[net-next-2.6.git] / fs / nilfs2 / the_nilfs.h

/*
 * the_nilfs.h - the_nilfs shared structure.
 *
 * 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 Ryusuke Konishi <ryusuke@osrg.net>
 *
 */

#ifndef _THE_NILFS_H
#define _THE_NILFS_H

#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/rbtree.h>
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/slab.h>
#include "sb.h"

/* the_nilfs struct */
enum {
	THE_NILFS_INIT = 0,     /* Information from super_block is set */
	THE_NILFS_LOADED,       /* Roll-back/roll-forward has done and
				   the latest checkpoint was loaded */
	THE_NILFS_DISCONTINUED,	/* 'next' pointer chain has broken */
	THE_NILFS_GC_RUNNING,	/* gc process is running */
	THE_NILFS_SB_DIRTY,	/* super block is dirty */
};

/**
 * struct the_nilfs - struct to supervise multiple nilfs mount points
 * @ns_flags: flags
 * @ns_bdev: block device
 * @ns_sem: semaphore for shared states
 * @ns_sbh: buffer heads of on-disk super blocks
 * @ns_sbp: pointers to super block data
 * @ns_sbwtime: previous write time of super block
 * @ns_sbwcount: write count of super block
 * @ns_sbsize: size of valid data in super block
 * @ns_seg_seq: segment sequence counter
 * @ns_segnum: index number of the latest full segment.
 * @ns_nextnum: index number of the full segment index to be used next
 * @ns_pseg_offset: offset of next partial segment in the current full segment
 * @ns_cno: next checkpoint number
 * @ns_ctime: write time of the last segment
 * @ns_nongc_ctime: write time of the last segment not for cleaner operation
 * @ns_ndirtyblks: Number of dirty data blocks
 * @ns_last_segment_lock: lock protecting fields for the latest segment
 * @ns_last_pseg: start block number of the latest segment
 * @ns_last_seq: sequence value of the latest segment
 * @ns_last_cno: checkpoint number of the latest segment
 * @ns_prot_seq: least sequence number of segments which must not be reclaimed
 * @ns_prev_seq: base sequence number used to decide if advance log cursor
 * @ns_segctor_sem: segment constructor semaphore
 * @ns_dat: DAT file inode
 * @ns_cpfile: checkpoint file inode
 * @ns_sufile: segusage file inode
 * @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
 * @ns_cptree_lock: lock protecting @ns_cptree
 * @ns_gc_inodes: dummy inodes to keep live blocks
 * @ns_blocksize_bits: bit length of block size
 * @ns_blocksize: block size
 * @ns_nsegments: number of segments in filesystem
 * @ns_blocks_per_segment: number of blocks per segment
 * @ns_r_segments_percentage: reserved segments percentage
 * @ns_nrsvsegs: number of reserved segments
 * @ns_first_data_block: block number of first data block
 * @ns_inode_size: size of on-disk inode
 * @ns_first_ino: first not-special inode number
 * @ns_crc_seed: seed value of CRC32 calculation
 */
struct the_nilfs {
	unsigned long		ns_flags;

	struct block_device    *ns_bdev;
	struct rw_semaphore	ns_sem;

	/*
	 * used for
	 * - loading the latest checkpoint exclusively.
	 * - allocating a new full segment.
	 * - protecting s_dirt in the super_block struct
	 *   (see nilfs_write_super) and the following fields.
	 */
	struct buffer_head     *ns_sbh[2];
	struct nilfs_super_block *ns_sbp[2];
	time_t			ns_sbwtime;
	unsigned		ns_sbwcount;
	unsigned		ns_sbsize;
	unsigned		ns_mount_state;

	/*
	 * Following fields are dedicated to a writable FS-instance.
	 * Except for the period seeking checkpoint, code outside the segment
	 * constructor must lock a segment semaphore while accessing these
	 * fields.
	 * The writable FS-instance is sole during a lifetime of the_nilfs.
	 */
	u64			ns_seg_seq;
	__u64			ns_segnum;
	__u64			ns_nextnum;
	unsigned long		ns_pseg_offset;
	__u64			ns_cno;
	time_t			ns_ctime;
	time_t			ns_nongc_ctime;
	atomic_t		ns_ndirtyblks;

	/*
	 * The following fields hold information on the latest partial segment
	 * written to disk with a super root.  These fields are protected by
	 * ns_last_segment_lock.
	 */
	spinlock_t		ns_last_segment_lock;
	sector_t		ns_last_pseg;
	u64			ns_last_seq;
	__u64			ns_last_cno;
	u64			ns_prot_seq;
	u64			ns_prev_seq;

	struct rw_semaphore	ns_segctor_sem;

