nilfs2: add inode and other major structures

/*

 * nilfs.h - NILFS local header file.

 *

 * 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>

 *            Ryusuke Konishi <ryusuke@osrg.net>

 */

#ifndef _NILFS_H

#define _NILFS_H

#include <linux/kernel.h>

#include <linux/buffer_head.h>

#include <linux/spinlock.h>

#include <linux/blkdev.h>

#include <linux/nilfs2_fs.h>

#include "the_nilfs.h"

#include "sb.h"

#include "bmap.h"

#include "bmap_union.h"

/*

 * NILFS filesystem version

 */

#define NILFS_VERSION		"2.0.5"

/*

 * nilfs inode data in memory

 */

struct nilfs_inode_info {

	__u32 i_flags;

	unsigned long  i_state;		/* Dynamic state flags */

	struct nilfs_bmap *i_bmap;

	union nilfs_bmap_union i_bmap_union;

	__u64 i_xattr;	/* sector_t ??? */

	__u32 i_dtime;

	__u32 i_dir_start_lookup;

	__u64 i_cno;		/* check point number for GC inode */

	struct address_space i_btnode_cache;

	struct list_head i_dirty;	/* List for connecting dirty files */

#ifdef CONFIG_NILFS_XATTR

	/*

	 * Extended attributes can be read independently of the main file

	 * data. Taking i_sem even when reading would cause contention

	 * between readers of EAs and writers of regular file data, so

	 * instead we synchronize on xattr_sem when reading or changing

	 * EAs.

	 */

	struct rw_semaphore xattr_sem;

#endif

#ifdef CONFIG_NILFS_POSIX_ACL

	struct posix_acl *i_acl;

	struct posix_acl *i_default_acl;

#endif

	struct buffer_head *i_bh;	/* i_bh contains a new or dirty

					   disk inode */

	struct inode vfs_inode;

};

static inline struct nilfs_inode_info *NILFS_I(const struct inode *inode)

{

	return container_of(inode, struct nilfs_inode_info, vfs_inode);

}

static inline struct nilfs_inode_info *

NILFS_BMAP_I(const struct nilfs_bmap *bmap)

{

	return container_of((union nilfs_bmap_union *)bmap,

			    struct nilfs_inode_info,

			    i_bmap_union);

}

static inline struct inode *NILFS_BTNC_I(struct address_space *btnc)

{

	struct nilfs_inode_info *ii =

		container_of(btnc, struct nilfs_inode_info, i_btnode_cache);

	return &ii->vfs_inode;

}

static inline struct inode *NILFS_AS_I(struct address_space *mapping)

{

	return (mapping->host) ? :

		container_of(mapping, struct inode, i_data);

}

/*

 * Dynamic state flags of NILFS on-memory inode (i_state)

 */

enum {

	NILFS_I_NEW = 0,		/* Inode is newly created */

	NILFS_I_DIRTY,			/* The file is dirty */

	NILFS_I_QUEUED,			/* inode is in dirty_files list */

	NILFS_I_BUSY,			/* inode is grabbed by a segment

					   constructor */

	NILFS_I_COLLECTED,		/* All dirty blocks are collected */

	NILFS_I_UPDATED,		/* The file has been written back */

	NILFS_I_INODE_DIRTY,		/* write_inode is requested */

	NILFS_I_BMAP,			/* has bmap and btnode_cache */

	NILFS_I_GCINODE,		/* inode for GC, on memory only */

	NILFS_I_GCDAT,			/* shadow DAT, on memory only */

};

/*

 * Macros to check inode numbers

 */

#define NILFS_MDT_INO_BITS   \

  ((unsigned int)(1 << NILFS_DAT_INO | 1 << NILFS_CPFILE_INO |		\

		  1 << NILFS_SUFILE_INO | 1 << NILFS_IFILE_INO |	\

		  1 << NILFS_ATIME_INO | 1 << NILFS_SKETCH_INO))

#define NILFS_SYS_INO_BITS   \

  ((unsigned int)(1 << NILFS_ROOT_INO) | NILFS_MDT_INO_BITS)

#define NILFS_FIRST_INO(sb)  (NILFS_SB(sb)->s_nilfs->ns_first_ino)

#define NILFS_MDT_INODE(sb, ino) \

  ((ino) < NILFS_FIRST_INO(sb) && (NILFS_MDT_INO_BITS & (1 << (ino))))

