linux/fs/nilfs2/segbuf.h
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   1/*
   2 * segbuf.h - NILFS Segment buffer prototypes and definitions
   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 <ryusuke@osrg.net>
  21 *
  22 */
  23#ifndef _NILFS_SEGBUF_H
  24#define _NILFS_SEGBUF_H
  25
  26#include <linux/fs.h>
  27#include <linux/buffer_head.h>
  28#include <linux/bio.h>
  29#include <linux/completion.h>
  30
  31/**
  32 * struct nilfs_segsum_info - On-memory segment summary
  33 * @flags: Flags
  34 * @nfinfo: Number of file information structures
  35 * @nblocks: Number of blocks included in the partial segment
  36 * @nsumblk: Number of summary blocks
  37 * @sumbytes: Byte count of segment summary
  38 * @nfileblk: Total number of file blocks
  39 * @seg_seq: Segment sequence number
  40 * @cno: Checkpoint number
  41 * @ctime: Creation time
  42 * @next: Block number of the next full segment
  43 */
  44struct nilfs_segsum_info {
  45        unsigned int            flags;
  46        unsigned long           nfinfo;
  47        unsigned long           nblocks;
  48        unsigned long           nsumblk;
  49        unsigned long           sumbytes;
  50        unsigned long           nfileblk;
  51        u64                     seg_seq;
  52        __u64                   cno;
  53        time_t                  ctime;
  54        sector_t                next;
  55};
  56
  57/**
  58 * struct nilfs_segment_buffer - Segment buffer
  59 * @sb_super: back pointer to a superblock struct
  60 * @sb_list: List head to chain this structure
  61 * @sb_sum: On-memory segment summary
  62 * @sb_segnum: Index number of the full segment
  63 * @sb_nextnum: Index number of the next full segment
  64 * @sb_fseg_start: Start block number of the full segment
  65 * @sb_fseg_end: End block number of the full segment
  66 * @sb_pseg_start: Disk block number of partial segment
  67 * @sb_rest_blocks: Number of residual blocks in the current segment
  68 * @sb_segsum_buffers: List of buffers for segment summaries
  69 * @sb_payload_buffers: List of buffers for segment payload
  70 * @sb_super_root: Pointer to buffer storing a super root block (if exists)
  71 * @sb_nbio: Number of flying bio requests
  72 * @sb_err: I/O error status
  73 * @sb_bio_event: Completion event of log writing
  74 */
  75struct nilfs_segment_buffer {
  76        struct super_block     *sb_super;
  77        struct list_head        sb_list;
  78
  79        /* Segment information */
  80        struct nilfs_segsum_info sb_sum;
  81        __u64                   sb_segnum;
  82        __u64                   sb_nextnum;
  83        sector_t                sb_fseg_start, sb_fseg_end;
  84        sector_t                sb_pseg_start;
  85        unsigned                sb_rest_blocks;
  86
  87        /* Buffers */
  88        struct list_head        sb_segsum_buffers;
  89        struct list_head        sb_payload_buffers; /* including super root */
  90        struct buffer_head     *sb_super_root;
  91
  92        /* io status */
  93        int                     sb_nbio;
  94        atomic_t                sb_err;
  95        struct completion       sb_bio_event;
  96};
  97
  98#define NILFS_LIST_SEGBUF(head)  \
  99        list_entry((head), struct nilfs_segment_buffer, sb_list)
 100#define NILFS_NEXT_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.next)
 101#define NILFS_PREV_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.prev)
 102#define NILFS_LAST_SEGBUF(head)    NILFS_LIST_SEGBUF((head)->prev)
 103#define NILFS_FIRST_SEGBUF(head)   NILFS_LIST_SEGBUF((head)->next)
 104#define NILFS_SEGBUF_IS_LAST(segbuf, head)  ((segbuf)->sb_list.next == (head))
 105
 106#define nilfs_for_each_segbuf_before(s, t, h) \
 107        for ((s) = NILFS_FIRST_SEGBUF(h); (s) != (t); \
 108             (s) = NILFS_NEXT_SEGBUF(s))
 109
 110#define NILFS_SEGBUF_FIRST_BH(head)  \
 111        (list_entry((head)->next, struct buffer_head, b_assoc_buffers))
 112#define NILFS_SEGBUF_NEXT_BH(bh)  \
 113        (list_entry((bh)->b_assoc_buffers.next, struct buffer_head, \
 114                    b_assoc_buffers))
 115#define NILFS_SEGBUF_BH_IS_LAST(bh, head)  ((bh)->b_assoc_buffers.next == head)
 116
 117extern struct kmem_cache *nilfs_segbuf_cachep;
 118
 119struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
 120void nilfs_segbuf_free(struct nilfs_segment_buffer *);
 121void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
 122                      struct the_nilfs *);
 123void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
 124                           struct nilfs_segment_buffer *prev);
 125void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
 126                                  struct the_nilfs *);
 127int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t, __u64);
 128int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
 129int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
 130                                struct buffer_head **);
 131void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
 132
 133static inline int nilfs_segbuf_simplex(struct nilfs_segment_buffer *segbuf)
 134{
 135        unsigned int flags = segbuf->sb_sum.flags;
 136
 137        return (flags & (NILFS_SS_LOGBGN | NILFS_SS_LOGEND)) ==
 138                (NILFS_SS_LOGBGN | NILFS_SS_LOGEND);
 139}
 140
 141static inline int nilfs_segbuf_empty(struct nilfs_segment_buffer *segbuf)
 142{
 143        return segbuf->sb_sum.nblocks == segbuf->sb_sum.nsumblk;
 144}
 145
 146static inline void
 147nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer *segbuf,
 148                               struct buffer_head *bh)
 149{
 150        list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_segsum_buffers);
 151        segbuf->sb_sum.nblocks++;
 152        segbuf->sb_sum.nsumblk++;
 153}
 154
 155static inline void
 156nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer *segbuf,
 157                                struct buffer_head *bh)
 158{
 159        list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_payload_buffers);
 160        segbuf->sb_sum.nblocks++;
 161}
 162
 163static inline void
 164nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer *segbuf,
 165                             struct buffer_head *bh)
 166{
 167        get_bh(bh);
 168        nilfs_segbuf_add_payload_buffer(segbuf, bh);
 169        segbuf->sb_sum.nfileblk++;
 170}
 171
 172void nilfs_clear_logs(struct list_head *logs);
 173void nilfs_truncate_logs(struct list_head *logs,
 174                         struct nilfs_segment_buffer *last);
 175int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs);
 176int nilfs_wait_on_logs(struct list_head *logs);
 177void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed);
 178
 179static inline void nilfs_destroy_logs(struct list_head *logs)
 180{
 181        nilfs_truncate_logs(logs, NULL);
 182}
 183
 184#endif /* _NILFS_SEGBUF_H */
 185
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