[GitHub/mt8127/android_kernel_alcatel_ttab.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/fs.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.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 */
};

/**
 * struct the_nilfs - struct to supervise multiple nilfs mount points
 * @ns_flags: flags
 * @ns_count: reference count
 * @ns_list: list head for nilfs_list
 * @ns_bdev: block device
 * @ns_bdi: backing dev info
 * @ns_writer: back pointer to writable nilfs_sb_info
 * @ns_sem: semaphore for shared states
 * @ns_super_sem: semaphore for global operations across super block instances
 * @ns_mount_mutex: mutex protecting mount process of nilfs
 * @ns_writer_sem: semaphore protecting ns_writer attach/detach
 * @ns_current: back pointer to current mount
 * @ns_sbh: buffer heads of on-disk super blocks
 * @ns_sbp: pointers to super block data
 * @ns_sbwtime: previous write time of super blocks
 * @ns_sbsize: size of valid data in super block
 * @ns_supers: list of nilfs super block structs
 * @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_free_segments_count: counter of free segments
 * @ns_segctor_sem: segment constructor semaphore
 * @ns_dat: DAT file inode
 * @ns_cpfile: checkpoint file inode
 * @ns_sufile: segusage file inode
 * @ns_gc_dat: shadow inode of the DAT file inode for GC
 * @ns_gc_inodes: dummy inodes to keep live blocks
 * @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks
 * @ns_blocksize_bits: bit length of 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;
	atomic_t		ns_count;
	struct list_head	ns_list;

	struct block_device    *ns_bdev;
	struct backing_dev_info *ns_bdi;
	struct nilfs_sb_info   *ns_writer;
	struct rw_semaphore	ns_sem;
	struct rw_semaphore	ns_super_sem;
	struct mutex		ns_mount_mutex;
	struct rw_semaphore	ns_writer_sem;

	/*
	 * components protected by ns_super_sem
	 */
	struct nilfs_sb_info   *ns_current;
	struct list_head	ns_supers;

	/*
	 * 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[2];
	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;
	unsigned long		ns_free_segments_count;

	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;
	struct inode	       *ns_gc_dat;

	/* GC inode list and hash table head */
	struct list_head	ns_gc_inodes;
	struct hlist_head      *ns_gc_inodes_h;

	/* Disk layout information (static) */
	unsigned int		ns_blocksize_bits;
	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 NILFS_GCINODE_HASH_BITS		8
#define NILFS_GCINODE_HASH_SIZE		(1<<NILFS_GCINODE_HASH_BITS)

#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)

/* Minimum interval of periodical update of superblocks (in seconds) */
#define NILFS_SB_FREQ		10
#define NILFS_ALTSB_FREQ	60  /* spare superblock */

void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
struct the_nilfs *find_or_create_nilfs(struct block_device *);
void put_nilfs(struct the_nilfs *);
int init_nilfs(struct the_nilfs *, struct nilfs_sb_info *, char *);
int load_nilfs(struct the_nilfs *, struct nilfs_sb_info *);
int nilfs_count_free_blocks(struct the_nilfs *, sector_t *);
struct nilfs_sb_info *nilfs_find_sbinfo(struct the_nilfs *, int, __u64);
int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);
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 get_nilfs(struct the_nilfs *nilfs)
{
	/* Caller must have at least one reference of the_nilfs. */
	atomic_inc(&nilfs->ns_count);
}

static inline void
nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
{
	down_write(&nilfs->ns_writer_sem);
	nilfs->ns_writer = sbi;
	up_write(&nilfs->ns_writer_sem);
}

static inline void
nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)
{
	down_write(&nilfs->ns_writer_sem);
	if (sbi == nilfs->ns_writer)
		nilfs->ns_writer = NULL;
	up_write(&nilfs->ns_writer_sem);
}

static inline void nilfs_put_sbinfo(struct nilfs_sb_info *sbi)
{
	if (atomic_dec_and_test(&sbi->s_count))
		kfree(sbi);
}

