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  * 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  */
  40 struct 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  */
  71 struct 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
 113 extern struct kmem_cache *nilfs_segbuf_cachep;
 114
 115 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
 116 void nilfs_segbuf_free(struct nilfs_segment_buffer *);
 117 void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
 118                       struct the_nilfs *);
 119 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
 120                            struct nilfs_segment_buffer *prev);
 121 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
 122                                   struct the_nilfs *);
 123 int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned int, time_t,
 124                        __u64);
 125 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
 126 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
 127                                 struct buffer_head **);
 128 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
 129
 130 static 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
 138 static inline int nilfs_segbuf_empty(struct nilfs_segment_buffer *segbuf)
 139 {
 140         return segbuf->sb_sum.nblocks == segbuf->sb_sum.nsumblk;
 141 }
 142
 143 static inline void
 144 nilfs_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
 152 static inline void
 153 nilfs_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
 160 static inline void
 161 nilfs_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
 169 void nilfs_clear_logs(struct list_head *logs);
 170 void nilfs_truncate_logs(struct list_head *logs,
 171                          struct nilfs_segment_buffer *last);
 172 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs);
 173 int nilfs_wait_on_logs(struct list_head *logs);
 174 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed);
 175
 176 static inline void nilfs_destroy_logs(struct list_head *logs)
 177 {
 178         nilfs_truncate_logs(logs, NULL);
 179 }
 180
 181 #endif /* _NILFS_SEGBUF_H */