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linux/fs/nilfs2/segment.h
Ryusuke Konishi e339ad31f5 nilfs2: introduce secondary super block 
The former versions didn't have extra super blocks.  This improves the
weak point by introducing another super block at unused region in tail of
the partition.

This doesn't break disk format compatibility; older versions just ingore
the secondary super block, and new versions just recover it if it doesn't
exist.  The partition created by an old mkfs may not have unused region,
but in that case, the secondary super block will not be added.

This doesn't make more redundant copies of the super block; it is a future
work.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-07 08:31:20 -07:00

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/*
* segment.h - NILFS Segment constructor prototypes and definitions
*
* 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_SEGMENT_H
#define _NILFS_SEGMENT_H
#include <linux/types.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/nilfs2_fs.h>
#include "sb.h"
/**
* struct nilfs_recovery_info - Recovery infomation
* @ri_need_recovery: Recovery status
* @ri_super_root: Block number of the last super root
* @ri_ri_cno: Number of the last checkpoint
* @ri_lsegs_start: Region for roll-forwarding (start block number)
* @ri_lsegs_end: Region for roll-forwarding (end block number)
* @ri_lseg_start_seq: Sequence value of the segment at ri_lsegs_start
* @ri_used_segments: List of segments to be mark active
* @ri_pseg_start: Block number of the last partial segment
* @ri_seq: Sequence number on the last partial segment
* @ri_segnum: Segment number on the last partial segment
* @ri_nextnum: Next segment number on the last partial segment
*/
struct nilfs_recovery_info {
int ri_need_recovery;
sector_t ri_super_root;
__u64 ri_cno;
sector_t ri_lsegs_start;
sector_t ri_lsegs_end;
u64 ri_lsegs_start_seq;
struct list_head ri_used_segments;
sector_t ri_pseg_start;
u64 ri_seq;
__u64 ri_segnum;
__u64 ri_nextnum;
};
/* ri_need_recovery */
#define NILFS_RECOVERY_SR_UPDATED 1 /* The super root was updated */
#define NILFS_RECOVERY_ROLLFORWARD_DONE 2 /* Rollforward was carried out */
/**
* struct nilfs_cstage - Context of collection stage
* @scnt: Stage count
* @flags: State flags
* @dirty_file_ptr: Pointer on dirty_files list, or inode of a target file
* @gc_inode_ptr: Pointer on the list of gc-inodes
*/
struct nilfs_cstage {
int scnt;
unsigned flags;
struct nilfs_inode_info *dirty_file_ptr;
struct nilfs_inode_info *gc_inode_ptr;
};
struct nilfs_segment_buffer;
struct nilfs_segsum_pointer {
struct buffer_head *bh;
unsigned offset; /* offset in bytes */
};
/**
* struct nilfs_sc_info - Segment constructor information
* @sc_super: Back pointer to super_block struct
* @sc_sbi: Back pointer to nilfs_sb_info struct
* @sc_nblk_inc: Block count of current generation
* @sc_dirty_files: List of files to be written
* @sc_gc_inodes: List of GC inodes having blocks to be written
* @sc_cleaning_segments: List of segments to be freed through construction
* @sc_copied_buffers: List of copied buffers (buffer heads) to freeze data
* @sc_dsync_inode: inode whose data pages are written for a sync operation
* @sc_dsync_start: start byte offset of data pages
* @sc_dsync_end: end byte offset of data pages (inclusive)
* @sc_segbufs: List of segment buffers
* @sc_segbuf_nblocks: Number of available blocks in segment buffers.
* @sc_curseg: Current segment buffer
* @sc_super_root: Pointer to the super root buffer
* @sc_stage: Collection stage
* @sc_finfo_ptr: pointer to the current finfo struct in the segment summary
* @sc_binfo_ptr: pointer to the current binfo struct in the segment summary
* @sc_blk_cnt: Block count of a file
* @sc_datablk_cnt: Data block count of a file
* @sc_nblk_this_inc: Number of blocks included in the current logical segment
* @sc_seg_ctime: Creation time
* @sc_flags: Internal flags
* @sc_state_lock: spinlock for sc_state and so on
* @sc_state: Segctord state flags
