xref: /linux/fs/nilfs2/segbuf.h (revision 60e13231561b3a4c5269bfa1ef6c0569ad6f28ec)
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 */
185