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