2 * include/linux/writeback.h
7 #include <linux/sched.h>
10 struct backing_dev_info;
12 extern spinlock_t inode_lock;
13 extern struct list_head inode_in_use;
14 extern struct list_head inode_unused;
19 enum writeback_sync_modes {
20 WB_SYNC_NONE, /* Don't wait on anything */
21 WB_SYNC_ALL, /* Wait on every mapping */
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.
29 struct writeback_control {
30 struct backing_dev_info *bdi; /* If !NULL, only write back this
32 struct super_block *sb; /* if !NULL, only write inodes from
34 enum writeback_sync_modes sync_mode;
35 unsigned long *older_than_this; /* If !NULL, only write back inodes
37 unsigned long wb_start; /* Time writeback_inodes_wb was
38 called. This is needed to avoid
39 extra jobs and livelock */
40 long nr_to_write; /* Write this many pages, and decrement
41 this for each page written */
42 long pages_skipped; /* Pages which were not written */
45 * For a_ops->writepages(): is start or end are non-zero then this is
46 * a hint that the filesystem need only write out the pages inside that
47 * byterange. The byte at `end' is included in the writeout request.
52 unsigned nonblocking:1; /* Don't get stuck on request queues */
53 unsigned encountered_congestion:1; /* An output: a queue is full */
54 unsigned for_kupdate:1; /* A kupdate writeback */
55 unsigned for_background:1; /* A background writeback */
56 unsigned for_reclaim:1; /* Invoked from the page allocator */
57 unsigned range_cyclic:1; /* range_start is cyclic */
58 unsigned more_io:1; /* more io to be dispatched */
60 * write_cache_pages() won't update wbc->nr_to_write and
61 * mapping->writeback_index if no_nrwrite_index_update
62 * is set. write_cache_pages() may write more than we
63 * requested and we want to make sure nr_to_write and
64 * writeback_index are updated in a consistent manner
65 * so we use a single control to update them
67 unsigned no_nrwrite_index_update:1;
74 int inode_wait(void *);
75 void writeback_inodes_sb(struct super_block *);
76 int writeback_inodes_sb_if_idle(struct super_block *);
77 void sync_inodes_sb(struct super_block *);
78 void writeback_inodes_wbc(struct writeback_control *wbc);
79 long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
80 void wakeup_flusher_threads(long nr_pages);
82 /* writeback.h requires fs.h; it, too, is not included from here. */
83 static inline void wait_on_inode(struct inode *inode)
86 wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
88 static inline void inode_sync_wait(struct inode *inode)
91 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
92 TASK_UNINTERRUPTIBLE);
99 void laptop_io_completion(struct backing_dev_info *info);
100 void laptop_sync_completion(void);
101 void laptop_mode_sync(struct work_struct *work);
102 void laptop_mode_timer_fn(unsigned long data);
103 void throttle_vm_writeout(gfp_t gfp_mask);
105 /* These are exported to sysctl. */
106 extern int dirty_background_ratio;
107 extern unsigned long dirty_background_bytes;
108 extern int vm_dirty_ratio;
109 extern unsigned long vm_dirty_bytes;
110 extern unsigned int dirty_writeback_interval;
111 extern unsigned int dirty_expire_interval;
112 extern int vm_highmem_is_dirtyable;
113 extern int block_dump;
114 extern int laptop_mode;
116 extern unsigned long determine_dirtyable_memory(void);
118 extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
119 void __user *buffer, size_t *lenp,
121 extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
122 void __user *buffer, size_t *lenp,
124 extern int dirty_ratio_handler(struct ctl_table *table, int write,
125 void __user *buffer, size_t *lenp,
127 extern int dirty_bytes_handler(struct ctl_table *table, int write,
128 void __user *buffer, size_t *lenp,
132 int dirty_writeback_centisecs_handler(struct ctl_table *, int,
133 void __user *, size_t *, loff_t *);
135 void get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
136 unsigned long *pbdi_dirty, struct backing_dev_info *bdi);
138 void page_writeback_init(void);
139 void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
140 unsigned long nr_pages_dirtied);
143 balance_dirty_pages_ratelimited(struct address_space *mapping)
145 balance_dirty_pages_ratelimited_nr(mapping, 1);
148 typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
151 int generic_writepages(struct address_space *mapping,
152 struct writeback_control *wbc);
153 int write_cache_pages(struct address_space *mapping,
154 struct writeback_control *wbc, writepage_t writepage,
156 int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
157 void set_page_dirty_balance(struct page *page, int page_mkwrite);
158 void writeback_set_ratelimit(void);
161 extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
165 #endif /* WRITEBACK_H */