[linux.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 <[email protected]>
 *
 */

#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>

struct nilfs_sc_info;

/* 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_writer: log writer
 * @ns_segctor_sem: semaphore protecting log write
 * @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_dirty_files: list of dirty files
 * @ns_inode_lock: lock protecting @ns_dirty_files
 * @ns_gc_inodes: dummy inodes to keep live blocks
 * @ns_next_generation: next generation number for inodes
 * @ns_next_gen_lock: lock protecting @ns_next_generation
 * @ns_mount_opt: mount options
 * @ns_resuid: uid for reserved blocks
 * @ns_resgid: gid for reserved blocks
 * @ns_interval: checkpoint creation interval
 * @ns_watermark: watermark for the number of dirty buffers
 * @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 nilfs_sc_info   *ns_writer;
	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;

	/* Dirty inode list */
	struct list_head	ns_dirty_files;
	spinlock_t		ns_inode_lock;

	/* GC inode list */
	struct list_head	ns_gc_inodes;

	/* Inode allocator */
	u32			ns_next_generation;
	spinlock_t		ns_next_gen_lock;

	/* Mount options */
	unsigned long		ns_mount_opt;

	uid_t			ns_resuid;
	gid_t			ns_resgid;
	unsigned long		ns_interval;
	unsigned long		ns_watermark;

	/* 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)

/*
 * Mount option operations
 */
#define nilfs_clear_opt(nilfs, opt)  \
	do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
#define nilfs_set_opt(nilfs, opt)  \
	do { (nilfs)->ns_mount_opt |= NILFS_MOUNT_##opt; } while (0)
#define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
#define nilfs_write_opt(nilfs, mask, opt)				\
	do { (nilfs)->ns_mount_opt =					\
		(((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) |	\
		 NILFS_MOUNT_##opt);					\
	} while (0)

