_SIZE * sizeof(__le64))
	88	#define NILFS_BMAP_KEY_BIT (sizeof(unsigned long) * 8 /* CHAR_BIT */)
	89	#define NILFS_BMAP_NEW_PTR_INIT \
	90	(1UL << (sizeof(unsigned long) * 8 /* CHAR_BIT */ - 1))
	91
	92	static inline int nilfs_bmap_is_new_ptr(unsigned long ptr)
	93	{
	94	return !!(ptr & NILFS_BMAP_NEW_PTR_INIT);
	95	}
	96
	97
	98	/**
	99	* struct nilfs_bmap - bmap structure
	100	* @b_u: raw data
	101	* @b_sem: semaphore
	102	* @b_inode: owner of bmap
	103	* @b_ops: bmap operation table
bdb265ea KS	104	* @b_last_allocated_key: last allocated key for data block
bdb265ea KS	105	* @b_last_allocated_ptr: last allocated ptr for data block
d4b96157	106	* @b_ptr_type: pointer type
bdb265ea	107	* @b_state: state
5ad2686e	108	* @b_nchildren_per_block: maximum number of child nodes for non-root nodes
bdb265ea KS	109	*/
	110	struct nilfs_bmap {
	111	union {
	112	__u8 u_flags;
	113	__le64 u_data[NILFS_BMAP_SIZE / sizeof(__le64)];
	114	} b_u;
	115	struct rw_semaphore b_sem;
	116	struct inode *b_inode;
	117	const struct nilfs_bmap_operations *b_ops;
bdb265ea KS	118	__u64 b_last_allocated_key;
bdb265ea KS	119	__u64 b_last_allocated_ptr;
d4b96157	120	int b_ptr_type;
bdb265ea	121	int b_state;
5ad2686e	122	__u16 b_nchildren_per_block;
bdb265ea KS	123	};
bdb265ea KS	124
d4b96157 RK	125	/* pointer type */
	126	#define NILFS_BMAP_PTR_P 0 /* physical block number (i.e. LBN) */
	127	#define NILFS_BMAP_PTR_VS 1 /* virtual block number (single
	128	version) */
	129	#define NILFS_BMAP_PTR_VM 2 /* virtual block number (has multiple
	130	versions) */
	131	#define NILFS_BMAP_PTR_U (-1) /* never perform pointer operations */
	132
	133	#define NILFS_BMAP_USE_VBN(bmap) ((bmap)->b_ptr_type > 0)
	134
bdb265ea KS	135	/* state */
	136	#define NILFS_BMAP_DIRTY 0x00000001
	137
f5974c8f VD	138	/**
	139	* struct nilfs_bmap_store - shadow copy of bmap state
	140	* @data: cached raw block mapping of on-disk inode
	141	* @last_allocated_key: cached value of last allocated key for data block
	142	* @last_allocated_ptr: cached value of last allocated ptr for data block
	143	* @state: cached value of state field of bmap structure
	144	*/
a8070dd3 RK	145	struct nilfs_bmap_store {
	146	__le64 data[NILFS_BMAP_SIZE / sizeof(__le64)];
	147	__u64 last_allocated_key;
	148	__u64 last_allocated_ptr;
	149	int state;
	150	};
bdb265ea KS	151
	152	int nilfs_bmap_test_and_clear_dirty(struct nilfs_bmap *);
	153	int nilfs_bmap_read(struct nilfs_bmap , struct nilfs_inode );
	154	void nilfs_bmap_write(struct nilfs_bmap , struct nilfs_inode );
c3a7abf0	155	int nilfs_bmap_lookup_contig(struct nilfs_bmap , __u64, __u64 , unsigned);
3568a13f RK	156	int nilfs_bmap_insert(struct nilfs_bmap *bmap, __u64 key, unsigned long rec);
	157	int nilfs_bmap_delete(struct nilfs_bmap *bmap, __u64 key);
	158	int nilfs_bmap_last_key(struct nilfs_bmap bmap, __u64 keyp);
	159	int nilfs_bmap_truncate(struct nilfs_bmap *bmap, __u64 key);
bdb265ea KS	160	void nilfs_bmap_clear(struct nilfs_bmap *);
	161	int nilfs_bmap_propagate(struct nilfs_bmap , struct buffer_head );
	162	void nilfs_bmap_lookup_dirty_buffers(struct nilfs_bmap , struct list_head );
	163	int nilfs_bmap_assign(struct nilfs_bmap , struct buffer_head *,
	164	unsigned long, union nilfs_binfo *);
	165	int nilfs_bmap_lookup_at_level(struct nilfs_bmap , __u64, int, __u64 );
	166	int nilfs_bmap_mark(struct nilfs_bmap *, __u64, int);
	167
	168	void nilfs_bmap_init_gc(struct nilfs_bmap *);
bdb265ea	169
a8070dd3 RK	170	void nilfs_bmap_save(const struct nilfs_bmap , struct nilfs_bmap_store );
a8070dd3 RK	171	void nilfs_bmap_restore(struct nilfs_bmap , const struct nilfs_bmap_store );
