LXR linux/fs/nilfs2/segbuf.h

   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#include <linux/backing-dev.h>
  31
  32/**
  33 * struct nilfs_segsum_info - On-memory segment summary
  34 * @flags: Flags
  35 * @nfinfo: Number of file information structures
  36 * @nblocks: Number of blocks included in the partial segment
  37 * @nsumblk: Number of summary blocks
  38 * @sumbytes: Byte count of segment summary
  39 * @nfileblk: Total number of file blocks
  40 * @seg_seq: Segment sequence 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        time_t                  ctime;
  53        sector_t                next;
  54};
  55
  56/* macro for the flags */
  57#define NILFS_SEG_HAS_SR(sum)    ((sum)->flags & NILFS_SS_SR)
  58#define NILFS_SEG_LOGBGN(sum)    ((sum)->flags & NILFS_SS_LOGBGN)
  59#define NILFS_SEG_LOGEND(sum)    ((sum)->flags & NILFS_SS_LOGEND)
  60#define NILFS_SEG_DSYNC(sum)     ((sum)->flags & NILFS_SS_SYNDT)
  61#define NILFS_SEG_SIMPLEX(sum) \
  62        (((sum)->flags & (NILFS_SS_LOGBGN | NILFS_SS_LOGEND)) == \
  63         (NILFS_SS_LOGBGN | NILFS_SS_LOGEND))
  64
  65#define NILFS_SEG_EMPTY(sum)    ((sum)->nblocks == (sum)->nsumblk)
  66
  67/**
  68 * struct nilfs_segment_buffer - Segment buffer
  69 * @sb_super: back pointer to a superblock struct
  70 * @sb_list: List head to chain this structure
  71 * @sb_sum: On-memory segment summary
  72 * @sb_segnum: Index number of the full segment
  73 * @sb_nextnum: Index number of the next full segment
  74 * @sb_fseg_start: Start block number of the full segment
  75 * @sb_fseg_end: End block number of the full segment
  76 * @sb_pseg_start: Disk block number of partial segment
  77 * @sb_rest_blocks: Number of residual blocks in the current segment
  78 * @sb_segsum_buffers: List of buffers for segment summaries
  79 * @sb_payload_buffers: List of buffers for segment payload
  80 * @sb_io_error: I/O error status
  81 */
  82struct nilfs_segment_buffer {
  83        struct super_block     *sb_super;
  84        struct list_head        sb_list;
  85
  86        /* Segment information */
  87        struct nilfs_segsum_info sb_sum;
  88        __u64                   sb_segnum;
  89        __u64                   sb_nextnum;
  90        sector_t                sb_fseg_start, sb_fseg_end;
  91        sector_t                sb_pseg_start;
  92        unsigned                sb_rest_blocks;
  93
  94        /* Buffers */
  95        struct list_head        sb_segsum_buffers;
  96        struct list_head        sb_payload_buffers; /* including super root */
  97
  98        /* io status */
  99        int                     sb_io_error;
 100};
 101
 102#define NILFS_LIST_SEGBUF(head)  \
 103        list_entry((head), struct nilfs_segment_buffer, sb_list)
 104#define NILFS_NEXT_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.next)
 105#define NILFS_PREV_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.prev)
 106#define NILFS_LAST_SEGBUF(head)    NILFS_LIST_SEGBUF((head)->prev)
 107#define NILFS_FIRST_SEGBUF(head)   NILFS_LIST_SEGBUF((head)->next)
 108#define NILFS_SEGBUF_IS_LAST(segbuf, head)  ((segbuf)->sb_list.next == (head))
 109
 110#define nilfs_for_each_segbuf_before(s, t, h) \
 111        for ((s) = NILFS_FIRST_SEGBUF(h); (s) != (t); \
 112             (s) = NILFS_NEXT_SEGBUF(s))
 113
 114#define NILFS_SEGBUF_FIRST_BH(head)  \
 115        (list_entry((head)->next, struct buffer_head, b_assoc_buffers))
 116#define NILFS_SEGBUF_NEXT_BH(bh)  \
 117        (list_entry((bh)->b_assoc_buffers.next, struct buffer_head, \
 118                    b_assoc_buffers))
 119#define NILFS_SEGBUF_BH_IS_LAST(bh, head)  ((bh)->b_assoc_buffers.next == head)
 120
 121
 122int __init nilfs_init_segbuf_cache(void);
 123void nilfs_destroy_segbuf_cache(void);
 124struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
 125void nilfs_segbuf_free(struct nilfs_segment_buffer *);
 126void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
 127                      struct the_nilfs *);
 128void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
 129                                  struct the_nilfs *);
 130int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t);
 131int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
 132int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
 133                                struct buffer_head **);
 134void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
 135void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *, u32);
 136void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *, u32);
 137
 138static inline void
 139nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer *segbuf,
 140                               struct buffer_head *bh)
 141{
 142        list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_segsum_buffers);
 143        segbuf->sb_sum.nblocks++;
 144        segbuf->sb_sum.nsumblk++;
 145}
 146
 147static inline void
 148nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer *segbuf,
 149                                struct buffer_head *bh)
 150{
 151        list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_payload_buffers);
 152        segbuf->sb_sum.nblocks++;
 153}
 154
 155static inline void
 156nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer *segbuf,
 157                             struct buffer_head *bh)
 158{
 159        get_bh(bh);
 160        nilfs_segbuf_add_payload_buffer(segbuf, bh);
 161        segbuf->sb_sum.nfileblk++;
 162}
 163
 164void nilfs_release_buffers(struct list_head *);
 165
 166static inline void nilfs_segbuf_clear(struct nilfs_segment_buffer *segbuf)
 167{
 168        nilfs_release_buffers(&segbuf->sb_segsum_buffers);
 169        nilfs_release_buffers(&segbuf->sb_payload_buffers);
 170}
 171
 172struct nilfs_write_info {
 173        struct bio             *bio;
 174        int                     start, end; /* The region to be submitted */
 175        int                     rest_blocks;
 176        int                     max_pages;
 177        int                     nr_vecs;
 178        sector_t                blocknr;
 179
 180        int                     nbio;
 181        atomic_t                err;
 182        struct completion       bio_event;
 183                                /* completion event of segment write */
 184
 185        /*
 186         * The following fields must be set explicitly
 187         */
 188        struct super_block     *sb;
 189        struct backing_dev_info *bdi; /* backing dev info */
 190        struct buffer_head     *bh_sr;
 191};
 192
 193
 194void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *,
 195                                struct nilfs_write_info *);
 196int nilfs_segbuf_write(struct nilfs_segment_buffer *,
 197                       struct nilfs_write_info *);
 198int nilfs_segbuf_wait(struct nilfs_segment_buffer *,
 199                      struct nilfs_write_info *);
 200
 201#endif /* _NILFS_SEGBUF_H */
 202