/**
 * 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 *nilfs, struct super_block *sb, char *data);
int load_nilfs(struct the_nilfs *nilfs, struct super_block *sb);
unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
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);
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 <[email protected]>
	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	34
3fd3fe5a RK	35	struct nilfs_sc_info;
3fd3fe5a RK	36
65b4643d RK	37	/* the_nilfs struct */
	38	enum {
	39	THE_NILFS_INIT = 0, /* Information from super_block is set */
65b4643d	40	THE_NILFS_DISCONTINUED, /* 'next' pointer chain has broken */
1cf58fa8	41	THE_NILFS_GC_RUNNING, /* gc process is running */
e605f0a7	42	THE_NILFS_SB_DIRTY, /* super block is dirty */
65b4643d RK	43	};
	44
	45	/**
	46	* struct the_nilfs - struct to supervise multiple nilfs mount points
	47	* @ns_flags: flags
65b4643d	48	* @ns_bdev: block device
65b4643d	49	* @ns_sem: semaphore for shared states
e339ad31 RK	50	* @ns_sbh: buffer heads of on-disk super blocks
e339ad31 RK	51	* @ns_sbp: pointers to super block data
b2ac86e1 JS	52	* @ns_sbwtime: previous write time of super block
b2ac86e1 JS	53	* @ns_sbwcount: write count of super block
e339ad31	54	* @ns_sbsize: size of valid data in super block
65b4643d RK	55	* @ns_seg_seq: segment sequence counter
	56	* @ns_segnum: index number of the latest full segment.
	57	* @ns_nextnum: index number of the full segment index to be used next
	58	* @ns_pseg_offset: offset of next partial segment in the current full segment
	59	* @ns_cno: next checkpoint number
	60	* @ns_ctime: write time of the last segment
	61	* @ns_nongc_ctime: write time of the last segment not for cleaner operation
	62	* @ns_ndirtyblks: Number of dirty data blocks
	63	* @ns_last_segment_lock: lock protecting fields for the latest segment
	64	* @ns_last_pseg: start block number of the latest segment
	65	* @ns_last_seq: sequence value of the latest segment
	66	* @ns_last_cno: checkpoint number of the latest segment
2c2e52fc	67	* @ns_prot_seq: least sequence number of segments which must not be reclaimed
32502047	68	* @ns_prev_seq: base sequence number used to decide if advance log cursor
3fd3fe5a RK	69	* @ns_writer: log writer
3fd3fe5a RK	70	* @ns_segctor_sem: semaphore protecting log write
65b4643d RK	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
693dd321 RK	76	* @ns_dirty_files: list of dirty files
693dd321 RK	77	* @ns_inode_lock: lock protecting @ns_dirty_files
65b4643d	78	* @ns_gc_inodes: dummy inodes to keep live blocks
9b1fc4e4 RK	79	* @ns_next_generation: next generation number for inodes
9b1fc4e4 RK	80	* @ns_next_gen_lock: lock protecting @ns_next_generation
3b2ce58b	81	* @ns_mount_opt: mount options
574e6c31 RK	82	* @ns_resuid: uid for reserved blocks
	83	* @ns_resgid: gid for reserved blocks
	84	* @ns_interval: checkpoint creation interval
	85	* @ns_watermark: watermark for the number of dirty buffers
65b4643d	86	* @ns_blocksize_bits: bit length of block size
92c60cca	87	* @ns_blocksize: block size
65b4643d RK	88	* @ns_nsegments: number of segments in filesystem
	89	* @ns_blocks_per_segment: number of blocks per segment
	90	* @ns_r_segments_percentage: reserved segments percentage
	91	* @ns_nrsvsegs: number of reserved segments
	92	* @ns_first_data_block: block number of first data block
	93	* @ns_inode_size: size of on-disk inode
	94	* @ns_first_ino: first not-special inode number
	95	* @ns_crc_seed: seed value of CRC32 calculation
	96	*/
	97	struct the_nilfs {
	98	unsigned long ns_flags;
65b4643d RK	99
65b4643d RK	100	struct block_device *ns_bdev;
65b4643d	101	struct rw_semaphore ns_sem;
65b4643d RK	102
	103	/*
	104	* used for
	105	* - loading the latest checkpoint exclusively.
	106	* - allocating a new full segment.
	107	* - protecting s_dirt in the super_block struct
	108	* (see nilfs_write_super) and the following fields.
	109	*/
e339ad31 RK	110	struct buffer_head *ns_sbh[2];
e339ad31 RK	111	struct nilfs_super_block *ns_sbp[2];
b2ac86e1 JS	112	time_t ns_sbwtime;
b2ac86e1 JS	113	unsigned ns_sbwcount;
e339ad31	114	unsigned ns_sbsize;
