[net-next-2.6.git] / include / linux / writeback.h

/*
 * include/linux/writeback.h
 */
#ifndef WRITEBACK_H
#define WRITEBACK_H

#include <linux/sched.h>
#include <linux/fs.h>

struct backing_dev_info;

extern spinlock_t inode_lock;
extern struct list_head inode_in_use;
extern struct list_head inode_unused;

/*
 * fs/fs-writeback.c
 */
enum writeback_sync_modes {
	WB_SYNC_NONE,	/* Don't wait on anything */
	WB_SYNC_ALL,	/* Wait on every mapping */
};

/*
 * A control structure which tells the writeback code what to do.  These are
 * always on the stack, and hence need no locking.  They are always initialised
 * in a manner such that unspecified fields are set to zero.
 */
struct writeback_control {
	struct backing_dev_info *bdi;	/* If !NULL, only write back this
					   queue */
	struct super_block *sb;		/* if !NULL, only write inodes from
					   this super_block */
	enum writeback_sync_modes sync_mode;
	unsigned long *older_than_this;	/* If !NULL, only write back inodes
					   older than this */
	unsigned long wb_start;         /* Time writeback_inodes_wb was
					   called. This is needed to avoid
					   extra jobs and livelock */
	long nr_to_write;		/* Write this many pages, and decrement
					   this for each page written */
	long pages_skipped;		/* Pages which were not written */

	/*
	 * For a_ops->writepages(): is start or end are non-zero then this is
	 * a hint that the filesystem need only write out the pages inside that
	 * byterange.  The byte at `end' is included in the writeout request.
	 */
	loff_t range_start;
	loff_t range_end;

	unsigned nonblocking:1;		/* Don't get stuck on request queues */
	unsigned encountered_congestion:1; /* An output: a queue is full */
	unsigned for_kupdate:1;		/* A kupdate writeback */
	unsigned for_background:1;	/* A background writeback */
	unsigned for_reclaim:1;		/* Invoked from the page allocator */
	unsigned range_cyclic:1;	/* range_start is cyclic */
	unsigned more_io:1;		/* more io to be dispatched */
	/*
	 * write_cache_pages() won't update wbc->nr_to_write and
	 * mapping->writeback_index if no_nrwrite_index_update
	 * is set.  write_cache_pages() may write more than we
	 * requested and we want to make sure nr_to_write and
	 * writeback_index are updated in a consistent manner
	 * so we use a single control to update them
	 */
	unsigned no_nrwrite_index_update:1;
};

/*
 * fs/fs-writeback.c
 */	
struct bdi_writeback;
int inode_wait(void *);
void writeback_inodes_sb(struct super_block *);
int writeback_inodes_sb_if_idle(struct super_block *);
void sync_inodes_sb(struct super_block *);
void writeback_inodes_wbc(struct writeback_control *wbc);
long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
void wakeup_flusher_threads(long nr_pages);

/* writeback.h requires fs.h; it, too, is not included from here. */
static inline void wait_on_inode(struct inode *inode)
{
	might_sleep();
	wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
}
static inline void inode_sync_wait(struct inode *inode)
{
	might_sleep();
	wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
							TASK_UNINTERRUPTIBLE);
}


/*
 * mm/page-writeback.c
 */
void laptop_io_completion(void);
void laptop_sync_completion(void);
void throttle_vm_writeout(gfp_t gfp_mask);