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>
	29	#include <linux/fs.h>
	30	#include <linux/blkdev.h>
	31	#include <linux/backing-dev.h>
	32	#include "sb.h"
	33
	34	/* the_nilfs struct */
	35	enum {
	36	THE_NILFS_INIT = 0, /* Information from super_block is set */
	37	THE_NILFS_LOADED, /* Roll-back/roll-forward has done and
	38	the latest checkpoint was loaded */
	39	THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
65b4643d RK	40	};
	41
	42	/**
	43	* struct the_nilfs - struct to supervise multiple nilfs mount points
	44	* @ns_flags: flags
	45	* @ns_count: reference count
33c8e57c	46	* @ns_list: list head for nilfs_list
65b4643d RK	47	* @ns_bdev: block device
	48	* @ns_bdi: backing dev info
	49	* @ns_writer: back pointer to writable nilfs_sb_info
	50	* @ns_sem: semaphore for shared states
e59399d0	51	* @ns_super_sem: semaphore for global operations across super block instances
aa7dfb89	52	* @ns_mount_mutex: mutex protecting mount process of nilfs
027d6404	53	* @ns_writer_sem: semaphore protecting ns_writer attach/detach
3f82ff55	54	* @ns_current: back pointer to current mount
e339ad31 RK	55	* @ns_sbh: buffer heads of on-disk super blocks
	56	* @ns_sbp: pointers to super block data
	57	* @ns_sbwtime: previous write time of super blocks
	58	* @ns_sbsize: size of valid data in super block
65b4643d RK	59	* @ns_supers: list of nilfs super block structs
	60	* @ns_seg_seq: segment sequence counter
	61	* @ns_segnum: index number of the latest full segment.
	62	* @ns_nextnum: index number of the full segment index to be used next
	63	* @ns_pseg_offset: offset of next partial segment in the current full segment
	64	* @ns_cno: next checkpoint number
	65	* @ns_ctime: write time of the last segment
	66	* @ns_nongc_ctime: write time of the last segment not for cleaner operation
	67	* @ns_ndirtyblks: Number of dirty data blocks
	68	* @ns_last_segment_lock: lock protecting fields for the latest segment
	69	* @ns_last_pseg: start block number of the latest segment
	70	* @ns_last_seq: sequence value of the latest segment
	71	* @ns_last_cno: checkpoint number of the latest segment
2c2e52fc	72	* @ns_prot_seq: least sequence number of segments which must not be reclaimed
65b4643d RK	73	* @ns_free_segments_count: counter of free segments
	74	* @ns_segctor_sem: segment constructor semaphore
	75	* @ns_dat: DAT file inode
	76	* @ns_cpfile: checkpoint file inode
	77	* @ns_sufile: segusage file inode
	78	* @ns_gc_dat: shadow inode of the DAT file inode for GC
	79	* @ns_gc_inodes: dummy inodes to keep live blocks
	80	* @ns_gc_inodes_h: hash list to keep dummy inode holding live blocks
65b4643d RK	81	* @ns_blocksize_bits: bit length of block size
	82	* @ns_nsegments: number of segments in filesystem
	83	* @ns_blocks_per_segment: number of blocks per segment
	84	* @ns_r_segments_percentage: reserved segments percentage
	85	* @ns_nrsvsegs: number of reserved segments
	86	* @ns_first_data_block: block number of first data block
	87	* @ns_inode_size: size of on-disk inode
	88	* @ns_first_ino: first not-special inode number
	89	* @ns_crc_seed: seed value of CRC32 calculation
	90	*/
	91	struct the_nilfs {
	92	unsigned long ns_flags;
	93	atomic_t ns_count;
33c8e57c	94	struct list_head ns_list;
65b4643d RK	95
	96	struct block_device *ns_bdev;
	97	struct backing_dev_info *ns_bdi;
	98	struct nilfs_sb_info *ns_writer;
	99	struct rw_semaphore ns_sem;
