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 range_start;
54 loff_t range_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 unsigned range_cyclic:1; /* range_start is cyclic */
62
63 void *fs_private; /* For use by ->writepages() */
64};
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_pdflush(long nr_pages);
87void laptop_io_completion(void);
88void laptop_sync_completion(void);
89void throttle_vm_writeout(gfp_t gfp_mask);
90
91/* These are exported to sysctl. */
92extern int dirty_background_ratio;
93extern int vm_dirty_ratio;
94extern int dirty_writeback_interval;
95extern int dirty_expire_interval;
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_nr(struct address_space *mapping,
106 unsigned long nr_pages_dirtied);
107
108static inline void
109balance_dirty_pages_ratelimited(struct address_space *mapping)
110{
111 balance_dirty_pages_ratelimited_nr(mapping, 1);
112}
113
114typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
115 void *data);
116
117int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
118int generic_writepages(struct address_space *mapping,
119 struct writeback_control *wbc);
120int write_cache_pages(struct address_space *mapping,
121 struct writeback_control *wbc, writepage_t writepage,
122 void *data);
123int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
124int sync_page_range(struct inode *inode, struct address_space *mapping,
125 loff_t pos, loff_t count);
126int sync_page_range_nolock(struct inode *inode, struct address_space *mapping,
127 loff_t pos, loff_t count);
128void set_page_dirty_balance(struct page *page);
129void writeback_set_ratelimit(void);
130
131/* pdflush.c */
132extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
133 read-only. */
134
135
136#endif /* WRITEBACK_H */