/* These are exported to sysctl. */
extern int dirty_background_ratio;
extern unsigned long dirty_background_bytes;
extern int vm_dirty_ratio;
extern unsigned long vm_dirty_bytes;
extern unsigned int dirty_writeback_interval;
extern unsigned int dirty_expire_interval;
extern int vm_highmem_is_dirtyable;
extern int block_dump;
extern int laptop_mode;

extern unsigned long determine_dirtyable_memory(void);

extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
		void __user *buffer, size_t *lenp,
		loff_t *ppos);
extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
		void __user *buffer, size_t *lenp,
		loff_t *ppos);
extern int dirty_ratio_handler(struct ctl_table *table, int write,
		void __user *buffer, size_t *lenp,
		loff_t *ppos);
extern int dirty_bytes_handler(struct ctl_table *table, int write,
		void __user *buffer, size_t *lenp,
		loff_t *ppos);

struct ctl_table;
int dirty_writeback_centisecs_handler(struct ctl_table *, int,
				      void __user *, size_t *, loff_t *);

void get_dirty_limits(unsigned long *pbackground, unsigned long *pdirty,
		      unsigned long *pbdi_dirty, struct backing_dev_info *bdi);

void page_writeback_init(void);
void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
					unsigned long nr_pages_dirtied);

static inline void
balance_dirty_pages_ratelimited(struct address_space *mapping)
{
	balance_dirty_pages_ratelimited_nr(mapping, 1);
}

typedef int (*writepage_t)(struct page *page, struct writeback_control *wbc,
				void *data);

int generic_writepages(struct address_space *mapping,
		       struct writeback_control *wbc);
int write_cache_pages(struct address_space *mapping,
		      struct writeback_control *wbc, writepage_t writepage,
		      void *data);
int do_writepages(struct address_space *mapping, struct writeback_control *wbc);
void set_page_dirty_balance(struct page *page, int page_mkwrite);
void writeback_set_ratelimit(void);

/* pdflush.c */
extern int nr_pdflush_threads;	/* Global so it can be exported to sysctl
				   read-only. */