#define NILFS_VALID_INODE(sb, ino) \

  ((ino) >= NILFS_FIRST_INO(sb) || (NILFS_SYS_INO_BITS & (1 << (ino))))

/**

 * struct nilfs_transaction_info: context information for synchronization

 * @ti_magic: Magic number

 * @ti_save: Backup of journal_info field of task_struct

 * @ti_flags: Flags

 * @ti_count: Nest level

 * @ti_garbage:	List of inode to be put when releasing semaphore

 */

struct nilfs_transaction_info {

	u32			ti_magic;

	void		       *ti_save;

				/* This should never used. If this happens,

				   one of other filesystems has a bug. */

	unsigned short		ti_flags;

	unsigned short		ti_count;

	struct list_head	ti_garbage;

};

/* ti_magic */

#define NILFS_TI_MAGIC		0xd9e392fb

/* ti_flags */

#define NILFS_TI_DYNAMIC_ALLOC	0x0001  /* Allocated from slab */

#define NILFS_TI_SYNC		0x0002	/* Force to construct segment at the

					   end of transaction. */

#define NILFS_TI_GC		0x0004	/* GC context */

#define NILFS_TI_COMMIT		0x0008	/* Change happened or not */

#define NILFS_TI_WRITER		0x0010	/* Constructor context */

int nilfs_transaction_begin(struct super_block *,

			    struct nilfs_transaction_info *, int);

int nilfs_transaction_end(struct super_block *, int);

static inline void nilfs_set_transaction_flag(unsigned int flag)

{

	struct nilfs_transaction_info *ti = current->journal_info;

	BUG_ON(!ti);

	ti->ti_flags |= flag;

}

static inline int nilfs_test_transaction_flag(unsigned int flag)

{

	struct nilfs_transaction_info *ti = current->journal_info;

	if (ti == NULL || ti->ti_magic != NILFS_TI_MAGIC)

		return 0;

	return !!(ti->ti_flags & flag);

}

static inline int nilfs_doing_gc(void)

{

	return nilfs_test_transaction_flag(NILFS_TI_GC);

}

static inline int nilfs_doing_construction(void)

{

	return nilfs_test_transaction_flag(NILFS_TI_WRITER);

}

static inline struct inode *nilfs_dat_inode(const struct the_nilfs *nilfs)

{

	return nilfs_doing_gc() ? nilfs->ns_gc_dat : nilfs->ns_dat;

}

/*

 * function prototype

 */

#ifdef CONFIG_NILFS_POSIX_ACL

#error "NILFS: not yet supported POSIX ACL"

extern int nilfs_permission(struct inode *, int, struct nameidata *);

extern int nilfs_acl_chmod(struct inode *);

extern int nilfs_init_acl(struct inode *, struct inode *);

#else

#define nilfs_permission   NULL

static inline int nilfs_acl_chmod(struct inode *inode)

{

	return 0;

}

static inline int nilfs_init_acl(struct inode *inode, struct inode *dir)

{

	inode->i_mode &= ~current_umask();

	return 0;

}

#endif

#define NILFS_ATIME_DISABLE

/* dir.c */

extern int nilfs_add_link(struct dentry *, struct inode *);

extern ino_t nilfs_inode_by_name(struct inode *, struct dentry *);

extern int nilfs_make_empty(struct inode *, struct inode *);

extern struct nilfs_dir_entry *

nilfs_find_entry(struct inode *, struct dentry *, struct page **);

extern int nilfs_delete_entry(struct nilfs_dir_entry *, struct page *);

extern int nilfs_empty_dir(struct inode *);

extern struct nilfs_dir_entry *nilfs_dotdot(struct inode *, struct page **);

extern void nilfs_set_link(struct inode *, struct nilfs_dir_entry *,

			   struct page *, struct inode *);

/* file.c */

extern int nilfs_sync_file(struct file *, struct dentry *, int);

/* ioctl.c */

int nilfs_ioctl(struct inode *, struct file *, unsigned int, unsigned long);

long nilfs_compat_ioctl(struct file *, unsigned int, unsigned long);

int nilfs_ioctl_prepare_clean_segments(struct the_nilfs *, void __user *);