	/*
	 * Following fields are lock free except for the period before
	 * the_nilfs is initialized.
	 */
	struct inode	       *ns_dat;
	struct inode	       *ns_cpfile;
	struct inode	       *ns_sufile;

	/* Checkpoint tree */
	struct rb_root		ns_cptree;
	spinlock_t		ns_cptree_lock;

	/* GC inode list */
	struct list_head	ns_gc_inodes;

	/* Disk layout information (static) */
	unsigned int		ns_blocksize_bits;
	unsigned int		ns_blocksize;
	unsigned long		ns_nsegments;
	unsigned long		ns_blocks_per_segment;
	unsigned long		ns_r_segments_percentage;
	unsigned long		ns_nrsvsegs;
	unsigned long		ns_first_data_block;
	int			ns_inode_size;
	int			ns_first_ino;
	u32			ns_crc_seed;
};

#define THE_NILFS_FNS(bit, name)					\
static inline void set_nilfs_##name(struct the_nilfs *nilfs)		\
{									\
	set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags);			\
}									\
static inline void clear_nilfs_##name(struct the_nilfs *nilfs)		\
{									\
	clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags);			\
}									\
static inline int nilfs_##name(struct the_nilfs *nilfs)			\
{									\
	return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags);		\
}

THE_NILFS_FNS(INIT, init)
THE_NILFS_FNS(LOADED, loaded)
THE_NILFS_FNS(DISCONTINUED, discontinued)
THE_NILFS_FNS(GC_RUNNING, gc_running)
THE_NILFS_FNS(SB_DIRTY, sb_dirty)

/**
 * struct nilfs_root - nilfs root object
 * @cno: checkpoint number
 * @rb_node: red-black tree node
 * @count: refcount of this structure
 * @nilfs: nilfs object
 * @ifile: inode file
 * @root: root inode
 * @inodes_count: number of inodes
 * @blocks_count: number of blocks (Reserved)
 */
struct nilfs_root {
	__u64 cno;
	struct rb_node rb_node;

	atomic_t count;
	struct the_nilfs *nilfs;
	struct inode *ifile;

	atomic_t inodes_count;
	atomic_t blocks_count;
};

/* Special checkpoint number */
#define NILFS_CPTREE_CURRENT_CNO	0

/* Minimum interval of periodical update of superblocks (in seconds) */
#define NILFS_SB_FREQ		10

static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
{
	u64 t = get_seconds();
	return t < nilfs->ns_sbwtime || t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
}

static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
{
	int flip_bits = nilfs->ns_sbwcount & 0x0FL;
	return (flip_bits != 0x08 && flip_bits != 0x0F);
}

void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
struct the_nilfs *alloc_nilfs(struct block_device *bdev);
void destroy_nilfs(struct the_nilfs *nilfs);
int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
int nilfs_discard_segments(struct the_nilfs *, __u64 *, size_t);
int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno);
struct nilfs_root *nilfs_find_or_create_root(struct the_nilfs *nilfs,
					     __u64 cno);
void nilfs_put_root(struct nilfs_root *root);
struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64);
int nilfs_near_disk_full(struct the_nilfs *);
void nilfs_fall_back_super_block(struct the_nilfs *);
void nilfs_swap_super_block(struct the_nilfs *);


static inline void nilfs_get_root(struct nilfs_root *root)
{
	atomic_inc(&root->count);
}

static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
{
	unsigned valid_fs;

	down_read(&nilfs->ns_sem);
	valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
	up_read(&nilfs->ns_sem);
	return valid_fs;
}

static inline void
nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
			sector_t *seg_start, sector_t *seg_end)
{
	*seg_start = (sector_t)nilfs->ns_blocks_per_segment * segnum;
	*seg_end = *seg_start + nilfs->ns_blocks_per_segment - 1;
	if (segnum == 0)
		*seg_start = nilfs->ns_first_data_block;
}

static inline sector_t
nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
{
	return (segnum == 0) ? nilfs->ns_first_data_block :
		(sector_t)nilfs->ns_blocks_per_segment * segnum;
}

static inline __u64
nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
{
	sector_t segnum = blocknr;

	sector_div(segnum, nilfs->ns_blocks_per_segment);
	return segnum;
}

static inline void
nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
			sector_t seg_end)
{
	/* terminate the current full segment (used in case of I/O-error) */
	nilfs->ns_pseg_offset = seg_end - seg_start + 1;
}

static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
{
	/* move forward with a full segment */
	nilfs->ns_segnum = nilfs->ns_nextnum;
	nilfs->ns_pseg_offset = 0;
	nilfs->ns_seg_seq++;
}

static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
{
	__u64 cno;

	spin_lock(&nilfs->ns_last_segment_lock);
	cno = nilfs->ns_last_cno;
	spin_unlock(&nilfs->ns_last_segment_lock);
	return cno;
}

static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
{
	return n == nilfs->ns_segnum || n == nilfs->ns_nextnum;
}

