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