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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02002 * include/linux/writeback.h
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 */
4#ifndef WRITEBACK_H
5#define WRITEBACK_H
6
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +04007#include <linux/sched.h>
Jens Axboef5ff8422007-09-21 09:19:54 +02008#include <linux/fs.h>
Alexey Dobriyane8edc6e2007-05-21 01:22:52 +04009
Linus Torvalds1da177e2005-04-16 15:20:36 -070010struct 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 * Yes, writeback.h requires sched.h
18 * No, sched.h is not included from here.
19 */
Jens Axboe22e2c502005-06-27 10:55:12 +020020static inline int task_is_pdflush(struct task_struct *task)
Linus Torvalds1da177e2005-04-16 15:20:36 -070021{
Jens Axboe22e2c502005-06-27 10:55:12 +020022 return task->flags & PF_FLUSHER;
Linus Torvalds1da177e2005-04-16 15:20:36 -070023}
24
Jens Axboe22e2c502005-06-27 10:55:12 +020025#define current_is_pdflush() task_is_pdflush(current)
26
Linus Torvalds1da177e2005-04-16 15:20:36 -070027/*
28 * fs/fs-writeback.c
29 */
30enum writeback_sync_modes {
31 WB_SYNC_NONE, /* Don't wait on anything */
32 WB_SYNC_ALL, /* Wait on every mapping */
Linus Torvalds1da177e2005-04-16 15:20:36 -070033};
34
35/*
36 * A control structure which tells the writeback code what to do. These are
37 * always on the stack, and hence need no locking. They are always initialised
38 * in a manner such that unspecified fields are set to zero.
39 */
40struct writeback_control {
41 struct backing_dev_info *bdi; /* If !NULL, only write back this
42 queue */
43 enum writeback_sync_modes sync_mode;
44 unsigned long *older_than_this; /* If !NULL, only write back inodes
45 older than this */
46 long nr_to_write; /* Write this many pages, and decrement
47 this for each page written */
48 long pages_skipped; /* Pages which were not written */
49
50 /*
51 * For a_ops->writepages(): is start or end are non-zero then this is
52 * a hint that the filesystem need only write out the pages inside that
53 * byterange. The byte at `end' is included in the writeout request.
54 */
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -070055 loff_t range_start;
56 loff_t range_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -070057
Andrew Morton22905f72005-11-16 15:07:01 -080058 unsigned nonblocking:1; /* Don't get stuck on request queues */
59 unsigned encountered_congestion:1; /* An output: a queue is full */
60 unsigned for_kupdate:1; /* A kupdate writeback */
61 unsigned for_reclaim:1; /* Invoked from the page allocator */
62 unsigned for_writepages:1; /* This is a writepages() call */
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -070063 unsigned range_cyclic:1; /* range_start is cyclic */
Fengguang Wu8bc3be22008-02-04 22:29:36 -080064 unsigned more_io:1; /* more io to be dispatched */
Aneesh Kumar K.V17bc6c32008-10-16 10:09:17 -040065 /*
66 * write_cache_pages() won't update wbc->nr_to_write and
67 * mapping->writeback_index if no_nrwrite_index_update
68 * is set. write_cache_pages() may write more than we
69 * requested and we want to make sure nr_to_write and
70 * writeback_index are updated in a consistent manner
71 * so we use a single control to update them
72 */
73 unsigned no_nrwrite_index_update:1;
Linus Torvalds1da177e2005-04-16 15:20:36 -070074};
75
76/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070077 * fs/fs-writeback.c
78 */
79void writeback_inodes(struct writeback_control *wbc);
Linus Torvalds1da177e2005-04-16 15:20:36 -070080int inode_wait(void *);
81void sync_inodes_sb(struct super_block *, int wait);
82void sync_inodes(int wait);
83
84/* writeback.h requires fs.h; it, too, is not included from here. */
85static inline void wait_on_inode(struct inode *inode)
86{
87 might_sleep();
88 wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
89 TASK_UNINTERRUPTIBLE);
90}
Joern Engel1c0eeaf2007-10-16 23:30:44 -070091static inline void inode_sync_wait(struct inode *inode)
92{
93 might_sleep();
