0ead399e08b5cfc549d1debf26f8e7915c7c9904
[linux-3.10.git] / include / linux / writeback.h
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
10 struct backing_dev_info;
11
12 extern spinlock_t inode_lock;
13
14 /*
15  * fs/fs-writeback.c
16  */
17 enum writeback_sync_modes {
18         WB_SYNC_NONE,   /* Don't wait on anything */
19         WB_SYNC_ALL,    /* Wait on every mapping */
20 };
21
22 /*
23  * A control structure which tells the writeback code what to do.  These are
24  * always on the stack, and hence need no locking.  They are always initialised
25  * in a manner such that unspecified fields are set to zero.
26  */
27 struct writeback_control {
28         enum writeback_sync_modes sync_mode;
29         unsigned long *older_than_this; /* If !NULL, only write back inodes
30                                            older than this */
31         unsigned long wb_start;         /* Time writeback_inodes_wb was
32                                            called. This is needed to avoid
33                                            extra jobs and livelock */
34         long nr_to_write;               /* Write this many pages, and decrement
35                                            this for each page written */
36         long pages_skipped;             /* Pages which were not written */
37
38         /*
39          * For a_ops->writepages(): is start or end are non-zero then this is
40          * a hint that the filesystem need only write out the pages inside that
41          * byterange.  The byte at `end' is included in the writeout request.
42          */
43         loff_t range_start;
44         loff_t range_end;
45
46         unsigned nonblocking:1;         /* Don't get stuck on request queues */
47         unsigned encountered_congestion:1; /* An output: a queue is full */
48         unsigned for_kupdate:1;         /* A kupdate writeback */
49         unsigned for_background:1;      /* A background writeback */
50         unsigned for_reclaim:1;         /* Invoked from the page allocator */
51         unsigned range_cyclic:1;        /* range_start is cyclic */
52         unsigned more_io:1;             /* more io to be dispatched */
53 };
54
55 /*
56  * fs/fs-writeback.c
57  */     
58 struct bdi_writeback;
59 int inode_wait(void *);
60 void writeback_inodes_sb(struct super_block *);
61 void writeback_inodes_sb_nr(struct super_block *, unsigned long nr);
62 int writeback_inodes_sb_if_idle(struct super_block *);
63 int writeback_inodes_sb_nr_if_idle(struct super_block *, unsigned long nr);
64 void sync_inodes_sb(struct super_block *);
65 void writeback_inodes_wb(struct bdi_writeback *wb,
66                 struct writeback_control *wbc);
67 long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
68 void wakeup_flusher_threads(long nr_pages);
69
70 /* writeback.h requires fs.h; it, too, is not included from here. */
71 static inline void wait_on_inode(struct inode *inode)
72 {
73         might_sleep();
74         wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
75 }
76 static inline void inode_sync_wait(struct inode *inode)
77 {
78         might_sleep();
79         wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
80                                                         TASK_UNINTERRUPTIBLE);
81 }
82
83
84 /*
85  * mm/page-writeback.c
86  */
87 #ifdef CONFIG_BLOCK
88 void laptop_io_completion(struct backing_dev_info *info);
89 void laptop_sync_completion(void);
90 void laptop_mode_sync(struct work_struct *work);
91 void laptop_mode_timer_fn(unsigned long data);
92 #else
93 static inline void laptop_sync_completion(void) { }
94 #endif
95 void throttle_vm_writeout(gfp_t gfp_mask);
96
97 /* These are exported to sysctl. */
98 extern int dirty_background_ratio;
99 extern unsigned long dirty_background_bytes;
100 extern int vm_dirty_ratio;
101 extern unsigned long vm_dirty_bytes;
102 extern unsigned int dirty_writeback_interval;
103 extern unsigned int dirty_expire_interval;
104 extern int vm_highmem_is_dirtyable;
105 extern int block_dump;
106 extern int laptop_mode;
107
108 extern unsigned long determine_dirtyable_memory(void);
109
110 extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
111                 void __user *buffer, size_t *lenp,
112                 loff_t *ppos);
113 extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
114                 void __user *buffer, size_t *lenp,
115                 loff_t *ppos);
116 extern int dirty_ratio_handler(struct ctl_table *table, int write,
117                 void __user *buffer, size_t *lenp,
118                 loff_t *ppos);
119 extern int dirty_bytes_handler(struct ctl_table *table, int write,
120                 void __user *buffer, size_t *lenp,
121                 loff_t *ppos);
122
123 struct ctl_table;
124 int dirty_writeback_centisecs_handler(struct ctl_table *, int,
125                                       void __user *, size_t *, loff_t *);
126
127 void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
128 unsigned long bdi_dirty_limit(struct backing_dev_info *bdi,
129                                unsigned long dirty);
130
131 void page_writeback_init(void);
132 void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
133                                         unsigned long nr_pages_dirtied);
134
135 static inline void
136 balance_dirty_pages_ratelimited(struct address_space *mapping)
137 {
138         balance_dirty_pages_ratelimited_nr(mapping, 1);
139 }
140
141 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
142                                 void *data);
143
144 int generic_writepages(struct address_space *mapping,
145                        struct writeback_control *wbc);
146 void tag_pages_for_writeback(struct address_space *mapping,
147                              pgoff_t start, pgoff_t end);
148 int write_cache_pages(struct address_space *mapping,
149                       struct writeback_control *wbc, writepage_t writepage,
150                       void *data);
151 int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
152 void set_page_dirty_balance(struct page *page, int page_mkwrite);
153 void writeback_set_ratelimit(void);
154 void tag_pages_for_writeback(struct address_space *mapping,
155                              pgoff_t start, pgoff_t end);
156
157 /* pdflush.c */
158 extern int nr_pdflush_threads;  /* Global so it can be exported to sysctl
159                                    read-only. */
160
161
162 #endif          /* WRITEBACK_H */