* @sc_flush_request: inode bitmap of metadata files to be flushed
* @sc_wait_request: Client request queue
* @sc_wait_daemon: Daemon wait queue
* @sc_wait_task: Start/end wait queue to control segctord task
* @sc_seq_request: Request counter
* @sc_seq_done: Completion counter
* @sc_sync: Request of explicit sync operation
* @sc_interval: Timeout value of background construction
* @sc_mjcp_freq: Frequency of creating checkpoints
* @sc_lseg_stime: Start time of the latest logical segment
* @sc_watermark: Watermark for the number of dirty buffers
* @sc_timer: Timer for segctord
* @sc_task: current thread of segctord
*/
struct nilfs_sc_info {
struct super_block *sc_super;
struct nilfs_sb_info *sc_sbi;
unsigned long sc_nblk_inc;
struct list_head sc_dirty_files;
struct list_head sc_gc_inodes;
struct list_head sc_cleaning_segments;
struct list_head sc_copied_buffers;
struct nilfs_inode_info *sc_dsync_inode;
loff_t sc_dsync_start;
loff_t sc_dsync_end;
/* Segment buffers */
struct list_head sc_segbufs;
unsigned long sc_segbuf_nblocks;
struct nilfs_segment_buffer *sc_curseg;
struct buffer_head *sc_super_root;
struct nilfs_cstage sc_stage;
struct nilfs_segsum_pointer sc_finfo_ptr;
struct nilfs_segsum_pointer sc_binfo_ptr;
unsigned long sc_blk_cnt;
unsigned long sc_datablk_cnt;
unsigned long sc_nblk_this_inc;
time_t sc_seg_ctime;
unsigned long sc_flags;
spinlock_t sc_state_lock;
unsigned long sc_state;
unsigned long sc_flush_request;
wait_queue_head_t sc_wait_request;
wait_queue_head_t sc_wait_daemon;
wait_queue_head_t sc_wait_task;
__u32 sc_seq_request;
__u32 sc_seq_done;
int sc_sync;
unsigned long sc_interval;
unsigned long sc_mjcp_freq;
unsigned long sc_lseg_stime; /* in 1/HZ seconds */
unsigned long sc_watermark;
struct timer_list *sc_timer;
struct task_struct *sc_task;
};
/* sc_flags */
enum {
NILFS_SC_DIRTY, /* One or more dirty meta-data blocks exist */
NILFS_SC_UNCLOSED, /* Logical segment is not closed */
NILFS_SC_SUPER_ROOT, /* The latest segment has a super root */
NILFS_SC_PRIOR_FLUSH, /* Requesting immediate flush without making a
checkpoint */
NILFS_SC_HAVE_DELTA, /* Next checkpoint will have update of files
other than DAT, cpfile, sufile, or files
moved by GC */
};
/* sc_state */
#define NILFS_SEGCTOR_QUIT 0x0001 /* segctord is being destroyed */
#define NILFS_SEGCTOR_COMMIT 0x0004 /* committed transaction exists */
/*
* Constant parameters
*/
#define NILFS_SC_CLEANUP_RETRY 3 /* Retry count of construction when
destroying segctord */
/*
* Default values of timeout, in seconds.
*/
#define NILFS_SC_DEFAULT_TIMEOUT 5 /* Timeout value of dirty blocks.
It triggers construction of a
logical segment with a super root */
#define NILFS_SC_DEFAULT_SR_FREQ 30 /* Maximum frequency of super root
creation */
/*
* The default threshold amount of data, in block counts.
*/
#define NILFS_SC_DEFAULT_WATERMARK 3600
/* segment.c */
extern int nilfs_init_transaction_cache(void);
extern void nilfs_destroy_transaction_cache(void);
extern void nilfs_relax_pressure_in_lock(struct super_block *);
extern int nilfs_construct_segment(struct super_block *);
extern int nilfs_construct_dsync_segment(struct super_block *, struct inode *,
loff_t, loff_t);
extern void nilfs_flush_segment(struct super_block *, ino_t);
extern int nilfs_clean_segments(struct super_block *, void __user *);
extern int nilfs_segctor_add_segments_to_be_freed(struct nilfs_sc_info *,
__u64 *, size_t);
extern void nilfs_segctor_clear_segments_to_be_freed(struct nilfs_sc_info *);
extern int nilfs_attach_segment_constructor(struct nilfs_sb_info *);
extern void nilfs_detach_segment_constructor(struct nilfs_sb_info *);
/* recovery.c */
extern int nilfs_read_super_root_block(struct super_block *, sector_t,
struct buffer_head **, int);
extern int nilfs_search_super_root(struct the_nilfs *, struct nilfs_sb_info *,
struct nilfs_recovery_info *);
extern int nilfs_recover_logical_segments(struct the_nilfs *,
struct nilfs_sb_info *,
struct nilfs_recovery_info *);
#endif /* _NILFS_SEGMENT_H */
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