/*
   * 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 "nilfs.h"
  
  struct nilfs_root;
  
  /**
   * struct nilfs_recovery_info - Recovery information
   * @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_root: root object of the current filesystem tree
   * @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_freesegs: array of segment numbers to be freed
   * @sc_nfreesegs: number of segments on @sc_freesegs
   * @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_write_logs: List of segment buffers to hold logs under writing
   * @sc_segbuf_nblocks: Number of available blocks in segment buffers.
   * @sc_curseg: Current segment 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_cno: checkpoint number of current log
   * @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_accept: Accepted request count
   * @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_root      *sc_root;
  
  	unsigned long		sc_nblk_inc;
  
  	struct list_head	sc_dirty_files;
  	struct list_head	sc_gc_inodes;
  
  	__u64		       *sc_freesegs;
  	size_t			sc_nfreesegs;
  
  	struct nilfs_inode_info *sc_dsync_inode;
  	loff_t			sc_dsync_start;
  	loff_t			sc_dsync_end;
  
  	/* Segment buffers */
  	struct list_head	sc_segbufs;
  	struct list_head	sc_write_logs;
  	unsigned long		sc_segbuf_nblocks;
  	struct nilfs_segment_buffer *sc_curseg;
  
  	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;
  	__u64			sc_cno;
  	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_accepted;
  	__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
  
  /* super.c */
  extern struct kmem_cache *nilfs_transaction_cachep;
  
  /* segment.c */
  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 *, struct nilfs_argv *,
  				void **);
  
  int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root);
  void nilfs_detach_log_writer(struct super_block *sb);
  
  /* recovery.c */
  extern int nilfs_read_super_root_block(struct the_nilfs *, sector_t,
  				       struct buffer_head **, int);
  extern int nilfs_search_super_root(struct the_nilfs *,
  				   struct nilfs_recovery_info *);
  int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs, struct super_block *sb,
  			      struct nilfs_recovery_info *ri);
  extern void nilfs_dispose_segment_list(struct list_head *);
  
  #endif /* _NILFS_SEGMENT_H */