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