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