bdb265ea	172
0f3fe33b RK	173	static inline int nilfs_bmap_lookup(struct nilfs_bmap *bmap, __u64 key,
	174	__u64 *ptr)
	175	{
	176	return nilfs_bmap_lookup_at_level(bmap, key, 1, ptr);
	177	}
	178
bdb265ea KS	179	/*
	180	* Internal use only
	181	*/
c3a7abf0	182	struct inode nilfs_bmap_get_dat(const struct nilfs_bmap );
d4b96157 RK	183
d4b96157 RK	184	static inline int nilfs_bmap_prepare_alloc_ptr(struct nilfs_bmap *bmap,
2e0c2c73 RK	185	union nilfs_bmap_ptr_req *req,
2e0c2c73 RK	186	struct inode *dat)
d4b96157	187	{
2e0c2c73 RK	188	if (dat)
2e0c2c73 RK	189	return nilfs_dat_prepare_alloc(dat, &req->bpr_req);
d4b96157 RK	190	/* ignore target ptr */
	191	req->bpr_ptr = bmap->b_last_allocated_ptr++;
	192	return 0;
	193	}
	194
	195	static inline void nilfs_bmap_commit_alloc_ptr(struct nilfs_bmap *bmap,
2e0c2c73 RK	196	union nilfs_bmap_ptr_req *req,
2e0c2c73 RK	197	struct inode *dat)
d4b96157	198	{
2e0c2c73 RK	199	if (dat)
2e0c2c73 RK	200	nilfs_dat_commit_alloc(dat, &req->bpr_req);
d4b96157 RK	201	}
	202
	203	static inline void nilfs_bmap_abort_alloc_ptr(struct nilfs_bmap *bmap,
2e0c2c73 RK	204	union nilfs_bmap_ptr_req *req,
2e0c2c73 RK	205	struct inode *dat)
d4b96157	206	{
2e0c2c73 RK	207	if (dat)
2e0c2c73 RK	208	nilfs_dat_abort_alloc(dat, &req->bpr_req);
d4b96157 RK	209	else
	210	bmap->b_last_allocated_ptr--;
	211	}
	212
d4b96157	213	static inline int nilfs_bmap_prepare_end_ptr(struct nilfs_bmap *bmap,
2e0c2c73 RK	214	union nilfs_bmap_ptr_req *req,
2e0c2c73 RK	215	struct inode *dat)
d4b96157	216	{
2e0c2c73	217	return dat ? nilfs_dat_prepare_end(dat, &req->bpr_req) : 0;
d4b96157 RK	218	}
	219
	220	static inline void nilfs_bmap_commit_end_ptr(struct nilfs_bmap *bmap,
2e0c2c73 RK	221	union nilfs_bmap_ptr_req *req,
2e0c2c73 RK	222	struct inode *dat)
d4b96157	223	{
2e0c2c73 RK	224	if (dat)
	225	nilfs_dat_commit_end(dat, &req->bpr_req,
	226	bmap->b_ptr_type == NILFS_BMAP_PTR_VS);
d4b96157 RK	227	}
	228
	229	static inline void nilfs_bmap_abort_end_ptr(struct nilfs_bmap *bmap,
2e0c2c73 RK	230	union nilfs_bmap_ptr_req *req,
2e0c2c73 RK	231	struct inode *dat)
d4b96157	232	{
2e0c2c73 RK	233	if (dat)
2e0c2c73 RK	234	nilfs_dat_abort_end(dat, &req->bpr_req);
d4b96157	235	}
bdb265ea	236
dc935be2 RK	237	static inline void nilfs_bmap_set_target_v(struct nilfs_bmap *bmap, __u64 key,
	238	__u64 ptr)
	239	{
	240	bmap->b_last_allocated_key = key;
	241	bmap->b_last_allocated_ptr = ptr;
	242	}
	243
bdb265ea KS	244	__u64 nilfs_bmap_data_get_key(const struct nilfs_bmap *,
	245	const struct buffer_head *);
	246
	247	__u64 nilfs_bmap_find_target_seq(const struct nilfs_bmap *, __u64);
	248	__u64 nilfs_bmap_find_target_in_group(const struct nilfs_bmap *);
	249
bdb265ea	250
bdb265ea KS	251	/* Assume that bmap semaphore is locked. */
	252	static inline int nilfs_bmap_dirty(const struct nilfs_bmap *bmap)
	253	{
	254	return !!(bmap->b_state & NILFS_BMAP_DIRTY);
	255	}
	256
	257	/* Assume that bmap semaphore is locked. */
	258	static inline void nilfs_bmap_set_dirty(struct nilfs_bmap *bmap)
	259	{
	260	bmap->b_state \|= NILFS_BMAP_DIRTY;
	261	}
	262
	263	/* Assume that bmap semaphore is locked. */
	264	static inline void nilfs_bmap_clear_dirty(struct nilfs_bmap *bmap)
	265	{
	266	bmap->b_state &= ~NILFS_BMAP_DIRTY;
	267	}
	268
	269
	270	#define NILFS_BMAP_LARGE 0x1
	271
	272	#define NILFS_BMAP_SMALL_LOW NILFS_DIRECT_KEY_MIN
	273	#define NILFS_BMAP_SMALL_HIGH NILFS_DIRECT_KEY_MAX
	274	#define NILFS_BMAP_LARGE_LOW NILFS_BTREE_ROOT_NCHILDREN_MAX
	275	#define NILFS_BMAP_LARGE_HIGH NILFS_BTREE_KEY_MAX
	276
	277	#endif /* _NILFS_BMAP_H */