50614bcf29
This adds a field to record the latest checkpoint number in the nilfs_segment_summary structure. This will help to recover the latest checkpoint number from logs on disk. This field is intended for crucial cases in which super blocks have lost pointer to the latest log. Even though this will change the disk format, both backward and forward compatibility is preserved by a size field prepared in the segment summary header. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
185 lines
6.4 KiB
C
185 lines
6.4 KiB
C
/*
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* segbuf.h - NILFS Segment buffer prototypes and definitions
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*
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* Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Written by Ryusuke Konishi <ryusuke@osrg.net>
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*
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*/
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#ifndef _NILFS_SEGBUF_H
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#define _NILFS_SEGBUF_H
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/bio.h>
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#include <linux/completion.h>
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/**
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* struct nilfs_segsum_info - On-memory segment summary
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* @flags: Flags
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* @nfinfo: Number of file information structures
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* @nblocks: Number of blocks included in the partial segment
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* @nsumblk: Number of summary blocks
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* @sumbytes: Byte count of segment summary
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* @nfileblk: Total number of file blocks
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* @seg_seq: Segment sequence number
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* @cno: Checkpoint number
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* @ctime: Creation time
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* @next: Block number of the next full segment
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*/
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struct nilfs_segsum_info {
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unsigned int flags;
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unsigned long nfinfo;
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unsigned long nblocks;
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unsigned long nsumblk;
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unsigned long sumbytes;
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unsigned long nfileblk;
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u64 seg_seq;
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__u64 cno;
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time_t ctime;
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sector_t next;
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};
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/* macro for the flags */
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#define NILFS_SEG_HAS_SR(sum) ((sum)->flags & NILFS_SS_SR)
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#define NILFS_SEG_LOGBGN(sum) ((sum)->flags & NILFS_SS_LOGBGN)
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#define NILFS_SEG_LOGEND(sum) ((sum)->flags & NILFS_SS_LOGEND)
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#define NILFS_SEG_DSYNC(sum) ((sum)->flags & NILFS_SS_SYNDT)
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#define NILFS_SEG_SIMPLEX(sum) \
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(((sum)->flags & (NILFS_SS_LOGBGN | NILFS_SS_LOGEND)) == \
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(NILFS_SS_LOGBGN | NILFS_SS_LOGEND))
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#define NILFS_SEG_EMPTY(sum) ((sum)->nblocks == (sum)->nsumblk)
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/**
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* struct nilfs_segment_buffer - Segment buffer
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* @sb_super: back pointer to a superblock struct
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* @sb_list: List head to chain this structure
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* @sb_sum: On-memory segment summary
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* @sb_segnum: Index number of the full segment
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* @sb_nextnum: Index number of the next full segment
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* @sb_fseg_start: Start block number of the full segment
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* @sb_fseg_end: End block number of the full segment
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* @sb_pseg_start: Disk block number of partial segment
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* @sb_rest_blocks: Number of residual blocks in the current segment
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* @sb_segsum_buffers: List of buffers for segment summaries
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* @sb_payload_buffers: List of buffers for segment payload
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* @sb_super_root: Pointer to buffer storing a super root block (if exists)
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* @sb_nbio: Number of flying bio requests
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* @sb_err: I/O error status
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* @sb_bio_event: Completion event of log writing
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*/
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struct nilfs_segment_buffer {
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struct super_block *sb_super;
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struct list_head sb_list;
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/* Segment information */
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struct nilfs_segsum_info sb_sum;
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__u64 sb_segnum;
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__u64 sb_nextnum;
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sector_t sb_fseg_start, sb_fseg_end;
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sector_t sb_pseg_start;
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unsigned sb_rest_blocks;
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/* Buffers */
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struct list_head sb_segsum_buffers;
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struct list_head sb_payload_buffers; /* including super root */
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struct buffer_head *sb_super_root;
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/* io status */
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int sb_nbio;
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atomic_t sb_err;
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struct completion sb_bio_event;
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};
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#define NILFS_LIST_SEGBUF(head) \
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list_entry((head), struct nilfs_segment_buffer, sb_list)
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#define NILFS_NEXT_SEGBUF(segbuf) NILFS_LIST_SEGBUF((segbuf)->sb_list.next)
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#define NILFS_PREV_SEGBUF(segbuf) NILFS_LIST_SEGBUF((segbuf)->sb_list.prev)
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#define NILFS_LAST_SEGBUF(head) NILFS_LIST_SEGBUF((head)->prev)
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#define NILFS_FIRST_SEGBUF(head) NILFS_LIST_SEGBUF((head)->next)
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#define NILFS_SEGBUF_IS_LAST(segbuf, head) ((segbuf)->sb_list.next == (head))
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#define nilfs_for_each_segbuf_before(s, t, h) \
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for ((s) = NILFS_FIRST_SEGBUF(h); (s) != (t); \
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(s) = NILFS_NEXT_SEGBUF(s))
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#define NILFS_SEGBUF_FIRST_BH(head) \
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(list_entry((head)->next, struct buffer_head, b_assoc_buffers))
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#define NILFS_SEGBUF_NEXT_BH(bh) \
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(list_entry((bh)->b_assoc_buffers.next, struct buffer_head, \
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b_assoc_buffers))
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#define NILFS_SEGBUF_BH_IS_LAST(bh, head) ((bh)->b_assoc_buffers.next == head)
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extern struct kmem_cache *nilfs_segbuf_cachep;
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int __init nilfs_init_segbuf_cache(void);
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void nilfs_destroy_segbuf_cache(void);
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struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
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void nilfs_segbuf_free(struct nilfs_segment_buffer *);
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void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
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struct the_nilfs *);
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void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
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struct nilfs_segment_buffer *prev);
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void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
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struct the_nilfs *);
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int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t, __u64);
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int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
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int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
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struct buffer_head **);
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void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
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static inline void
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nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer *segbuf,
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struct buffer_head *bh)
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{
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list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_segsum_buffers);
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segbuf->sb_sum.nblocks++;
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segbuf->sb_sum.nsumblk++;
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}
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static inline void
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nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer *segbuf,
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struct buffer_head *bh)
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{
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list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_payload_buffers);
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segbuf->sb_sum.nblocks++;
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}
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static inline void
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nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer *segbuf,
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struct buffer_head *bh)
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{
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get_bh(bh);
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nilfs_segbuf_add_payload_buffer(segbuf, bh);
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segbuf->sb_sum.nfileblk++;
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}
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void nilfs_clear_logs(struct list_head *logs);
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void nilfs_truncate_logs(struct list_head *logs,
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struct nilfs_segment_buffer *last);
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int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs);
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int nilfs_wait_on_logs(struct list_head *logs);
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void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed);
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static inline void nilfs_destroy_logs(struct list_head *logs)
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{
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nilfs_truncate_logs(logs, NULL);
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}
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#endif /* _NILFS_SEGBUF_H */
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