Linux kernel mirror (for testing)
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linux
1/*
2 * include/linux/writeback.h
3 */
4#ifndef WRITEBACK_H
5#define WRITEBACK_H
6
7#include <linux/sched.h>
8
9struct backing_dev_info;
10
11extern spinlock_t inode_lock;
12extern struct list_head inode_in_use;
13extern struct list_head inode_unused;
14
15/*
16 * Yes, writeback.h requires sched.h
17 * No, sched.h is not included from here.
18 */
19static inline int task_is_pdflush(struct task_struct *task)
20{
21 return task->flags & PF_FLUSHER;
22}
23
24#define current_is_pdflush() task_is_pdflush(current)
25
26/*
27 * fs/fs-writeback.c
28 */
29enum writeback_sync_modes {
30 WB_SYNC_NONE, /* Don't wait on anything */
31 WB_SYNC_ALL, /* Wait on every mapping */
32 WB_SYNC_HOLD, /* Hold the inode on sb_dirty for sys_sync() */
33};
34
35/*
36 * A control structure which tells the writeback code what to do. These are
37 * always on the stack, and hence need no locking. They are always initialised
38 * in a manner such that unspecified fields are set to zero.
39 */
40struct writeback_control {
41 struct backing_dev_info *bdi; /* If !NULL, only write back this
42 queue */
43 enum writeback_sync_modes sync_mode;
44 unsigned long *older_than_this; /* If !NULL, only write back inodes
45 older than this */
46 long nr_to_write; /* Write this many pages, and decrement
47 this for each page written */
48 long pages_skipped; /* Pages which were not written */
49
50 /*
51 * For a_ops->writepages(): is start or end are non-zero then this is
52 * a hint that the filesystem need only write out the pages inside that
53 * byterange. The byte at `end' is included in the writeout request.
54 */
55 loff_t range_start;
56 loff_t range_end;
57
58 unsigned nonblocking:1; /* Don't get stuck on request queues */
59 unsigned encountered_congestion:1; /* An output: a queue is full */
60 unsigned for_kupdate:1; /* A kupdate writeback */
61 unsigned for_reclaim:1; /* Invoked from the page allocator */
62 unsigned for_writepages:1; /* This is a writepages() call */
63 unsigned range_cyclic:1; /* range_start is cyclic */
64
65 void *fs_private; /* For use by ->writepages() */
66};
67
68/*
69 * fs/fs-writeback.c
70 */
71void writeback_inodes(struct writeback_control *wbc);
72void wake_up_inode(struct inode *inode);
73int inode_wait(void *);
74void sync_inodes_sb(struct super_block *, int wait);
75void sync_inodes(int wait);
76
77/* writeback.h requires fs.h; it, too, is not included from here. */
78static inline void wait_on_inode(struct inode *inode)
79{
80 might_sleep();
81 wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
82 TASK_UNINTERRUPTIBLE);
83}
84
85/*
86 * mm/page-writeback.c
87 */
88int wakeup_pdflush(long nr_pages);
89void laptop_io_completion(void);
90void laptop_sync_completion(void);
91void throttle_vm_writeout(gfp_t gfp_mask);
92
93/* These are exported to sysctl. */
94extern int dirty_background_ratio;
95extern int vm_dirty_ratio;
96extern int dirty_writeback_interval;
97extern int dirty_expire_interval;
98extern int block_dump;
99extern int laptop_mode;
100
101struct ctl_table;
102struct file;
103int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *,
104 void __user *, size_t *, loff_t *);
105
106void page_writeback_init(void);
107void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
108 unsigned long nr_pages_dirtied);
109
110static inline void
111balance_dirty_pages_ratelimited(struct address_space *mapping)
112{
113 balance_dirty_pages_ratelimited_nr(mapping, 1);
114}
115
116typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
117 void *data);
118
119int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
120int generic_writepages(struct address_space *mapping,
121 struct writeback_control *wbc);
122int write_cache_pages(struct address_space *mapping,
123 struct writeback_control *wbc, writepage_t writepage,
124 void *data);
125int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
126int sync_page_range(struct inode *inode, struct address_space *mapping,
127 loff_t pos, loff_t count);
128int sync_page_range_nolock(struct inode *inode, struct address_space *mapping,
129 loff_t pos, loff_t count);
130void set_page_dirty_balance(struct page *page, int page_mkwrite);
131void writeback_set_ratelimit(void);
132
133/* pdflush.c */
134extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
135 read-only. */
136
137
138#endif /* WRITEBACK_H */