#endif /* _THE_NILFS_H */
Commit	Line	Data
65b4643d RK	1	/*
	2	* the_nilfs.h - the_nilfs shared structure.
	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 Ryusuke Konishi <ryusuke@osrg.net>
	21	*
	22	*/
	23
	24	#ifndef _THE_NILFS_H
	25	#define _THE_NILFS_H
	26
	27	#include <linux/types.h>
	28	#include <linux/buffer_head.h>
ba65ae47	29	#include <linux/rbtree.h>
65b4643d RK	30	#include <linux/fs.h>
	31	#include <linux/blkdev.h>
	32	#include <linux/backing-dev.h>
5a0e3ad6	33	#include <linux/slab.h>
65b4643d RK	34	#include "sb.h"
	35
	36	/* the_nilfs struct */
	37	enum {
	38	THE_NILFS_INIT = 0, /* Information from super_block is set */
	39	THE_NILFS_LOADED, /* Roll-back/roll-forward has done and
	40	the latest checkpoint was loaded */
	41	THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
1cf58fa8	42	THE_NILFS_GC_RUNNING, /* gc process is running */
e605f0a7	43	THE_NILFS_SB_DIRTY, /* super block is dirty */
65b4643d RK	44	};
	45
	46	/**
	47	* struct the_nilfs - struct to supervise multiple nilfs mount points
	48	* @ns_flags: flags
65b4643d	49	* @ns_bdev: block device
65b4643d	50	* @ns_sem: semaphore for shared states
e339ad31 RK	51	* @ns_sbh: buffer heads of on-disk super blocks
e339ad31 RK	52	* @ns_sbp: pointers to super block data
b2ac86e1 JS	53	* @ns_sbwtime: previous write time of super block
b2ac86e1 JS	54	* @ns_sbwcount: write count of super block
e339ad31	55	* @ns_sbsize: size of valid data in super block
65b4643d RK	56	* @ns_seg_seq: segment sequence counter
	57	* @ns_segnum: index number of the latest full segment.
	58	* @ns_nextnum: index number of the full segment index to be used next
	59	* @ns_pseg_offset: offset of next partial segment in the current full segment
	60	* @ns_cno: next checkpoint number
	61	* @ns_ctime: write time of the last segment
	62	* @ns_nongc_ctime: write time of the last segment not for cleaner operation
	63	* @ns_ndirtyblks: Number of dirty data blocks
	64	* @ns_last_segment_lock: lock protecting fields for the latest segment
	65	* @ns_last_pseg: start block number of the latest segment
	66	* @ns_last_seq: sequence value of the latest segment
	67	* @ns_last_cno: checkpoint number of the latest segment
2c2e52fc	68	* @ns_prot_seq: least sequence number of segments which must not be reclaimed
32502047	69	* @ns_prev_seq: base sequence number used to decide if advance log cursor
65b4643d RK	70	* @ns_segctor_sem: segment constructor semaphore
	71	* @ns_dat: DAT file inode
	72	* @ns_cpfile: checkpoint file inode
	73	* @ns_sufile: segusage file inode
ba65ae47 RK	74	* @ns_cptree: rb-tree of all mounted checkpoints (nilfs_root)
ba65ae47 RK	75	* @ns_cptree_lock: lock protecting @ns_cptree
65b4643d	76	* @ns_gc_inodes: dummy inodes to keep live blocks
65b4643d	77	* @ns_blocksize_bits: bit length of block size
92c60cca	78	* @ns_blocksize: block size
65b4643d RK	79	* @ns_nsegments: number of segments in filesystem
	80	* @ns_blocks_per_segment: number of blocks per segment
	81	* @ns_r_segments_percentage: reserved segments percentage
	82	* @ns_nrsvsegs: number of reserved segments
	83	* @ns_first_data_block: block number of first data block
	84	* @ns_inode_size: size of on-disk inode
	85	* @ns_first_ino: first not-special inode number
	86	* @ns_crc_seed: seed value of CRC32 calculation
	87	*/
	88	struct the_nilfs {
	89	unsigned long ns_flags;
65b4643d RK	90
65b4643d RK	91	struct block_device *ns_bdev;
65b4643d	92	struct rw_semaphore ns_sem;
65b4643d RK	93
	94	/*
	95	* used for
	96	* - loading the latest checkpoint exclusively.
	97	* - allocating a new full segment.
	98	* - protecting s_dirt in the super_block struct
