linux/fs/nilfs2/segbuf.h
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   1/* SPDX-License-Identifier: GPL-2.0+ */
   2/*
   3 * segbuf.h - NILFS Segment buffer prototypes and definitions
   4 *
   5 * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6 *
   7 * Written by Ryusuke Konishi.
   8 *
   9 */
  10#ifndef _NILFS_SEGBUF_H
  11#define _NILFS_SEGBUF_H
  12
  13#include <linux/fs.h>
  14#include <linux/buffer_head.h>
  15#include <linux/bio.h>
  16#include <linux/completion.h>
  17
  18/**
  19 * struct nilfs_segsum_info - On-memory segment summary
  20 * @flags: Flags
  21 * @nfinfo: Number of file information structures
  22 * @nblocks: Number of blocks included in the partial segment
  23 * @nsumblk: Number of summary blocks
  24 * @sumbytes: Byte count of segment summary
  25 * @nfileblk: Total number of file blocks
  26 * @seg_seq: Segment sequence number
  27 * @cno: Checkpoint number
  28 * @ctime: Creation time
  29 * @next: Block number of the next full segment
  30 */
  31struct nilfs_segsum_info {
  32        unsigned int            flags;
  33        unsigned long           nfinfo;
  34        unsigned long           nblocks;
  35        unsigned long           nsumblk;
  36        unsigned long           sumbytes;
  37        unsigned long           nfileblk;
  38        u64                     seg_seq;
  39        __u64                   cno;
  40        time64_t                ctime;
  41        sector_t                next;
  42};
  43
  44/**
  45 * struct nilfs_segment_buffer - Segment buffer
  46 * @sb_super: back pointer to a superblock struct
  47 * @sb_list: List head to chain this structure
  48 * @sb_sum: On-memory segment summary
  49 * @sb_segnum: Index number of the full segment
  50 * @sb_nextnum: Index number of the next full segment
  51 * @sb_fseg_start: Start block number of the full segment
  52 * @sb_fseg_end: End block number of the full segment
  53 * @sb_pseg_start: Disk block number of partial segment
  54 * @sb_rest_blocks: Number of residual blocks in the current segment
  55 * @sb_segsum_buffers: List of buffers for segment summaries
  56 * @sb_payload_buffers: List of buffers for segment payload
  57 * @sb_super_root: Pointer to buffer storing a super root block (if exists)
  58 * @sb_nbio: Number of flying bio requests
  59 * @sb_err: I/O error status
  60 * @sb_bio_event: Completion event of log writing
  61 */
  62struct nilfs_segment_buffer {
  63        struct super_block     *sb_super;
  64        struct list_head        sb_list;
  65
  66        /* Segment information */
  67        struct nilfs_segsum_info sb_sum;
  68        __u64                   sb_segnum;
  69        __u64                   sb_nextnum;
  70        sector_t                sb_fseg_start, sb_fseg_end;
  71        sector_t                sb_pseg_start;
  72        unsigned int            sb_rest_blocks;
  73
  74        /* Buffers */
  75        struct list_head        sb_segsum_buffers;
  76        struct list_head        sb_payload_buffers; /* including super root */
  77        struct buffer_head     *sb_super_root;
  78
  79        /* io status */
  80        int                     sb_nbio;
  81        atomic_t                sb_err;
  82        struct completion       sb_bio_event;
  83};
  84
  85#define NILFS_LIST_SEGBUF(head)  \
  86        list_entry((head), struct nilfs_segment_buffer, sb_list)
  87#define NILFS_NEXT_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.next)
  88#define NILFS_PREV_SEGBUF(segbuf)  NILFS_LIST_SEGBUF((segbuf)->sb_list.prev)
  89#define NILFS_LAST_SEGBUF(head)    NILFS_LIST_SEGBUF((head)->prev)
  90#define NILFS_FIRST_SEGBUF(head)   NILFS_LIST_SEGBUF((head)->next)
  91#define NILFS_SEGBUF_IS_LAST(segbuf, head)  ((segbuf)->sb_list.next == (head))
  92
  93#define nilfs_for_each_segbuf_before(s, t, h) \
  94        for ((s) = NILFS_FIRST_SEGBUF(h); (s) != (t); \
  95             (s) = NILFS_NEXT_SEGBUF(s))
  96
  97#define NILFS_SEGBUF_FIRST_BH(head)  \
  98        (list_entry((head)->next, struct buffer_head, b_assoc_buffers))
  99#define NILFS_SEGBUF_NEXT_BH(bh)  \
 100        (list_entry((bh)->b_assoc_buffers.next, struct buffer_head, \
 101                    b_assoc_buffers))
 102#define NILFS_SEGBUF_BH_IS_LAST(bh, head)  ((bh)->b_assoc_buffers.next == head)
 103
 104extern struct kmem_cache *nilfs_segbuf_cachep;
 105
 106struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
 107void nilfs_segbuf_free(struct nilfs_segment_buffer *);
 108void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
 109                      struct the_nilfs *);
 110void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
 111                           struct nilfs_segment_buffer *prev);
 112void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
 113                                  struct the_nilfs *);
 114int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned int, time64_t,
 115                       __u64);
 116int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
 117int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
 118                                struct buffer_head **);
 119void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
 120
 121static inline int nilfs_segbuf_simplex(struct nilfs_segment_buffer *segbuf)
 122{
 123        unsigned int flags = segbuf->sb_sum.flags;
 124
 125        return (flags & (NILFS_SS_LOGBGN | NILFS_SS_LOGEND)) ==
 126                (NILFS_SS_LOGBGN | NILFS_SS_LOGEND);
 127}
 128
 129static inline int nilfs_segbuf_empty(struct nilfs_segment_buffer *segbuf)
 130{
 131        return segbuf->sb_sum.nblocks == segbuf->sb_sum.nsumblk;
 132}
 133
 134static inline void
 135nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer *segbuf,
 136                               struct buffer_head *bh)
 137{
 138        list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_segsum_buffers);
 139        segbuf->sb_sum.nblocks++;
 140        segbuf->sb_sum.nsumblk++;
 141}
 142
 143static inline void
 144nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer *segbuf,
 145                                struct buffer_head *bh)
 146{
 147        list_add_tail(&bh->b_assoc_buffers, &segbuf->sb_payload_buffers);
 148        segbuf->sb_sum.nblocks++;
 149}
 150
 151static inline void
 152nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer *segbuf,
 153                             struct buffer_head *bh)
 154{
 155        get_bh(bh);
 156        nilfs_segbuf_add_payload_buffer(segbuf, bh);
 157        segbuf->sb_sum.nfileblk++;
 158}
 159
 160void nilfs_clear_logs(struct list_head *logs);
 161void nilfs_truncate_logs(struct list_head *logs,
 162                         struct nilfs_segment_buffer *last);
 163int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs);
 164int nilfs_wait_on_logs(struct list_head *logs);
 165void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed);
 166
 167static inline void nilfs_destroy_logs(struct list_head *logs)
 168{
 169        nilfs_truncate_logs(logs, NULL);
 170}
 171
 172#endif /* _NILFS_SEGBUF_H */
 173