[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;

/*
 * Yes, writeback.h requires sched.h
 * No, sched.h is not included from here.
 */
static inline int task_is_pdflush(struct task_struct *task)
{
	return task->flags & PF_FLUSHER;
}

#define current_is_pdflush()	task_is_pdflush(current)

/*
 * fs/fs-writeback.c
 */
enum writeback_sync_modes {
	WB_SYNC_NONE,	/* Don't wait on anything */
	WB_SYNC_ALL,	/* Wait on every mapping */
	WB_SYNC_HOLD,	/* Hold the inode on sb_dirty for sys_sync() */
};

/*
 * 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 */
	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 for_writepages:1;	/* This is a writepages() call */
	unsigned range_cyclic:1;	/* range_start is cyclic */
	unsigned more_io:1;		/* more io to be dispatched */
};

/*
 * fs/fs-writeback.c
 */	
void writeback_inodes(struct writeback_control *wbc);
int inode_wait(void *);
void sync_inodes_sb(struct super_block *, int wait);
void sync_inodes(int wait);

/* 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
 */
int wakeup_pdflush(long nr_pages);
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 int vm_dirty_ratio;
extern int dirty_writeback_interval;
extern int dirty_expire_interval;
extern int vm_highmem_is_dirtyable;
extern int block_dump;
extern int laptop_mode;

extern int dirty_ratio_handler(struct ctl_table *table, int write,
		struct file *filp, void __user *buffer, size_t *lenp,
		loff_t *ppos);

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

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 pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
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);
int sync_page_range(struct inode *inode, struct address_space *mapping,
			loff_t pos, loff_t count);
int sync_page_range_nolock(struct inode *inode, struct address_space *mapping,
			   loff_t pos, loff_t count);
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
	16	/*
	17	* Yes, writeback.h requires sched.h
	18	* No, sched.h is not included from here.
	19	*/
22e2c507	20	static inline int task_is_pdflush(struct task_struct *task)
1da177e4	21	{
22e2c507	22	return task->flags & PF_FLUSHER;
1da177e4 LT	23	}
1da177e4 LT	24
22e2c507 JA	25	#define current_is_pdflush() task_is_pdflush(current)
22e2c507 JA	26
1da177e4 LT	27	/*
	28	* fs/fs-writeback.c
	29	*/
	30	enum 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	*/
	41	struct 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	*/
111ebb6e OH	56	loff_t range_start;
111ebb6e OH	57	loff_t range_end;
1da177e4	58
22905f77 AM	59	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 */
111ebb6e	64	unsigned range_cyclic:1; /* range_start is cyclic */
8bc3be27	65	unsigned more_io:1; /* more io to be dispatched */
1da177e4 LT	66	};
1da177e4 LT	67
1da177e4 LT	68	/*
	69	* fs/fs-writeback.c
	70	*/
	71	void writeback_inodes(struct writeback_control *wbc);
1da177e4 LT	72	int inode_wait(void *);
	73	void sync_inodes_sb(struct super_block *, int wait);
	74	void sync_inodes(int wait);
	75
	76	/* writeback.h requires fs.h; it, too, is not included from here. */
	77	static 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	}
1c0eeaf5 JE	83	static 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
1da177e4 LT	90
	91	/*
	92	* mm/page-writeback.c
	93	*/
687a21ce	94	int wakeup_pdflush(long nr_pages);
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;
	101	extern int vm_dirty_ratio;
f6ef9438 BS	102	extern int dirty_writeback_interval;
f6ef9438 BS	103	extern int dirty_expire_interval;
195cf453	104	extern int vm_highmem_is_dirtyable;
1da177e4 LT	105	extern int block_dump;
	106	extern int laptop_mode;
	107
04fbfdc1 PZ	108	extern int dirty_ratio_handler(struct ctl_table *table, int write,
	109	struct file filp, void __user buffer, size_t *lenp,
	110	loff_t *ppos);
	111
1da177e4 LT	112	struct ctl_table;
	113	struct file;
	114	int dirty_writeback_centisecs_handler(struct ctl_table , int, struct file ,
	115	void __user , size_t , loff_t *);
	116
	117	void page_writeback_init(void);
fa5a734e AM	118	void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
	119	unsigned long nr_pages_dirtied);
	120
	121	static inline void
	122	balance_dirty_pages_ratelimited(struct address_space *mapping)
	123	{
	124	balance_dirty_pages_ratelimited_nr(mapping, 1);
	125	}
	126
0ea97180 MS	127	typedef int (writepage_t)(struct page page, struct writeback_control *wbc,
	128	void *data);
	129
1da177e4	130	int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
0ea97180 MS	131	int generic_writepages(struct address_space *mapping,
	132	struct writeback_control *wbc);
	133	int write_cache_pages(struct address_space *mapping,
	134	struct writeback_control *wbc, writepage_t writepage,
	135	void *data);
1da177e4 LT	136	int do_writepages(struct address_space mapping, struct writeback_control wbc);
1da177e4 LT	137	int sync_page_range(struct inode inode, struct address_space mapping,
268fc16e OH	138	loff_t pos, loff_t count);
	139	int sync_page_range_nolock(struct inode inode, struct address_space mapping,
	140	loff_t pos, loff_t count);
a200ee18	141	void set_page_dirty_balance(struct page *page, int page_mkwrite);
2d1d43f6	142	void writeback_set_ratelimit(void);
1da177e4 LT	143
	144	/* pdflush.c */
	145	extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
	146	read-only. */
	147
	148
	149	#endif /* WRITEBACK_H */