e59399d0	100	struct rw_semaphore ns_super_sem;
aa7dfb89	101	struct mutex ns_mount_mutex;
027d6404	102	struct rw_semaphore ns_writer_sem;
65b4643d	103
e59399d0 RK	104	/*
	105	* components protected by ns_super_sem
	106	*/
3f82ff55	107	struct nilfs_sb_info *ns_current;
e59399d0	108	struct list_head ns_supers;
3f82ff55	109
65b4643d RK	110	/*
	111	* used for
	112	* - loading the latest checkpoint exclusively.
	113	* - allocating a new full segment.
	114	* - protecting s_dirt in the super_block struct
	115	* (see nilfs_write_super) and the following fields.
	116	*/
e339ad31 RK	117	struct buffer_head *ns_sbh[2];
	118	struct nilfs_super_block *ns_sbp[2];
	119	time_t ns_sbwtime[2];
	120	unsigned ns_sbsize;
65b4643d	121	unsigned ns_mount_state;
65b4643d RK	122
	123	/*
	124	* Following fields are dedicated to a writable FS-instance.
	125	* Except for the period seeking checkpoint, code outside the segment
47420c79 RK	126	* constructor must lock a segment semaphore while accessing these
47420c79 RK	127	* fields.
65b4643d RK	128	* The writable FS-instance is sole during a lifetime of the_nilfs.
	129	*/
	130	u64 ns_seg_seq;
	131	__u64 ns_segnum;
	132	__u64 ns_nextnum;
	133	unsigned long ns_pseg_offset;
	134	__u64 ns_cno;
	135	time_t ns_ctime;
	136	time_t ns_nongc_ctime;
	137	atomic_t ns_ndirtyblks;
	138
	139	/*
	140	* The following fields hold information on the latest partial segment
	141	* written to disk with a super root. These fields are protected by
	142	* ns_last_segment_lock.
	143	*/
	144	spinlock_t ns_last_segment_lock;
	145	sector_t ns_last_pseg;
	146	u64 ns_last_seq;
	147	__u64 ns_last_cno;
2c2e52fc	148	u64 ns_prot_seq;
65b4643d RK	149	unsigned long ns_free_segments_count;
	150
	151	struct rw_semaphore ns_segctor_sem;
	152
	153	/*
	154	* Following fields are lock free except for the period before
	155	* the_nilfs is initialized.
	156	*/
	157	struct inode *ns_dat;
	158	struct inode *ns_cpfile;
	159	struct inode *ns_sufile;
	160	struct inode *ns_gc_dat;
	161
	162	/* GC inode list and hash table head */
	163	struct list_head ns_gc_inodes;
	164	struct hlist_head *ns_gc_inodes_h;
	165
65b4643d RK	166	/* Disk layout information (static) */
	167	unsigned int ns_blocksize_bits;
	168	unsigned long ns_nsegments;
	169	unsigned long ns_blocks_per_segment;
	170	unsigned long ns_r_segments_percentage;
	171	unsigned long ns_nrsvsegs;
	172	unsigned long ns_first_data_block;
	173	int ns_inode_size;
	174	int ns_first_ino;
	175	u32 ns_crc_seed;
	176	};
	177
	178	#define NILFS_GCINODE_HASH_BITS 8
	179	#define NILFS_GCINODE_HASH_SIZE (1<<NILFS_GCINODE_HASH_BITS)
	180
	181	#define THE_NILFS_FNS(bit, name) \
	182	static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
	183	{ \
	184	set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	185	} \
	186	static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
	187	{ \
	188	clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	189	} \
	190	static inline int nilfs_##name(struct the_nilfs *nilfs) \
	191	{ \
	192	return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	193	}
	194
	195	THE_NILFS_FNS(INIT, init)
	196	THE_NILFS_FNS(LOADED, loaded)
	197	THE_NILFS_FNS(DISCONTINUED, discontinued)
65b4643d	198
e339ad31 RK	199	/* Minimum interval of periodical update of superblocks (in seconds) */
	200	#define NILFS_SB_FREQ 10
	201	#define NILFS_ALTSB_FREQ 60 /* spare superblock */
	202
65b4643d	203	void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
