1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * 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 */
31 struct 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 */
62 struct 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
104 extern struct kmem_cache *nilfs_segbuf_cachep;
105
106 struct nilfs_segment_buffer *nilfs_segbuf_new(struct super_block *);
107 void nilfs_segbuf_free(struct nilfs_segment_buffer *);
108 void nilfs_segbuf_map(struct nilfs_segment_buffer *, __u64, unsigned long,
109 struct the_nilfs *);
110 void nilfs_segbuf_map_cont(struct nilfs_segment_buffer *segbuf,
111 struct nilfs_segment_buffer *prev);
112 void nilfs_segbuf_set_next_segnum(struct nilfs_segment_buffer *, __u64,
113 struct the_nilfs *);
114 int nilfs_segbuf_reset(struct nilfs_segment_buffer *, unsigned int, time64_t,
115 __u64);
116 int nilfs_segbuf_extend_segsum(struct nilfs_segment_buffer *);
117 int nilfs_segbuf_extend_payload(struct nilfs_segment_buffer *,
118 struct buffer_head **);
119 void nilfs_segbuf_fill_in_segsum(struct nilfs_segment_buffer *);
120
121 static 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
129 static inline int nilfs_segbuf_empty(struct nilfs_segment_buffer *segbuf)
130 {
131 return segbuf->sb_sum.nblocks == segbuf->sb_sum.nsumblk;
132 }
133
134 static inline void
135 nilfs_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
143 static inline void
144 nilfs_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
151 static inline void
152 nilfs_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
160 void nilfs_clear_logs(struct list_head *logs);
161 void nilfs_truncate_logs(struct list_head *logs,
162 struct nilfs_segment_buffer *last);
163 int nilfs_write_logs(struct list_head *logs, struct the_nilfs *nilfs);
164 int nilfs_wait_on_logs(struct list_head *logs);
165 void nilfs_add_checksums_on_logs(struct list_head *logs, u32 seed);
166
167 static inline void nilfs_destroy_logs(struct list_head *logs)
168 {
169 nilfs_truncate_logs(logs, NULL);
170 }
171
172 #endif /* _NILFS_SEGBUF_H */
173
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