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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 */
33 WB_SYNC_HOLD, /* Hold the inode on sb_dirty for sys_sync() */
34};
35
36/*
37 * A control structure which tells the writeback code what to do. These are
38 * always on the stack, and hence need no locking. They are always initialised
39 * in a manner such that unspecified fields are set to zero.
40 */
41struct writeback_control {
42 struct backing_dev_info *bdi; /* If !NULL, only write back this
43 queue */
44 enum writeback_sync_modes sync_mode;
45 unsigned long *older_than_this; /* If !NULL, only write back inodes
46 older than this */
47 long nr_to_write; /* Write this many pages, and decrement
48 this for each page written */
49 long pages_skipped; /* Pages which were not written */
50
51 /*
52 * For a_ops->writepages(): is start or end are non-zero then this is
53 * a hint that the filesystem need only write out the pages inside that
54 * byterange. The byte at `end' is included in the writeout request.
55 */
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -070056 loff_t range_start;
57 loff_t range_end;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Andrew Morton22905f72005-11-16 15:07:01 -080059 unsigned nonblocking:1; /* Don't get stuck on request queues */
60 unsigned encountered_congestion:1; /* An output: a queue is full */
61 unsigned for_kupdate:1; /* A kupdate writeback */
62 unsigned for_reclaim:1; /* Invoked from the page allocator */
63 unsigned for_writepages:1; /* This is a writepages() call */
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -070064 unsigned range_cyclic:1; /* range_start is cyclic */
Fengguang Wu2e6883b2007-10-16 23:30:43 -070065 unsigned more_io:1; /* more io to be dispatched */
Linus Torvalds1da177e2005-04-16 15:20:36 -070066};
67
68/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070069 * fs/fs-writeback.c
70 */
71void writeback_inodes(struct writeback_control *wbc);
Linus Torvalds1da177e2005-04-16 15:20:36 -070072int inode_wait(void *);
73void sync_inodes_sb(struct super_block *, int wait);
74void sync_inodes(int wait);
75
76/* writeback.h requires fs.h; it, too, is not included from here. */
77static inline void wait_on_inode(struct inode *inode)
78{
79 might_sleep();
80 wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
81 TASK_UNINTERRUPTIBLE);
82}
Joern Engel1c0eeaf2007-10-16 23:30:44 -070083static inline void inode_sync_wait(struct inode *inode)
84{
85 might_sleep();
86 wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
87 TASK_UNINTERRUPTIBLE);
88}
89
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
91/*
92 * mm/page-writeback.c
93 */
Pekka J Enberg687a21c2005-06-28 20:44:55 -070094int wakeup_pdflush(long nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -070095void laptop_io_completion(void);
96void laptop_sync_completion(void);
Andrew Morton232ea4d2007-02-28 20:13:21 -080097void throttle_vm_writeout(gfp_t gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -070098
99/* These are exported to sysctl. */
100extern int dirty_background_ratio;
101extern int vm_dirty_ratio;
Bart Samwelf6ef9432006-03-24 03:15:48 -0800102extern int dirty_writeback_interval;
103extern int dirty_expire_interval;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104extern int block_dump;
105extern int laptop_mode;
106
Peter Zijlstra04fbfdc2007-10-16 23:25:50 -0700107extern int dirty_ratio_handler(struct ctl_table *table, int write,
108 struct file *filp, void __user *buffer, size_t *lenp,
109 loff_t *ppos);
110
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111struct ctl_table;
112struct file;
113int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *,
114 void __user *, size_t *, loff_t *);
115
116void page_writeback_init(void);
Andrew Mortonfa5a7342006-03-24 03:18:10 -0800117void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
118 unsigned long nr_pages_dirtied);
119
120static inline void
121balance_dirty_pages_ratelimited(struct address_space *mapping)
122{
123 balance_dirty_pages_ratelimited_nr(mapping, 1);
124}
125
Miklos Szeredi0ea97182007-05-10 22:22:51 -0700126typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
127 void *data);
128
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
Miklos Szeredi0ea97182007-05-10 22:22:51 -0700130int generic_writepages(struct address_space *mapping,
131 struct writeback_control *wbc);
132int write_cache_pages(struct address_space *mapping,
133 struct writeback_control *wbc, writepage_t writepage,
134 void *data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700135int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
136int sync_page_range(struct inode *inode, struct address_space *mapping,
OGAWA Hirofumi268fc162006-01-08 01:02:12 -0800137 loff_t pos, loff_t count);
138int sync_page_range_nolock(struct inode *inode, struct address_space *mapping,
139 loff_t pos, loff_t count);
Peter Zijlstraa200ee12007-10-08 18:54:37 +0200140void set_page_dirty_balance(struct page *page, int page_mkwrite);
Chandra Seetharaman2d1d43f2006-09-29 02:01:25 -0700141void writeback_set_ratelimit(void);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142
143/* pdflush.c */
144extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
145 read-only. */
146
147
148#endif /* WRITEBACK_H */