#endif		/* WRITEBACK_H */
Commit	Line	Data
1da177e4	1	/*
f30c2269	2	* include/linux/writeback.h
1da177e4 LT	3	*/
	4	#ifndef WRITEBACK_H
	5	#define WRITEBACK_H
	6
e8edc6e0	7	#include <linux/sched.h>
f5ff8422	8	#include <linux/fs.h>
e8edc6e0	9
1da177e4 LT	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
1da177e4 LT	16	/*
	17	* fs/fs-writeback.c
	18	*/
	19	enum writeback_sync_modes {
	20	WB_SYNC_NONE, /* Don't wait on anything */
	21	WB_SYNC_ALL, /* Wait on every mapping */
1da177e4 LT	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 */
03ba3782 JA	32	struct super_block sb; / if !NULL, only write inodes from
03ba3782 JA	33	this super_block */
1da177e4 LT	34	enum writeback_sync_modes sync_mode;
	35	unsigned long older_than_this; / If !NULL, only write back inodes
	36	older than this */
f11c9c5c ES	37	unsigned long wb_start; /* Time writeback_inodes_wb was
	38	called. This is needed to avoid
	39	extra jobs and livelock */
1da177e4 LT	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 */
	43
	44	/*
	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.
	48	*/
111ebb6e OH	49	loff_t range_start;
111ebb6e OH	50	loff_t range_end;
1da177e4	51
22905f77 AM	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 */
b17621fe	55	unsigned for_background:1; /* A background writeback */
22905f77	56	unsigned for_reclaim:1; /* Invoked from the page allocator */
111ebb6e	57	unsigned range_cyclic:1; /* range_start is cyclic */
8bc3be27	58	unsigned more_io:1; /* more io to be dispatched */
17bc6c30 AK	59	/*
	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
	66	*/
	67	unsigned no_nrwrite_index_update:1;
1da177e4 LT	68	};
1da177e4 LT	69
1da177e4 LT	70	/*
	71	* fs/fs-writeback.c
	72	*/
03ba3782	73	struct bdi_writeback;
1da177e4	74	int inode_wait(void *);
b6e51316	75	void writeback_inodes_sb(struct super_block *);
17bd55d0	76	int writeback_inodes_sb_if_idle(struct super_block *);
b6e51316	77	void sync_inodes_sb(struct super_block *);
03ba3782 JA	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);
1da177e4 LT	81
	82	/* writeback.h requires fs.h; it, too, is not included from here. */
	83	static inline void wait_on_inode(struct inode *inode)
	84	{
	85	might_sleep();
eaff8079	86	wait_on_bit(&inode->i_state, __I_NEW, inode_wait, TASK_UNINTERRUPTIBLE);
1da177e4	87	}
1c0eeaf5 JE	88	static inline void inode_sync_wait(struct inode *inode)
	89	{
	90	might_sleep();
	91	wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
	92	TASK_UNINTERRUPTIBLE);
	93	}
	94
1da177e4 LT	95
	96	/*
	97	* mm/page-writeback.c
	98	*/
1da177e4 LT	99	void laptop_io_completion(void);
1da177e4 LT	100	void laptop_sync_completion(void);
232ea4d6	101	void throttle_vm_writeout(gfp_t gfp_mask);
1da177e4 LT	102
	103	/* These are exported to sysctl. */
	104	extern int dirty_background_ratio;
2da02997	105	extern unsigned long dirty_background_bytes;
1da177e4	106	extern int vm_dirty_ratio;
2da02997	107	extern unsigned long vm_dirty_bytes;
704503d8 AD	108	extern unsigned int dirty_writeback_interval;
704503d8 AD	109	extern unsigned int dirty_expire_interval;
195cf453	110	extern int vm_highmem_is_dirtyable;
1da177e4 LT	111	extern int block_dump;
	112	extern int laptop_mode;
	113
3eefae99 SR	114	extern unsigned long determine_dirtyable_memory(void);
3eefae99 SR	115
2da02997	116	extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
8d65af78	117	void __user buffer, size_t lenp,
2da02997 DR	118	loff_t *ppos);
2da02997 DR	119	extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
8d65af78	120	void __user buffer, size_t lenp,
2da02997	121	loff_t *ppos);
04fbfdc1	122	extern int dirty_ratio_handler(struct ctl_table *table, int write,
8d65af78	123	void __user buffer, size_t lenp,
04fbfdc1	124	loff_t *ppos);
2da02997	125	extern int dirty_bytes_handler(struct ctl_table *table, int write,
8d65af78	126	void __user buffer, size_t lenp,
2da02997	127	loff_t *ppos);
04fbfdc1	128
1da177e4	129	struct ctl_table;
8d65af78	130	int dirty_writeback_centisecs_handler(struct ctl_table *, int,
1da177e4 LT	131	void __user , size_t , loff_t *);
1da177e4 LT	132
364aeb28 DR	133	void get_dirty_limits(unsigned long pbackground, unsigned long pdirty,
364aeb28 DR	134	unsigned long pbdi_dirty, struct backing_dev_info bdi);
cf0ca9fe	135
1da177e4	136	void page_writeback_init(void);
fa5a734e AM	137	void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
	138	unsigned long nr_pages_dirtied);
	139
	140	static inline void
	141	balance_dirty_pages_ratelimited(struct address_space *mapping)
	142	{
	143	balance_dirty_pages_ratelimited_nr(mapping, 1);
	144	}
	145
0ea97180 MS	146	typedef int (writepage_t)(struct page page, struct writeback_control *wbc,
	147	void *data);
	148
0ea97180 MS	149	int generic_writepages(struct address_space *mapping,
	150	struct writeback_control *wbc);
	151	int write_cache_pages(struct address_space *mapping,
	152	struct writeback_control *wbc, writepage_t writepage,
	153	void *data);
1da177e4	154	int do_writepages(struct address_space mapping, struct writeback_control wbc);
a200ee18	155	void set_page_dirty_balance(struct page *page, int page_mkwrite);
2d1d43f6	156	void writeback_set_ratelimit(void);
1da177e4 LT	157
	158	/* pdflush.c */
	159	extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
	160	read-only. */
	161
	162
	163	#endif /* WRITEBACK_H */