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