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  */
  44 struct 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  */
  82 struct 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
 122 int __init nilfs_init_segbuf_cache(void);
 123 void nilfs_destroy_segbuf_cache(void);
 124 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
 125 void nilfs_segbuf_free(struct nilfs_segment_buffer *);
 126 void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
 127                       struct the_nilfs *);
 128 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
 129                                   struct the_nilfs *);
 130 int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t);
 131 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
 132 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
 133                                 struct buffer_head **);
 134 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
 135 void nilfs_segbuf_fill_in_segsum_crc(struct nilfs_segment_buffer *, u32);
 136 void nilfs_segbuf_fill_in_data_crc(struct nilfs_segment_buffer *, u32);
 137
 138 static inline void
 139 nilfs_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
 147 static inline void
 148 nilfs_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
 155 static inline void
 156 nilfs_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
 164 void nilfs_release_buffers(struct list_head *);
 165
 166 static 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
 172 struct 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
 194 void nilfs_segbuf_prepare_write(struct nilfs_segment_buffer *,
 195                                 struct nilfs_write_info *);
 196 int nilfs_segbuf_write(struct nilfs_segment_buffer *,
 197                        struct nilfs_write_info *);
 198 int nilfs_segbuf_wait(struct nilfs_segment_buffer *,
 199                       struct nilfs_write_info *);
 200
 201 #endif /* _NILFS_SEGBUF_H */