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
nilfs_segbuf_simplex(struct nilfs_segment_buffer * segbuf)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
nilfs_segbuf_empty(struct nilfs_segment_buffer * segbuf)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
nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer * segbuf,struct buffer_head * bh)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
nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer * segbuf,struct buffer_head * bh)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
nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer * segbuf,struct buffer_head * bh)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
nilfs_destroy_logs(struct list_head * logs)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 */
182