original development tree for Linux kernel GTP module; now long in mainline.
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/*
* segbuf.h - NILFS Segment buffer 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_SEGBUF_H
#define _NILFS_SEGBUF_H
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/bio.h>
#include <linux/completion.h>
/**
* struct nilfs_segsum_info - On-memory segment summary
* @flags: Flags
* @nfinfo: Number of file information structures
* @nblocks: Number of blocks included in the partial segment
* @nsumblk: Number of summary blocks
* @sumbytes: Byte count of segment summary
* @nfileblk: Total number of file blocks
* @seg_seq: Segment sequence number
* @cno: Checkpoint number
* @ctime: Creation time
* @next: Block number of the next full segment
*/
struct nilfs_segsum_info {
unsigned int flags;
unsigned long nfinfo;
unsigned long nblocks;
unsigned long nsumblk;
unsigned long sumbytes;
unsigned long nfileblk;
u64 seg_seq;
__u64 cno;
time_t ctime;
sector_t next;
};
/**
* struct nilfs_segment_buffer - Segment buffer
* @sb_super: back pointer to a superblock struct
* @sb_list: List head to chain this structure
* @sb_sum: On-memory segment summary
* @sb_segnum: Index number of the full segment
* @sb_nextnum: Index number of the next full segment
* @sb_fseg_start: Start block number of the full segment
* @sb_fseg_end: End block number of the full segment
* @sb_pseg_start: Disk block number of partial segment
* @sb_rest_blocks: Number of residual blocks in the current segment
* @sb_segsum_buffers: List of buffers for segment summaries
* @sb_payload_buffers: List of buffers for segment payload
* @sb_super_root: Pointer to buffer storing a super root block (if exists)
* @sb_nbio: Number of flying bio requests
* @sb_err: I/O error status
* @sb_bio_event: Completion event of log writing
*/
struct nilfs_segment_buffer {
struct super_block *sb_super;
struct list_head sb_list;
/* Segment information */
struct nilfs_segsum_info sb_sum;
__u64 sb_segnum;
__u64 sb_nextnum;
sector_t sb_fseg_start, sb_fseg_end;
sector_t sb_pseg_start;
unsigned sb_rest_blocks;
/* Buffers */
struct list_head sb_segsum_buffers;
struct list_head sb_payload_buffers; /* including super root */
struct buffer_head *sb_super_root;
/* io status */
int sb_nbio;
atomic_t sb_err;
struct completion sb_bio_event;
};
#define NILFS_LIST_SEGBUF(head) \
list_entry((head), struct nilfs_segment_buffer, sb_list)
#define NILFS_NEXT_SEGBUF(segbuf) NILFS_LIST_SEGBUF((segbuf)->sb_list.next)
#define NILFS_PREV_SEGBUF(segbuf) NILFS_LIST_SEGBUF((segbuf)->sb_list.prev)
#define NILFS_LAST_SEGBUF(head) NILFS_LIST_SEGBUF((head)->prev)
#define NILFS_FIRST_SEGBUF(head) NILFS_LIST_SEGBUF((head)->next)
#define NILFS_SEGBUF_IS_LAST(segbuf, head) ((segbuf)->sb_list.next == (head))
#define nilfs_for_each_segbuf_before(s, t, h) \
for ((s) = NILFS_FIRST_SEGBUF(h); (s) != (t); \
(s) = NILFS_NEXT_SEGBUF(s))
#define NILFS_SEGBUF_FIRST_BH(head) \
(list_entry((head)->next, struct buffer_head, b_assoc_buffers))
#define NILFS_SEGBUF_NEXT_BH(bh) \
(list_entry((bh)->b_assoc_buffers.next, struct buffer_head, \
b_assoc_buffers))
#define NILFS_SEGBUF_BH_IS_LAST(bh, head) ((bh)->b_assoc_buffers.next == head)
extern struct kmem_cache *nilfs_segbuf_cachep;
struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
void nilfs_segbuf_free(struct nilfs_segment_buffer *);
void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
struct the_nilfs *);
void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
struct nilfs_segment_buffer *prev);
void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
struct the_nilfs *);
int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t, __u64);
int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
struct buffer_head **);
void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
static inline int nilfs_segbuf_simplex(struct nilfs_segment_buffer *segbuf)
{
unsigned int flags = segbuf->sb_sum.flags;
return (flags & (NILFS_SS_LOGBGN | NILFS_SS_LOGEND)) ==
(NILFS_SS_LOGBGN | NILFS_SS_LOGEND);
}
static inline int nilfs_segbuf_empty(struct nilfs_segment_buffer *segbuf)
{
return segbuf->sb_sum.nblocks == segbuf->sb_sum.nsumblk;
}
static inline void
nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer *segbuf,
struct buffer_head *bh)
{
list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_segsum_buffers);
segbuf->sb_sum.nblocks++;
segbuf->sb_sum.nsumblk++;
}
static inline void
nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer *segbuf,
struct buffer_head *bh)
{
list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_payload_buffers);
segbuf->sb_sum.nblocks++;
}
static inline void
nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer *segbuf,
struct buffer_head *bh)
{
get_bh(bh);
nilfs_segbuf_add_payload_buffer(segbuf, bh);
segbuf->sb_sum.nfileblk++;
}
void nilfs_clear_logs(struct list_head *logs);
void nilfs_truncate_logs(struct list_head *logs,
struct nilfs_segment_buffer *last);
int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs);
int nilfs_wait_on_logs(struct list_head *logs);
void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed);
static inline void nilfs_destroy_logs(struct list_head *logs)
{
nilfs_truncate_logs(logs, NULL);
}
#endif /* _NILFS_SEGBUF_H */