	99	* (see nilfs_write_super) and the following fields.
	100	*/
e339ad31 RK	101	struct buffer_head *ns_sbh[2];
e339ad31 RK	102	struct nilfs_super_block *ns_sbp[2];
b2ac86e1 JS	103	time_t ns_sbwtime;
b2ac86e1 JS	104	unsigned ns_sbwcount;
e339ad31	105	unsigned ns_sbsize;
65b4643d	106	unsigned ns_mount_state;
65b4643d RK	107
	108	/*
	109	* Following fields are dedicated to a writable FS-instance.
	110	* Except for the period seeking checkpoint, code outside the segment
47420c79 RK	111	* constructor must lock a segment semaphore while accessing these
47420c79 RK	112	* fields.
65b4643d RK	113	* The writable FS-instance is sole during a lifetime of the_nilfs.
	114	*/
	115	u64 ns_seg_seq;
	116	__u64 ns_segnum;
	117	__u64 ns_nextnum;
	118	unsigned long ns_pseg_offset;
	119	__u64 ns_cno;
	120	time_t ns_ctime;
	121	time_t ns_nongc_ctime;
	122	atomic_t ns_ndirtyblks;
	123
	124	/*
	125	* The following fields hold information on the latest partial segment
	126	* written to disk with a super root. These fields are protected by
	127	* ns_last_segment_lock.
	128	*/
	129	spinlock_t ns_last_segment_lock;
	130	sector_t ns_last_pseg;
	131	u64 ns_last_seq;
	132	__u64 ns_last_cno;
2c2e52fc	133	u64 ns_prot_seq;
32502047	134	u64 ns_prev_seq;
65b4643d RK	135
	136	struct rw_semaphore ns_segctor_sem;
	137
	138	/*
	139	* Following fields are lock free except for the period before
	140	* the_nilfs is initialized.
	141	*/
	142	struct inode *ns_dat;
	143	struct inode *ns_cpfile;
	144	struct inode *ns_sufile;
65b4643d	145
ba65ae47 RK	146	/* Checkpoint tree */
	147	struct rb_root ns_cptree;
	148	spinlock_t ns_cptree_lock;
	149
263d90ce	150	/* GC inode list */
65b4643d	151	struct list_head ns_gc_inodes;
65b4643d	152
65b4643d RK	153	/* Disk layout information (static) */
65b4643d RK	154	unsigned int ns_blocksize_bits;
92c60cca	155	unsigned int ns_blocksize;
65b4643d RK	156	unsigned long ns_nsegments;
	157	unsigned long ns_blocks_per_segment;
	158	unsigned long ns_r_segments_percentage;
	159	unsigned long ns_nrsvsegs;
	160	unsigned long ns_first_data_block;
	161	int ns_inode_size;
	162	int ns_first_ino;
	163	u32 ns_crc_seed;
	164	};
	165
65b4643d RK	166	#define THE_NILFS_FNS(bit, name) \
	167	static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
	168	{ \
	169	set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	170	} \
	171	static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
	172	{ \
	173	clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	174	} \
	175	static inline int nilfs_##name(struct the_nilfs *nilfs) \
	176	{ \
	177	return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	178	}
	179
	180	THE_NILFS_FNS(INIT, init)
	181	THE_NILFS_FNS(LOADED, loaded)
	182	THE_NILFS_FNS(DISCONTINUED, discontinued)
1cf58fa8	183	THE_NILFS_FNS(GC_RUNNING, gc_running)
e605f0a7	184	THE_NILFS_FNS(SB_DIRTY, sb_dirty)
65b4643d	185
ba65ae47 RK	186	/**
	187	* struct nilfs_root - nilfs root object
	188	* @cno: checkpoint number
	189	* @rb_node: red-black tree node
	190	* @count: refcount of this structure
	191	* @nilfs: nilfs object
	192	* @ifile: inode file
	193	* @root: root inode
	194	* @inodes_count: number of inodes
	195	* @blocks_count: number of blocks (Reserved)
	196	*/
	197	struct nilfs_root {
	198	__u64 cno;
	199	struct rb_node rb_node;
	200
	201	atomic_t count;
	202	struct the_nilfs *nilfs;
	203	struct inode *ifile;
	204
	205	atomic_t inodes_count;
	206	atomic_t blocks_count;
	207	};
	208
	209	/* Special checkpoint number */
	210	#define NILFS_CPTREE_CURRENT_CNO 0
	211
e339ad31 RK	212	/* Minimum interval of periodical update of superblocks (in seconds) */
e339ad31 RK	213	#define NILFS_SB_FREQ 10
e339ad31	214
