[linux-block.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 */
	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_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 *);
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_LOCK, 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 */
	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	*/
111ebb6e OH	46	loff_t range_start;
111ebb6e OH	47	loff_t range_end;
1da177e4	48
22905f77 AM	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_reclaim:1; /* Invoked from the page allocator */
111ebb6e	53	unsigned range_cyclic:1; /* range_start is cyclic */
8bc3be27	54	unsigned more_io:1; /* more io to be dispatched */
17bc6c30 AK	55	/*
	56	* write_cache_pages() won't update wbc->nr_to_write and
	57	* mapping->writeback_index if no_nrwrite_index_update
	58	* is set. write_cache_pages() may write more than we
	59	* requested and we want to make sure nr_to_write and
	60	* writeback_index are updated in a consistent manner
	61	* so we use a single control to update them
	62	*/
	63	unsigned no_nrwrite_index_update:1;
1da177e4 LT	64	};
1da177e4 LT	65
1da177e4 LT	66	/*
	67	* fs/fs-writeback.c
	68	*/
03ba3782	69	struct bdi_writeback;
1da177e4	70	int inode_wait(void *);
b6e51316 JA	71	void writeback_inodes_sb(struct super_block *);
b6e51316 JA	72	void sync_inodes_sb(struct super_block *);
03ba3782 JA	73	void writeback_inodes_wbc(struct writeback_control *wbc);
	74	long wb_do_writeback(struct bdi_writeback *wb, int force_wait);
	75	void wakeup_flusher_threads(long nr_pages);
1da177e4 LT	76
	77	/* writeback.h requires fs.h; it, too, is not included from here. */
	78	static inline void wait_on_inode(struct inode *inode)
	79	{
	80	might_sleep();
	81	wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
	82	TASK_UNINTERRUPTIBLE);
	83	}
1c0eeaf5 JE	84	static inline void inode_sync_wait(struct inode *inode)
	85	{
	86	might_sleep();
	87	wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
	88	TASK_UNINTERRUPTIBLE);
	89	}
	90
1da177e4 LT	91
	92	/*
	93	* mm/page-writeback.c
	94	*/
1da177e4 LT	95	void laptop_io_completion(void);
1da177e4 LT	96	void laptop_sync_completion(void);
232ea4d6	97	void throttle_vm_writeout(gfp_t gfp_mask);
1da177e4 LT	98
	99	/* These are exported to sysctl. */
	100	extern int dirty_background_ratio;
2da02997	101	extern unsigned long dirty_background_bytes;
1da177e4	102	extern int vm_dirty_ratio;
2da02997	103	extern unsigned long vm_dirty_bytes;
704503d8 AD	104	extern unsigned int dirty_writeback_interval;
704503d8 AD	105	extern unsigned int dirty_expire_interval;
195cf453	106	extern int vm_highmem_is_dirtyable;
1da177e4 LT	107	extern int block_dump;
	108	extern int laptop_mode;
	109
3eefae99 SR	110	extern unsigned long determine_dirtyable_memory(void);
3eefae99 SR	111
2da02997	112	extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
8d65af78	113	void __user buffer, size_t lenp,
2da02997 DR	114	loff_t *ppos);
2da02997 DR	115	extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
8d65af78	116	void __user buffer, size_t lenp,
2da02997	117	loff_t *ppos);
04fbfdc1	118	extern int dirty_ratio_handler(struct ctl_table *table, int write,
8d65af78	119	void __user buffer, size_t lenp,
04fbfdc1	120	loff_t *ppos);
2da02997	121	extern int dirty_bytes_handler(struct ctl_table *table, int write,
8d65af78	122	void __user buffer, size_t lenp,
2da02997	123	loff_t *ppos);
04fbfdc1	124
1da177e4	125	struct ctl_table;
8d65af78	126	int dirty_writeback_centisecs_handler(struct ctl_table *, int,
1da177e4 LT	127	void __user , size_t , loff_t *);
1da177e4 LT	128
364aeb28 DR	129	void get_dirty_limits(unsigned long pbackground, unsigned long pdirty,
364aeb28 DR	130	unsigned long pbdi_dirty, struct backing_dev_info bdi);
cf0ca9fe	131
1da177e4	132	void page_writeback_init(void);
fa5a734e AM	133	void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
	134	unsigned long nr_pages_dirtied);
	135
	136	static inline void
	137	balance_dirty_pages_ratelimited(struct address_space *mapping)
	138	{
	139	balance_dirty_pages_ratelimited_nr(mapping, 1);
	140	}
	141
0ea97180 MS	142	typedef int (writepage_t)(struct page page, struct writeback_control *wbc,
	143	void *data);
	144
0ea97180 MS	145	int generic_writepages(struct address_space *mapping,
	146	struct writeback_control *wbc);
	147	int write_cache_pages(struct address_space *mapping,
	148	struct writeback_control *wbc, writepage_t writepage,
	149	void *data);
1da177e4	150	int do_writepages(struct address_space mapping, struct writeback_control wbc);
a200ee18	151	void set_page_dirty_balance(struct page *page, int page_mkwrite);
2d1d43f6	152	void writeback_set_ratelimit(void);
1da177e4 LT	153
	154	/* pdflush.c */
	155	extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
	156	read-only. */
	157
	158
	159	#endif /* WRITEBACK_H */