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1/*
2 * include/linux/writeback.h
3 */
4#ifndef WRITEBACK_H
5#define WRITEBACK_H
6
7#include <linux/sched.h>
8#include <linux/fs.h>
9
10struct backing_dev_info;
11
12extern spinlock_t inode_wb_list_lock;
13
14/*
15 * fs/fs-writeback.c
16 */
17enum writeback_sync_modes {
18 WB_SYNC_NONE, /* Don't wait on anything */
19 WB_SYNC_ALL, /* Wait on every mapping */
20};
21
22/*
23 * A control structure which tells the writeback code what to do. These are
24 * always on the stack, and hence need no locking. They are always initialised
25 * in a manner such that unspecified fields are set to zero.
26 */
27struct writeback_control {
28 enum writeback_sync_modes sync_mode;
29 unsigned long *older_than_this; /* If !NULL, only write back inodes
30 older than this */
31 unsigned long wb_start; /* Time writeback_inodes_wb was
32 called. This is needed to avoid
33 extra jobs and livelock */
34 long nr_to_write; /* Write this many pages, and decrement
35 this for each page written */
36 long pages_skipped; /* Pages which were not written */
37
38 /*
39 * For a_ops->writepages(): is start or end are non-zero then this is
40 * a hint that the filesystem need only write out the pages inside that
41 * byterange. The byte at `end' is included in the writeout request.
42 */
43 loff_t range_start;
44 loff_t range_end;
45
46 unsigned nonblocking:1; /* Don't get stuck on request queues */
47 unsigned encountered_congestion:1; /* An output: a queue is full */
48 unsigned for_kupdate:1; /* A kupdate writeback */
49 unsigned for_background:1; /* A background writeback */
50 unsigned for_reclaim:1; /* Invoked from the page allocator */
51 unsigned range_cyclic:1; /* range_start is cyclic */
52 unsigned more_io:1; /* more io to be dispatched */
53};
54
55/*
56 * fs/fs-writeback.c
57 */
58struct bdi_writeback;
59int inode_wait(void *);
60void writeback_inodes_sb(struct super_block *);
61void writeback_inodes_sb_nr(struct super_block *, unsigned long nr);
62int writeback_inodes_sb_if_idle(struct super_block *);
63int writeback_inodes_sb_nr_if_idle(struct super_block *, unsigned long nr);
64void sync_inodes_sb(struct super_block *);
65void writeback_inodes_wb(struct bdi_writeback *wb,
66 struct writeback_control *wbc);
67long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
68void wakeup_flusher_threads(long nr_pages);
69
70/* writeback.h requires fs.h; it, too, is not included from here. */
71static inline void wait_on_inode(struct inode *inode)
72{
73 might_sleep();
74 wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
75}
76static inline void inode_sync_wait(struct inode *inode)
77{
78 might_sleep();
79 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
80 TASK_UNINTERRUPTIBLE);
81}
82
83
84/*
85 * mm/page-writeback.c
86 */
87#ifdef CONFIG_BLOCK
88void laptop_io_completion(struct backing_dev_info *info);
89void laptop_sync_completion(void);
90void laptop_mode_sync(struct work_struct *work);
91void laptop_mode_timer_fn(unsigned long data);
92#else
93static inline void laptop_sync_completion(void) { }
94#endif
95void throttle_vm_writeout(gfp_t gfp_mask);
96
97/* These are exported to sysctl. */
98extern int dirty_background_ratio;
99extern unsigned long dirty_background_bytes;
100extern int vm_dirty_ratio;
101extern unsigned long vm_dirty_bytes;
102extern unsigned int dirty_writeback_interval;
103extern unsigned int dirty_expire_interval;
104extern int vm_highmem_is_dirtyable;
105extern int block_dump;
106extern int laptop_mode;
107
108extern unsigned long determine_dirtyable_memory(void);
109
110extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
111 void __user *buffer, size_t *lenp,
112 loff_t *ppos);
113extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
114 void __user *buffer, size_t *lenp,
115 loff_t *ppos);
116extern int dirty_ratio_handler(struct ctl_table *table, int write,
117 void __user *buffer, size_t *lenp,
118 loff_t *ppos);
119extern int dirty_bytes_handler(struct ctl_table *table, int write,
120 void __user *buffer, size_t *lenp,
121 loff_t *ppos);
122
123struct ctl_table;
124int dirty_writeback_centisecs_handler(struct ctl_table *, int,
125 void __user *, size_t *, loff_t *);
126
127void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
128unsigned long bdi_dirty_limit(struct backing_dev_info *bdi,
129 unsigned long dirty);
130
131void page_writeback_init(void);
132void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
133 unsigned long nr_pages_dirtied);
134
135static inline void
136balance_dirty_pages_ratelimited(struct address_space *mapping)
137{
138 balance_dirty_pages_ratelimited_nr(mapping, 1);
139}
140
141typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
142 void *data);
143
144int generic_writepages(struct address_space *mapping,
145 struct writeback_control *wbc);
146void tag_pages_for_writeback(struct address_space *mapping,
147 pgoff_t start, pgoff_t end);
148int write_cache_pages(struct address_space *mapping,
149 struct writeback_control *wbc, writepage_t writepage,
150 void *data);
151int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
152void set_page_dirty_balance(struct page *page, int page_mkwrite);
153void writeback_set_ratelimit(void);
154void tag_pages_for_writeback(struct address_space *mapping,
155 pgoff_t start, pgoff_t end);
156
157/* pdflush.c */
158extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
159 read-only. */
160
161
162#endif /* WRITEBACK_H */