2 * include/linux/writeback.h
7 #include <linux/sched.h>
10 struct backing_dev_info;
12 extern spinlock_t inode_lock;
17 enum writeback_sync_modes {
18 WB_SYNC_NONE, /* Don't wait on anything */
19 WB_SYNC_ALL, /* Wait on every mapping */
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.
27 struct writeback_control {
28 enum writeback_sync_modes sync_mode;
29 unsigned long *older_than_this; /* If !NULL, only write back inodes
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 */
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.
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 */
59 int inode_wait(void *);
60 void writeback_inodes_sb(struct super_block *);
61 int writeback_inodes_sb_if_idle(struct super_block *);
62 void sync_inodes_sb(struct super_block *);
63 void writeback_inodes_wb(struct bdi_writeback *wb,
64 struct writeback_control *wbc);
65 long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
66 void wakeup_flusher_threads(long nr_pages);
68 /* writeback.h requires fs.h; it, too, is not included from here. */
69 static inline void wait_on_inode(struct inode *inode)
72 wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
74 static inline void inode_sync_wait(struct inode *inode)
77 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
78 TASK_UNINTERRUPTIBLE);
86 void laptop_io_completion(struct backing_dev_info *info);
87 void laptop_sync_completion(void);
88 void laptop_mode_sync(struct work_struct *work);
89 void laptop_mode_timer_fn(unsigned long data);
91 static inline void laptop_sync_completion(void) { }
93 void throttle_vm_writeout(gfp_t gfp_mask);
95 /* These are exported to sysctl. */
96 extern int dirty_background_ratio;
97 extern unsigned long dirty_background_bytes;
98 extern int vm_dirty_ratio;
99 extern unsigned long vm_dirty_bytes;
100 extern unsigned int dirty_writeback_interval;
101 extern unsigned int dirty_expire_interval;
102 extern int vm_highmem_is_dirtyable;
103 extern int block_dump;
104 extern int laptop_mode;
106 extern unsigned long determine_dirtyable_memory(void);
108 extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
109 void __user *buffer, size_t *lenp,
111 extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
112 void __user *buffer, size_t *lenp,
114 extern int dirty_ratio_handler(struct ctl_table *table, int write,
115 void __user *buffer, size_t *lenp,
117 extern int dirty_bytes_handler(struct ctl_table *table, int write,
118 void __user *buffer, size_t *lenp,
122 int dirty_writeback_centisecs_handler(struct ctl_table *, int,
123 void __user *, size_t *, loff_t *);
125 void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty);
126 unsigned long bdi_dirty_limit(struct backing_dev_info *bdi,
127 unsigned long dirty);
129 void page_writeback_init(void);
130 void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
131 unsigned long nr_pages_dirtied);
134 balance_dirty_pages_ratelimited(struct address_space *mapping)
136 balance_dirty_pages_ratelimited_nr(mapping, 1);
139 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
142 int generic_writepages(struct address_space *mapping,
143 struct writeback_control *wbc);
144 void tag_pages_for_writeback(struct address_space *mapping,
145 pgoff_t start, pgoff_t end);
146 int write_cache_pages(struct address_space *mapping,
147 struct writeback_control *wbc, writepage_t writepage,
149 int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
150 void set_page_dirty_balance(struct page *page, int page_mkwrite);
151 void writeback_set_ratelimit(void);
152 void tag_pages_for_writeback(struct address_space *mapping,
153 pgoff_t start, pgoff_t end);
156 extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
160 #endif /* WRITEBACK_H */