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
nilfs_segbuf_simplex(struct nilfs_segment_buffer * segbuf)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
nilfs_segbuf_empty(struct nilfs_segment_buffer * segbuf)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
nilfs_segbuf_add_segsum_buffer(struct nilfs_segment_buffer * segbuf,struct buffer_head * bh)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
nilfs_segbuf_add_payload_buffer(struct nilfs_segment_buffer * segbuf,struct buffer_head * bh)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
nilfs_segbuf_add_file_buffer(struct nilfs_segment_buffer * segbuf,struct buffer_head * bh)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
nilfs_destroy_logs(struct list_head * logs)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 */
185