65b4643d	115	unsigned ns_mount_state;
65b4643d RK	116
	117	/*
	118	* Following fields are dedicated to a writable FS-instance.
	119	* Except for the period seeking checkpoint, code outside the segment
47420c79 RK	120	* constructor must lock a segment semaphore while accessing these
47420c79 RK	121	* fields.
65b4643d RK	122	* The writable FS-instance is sole during a lifetime of the_nilfs.
	123	*/
	124	u64 ns_seg_seq;
	125	__u64 ns_segnum;
	126	__u64 ns_nextnum;
	127	unsigned long ns_pseg_offset;
	128	__u64 ns_cno;
	129	time_t ns_ctime;
	130	time_t ns_nongc_ctime;
	131	atomic_t ns_ndirtyblks;
	132
	133	/*
	134	* The following fields hold information on the latest partial segment
	135	* written to disk with a super root. These fields are protected by
	136	* ns_last_segment_lock.
	137	*/
	138	spinlock_t ns_last_segment_lock;
	139	sector_t ns_last_pseg;
	140	u64 ns_last_seq;
	141	__u64 ns_last_cno;
2c2e52fc	142	u64 ns_prot_seq;
32502047	143	u64 ns_prev_seq;
65b4643d	144
3fd3fe5a	145	struct nilfs_sc_info *ns_writer;
65b4643d RK	146	struct rw_semaphore ns_segctor_sem;
	147
	148	/*
	149	* Following fields are lock free except for the period before
	150	* the_nilfs is initialized.
	151	*/
	152	struct inode *ns_dat;
	153	struct inode *ns_cpfile;
	154	struct inode *ns_sufile;
65b4643d	155
ba65ae47 RK	156	/* Checkpoint tree */
	157	struct rb_root ns_cptree;
	158	spinlock_t ns_cptree_lock;
	159
693dd321 RK	160	/* Dirty inode list */
	161	struct list_head ns_dirty_files;
	162	spinlock_t ns_inode_lock;
	163
263d90ce	164	/* GC inode list */
65b4643d	165	struct list_head ns_gc_inodes;
65b4643d	166
9b1fc4e4 RK	167	/* Inode allocator */
	168	u32 ns_next_generation;
	169	spinlock_t ns_next_gen_lock;
	170
3b2ce58b RK	171	/* Mount options */
	172	unsigned long ns_mount_opt;
	173
574e6c31 RK	174	uid_t ns_resuid;
	175	gid_t ns_resgid;
	176	unsigned long ns_interval;
	177	unsigned long ns_watermark;
	178
65b4643d RK	179	/* Disk layout information (static) */
65b4643d RK	180	unsigned int ns_blocksize_bits;
92c60cca	181	unsigned int ns_blocksize;
65b4643d RK	182	unsigned long ns_nsegments;
	183	unsigned long ns_blocks_per_segment;
	184	unsigned long ns_r_segments_percentage;
	185	unsigned long ns_nrsvsegs;
	186	unsigned long ns_first_data_block;
	187	int ns_inode_size;
	188	int ns_first_ino;
	189	u32 ns_crc_seed;
	190	};
	191
65b4643d RK	192	#define THE_NILFS_FNS(bit, name) \
	193	static inline void set_nilfs_##name(struct the_nilfs *nilfs) \
	194	{ \
	195	set_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	196	} \
	197	static inline void clear_nilfs_##name(struct the_nilfs *nilfs) \
	198	{ \
	199	clear_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	200	} \
	201	static inline int nilfs_##name(struct the_nilfs *nilfs) \
	202	{ \
	203	return test_bit(THE_NILFS_##bit, &(nilfs)->ns_flags); \
	204	}
	205
	206	THE_NILFS_FNS(INIT, init)
65b4643d	207	THE_NILFS_FNS(DISCONTINUED, discontinued)
1cf58fa8	208	THE_NILFS_FNS(GC_RUNNING, gc_running)
e605f0a7	209	THE_NILFS_FNS(SB_DIRTY, sb_dirty)
65b4643d	210
3b2ce58b RK	211	/*
	212	* Mount option operations
	213	*/
	214	#define nilfs_clear_opt(nilfs, opt) \
	215	do { (nilfs)->ns_mount_opt &= ~NILFS_MOUNT_##opt; } while (0)
	216	#define nilfs_set_opt(nilfs, opt) \
	217	do { (nilfs)->ns_mount_opt \|= NILFS_MOUNT_##opt; } while (0)
	218	#define nilfs_test_opt(nilfs, opt) ((nilfs)->ns_mount_opt & NILFS_MOUNT_##opt)
	219	#define nilfs_write_opt(nilfs, mask, opt) \
	220	do { (nilfs)->ns_mount_opt = \
	221	(((nilfs)->ns_mount_opt & ~NILFS_MOUNT_##mask) \| \
	222	NILFS_MOUNT_##opt); \
	223	} while (0)
	224
ba65ae47 RK	225	/**
	226	* struct nilfs_root - nilfs root object
	227	* @cno: checkpoint number
	228	* @rb_node: red-black tree node
	229	* @count: refcount of this structure
	230	* @nilfs: nilfs object
	231	* @ifile: inode file
	232	* @root: root inode
	233	* @inodes_count: number of inodes
	234	* @blocks_count: number of blocks (Reserved)
	235	*/
	236	struct nilfs_root {
	237	__u64 cno;
	238	struct rb_node rb_node;
	239
	240	atomic_t count;
	241	struct the_nilfs *nilfs;
	242	struct inode *ifile;
	243
	244	atomic_t inodes_count;
