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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_lock;
13extern struct list_head inode_in_use;
14extern struct list_head inode_unused;
15
16/*
17 * fs/fs-writeback.c
18 */
19enum writeback_sync_modes {
20 WB_SYNC_NONE, /* Don't wait on anything */
21 WB_SYNC_ALL, /* Wait on every mapping */
22};
23
24/*
25 * A control structure which tells the writeback code what to do. These are
26 * always on the stack, and hence need no locking. They are always initialised
27 * in a manner such that unspecified fields are set to zero.
28 */
29struct writeback_control {
30 struct backing_dev_info *bdi; /* If !NULL, only write back this
31 queue */
32 struct super_block *sb; /* if !NULL, only write inodes from
33 this super_block */
34 enum writeback_sync_modes sync_mode;
35 unsigned long *older_than_this; /* If !NULL, only write back inodes
36 older than this */
37 long nr_to_write; /* Write this many pages, and decrement
38 this for each page written */
39 long pages_skipped; /* Pages which were not written */
40
41 /*
42 * For a_ops->writepages(): is start or end are non-zero then this is
43 * a hint that the filesystem need only write out the pages inside that
44 * byterange. The byte at `end' is included in the writeout request.
45 */
46 loff_t range_start;
47 loff_t range_end;
48
49 unsigned nonblocking:1; /* Don't get stuck on request queues */
50 unsigned encountered_congestion:1; /* An output: a queue is full */
51 unsigned for_kupdate:1; /* A kupdate writeback */
52 unsigned for_reclaim:1; /* Invoked from the page allocator */
53 unsigned range_cyclic:1; /* range_start is cyclic */
54 unsigned more_io:1; /* more io to be dispatched */
55 /*
56 * write_cache_pages() won't update wbc->nr_to_write and
57 * mapping->writeback_index if no_nrwrite_index_update
58 * is set. write_cache_pages() may write more than we
59 * requested and we want to make sure nr_to_write and
60 * writeback_index are updated in a consistent manner
61 * so we use a single control to update them
62 */
63 unsigned no_nrwrite_index_update:1;
64};
65
66/*
67 * fs/fs-writeback.c
68 */
69struct bdi_writeback;
70int inode_wait(void *);
71void writeback_inodes_sb(struct super_block *);
72void sync_inodes_sb(struct super_block *);
73void writeback_inodes_wbc(struct writeback_control *wbc);
74long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
75void wakeup_flusher_threads(long nr_pages);
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}
84static inline void inode_sync_wait(struct inode *inode)
85{
86 might_sleep();
87 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
88 TASK_UNINTERRUPTIBLE);
89}
90
91
92/*
93 * mm/page-writeback.c
94 */
95void laptop_io_completion(void);
96void laptop_sync_completion(void);
97void throttle_vm_writeout(gfp_t gfp_mask);
98
99/* These are exported to sysctl. */
100extern int dirty_background_ratio;
101extern unsigned long dirty_background_bytes;
102extern int vm_dirty_ratio;
103extern unsigned long vm_dirty_bytes;
104extern unsigned int dirty_writeback_interval;
105extern unsigned int dirty_expire_interval;
106extern int vm_highmem_is_dirtyable;
107extern int block_dump;
108extern int laptop_mode;
109
110extern unsigned long determine_dirtyable_memory(void);
111
112extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
113 void __user *buffer, size_t *lenp,
114 loff_t *ppos);
115extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
116 void __user *buffer, size_t *lenp,
117 loff_t *ppos);
118extern int dirty_ratio_handler(struct ctl_table *table, int write,
119 void __user *buffer, size_t *lenp,
120 loff_t *ppos);
121extern int dirty_bytes_handler(struct ctl_table *table, int write,
122 void __user *buffer, size_t *lenp,
123 loff_t *ppos);
124
125struct ctl_table;
126int dirty_writeback_centisecs_handler(struct ctl_table *, int,
127 void __user *, size_t *, loff_t *);
128
129void get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
130 unsigned long *pbdi_dirty, struct backing_dev_info *bdi);
131
132void page_writeback_init(void);
133void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
134 unsigned long nr_pages_dirtied);
135
136static inline void
137balance_dirty_pages_ratelimited(struct address_space *mapping)
138{
139 balance_dirty_pages_ratelimited_nr(mapping, 1);
140}
141
142typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
143 void *data);
144
145int generic_writepages(struct address_space *mapping,
146 struct writeback_control *wbc);
147int write_cache_pages(struct address_space *mapping,
148 struct writeback_control *wbc, writepage_t writepage,
149 void *data);
150int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
151void set_page_dirty_balance(struct page *page, int page_mkwrite);
152void writeback_set_ratelimit(void);
153
154/* pdflush.c */
155extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
156 read-only. */
157
158
159#endif /* WRITEBACK_H */