/* inode.c */

extern struct inode *nilfs_new_inode(struct inode *, int);

extern void nilfs_free_inode(struct inode *);

extern int nilfs_get_block(struct inode *, sector_t, struct buffer_head *, int);

extern void nilfs_set_inode_flags(struct inode *);

extern int nilfs_read_inode_common(struct inode *, struct nilfs_inode *);

extern void nilfs_write_inode_common(struct inode *, struct nilfs_inode *, int);

extern struct inode *nilfs_iget(struct super_block *, unsigned long);

extern void nilfs_update_inode(struct inode *, struct buffer_head *);

extern void nilfs_truncate(struct inode *);

extern void nilfs_delete_inode(struct inode *);

extern int nilfs_setattr(struct dentry *, struct iattr *);

extern int nilfs_load_inode_block(struct nilfs_sb_info *, struct inode *,

				  struct buffer_head **);

extern int nilfs_inode_dirty(struct inode *);

extern int nilfs_set_file_dirty(struct nilfs_sb_info *, struct inode *,

				unsigned);

extern int nilfs_mark_inode_dirty(struct inode *);

extern void nilfs_dirty_inode(struct inode *);

/* namei.c */

extern struct dentry *nilfs_get_parent(struct dentry *);

/* super.c */

extern struct inode *nilfs_alloc_inode(struct super_block *);

extern void nilfs_destroy_inode(struct inode *);

extern void nilfs_error(struct super_block *, const char *, const char *, ...)

	__attribute__ ((format (printf, 3, 4)));

extern void nilfs_warning(struct super_block *, const char *, const char *, ...)

       __attribute__ ((format (printf, 3, 4)));

extern struct nilfs_super_block *

nilfs_load_super_block(struct super_block *, struct buffer_head **);

extern struct nilfs_super_block *

nilfs_reload_super_block(struct super_block *, struct buffer_head **, int);

extern int nilfs_store_magic_and_option(struct super_block *,

					struct nilfs_super_block *, char *);

extern void nilfs_update_last_segment(struct nilfs_sb_info *, int);

extern int nilfs_commit_super(struct nilfs_sb_info *);

extern int nilfs_attach_checkpoint(struct nilfs_sb_info *, __u64);

extern void nilfs_detach_checkpoint(struct nilfs_sb_info *);

/* gcinode.c */

int nilfs_gccache_submit_read_data(struct inode *, sector_t, sector_t, __u64,

				   struct buffer_head **);

int nilfs_gccache_submit_read_node(struct inode *, sector_t, __u64,

				   struct buffer_head **);

int nilfs_gccache_wait_and_mark_dirty(struct buffer_head *);

int nilfs_init_gccache(struct the_nilfs *);

void nilfs_destroy_gccache(struct the_nilfs *);

void nilfs_clear_gcinode(struct inode *);

struct inode *nilfs_gc_iget(struct the_nilfs *, ino_t, __u64);

void nilfs_remove_all_gcinode(struct the_nilfs *);

/* gcdat.c */

int nilfs_init_gcdat_inode(struct the_nilfs *);

void nilfs_commit_gcdat_inode(struct the_nilfs *);

void nilfs_clear_gcdat_inode(struct the_nilfs *);

/*

 * Inodes and files operations

 */

extern struct file_operations nilfs_dir_operations;

extern struct inode_operations nilfs_file_inode_operations;

extern struct file_operations nilfs_file_operations;

extern struct address_space_operations nilfs_aops;

extern struct inode_operations nilfs_dir_inode_operations;

extern struct inode_operations nilfs_special_inode_operations;

extern struct inode_operations nilfs_symlink_inode_operations;

/*

 * filesystem type

 */

extern struct file_system_type nilfs_fs_type;

#endif	/* _NILFS_H */

/*

 * sb.h - NILFS on-memory super block 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 _NILFS_SB

#define _NILFS_SB

#include <linux/types.h>

#include <linux/fs.h>

/*

 * Mount options

 */

struct nilfs_mount_options {

	unsigned long mount_opt;

	__u64 snapshot_cno;

};

struct the_nilfs;

struct nilfs_sc_info;

/*

 * NILFS super-block data in memory

 */

struct nilfs_sb_info {

	/* Snapshot status */

	__u64 s_snapshot_cno;		/* Checkpoint number */

	atomic_t s_inodes_count;

	atomic_t s_blocks_count;	/* Reserved (might be deleted) */

	/* Mount options */

	unsigned long s_mount_opt;

	uid_t s_resuid;

	gid_t s_resgid;

	unsigned long s_interval;	/* construction interval */

	unsigned long s_watermark;	/* threshold of data amount

					   for the segment construction */

	/* Fundamental members */

	struct super_block *s_super;	/* reverse pointer to super_block */

	struct the_nilfs *s_nilfs;

	struct list_head s_list;	/* list head for nilfs->ns_supers */

	/* Segment constructor */

	struct list_head s_dirty_files;	/* dirty files list */

	struct nilfs_sc_info *s_sc_info; /* segment constructor info */

	spinlock_t s_inode_lock;	/* Lock for the nilfs inode.

