linux/fs/nilfs2/segbuf.h
<<
>>
Prefs
   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 * Written by Ryusuke Konishi.
  17 *
  18 */
  19#ifndef _NILFS_SEGBUF_H
  20#define _NILFS_SEGBUF_H
  21
  22#include <linux/fs.h>
  23#include <linux/buffer_head.h>
  24#include <linux/bio.h>
  25#include <linux/completion.h>
  26
  27/**
  28 * struct nilfs_segsum_info - On-memory segment summary
  29 * @flags: Flags
  30 * @nfinfo: Number of file information structures
  31 * @nblocks: Number of blocks included in the partial segment
  32 * @nsumblk: Number of summary blocks
  33 * @sumbytes: Byte count of segment summary
  34 * @nfileblk: Total number of file blocks
  35 * @seg_seq: Segment sequence number
  36 * @cno: Checkpoint number
  37 * @ctime: Creation time
  38 * @next: Block number of the next full segment
  39 */
  40struct nilfs_segsum_info {
  41        unsigned int            flags;
  42        unsigned long           nfinfo;
  43        unsigned long           nblocks;
  44        unsigned long           nsumblk;
  45        unsigned long           sumbytes;
  46        unsigned long           nfileblk;
  47        u64                     seg_seq;
  48        __u64                   cno;
  49        time_t                  ctime;
  50        sector_t                next;
  51};
  52
  53/**
  54 * struct nilfs_segment_buffer - Segment buffer
  55 * @sb_super: back pointer to a superblock struct
  56 * @sb_list: List head to chain this structure
  57 * @sb_sum: On-memory segment summary
  58 * @sb_segnum: Index number of the full segment
  59 * @sb_nextnum: Index number of the next full segment
  60 * @sb_fseg_start: Start block number of the full segment
  61 * @sb_fseg_end: End block number of the full segment
  62 * @sb_pseg_start: Disk block number of partial segment
  63 * @sb_rest_blocks: Number of residual blocks in the current segment
  64 * @sb_segsum_buffers: List of buffers for segment summaries
  65 * @sb_payload_buffers: List of buffers for segment payload
  66 * @sb_super_root: Pointer to buffer storing a super root block (if exists)
  67 * @sb_nbio: Number of flying bio requests
  68 * @sb_err: I/O error status
  69 * @sb_bio_event: Completion event of log writing
  70 */
  71struct nilfs_segment_buffer {
  72        struct super_block     *sb_super;
  73        struct list_head        sb_list;
  74
  75        /* Segment information */
  76        struct nilfs_segsum_info sb_sum;
  77        __u64                   sb_segnum;
  78        __u64                   sb_nextnum;
  79        sector_t                sb_fseg_start, sb_fseg_end;
  80        sector_t                sb_pseg_start;
  81        unsigned int            sb_rest_blocks;
  82
  83        /* Buffers */
  84        struct list_head        sb_segsum_buffers;
  85        struct list_head        sb_payload_buffers; /* including super root */
  86        struct buffer_head     *sb_super_root;
  87
  88        /* io status */
  89        int                     sb_nbio;
  90        atomic_t                sb_err;
  91        struct completion       sb_bio_event;
  92};
  93
  94#define NILFS_LIST_SEGBUF(head)  \
  95        list_entry((head), struct nilfs_segment_buffer, sb_list)
  96#define NILFS_NEXT_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.next)
  97#define NILFS_PREV_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.prev)
  98#define NILFS_LAST_SEGBUF(head)    NILFS_LIST_SEGBUF((head)->prev)
  99#define NILFS_FIRST_SEGBUF(head)   NILFS_LIST_SEGBUF((head)->next)
 100#define NILFS_SEGBUF_IS_LAST(segbuf, head)  ((segbuf)->sb_list.next == (head))
 101
 102#define nilfs_for_each_segbuf_before(s, t, h) \
 103        for ((s) = NILFS_FIRST_SEGBUF(h); (s) != (t); \
 104             (s) = NILFS_NEXT_SEGBUF(s))
 105
 106#define NILFS_SEGBUF_FIRST_BH(head)  \
 107        (list_entry((head)->next, struct buffer_head, b_assoc_buffers))
 108#define NILFS_SEGBUF_NEXT_BH(bh)  \
 109        (list_entry((bh)->b_assoc_buffers.next, struct buffer_head, \
 110                    b_assoc_buffers))
 111#define NILFS_SEGBUF_BH_IS_LAST(bh, head)  ((bh)->b_assoc_buffers.next == head)
 112
 113extern struct kmem_cache *nilfs_segbuf_cachep;
 114
 115struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
 116void nilfs_segbuf_free(struct nilfs_segment_buffer *);
 117void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
 118                      struct the_nilfs *);
 119void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
 120                           struct nilfs_segment_buffer *prev);
 121void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
 122                                  struct the_nilfs *);
 123int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned int, time_t,
 124                       __u64);
 125int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
 126int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
 127                                struct buffer_head **);
 128void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
 129
 130static inline int nilfs_segbuf_simplex(struct nilfs_segment_buffer *segbuf)
 131{
 132        unsigned int flags = segbuf->sb_sum.flags;
 133
 134        return (flags & (NILFS_SS_LOGBGN | NILFS_SS_LOGEND)) ==
 135                (NILFS_SS_LOGBGN | NILFS_SS_LOGEND);
 136}
 137
 138static inline int nilfs_segbuf_empty(struct nilfs_segment_buffer *segbuf)
 139{
 140        return segbuf->sb_sum.nblocks == segbuf->sb_sum.nsumblk;
 141}
 142
 143static inline void
 144nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer *segbuf,
 145                               struct buffer_head *bh)
 146{
 147        list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_segsum_buffers);
 148        segbuf->sb_sum.nblocks++;
 149        segbuf->sb_sum.nsumblk++;
 150}
 151
 152static inline void
 153nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer *segbuf,
 154                                struct buffer_head *bh)
 155{
 156        list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_payload_buffers);
 157        segbuf->sb_sum.nblocks++;
 158}
 159
 160static inline void
 161nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer *segbuf,
 162                             struct buffer_head *bh)
 163{
 164        get_bh(bh);
 165        nilfs_segbuf_add_payload_buffer(segbuf, bh);
 166        segbuf->sb_sum.nfileblk++;
 167}
 168
 169void nilfs_clear_logs(struct list_head *logs);
 170void nilfs_truncate_logs(struct list_head *logs,
 171                         struct nilfs_segment_buffer *last);
 172int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs);
 173int nilfs_wait_on_logs(struct list_head *logs);
 174void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed);
 175
 176static inline void nilfs_destroy_logs(struct list_head *logs)
 177{
 178        nilfs_truncate_logs(logs, NULL);
 179}
 180
 181#endif /* _NILFS_SEGBUF_H */
 182