33c8e57c	204	struct the_nilfs find_or_create_nilfs(struct block_device );
65b4643d RK	205	void put_nilfs(struct the_nilfs *);
	206	int init_nilfs(struct the_nilfs , struct nilfs_sb_info , char *);
	207	int load_nilfs(struct the_nilfs , struct nilfs_sb_info );
	208	int nilfs_count_free_blocks(struct the_nilfs , sector_t );
6dd47406	209	struct nilfs_sb_info nilfs_find_sbinfo(struct the_nilfs , int, __u64);
65b4643d RK	210	int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);
65b4643d RK	211	int nilfs_near_disk_full(struct the_nilfs *);
e339ad31 RK	212	void nilfs_fall_back_super_block(struct the_nilfs *);
e339ad31 RK	213	void nilfs_swap_super_block(struct the_nilfs *);
65b4643d RK	214
	215
	216	static inline void get_nilfs(struct the_nilfs *nilfs)
	217	{
	218	/* Caller must have at least one reference of the_nilfs. */
	219	atomic_inc(&nilfs->ns_count);
	220	}
	221
65b4643d RK	222	static inline void
	223	nilfs_attach_writer(struct the_nilfs nilfs, struct nilfs_sb_info sbi)
	224	{
027d6404	225	down_write(&nilfs->ns_writer_sem);
65b4643d	226	nilfs->ns_writer = sbi;
027d6404	227	up_write(&nilfs->ns_writer_sem);
65b4643d RK	228	}
	229
	230	static inline void
	231	nilfs_detach_writer(struct the_nilfs nilfs, struct nilfs_sb_info sbi)
	232	{
027d6404	233	down_write(&nilfs->ns_writer_sem);
65b4643d RK	234	if (sbi == nilfs->ns_writer)
65b4643d RK	235	nilfs->ns_writer = NULL;
027d6404	236	up_write(&nilfs->ns_writer_sem);
65b4643d RK	237	}
65b4643d RK	238
6dd47406 RK	239	static inline void nilfs_put_sbinfo(struct nilfs_sb_info *sbi)
6dd47406 RK	240	{
a9245860	241	if (atomic_dec_and_test(&sbi->s_count))
6dd47406 RK	242	kfree(sbi);
	243	}
	244
65b4643d RK	245	static inline void
	246	nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
	247	sector_t seg_start, sector_t seg_end)
	248	{
	249	seg_start = (sector_t)nilfs->ns_blocks_per_segment segnum;
	250	seg_end = seg_start + nilfs->ns_blocks_per_segment - 1;
	251	if (segnum == 0)
	252	*seg_start = nilfs->ns_first_data_block;
	253	}
	254
	255	static inline sector_t
	256	nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
	257	{
	258	return (segnum == 0) ? nilfs->ns_first_data_block :
	259	(sector_t)nilfs->ns_blocks_per_segment * segnum;
	260	}
	261
	262	static inline __u64
	263	nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
	264	{
	265	sector_t segnum = blocknr;
	266
	267	sector_div(segnum, nilfs->ns_blocks_per_segment);
	268	return segnum;
	269	}
	270
	271	static inline void
	272	nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
	273	sector_t seg_end)
	274	{
	275	/* terminate the current full segment (used in case of I/O-error) */
	276	nilfs->ns_pseg_offset = seg_end - seg_start + 1;
	277	}
	278
	279	static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
	280	{
	281	/* move forward with a full segment */
	282	nilfs->ns_segnum = nilfs->ns_nextnum;
	283	nilfs->ns_pseg_offset = 0;
	284	nilfs->ns_seg_seq++;
	285	}
	286
	287	static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
	288	{
	289	__u64 cno;
	290
	291	spin_lock(&nilfs->ns_last_segment_lock);
	292	cno = nilfs->ns_last_cno;
	293	spin_unlock(&nilfs->ns_last_segment_lock);
	294	return cno;
	295	}
	296
cece5520 RK	297	static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
	298	{
	299	return n == nilfs->ns_segnum \|\| n == nilfs->ns_nextnum;
	300	}
	301
65b4643d	302	#endif /* _THE_NILFS_H */