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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * include/linux/writeback.h. | |
3 | */ | |
4 | #ifndef WRITEBACK_H | |
5 | #define WRITEBACK_H | |
6 | ||
7 | struct backing_dev_info; | |
8 | ||
9 | extern spinlock_t inode_lock; | |
10 | extern struct list_head inode_in_use; | |
11 | extern struct list_head inode_unused; | |
12 | ||
13 | /* | |
14 | * Yes, writeback.h requires sched.h | |
15 | * No, sched.h is not included from here. | |
16 | */ | |
17 | static inline int current_is_pdflush(void) | |
18 | { | |
19 | return current->flags & PF_FLUSHER; | |
20 | } | |
21 | ||
22 | /* | |
23 | * fs/fs-writeback.c | |
24 | */ | |
25 | enum writeback_sync_modes { | |
26 | WB_SYNC_NONE, /* Don't wait on anything */ | |
27 | WB_SYNC_ALL, /* Wait on every mapping */ | |
28 | WB_SYNC_HOLD, /* Hold the inode on sb_dirty for sys_sync() */ | |
29 | }; | |
30 | ||
31 | /* | |
32 | * A control structure which tells the writeback code what to do. These are | |
33 | * always on the stack, and hence need no locking. They are always initialised | |
34 | * in a manner such that unspecified fields are set to zero. | |
35 | */ | |
36 | struct writeback_control { | |
37 | struct backing_dev_info *bdi; /* If !NULL, only write back this | |
38 | queue */ | |
39 | enum writeback_sync_modes sync_mode; | |
40 | unsigned long *older_than_this; /* If !NULL, only write back inodes | |
41 | older than this */ | |
42 | long nr_to_write; /* Write this many pages, and decrement | |
43 | this for each page written */ | |
44 | long pages_skipped; /* Pages which were not written */ | |
45 | ||
46 | /* | |
47 | * For a_ops->writepages(): is start or end are non-zero then this is | |
48 | * a hint that the filesystem need only write out the pages inside that | |
49 | * byterange. The byte at `end' is included in the writeout request. | |
50 | */ | |
51 | loff_t start; | |
52 | loff_t end; | |
53 | ||
54 | unsigned nonblocking:1; /* Don't get stuck on request queues */ | |
55 | unsigned encountered_congestion:1; /* An output: a queue is full */ | |
56 | unsigned for_kupdate:1; /* A kupdate writeback */ | |
57 | unsigned for_reclaim:1; /* Invoked from the page allocator */ | |
58 | }; | |
59 | ||
60 | /* | |
61 | * ->writepage() return values (make these much larger than a pagesize, in | |
62 | * case some fs is returning number-of-bytes-written from writepage) | |
63 | */ | |
64 | #define WRITEPAGE_ACTIVATE 0x80000 /* IO was not started: activate page */ | |
65 | ||
66 | /* | |
67 | * fs/fs-writeback.c | |
68 | */ | |
69 | void writeback_inodes(struct writeback_control *wbc); | |
70 | void wake_up_inode(struct inode *inode); | |
71 | int inode_wait(void *); | |
72 | void sync_inodes_sb(struct super_block *, int wait); | |
73 | void sync_inodes(int wait); | |
74 | ||
75 | /* writeback.h requires fs.h; it, too, is not included from here. */ | |
76 | static inline void wait_on_inode(struct inode *inode) | |
77 | { | |
78 | might_sleep(); | |
79 | wait_on_bit(&inode->i_state, __I_LOCK, inode_wait, | |
80 | TASK_UNINTERRUPTIBLE); | |
81 | } | |
82 | ||
83 | /* | |
84 | * mm/page-writeback.c | |
85 | */ | |
86 | int wakeup_bdflush(long nr_pages); | |
87 | void laptop_io_completion(void); | |
88 | void laptop_sync_completion(void); | |
89 | void throttle_vm_writeout(void); | |
90 | ||
91 | /* These are exported to sysctl. */ | |
92 | extern int dirty_background_ratio; | |
93 | extern int vm_dirty_ratio; | |
94 | extern int dirty_writeback_centisecs; | |
95 | extern int dirty_expire_centisecs; | |
96 | extern int block_dump; | |
97 | extern int laptop_mode; | |
98 | ||
99 | struct ctl_table; | |
100 | struct file; | |
101 | int dirty_writeback_centisecs_handler(struct ctl_table *, int, struct file *, | |
102 | void __user *, size_t *, loff_t *); | |
103 | ||
104 | void page_writeback_init(void); | |
105 | void balance_dirty_pages_ratelimited(struct address_space *mapping); | |
106 | int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0); | |
107 | int do_writepages(struct address_space *mapping, struct writeback_control *wbc); | |
108 | int sync_page_range(struct inode *inode, struct address_space *mapping, | |
109 | loff_t pos, size_t count); | |
110 | int sync_page_range_nolock(struct inode *inode, struct address_space | |
111 | *mapping, loff_t pos, size_t count); | |
112 | ||
113 | /* pdflush.c */ | |
114 | extern int nr_pdflush_threads; /* Global so it can be exported to sysctl | |
115 | read-only. */ | |
116 | ||
117 | ||
118 | #endif /* WRITEBACK_H */ |