					   It covers s_dirty_files list */

	/* Metadata files */

	struct inode *s_ifile;		/* index file inode */

	/* Inode allocator */

	spinlock_t s_next_gen_lock;

	u32 s_next_generation;

};

static inline struct nilfs_sb_info *NILFS_SB(struct super_block *sb)

{

	return sb->s_fs_info;

}

static inline struct nilfs_sc_info *NILFS_SC(struct nilfs_sb_info *sbi)

{

	return sbi->s_sc_info;

}

/*

 * Bit operations for the mount option

 */

#define nilfs_clear_opt(sbi, opt)  \

	do { (sbi)->s_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)

#define nilfs_set_opt(sbi, opt)  \

	do { (sbi)->s_mount_opt |= NILFS_MOUNT_##opt; } while (0)

#define nilfs_test_opt(sbi, opt)   ((sbi)->s_mount_opt & NILFS_MOUNT_##opt)

#define nilfs_write_opt(sbi, mask, opt)					\

	do { (sbi)->s_mount_opt =					\

		(((sbi)->s_mount_opt & ~NILFS_MOUNT_##mask) |		\

		 NILFS_MOUNT_##opt);					\

	} while (0)

#endif /* _NILFS_SB */

/*

 * 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 */

	THE_NILFS_COND_NONGC_WRITE,	/* Condition to wake up cleanerd */

};

/**

 * struct the_nilfs - struct to supervise multiple nilfs mount points

 * @ns_flags: flags

 * @ns_count: reference count

 * @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_writer_mutex: mutex protecting ns_writer attach/detach

 * @ns_writer_refcount: number of referrers on ns_writer

 * @ns_sbh: buffer head of the on-disk super block

 * @ns_sbp: pointer to the super block data

 * @ns_used_segments: list of full segments in volatile active state

 * @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_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_cleanerd_wq: wait queue for cleanerd

 * @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 block_device    *ns_bdev;

	struct backing_dev_info *ns_bdi;

	struct nilfs_sb_info   *ns_writer;

	struct rw_semaphore	ns_sem;

	struct mutex		ns_writer_mutex;

	atomic_t		ns_writer_refcount;

	/*

	 * 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;

	struct nilfs_super_block *ns_sbp;

	struct list_head	ns_used_segments;

	unsigned		ns_mount_state;

	struct list_head	ns_supers;

	/*

	 * 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 with transaction_begin()

	 * and transaction_end(), when 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;

	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;

	/* cleanerd */

	wait_queue_head_t	ns_cleanerd_wq;

	/* 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)

THE_NILFS_FNS(COND_NONGC_WRITE, cond_nongc_write)

void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);

struct the_nilfs *alloc_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 *);

void nilfs_dispose_used_segments(struct the_nilfs *);

int nilfs_checkpoint_is_mounted(struct the_nilfs *, __u64, int);

int nilfs_near_disk_full(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 struct nilfs_sb_info *nilfs_get_writer(struct the_nilfs *nilfs)

{

	if (atomic_inc_and_test(&nilfs->ns_writer_refcount))

		mutex_lock(&nilfs->ns_writer_mutex);

	return nilfs->ns_writer;

}

static inline void nilfs_put_writer(struct the_nilfs *nilfs)

{

	if (atomic_add_negative(-1, &nilfs->ns_writer_refcount))

		mutex_unlock(&nilfs->ns_writer_mutex);

}

static inline void

nilfs_attach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)

{

	mutex_lock(&nilfs->ns_writer_mutex);

	nilfs->ns_writer = sbi;

	mutex_unlock(&nilfs->ns_writer_mutex);

}

static inline void

nilfs_detach_writer(struct the_nilfs *nilfs, struct nilfs_sb_info *sbi)

{

	mutex_lock(&nilfs->ns_writer_mutex);

	if (sbi == nilfs->ns_writer)

		nilfs->ns_writer = NULL;

	mutex_unlock(&nilfs->ns_writer_mutex);

}

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;

}

#endif /* _THE_NILFS_H */