79efdd94 JS	215	static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
	216	{
	217	u64 t = get_seconds();
b2ac86e1	218	return t < nilfs->ns_sbwtime \|\| t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
79efdd94 JS	219	}
79efdd94 JS	220
b2ac86e1	221	static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
79efdd94	222	{
b2ac86e1 JS	223	int flip_bits = nilfs->ns_sbwcount & 0x0FL;
b2ac86e1 JS	224	return (flip_bits != 0x08 && flip_bits != 0x0F);
79efdd94 JS	225	}
79efdd94 JS	226
65b4643d	227	void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
348fe8da RK	228	struct the_nilfs alloc_nilfs(struct block_device bdev);
348fe8da RK	229	void destroy_nilfs(struct the_nilfs *nilfs);
65b4643d RK	230	int init_nilfs(struct the_nilfs , struct nilfs_sb_info , char *);
65b4643d RK	231	int load_nilfs(struct the_nilfs , struct nilfs_sb_info );
e902ec99	232	int nilfs_discard_segments(struct the_nilfs , __u64 , size_t);
65b4643d	233	int nilfs_count_free_blocks(struct the_nilfs , sector_t );
ba65ae47 RK	234	struct nilfs_root nilfs_lookup_root(struct the_nilfs nilfs, __u64 cno);
	235	struct nilfs_root nilfs_find_or_create_root(struct the_nilfs nilfs,
	236	__u64 cno);
	237	void nilfs_put_root(struct nilfs_root *root);
6dd47406	238	struct nilfs_sb_info nilfs_find_sbinfo(struct the_nilfs , int, __u64);
65b4643d	239	int nilfs_near_disk_full(struct the_nilfs *);
e339ad31 RK	240	void nilfs_fall_back_super_block(struct the_nilfs *);
e339ad31 RK	241	void nilfs_swap_super_block(struct the_nilfs *);
65b4643d RK	242
65b4643d RK	243
ba65ae47 RK	244	static inline void nilfs_get_root(struct nilfs_root *root)
	245	{
	246	atomic_inc(&root->count);
	247	}
	248
a057d2c0 RK	249	static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
	250	{
	251	unsigned valid_fs;
	252
	253	down_read(&nilfs->ns_sem);
	254	valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
	255	up_read(&nilfs->ns_sem);
	256	return valid_fs;
	257	}
	258
65b4643d RK	259	static inline void
	260	nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
	261	sector_t seg_start, sector_t seg_end)
	262	{
	263	seg_start = (sector_t)nilfs->ns_blocks_per_segment segnum;
	264	seg_end = seg_start + nilfs->ns_blocks_per_segment - 1;
	265	if (segnum == 0)
	266	*seg_start = nilfs->ns_first_data_block;
	267	}
	268
	269	static inline sector_t
	270	nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
	271	{
	272	return (segnum == 0) ? nilfs->ns_first_data_block :
	273	(sector_t)nilfs->ns_blocks_per_segment * segnum;
	274	}
	275
	276	static inline __u64
	277	nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
	278	{
	279	sector_t segnum = blocknr;
	280
	281	sector_div(segnum, nilfs->ns_blocks_per_segment);
	282	return segnum;
	283	}
	284
	285	static inline void
	286	nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
	287	sector_t seg_end)
	288	{
	289	/* terminate the current full segment (used in case of I/O-error) */
	290	nilfs->ns_pseg_offset = seg_end - seg_start + 1;
	291	}
	292
	293	static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
	294	{
	295	/* move forward with a full segment */
	296	nilfs->ns_segnum = nilfs->ns_nextnum;
	297	nilfs->ns_pseg_offset = 0;
	298	nilfs->ns_seg_seq++;
	299	}
	300
	301	static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
	302	{
	303	__u64 cno;
	304
	305	spin_lock(&nilfs->ns_last_segment_lock);
	306	cno = nilfs->ns_last_cno;
	307	spin_unlock(&nilfs->ns_last_segment_lock);
	308	return cno;
	309	}
	310
cece5520 RK	311	static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
	312	{
	313	return n == nilfs->ns_segnum \|\| n == nilfs->ns_nextnum;
	314	}
	315
65b4643d	316	#endif /* _THE_NILFS_H */