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
  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  */
  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         __u64                   cno;
  53         time_t                  ctime;
  54         sector_t                next;
  55 };
  56
  57 /* macro for the flags */
  58 #define NILFS_SEG_HAS_SR(sum)    ((sum)->flags & NILFS_SS_SR)
  59 #define NILFS_SEG_LOGBGN(sum)    ((sum)->flags & NILFS_SS_LOGBGN)
  60 #define NILFS_SEG_LOGEND(sum)    ((sum)->flags & NILFS_SS_LOGEND)
  61 #define NILFS_SEG_DSYNC(sum)     ((sum)->flags & NILFS_SS_SYNDT)
  62 #define NILFS_SEG_SIMPLEX(sum) \
  63         (((sum)->flags & (NILFS_SS_LOGBGN | NILFS_SS_LOGEND)) == \
  64          (NILFS_SS_LOGBGN | NILFS_SS_LOGEND))
  65
  66 #define NILFS_SEG_EMPTY(sum)    ((sum)->nblocks == (sum)->nsumblk)
  67
  68 /**
  69  * struct nilfs_segment_buffer - Segment buffer
  70  * @sb_super: back pointer to a superblock struct
  71  * @sb_list: List head to chain this structure
  72  * @sb_sum: On-memory segment summary
  73  * @sb_segnum: Index number of the full segment
  74  * @sb_nextnum: Index number of the next full segment
  75  * @sb_fseg_start: Start block number of the full segment
  76  * @sb_fseg_end: End block number of the full segment
  77  * @sb_pseg_start: Disk block number of partial segment
  78  * @sb_rest_blocks: Number of residual blocks in the current segment
  79  * @sb_segsum_buffers: List of buffers for segment summaries
  80  * @sb_payload_buffers: List of buffers for segment payload
  81  * @sb_super_root: Pointer to buffer storing a super root block (if exists)
  82  * @sb_nbio: Number of flying bio requests
  83  * @sb_err: I/O error status
  84  * @sb_bio_event: Completion event of log writing
  85  */
  86 struct nilfs_segment_buffer {
  87         struct super_block     *sb_super;
  88         struct list_head        sb_list;
  89
  90         /* Segment information */
  91         struct nilfs_segsum_info sb_sum;
  92         __u64                   sb_segnum;
  93         __u64                   sb_nextnum;
  94         sector_t                sb_fseg_start, sb_fseg_end;
  95         sector_t                sb_pseg_start;
  96         unsigned                sb_rest_blocks;
  97
  98         /* Buffers */
  99         struct list_head        sb_segsum_buffers;
 100         struct list_head        sb_payload_buffers; /* including super root */
 101         struct buffer_head     *sb_super_root;
 102
 103         /* io status */
 104         int                     sb_nbio;
 105         atomic_t                sb_err;
 106         struct completion       sb_bio_event;
 107 };
 108
 109 #define NILFS_LIST_SEGBUF(head)  \
 110         list_entry((head), struct nilfs_segment_buffer, sb_list)
 111 #define NILFS_NEXT_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.next)
 112 #define NILFS_PREV_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.prev)
 113 #define NILFS_LAST_SEGBUF(head)    NILFS_LIST_SEGBUF((head)->prev)
 114 #define NILFS_FIRST_SEGBUF(head)   NILFS_LIST_SEGBUF((head)->next)
 115 #define NILFS_SEGBUF_IS_LAST(segbuf, head)  ((segbuf)->sb_list.next == (head))
 116
 117 #define nilfs_for_each_segbuf_before(s, t, h) \
 118         for ((s) = NILFS_FIRST_SEGBUF(h); (s) != (t); \
 119              (s) = NILFS_NEXT_SEGBUF(s))
 120
 121 #define NILFS_SEGBUF_FIRST_BH(head)  \
 122         (list_entry((head)->next, struct buffer_head, b_assoc_buffers))
 123 #define NILFS_SEGBUF_NEXT_BH(bh)  \
 124         (list_entry((bh)->b_assoc_buffers.next, struct buffer_head, \
 125                     b_assoc_buffers))
 126 #define NILFS_SEGBUF_BH_IS_LAST(bh, head)  ((bh)->b_assoc_buffers.next == head)
 127
 128 extern struct kmem_cache *nilfs_segbuf_cachep;
 129
 130 int __init nilfs_init_segbuf_cache(void);
 131 void nilfs_destroy_segbuf_cache(void);
 132 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
 133 void nilfs_segbuf_free(struct nilfs_segment_buffer *);
 134 void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
 135                       struct the_nilfs *);
 136 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
 137                            struct nilfs_segment_buffer *prev);
 138 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
 139                                   struct the_nilfs *);
 140 int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned, time_t, __u64);
 141 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
 142 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
 143                                 struct buffer_head **);
 144 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
 145
 146 static inline void
 147 nilfs_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
 155 static inline void
 156 nilfs_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
 163 static inline void
 164 nilfs_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
 172 void nilfs_clear_logs(struct list_head *logs);
 173 void nilfs_truncate_logs(struct list_head *logs,
 174                          struct nilfs_segment_buffer *last);
 175 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs);
 176 int nilfs_wait_on_logs(struct list_head *logs);
 177 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed);
 178
 179 static inline void nilfs_destroy_logs(struct list_head *logs)
 180 {
 181         nilfs_truncate_logs(logs, NULL);
 182 }
 183
 184 #endif /* _NILFS_SEGBUF_H */