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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_background:1; /* A background writeback */
53 unsigned for_reclaim:1; /* Invoked from the page allocator */
54 unsigned range_cyclic:1; /* range_start is cyclic */
55 unsigned more_io:1; /* more io to be dispatched */
56 /*
57 * write_cache_pages() won't update wbc->nr_to_write and
58 * mapping->writeback_index if no_nrwrite_index_update
59 * is set. write_cache_pages() may write more than we
60 * requested and we want to make sure nr_to_write and
61 * writeback_index are updated in a consistent manner
62 * so we use a single control to update them
63 */
64 unsigned no_nrwrite_index_update:1;
65};
66
67/*
68 * fs/fs-writeback.c
69 */
70struct bdi_writeback;
71int inode_wait(void *);
72void writeback_inodes_sb(struct super_block *);
73int writeback_inodes_sb_if_idle(struct super_block *);
74void sync_inodes_sb(struct super_block *);
75void writeback_inodes_wbc(struct writeback_control *wbc);
76long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
77void wakeup_flusher_threads(long nr_pages);
78
79/* writeback.h requires fs.h; it, too, is not included from here. */
80static inline void wait_on_inode(struct inode *inode)
81{
82 might_sleep();
83 wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
84}
85static inline void inode_sync_wait(struct inode *inode)
86{
87 might_sleep();
88 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
89 TASK_UNINTERRUPTIBLE);
90}
91
92
93/*
94 * mm/page-writeback.c
95 */
96void laptop_io_completion(void);
97void laptop_sync_completion(void);
98void throttle_vm_writeout(gfp_t gfp_mask);
99
100/* These are exported to sysctl. */
101extern int dirty_background_ratio;
102extern unsigned long dirty_background_bytes;
103extern int vm_dirty_ratio;
104extern unsigned long vm_dirty_bytes;
105extern unsigned int dirty_writeback_interval;
106extern unsigned int dirty_expire_interval;
107extern int vm_highmem_is_dirtyable;
108extern int block_dump;
109extern int laptop_mode;
110
111extern unsigned long determine_dirtyable_memory(void);
112
113extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
114 void __user *buffer, size_t *lenp,
115 loff_t *ppos);
116extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
117 void __user *buffer, size_t *lenp,
118 loff_t *ppos);
119extern int dirty_ratio_handler(struct ctl_table *table, int write,
120 void __user *buffer, size_t *lenp,
121 loff_t *ppos);
122extern int dirty_bytes_handler(struct ctl_table *table, int write,
123 void __user *buffer, size_t *lenp,
124 loff_t *ppos);
125
126struct ctl_table;
127int dirty_writeback_centisecs_handler(struct ctl_table *, int,
128 void __user *, size_t *, loff_t *);
129
130void get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
131 unsigned long *pbdi_dirty, struct backing_dev_info *bdi);
132
133void page_writeback_init(void);
134void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
135 unsigned long nr_pages_dirtied);
136
137static inline void
138balance_dirty_pages_ratelimited(struct address_space *mapping)
139{
140 balance_dirty_pages_ratelimited_nr(mapping, 1);
141}
142
143typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
144 void *data);
145
146int generic_writepages(struct address_space *mapping,
147 struct writeback_control *wbc);
148int write_cache_pages(struct address_space *mapping,
149 struct writeback_control *wbc, writepage_t writepage,
150 void *data);
151int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
152void set_page_dirty_balance(struct page *page, int page_mkwrite);
153void writeback_set_ratelimit(void);
154
155/* pdflush.c */
156extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
157 read-only. */
158
159
160#endif /* WRITEBACK_H */