	245	atomic_t blocks_count;
	246	};
	247
	248	/* Special checkpoint number */
	249	#define NILFS_CPTREE_CURRENT_CNO 0
	250
e339ad31 RK	251	/* Minimum interval of periodical update of superblocks (in seconds) */
e339ad31 RK	252	#define NILFS_SB_FREQ 10
e339ad31	253
79efdd94 JS	254	static inline int nilfs_sb_need_update(struct the_nilfs *nilfs)
	255	{
	256	u64 t = get_seconds();
b2ac86e1	257	return t < nilfs->ns_sbwtime \|\| t > nilfs->ns_sbwtime + NILFS_SB_FREQ;
79efdd94 JS	258	}
79efdd94 JS	259
b2ac86e1	260	static inline int nilfs_sb_will_flip(struct the_nilfs *nilfs)
79efdd94	261	{
b2ac86e1 JS	262	int flip_bits = nilfs->ns_sbwcount & 0x0FL;
b2ac86e1 JS	263	return (flip_bits != 0x08 && flip_bits != 0x0F);
79efdd94 JS	264	}
79efdd94 JS	265
65b4643d	266	void nilfs_set_last_segment(struct the_nilfs *, sector_t, u64, __u64);
348fe8da RK	267	struct the_nilfs alloc_nilfs(struct block_device bdev);
348fe8da RK	268	void destroy_nilfs(struct the_nilfs *nilfs);
f7545144 RK	269	int init_nilfs(struct the_nilfs nilfs, struct super_block sb, char *data);
f7545144 RK	270	int load_nilfs(struct the_nilfs nilfs, struct super_block sb);
4e33f9ea RK	271	unsigned long nilfs_nrsvsegs(struct the_nilfs *nilfs, unsigned long nsegs);
4e33f9ea RK	272	void nilfs_set_nsegments(struct the_nilfs *nilfs, unsigned long nsegs);
e902ec99	273	int nilfs_discard_segments(struct the_nilfs , __u64 , size_t);
65b4643d	274	int nilfs_count_free_blocks(struct the_nilfs , sector_t );
ba65ae47 RK	275	struct nilfs_root nilfs_lookup_root(struct the_nilfs nilfs, __u64 cno);
	276	struct nilfs_root nilfs_find_or_create_root(struct the_nilfs nilfs,
	277	__u64 cno);
	278	void nilfs_put_root(struct nilfs_root *root);
65b4643d	279	int nilfs_near_disk_full(struct the_nilfs *);
e339ad31 RK	280	void nilfs_fall_back_super_block(struct the_nilfs *);
e339ad31 RK	281	void nilfs_swap_super_block(struct the_nilfs *);
65b4643d RK	282
65b4643d RK	283
ba65ae47 RK	284	static inline void nilfs_get_root(struct nilfs_root *root)
	285	{
	286	atomic_inc(&root->count);
	287	}
	288
a057d2c0 RK	289	static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
	290	{
	291	unsigned valid_fs;
	292
	293	down_read(&nilfs->ns_sem);
	294	valid_fs = (nilfs->ns_mount_state & NILFS_VALID_FS);
	295	up_read(&nilfs->ns_sem);
	296	return valid_fs;
	297	}
	298
65b4643d RK	299	static inline void
	300	nilfs_get_segment_range(struct the_nilfs *nilfs, __u64 segnum,
	301	sector_t seg_start, sector_t seg_end)
	302	{
	303	seg_start = (sector_t)nilfs->ns_blocks_per_segment segnum;
	304	seg_end = seg_start + nilfs->ns_blocks_per_segment - 1;
	305	if (segnum == 0)
	306	*seg_start = nilfs->ns_first_data_block;
	307	}
	308
	309	static inline sector_t
	310	nilfs_get_segment_start_blocknr(struct the_nilfs *nilfs, __u64 segnum)
	311	{
	312	return (segnum == 0) ? nilfs->ns_first_data_block :
	313	(sector_t)nilfs->ns_blocks_per_segment * segnum;
	314	}
	315
	316	static inline __u64
	317	nilfs_get_segnum_of_block(struct the_nilfs *nilfs, sector_t blocknr)
	318	{
	319	sector_t segnum = blocknr;
	320
	321	sector_div(segnum, nilfs->ns_blocks_per_segment);
	322	return segnum;
	323	}
	324
	325	static inline void
	326	nilfs_terminate_segment(struct the_nilfs *nilfs, sector_t seg_start,
	327	sector_t seg_end)
	328	{
	329	/* terminate the current full segment (used in case of I/O-error) */
	330	nilfs->ns_pseg_offset = seg_end - seg_start + 1;
	331	}
	332
	333	static inline void nilfs_shift_to_next_segment(struct the_nilfs *nilfs)
	334	{
	335	/* move forward with a full segment */
	336	nilfs->ns_segnum = nilfs->ns_nextnum;
	337	nilfs->ns_pseg_offset = 0;
	338	nilfs->ns_seg_seq++;
	339	}
	340
	341	static inline __u64 nilfs_last_cno(struct the_nilfs *nilfs)
	342	{
	343	__u64 cno;
	344
	345	spin_lock(&nilfs->ns_last_segment_lock);
	346	cno = nilfs->ns_last_cno;
	347	spin_unlock(&nilfs->ns_last_segment_lock);
	348	return cno;
	349	}
	350
cece5520 RK	351	static inline int nilfs_segment_is_active(struct the_nilfs *nilfs, __u64 n)
	352	{
	353	return n == nilfs->ns_segnum \|\| n == nilfs->ns_nextnum;
	354	}
	355
65b4643d	356	#endif /* _THE_NILFS_H */