Line data Source code
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 : extern struct list_head inode_in_use;
14 : extern struct list_head inode_unused;
15 1 :
16 : /*
17 : * fs/fs-writeback.c
18 : */
19 : enum writeback_sync_modes {
20 1 : WB_SYNC_NONE, /* Don't wait on anything */
21 : WB_SYNC_ALL, /* Wait on every mapping */
22 : };
23 :
24 : /*
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.
28 : */
29 : struct writeback_control {
30 : struct backing_dev_info *bdi; /* If !NULL, only write back this
31 : queue */
32 : struct super_block *sb; /* if !NULL, only write inodes from
33 : this super_block */
34 : enum writeback_sync_modes sync_mode;
35 : unsigned long *older_than_this; /* If !NULL, only write back inodes
36 : older than this */
37 : long nr_to_write; /* Write this many pages, and decrement
38 : this for each page written */
39 : long pages_skipped; /* Pages which were not written */
40 :
41 : /*
42 : * For a_ops->writepages(): is start or end are non-zero then this is
43 : * a hint that the filesystem need only write out the pages inside that
44 : * byterange. The byte at `end' is included in the writeout request.
45 : */
46 : loff_t range_start;
47 : loff_t range_end;
48 :
49 : unsigned nonblocking:1; /* Don't get stuck on request queues */
50 : unsigned encountered_congestion:1; /* An output: a queue is full */
51 : unsigned for_kupdate:1; /* A kupdate writeback */
52 : unsigned for_background:1; /* A background writeback */
53 : unsigned for_reclaim:1; /* Invoked from the page allocator */
54 : unsigned range_cyclic:1; /* range_start is cyclic */
55 : unsigned more_io:1; /* more io to be dispatched */
56 : /*
57 : * write_cache_pages() won't update wbc->nr_to_write and
58 : * mapping->writeback_index if no_nrwrite_index_update
59 : * is set. write_cache_pages() may write more than we
60 : * requested and we want to make sure nr_to_write and
61 : * writeback_index are updated in a consistent manner
62 : * so we use a single control to update them
63 : */
64 : unsigned no_nrwrite_index_update:1;
65 : };
66 1 :
67 : /*
68 : * fs/fs-writeback.c
69 : */
70 : struct bdi_writeback;
71 : int inode_wait(void *);
72 : void writeback_inodes_sb(struct super_block *);
73 : int writeback_inodes_sb_if_idle(struct super_block *);
74 : void sync_inodes_sb(struct super_block *);
75 : void writeback_inodes_wbc(struct writeback_control *wbc);
76 : long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
77 : void wakeup_flusher_threads(long nr_pages);
78 :
79 : /* writeback.h requires fs.h; it, too, is not included from here. */
80 : static inline void wait_on_inode(struct inode *inode)
81 : {
82 : might_sleep();
83 : wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
84 : }
85 : static inline void inode_sync_wait(struct inode *inode)
86 : {
87 : might_sleep();
88 : wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
89 : TASK_UNINTERRUPTIBLE);
90 : }
91 :
92 :
93 : /*
94 : * mm/page-writeback.c
95 : */
96 : void laptop_io_completion(void);
97 : void laptop_sync_completion(void);
98 : void throttle_vm_writeout(gfp_t gfp_mask);
99 :
100 : /* These are exported to sysctl. */
101 : extern int dirty_background_ratio;
102 : extern unsigned long dirty_background_bytes;
103 : extern int vm_dirty_ratio;
104 : extern unsigned long vm_dirty_bytes;
105 : extern unsigned int dirty_writeback_interval;
106 : extern unsigned int dirty_expire_interval;
107 : extern int vm_highmem_is_dirtyable;
108 : extern int block_dump;
109 : extern int laptop_mode;
110 :
111 : extern unsigned long determine_dirtyable_memory(void);
112 :
113 : extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
114 : void __user *buffer, size_t *lenp,
115 : loff_t *ppos);
116 : extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
117 : void __user *buffer, size_t *lenp,
118 : loff_t *ppos);
119 : extern int dirty_ratio_handler(struct ctl_table *table, int write,
120 : void __user *buffer, size_t *lenp,
121 : loff_t *ppos);
122 : extern int dirty_bytes_handler(struct ctl_table *table, int write,
123 : void __user *buffer, size_t *lenp,
124 : loff_t *ppos);
125 :
126 : struct ctl_table;
127 : int dirty_writeback_centisecs_handler(struct ctl_table *, int,
128 : void __user *, size_t *, loff_t *);
129 :
130 : void get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
131 : unsigned long *pbdi_dirty, struct backing_dev_info *bdi);
132 :
133 : void page_writeback_init(void);
134 : void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
135 : unsigned long nr_pages_dirtied);
136 :
137 : static inline void
138 : balance_dirty_pages_ratelimited(struct address_space *mapping)
139 : {
140 : balance_dirty_pages_ratelimited_nr(mapping, 1);
141 : }
142 :
143 : typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
144 : void *data);
145 :
146 : int generic_writepages(struct address_space *mapping,
147 : struct writeback_control *wbc);
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 :
155 : /* pdflush.c */
156 : extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
157 : read-only. */
158 :
159 :
160 : #endif /* WRITEBACK_H */
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