Linux kernel mirror (for testing)
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1/*
2 * include/linux/writeback.h.
3 */
4#ifndef WRITEBACK_H
5#define WRITEBACK_H
6
7struct backing_dev_info;
8
9extern spinlock_t inode_lock;
10extern struct list_head inode_in_use;
11extern struct list_head inode_unused;
12
13/*
14 * Yes, writeback.h requires sched.h
15 * No, sched.h is not included from here.
16 */
17static inline int current_is_pdflush(void)
18{
19 return current->flags & PF_FLUSHER;
20}
21
22/*
23 * fs/fs-writeback.c
24 */
25enum writeback_sync_modes {
26 WB_SYNC_NONE, /* Don't wait on anything */
27 WB_SYNC_ALL, /* Wait on every mapping */
28 WB_SYNC_HOLD, /* Hold the inode on sb_dirty for sys_sync() */
29};
30
31/*
32 * A control structure which tells the writeback code what to do. These are
33 * always on the stack, and hence need no locking. They are always initialised
34 * in a manner such that unspecified fields are set to zero.
35 */
36struct writeback_control {
37 struct backing_dev_info *bdi; /* If !NULL, only write back this
38 queue */
39 enum writeback_sync_modes sync_mode;
40 unsigned long *older_than_this; /* If !NULL, only write back inodes
41 older than this */
42 long nr_to_write; /* Write this many pages, and decrement
43 this for each page written */
44 long pages_skipped; /* Pages which were not written */
45
46 /*
47 * For a_ops->writepages(): is start or end are non-zero then this is
48 * a hint that the filesystem need only write out the pages inside that
49 * byterange. The byte at `end' is included in the writeout request.
50 */
51 loff_t start;
52 loff_t end;
53
54 unsigned nonblocking:1; /* Don't get stuck on request queues */
55 unsigned encountered_congestion:1; /* An output: a queue is full */
56 unsigned for_kupdate:1; /* A kupdate writeback */
57 unsigned for_reclaim:1; /* Invoked from the page allocator */
58};
59
60/*
61 * ->writepage() return values (make these much larger than a pagesize, in
62 * case some fs is returning number-of-bytes-written from writepage)
63 */
64#define WRITEPAGE_ACTIVATE 0x80000 /* IO was not started: activate page */
65
66/*
67 * fs/fs-writeback.c
68 */
69void writeback_inodes(struct writeback_control *wbc);
70void wake_up_inode(struct inode *inode);
71int inode_wait(void *);
72void sync_inodes_sb(struct super_block *, int wait);
73void sync_inodes(int wait);
74
75/* writeback.h requires fs.h; it, too, is not included from here. */
76static inline void wait_on_inode(struct inode *inode)
77{
78 might_sleep();
79 wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
80 TASK_UNINTERRUPTIBLE);
81}
82
83/*
84 * mm/page-writeback.c
85 */
86int wakeup_bdflush(long nr_pages);
87void laptop_io_completion(void);
88void laptop_sync_completion(void);
89void throttle_vm_writeout(void);
90
91/* These are exported to sysctl. */
92extern int dirty_background_ratio;
93extern int vm_dirty_ratio;
94extern int dirty_writeback_centisecs;
95extern int dirty_expire_centisecs;
96extern int block_dump;
97extern int laptop_mode;
98
99struct ctl_table;
100struct file;
101int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *,
102 void __user *, size_t *, loff_t *);
103
104void page_writeback_init(void);
105void balance_dirty_pages_ratelimited(struct address_space *mapping);
106int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
107int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
108int sync_page_range(struct inode *inode, struct address_space *mapping,
109 loff_t pos, size_t count);
110int sync_page_range_nolock(struct inode *inode, struct address_space
111 *mapping, loff_t pos, size_t count);
112
113/* pdflush.c */
114extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
115 read-only. */
116
117
118#endif /* WRITEBACK_H */