94 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
95 TASK_UNINTERRUPTIBLE);
96}
97
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
99/*
100 * mm/page-writeback.c
101 */
Pekka J Enberg687a21c2005-06-28 20:44:55 -0700102int wakeup_pdflush(long nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103void laptop_io_completion(void);
104void laptop_sync_completion(void);
Andrew Morton232ea4d2007-02-28 20:13:21 -0800105void throttle_vm_writeout(gfp_t gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106
107/* These are exported to sysctl. */
108extern int dirty_background_ratio;
David Rientjes2da02992009-01-06 14:39:31 -0800109extern unsigned long dirty_background_bytes;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110extern int vm_dirty_ratio;
David Rientjes2da02992009-01-06 14:39:31 -0800111extern unsigned long vm_dirty_bytes;
Alexey Dobriyan704503d2009-03-31 15:23:18 -0700112extern unsigned int dirty_writeback_interval;
113extern unsigned int dirty_expire_interval;
Bron Gondwana195cf4532008-02-04 22:29:20 -0800114extern int vm_highmem_is_dirtyable;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115extern int block_dump;
116extern int laptop_mode;
117
Steven Rostedt3eefae92008-05-12 21:21:04 +0200118extern unsigned long determine_dirtyable_memory(void);
119
David Rientjes2da02992009-01-06 14:39:31 -0800120extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
121 struct file *filp, void __user *buffer, size_t *lenp,
122 loff_t *ppos);
123extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
124 struct file *filp, void __user *buffer, size_t *lenp,
125 loff_t *ppos);
Peter Zijlstra04fbfdc2007-10-16 23:25:50 -0700126extern int dirty_ratio_handler(struct ctl_table *table, int write,
127 struct file *filp, void __user *buffer, size_t *lenp,
128 loff_t *ppos);
David Rientjes2da02992009-01-06 14:39:31 -0800129extern int dirty_bytes_handler(struct ctl_table *table, int write,
130 struct file *filp, void __user *buffer, size_t *lenp,
131 loff_t *ppos);
Peter Zijlstra04fbfdc2007-10-16 23:25:50 -0700132
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133struct ctl_table;
134struct file;
135int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *,
136 void __user *, size_t *, loff_t *);
137
David Rientjes364aeb22009-01-06 14:39:29 -0800138void get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
139 unsigned long *pbdi_dirty, struct backing_dev_info *bdi);
Peter Zijlstracf0ca9f2008-04-30 00:54:32 -0700140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141void page_writeback_init(void);
Andrew Mortonfa5a7342006-03-24 03:18:10 -0800142void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
143 unsigned long nr_pages_dirtied);
144
145static inline void
146balance_dirty_pages_ratelimited(struct address_space *mapping)
147{
148 balance_dirty_pages_ratelimited_nr(mapping, 1);
149}
150
Miklos Szeredi0ea97182007-05-10 22:22:51 -0700151typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
152 void *data);
153
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
Miklos Szeredi0ea97182007-05-10 22:22:51 -0700155int generic_writepages(struct address_space *mapping,
156 struct writeback_control *wbc);
157int write_cache_pages(struct address_space *mapping,
158 struct writeback_control *wbc, writepage_t writepage,
159 void *data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
161int sync_page_range(struct inode *inode, struct address_space *mapping,
OGAWA Hirofumi268fc162006-01-08 01:02:12 -0800162 loff_t pos, loff_t count);
163int sync_page_range_nolock(struct inode *inode, struct address_space *mapping,
164 loff_t pos, loff_t count);
Peter Zijlstraa200ee12007-10-08 18:54:37 +0200165void set_page_dirty_balance(struct page *page, int page_mkwrite);
Chandra Seetharaman2d1d43f2006-09-29 02:01:25 -0700166void writeback_set_ratelimit(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167
168/* pdflush.c */
169extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
170 read-only. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171
172
173#endif /* WRITEBACK_H */