[deliverable/linux.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 */
};

/*
 * 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 */
	/*
	 * 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
 */	
void writeback_inodes(struct writeback_control *wbc);
int inode_wait(void *);
void sync_inodes_sb(struct super_block *, 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 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,
		struct file *filp, void __user *buffer, size_t *lenp,
		loff_t *ppos);
extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
		struct file *filp, void __user *buffer, size_t *lenp,
		loff_t *ppos);
extern int dirty_ratio_handler(struct ctl_table *table, int write,
		struct file *filp, void __user *buffer, size_t *lenp,
		loff_t *ppos);
extern int dirty_bytes_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 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 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 */
1da177e4 LT	33	};
	34
	35	/*
	36	* A control structure which tells the writeback code what to do. These are
	37	* always on the stack, and hence need no locking. They are always initialised
	38	* in a manner such that unspecified fields are set to zero.
	39	*/
	40	struct writeback_control {
	41	struct backing_dev_info bdi; / If !NULL, only write back this
	42	queue */
	43	enum writeback_sync_modes sync_mode;
	44	unsigned long older_than_this; / If !NULL, only write back inodes
	45	older than this */
	46	long nr_to_write; /* Write this many pages, and decrement
	47	this for each page written */
	48	long pages_skipped; /* Pages which were not written */
	49
	50	/*
	51	* For a_ops->writepages(): is start or end are non-zero then this is
	52	* a hint that the filesystem need only write out the pages inside that
	53	* byterange. The byte at `end' is included in the writeout request.
	54	*/
111ebb6e OH	55	loff_t range_start;
111ebb6e OH	56	loff_t range_end;
1da177e4	57
22905f77 AM	58	unsigned nonblocking:1; /* Don't get stuck on request queues */
	59	unsigned encountered_congestion:1; /* An output: a queue is full */
	60	unsigned for_kupdate:1; /* A kupdate writeback */
	61	unsigned for_reclaim:1; /* Invoked from the page allocator */
	62	unsigned for_writepages:1; /* This is a writepages() call */
111ebb6e	63	unsigned range_cyclic:1; /* range_start is cyclic */
8bc3be27	64	unsigned more_io:1; /* more io to be dispatched */
17bc6c30 AK	65	/*
	66	* write_cache_pages() won't update wbc->nr_to_write and
	67	* mapping->writeback_index if no_nrwrite_index_update
	68	* is set. write_cache_pages() may write more than we
	69	* requested and we want to make sure nr_to_write and
	70	* writeback_index are updated in a consistent manner
	71	* so we use a single control to update them
	72	*/
	73	unsigned no_nrwrite_index_update:1;
1da177e4 LT	74	};
1da177e4 LT	75
1da177e4 LT	76	/*
	77	* fs/fs-writeback.c
	78	*/
	79	void writeback_inodes(struct writeback_control *wbc);
1da177e4 LT	80	int inode_wait(void *);
1da177e4 LT	81	void sync_inodes_sb(struct super_block *, int wait);
1da177e4 LT	82
	83	/* writeback.h requires fs.h; it, too, is not included from here. */
	84	static inline void wait_on_inode(struct inode *inode)
	85	{
	86	might_sleep();
	87	wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
	88	TASK_UNINTERRUPTIBLE);
	89	}
1c0eeaf5 JE	90	static inline void inode_sync_wait(struct inode *inode)
	91	{
	92	might_sleep();
	93	wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
	94	TASK_UNINTERRUPTIBLE);
	95	}
	96
1da177e4 LT	97
	98	/*
	99	* mm/page-writeback.c
	100	*/
687a21ce	101	int wakeup_pdflush(long nr_pages);
1da177e4 LT	102	void laptop_io_completion(void);
1da177e4 LT	103	void laptop_sync_completion(void);
232ea4d6	104	void throttle_vm_writeout(gfp_t gfp_mask);
1da177e4 LT	105
	106	/* These are exported to sysctl. */
	107	extern int dirty_background_ratio;
2da02997	108	extern unsigned long dirty_background_bytes;
1da177e4	109	extern int vm_dirty_ratio;
2da02997	110	extern unsigned long vm_dirty_bytes;
704503d8 AD	111	extern unsigned int dirty_writeback_interval;
704503d8 AD	112	extern unsigned int dirty_expire_interval;
195cf453	113	extern int vm_highmem_is_dirtyable;
1da177e4 LT	114	extern int block_dump;
	115	extern int laptop_mode;
	116
3eefae99 SR	117	extern unsigned long determine_dirtyable_memory(void);
3eefae99 SR	118
2da02997 DR	119	extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
	120	struct file filp, void __user buffer, size_t *lenp,
	121	loff_t *ppos);
	122	extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
	123	struct file filp, void __user buffer, size_t *lenp,
	124	loff_t *ppos);
04fbfdc1 PZ	125	extern int dirty_ratio_handler(struct ctl_table *table, int write,
	126	struct file filp, void __user buffer, size_t *lenp,
	127	loff_t *ppos);
2da02997 DR	128	extern int dirty_bytes_handler(struct ctl_table *table, int write,
	129	struct file filp, void __user buffer, size_t *lenp,
	130	loff_t *ppos);
04fbfdc1	131
1da177e4 LT	132	struct ctl_table;
	133	struct file;
	134	int dirty_writeback_centisecs_handler(struct ctl_table , int, struct file ,
	135	void __user , size_t , loff_t *);
	136
364aeb28 DR	137	void get_dirty_limits(unsigned long pbackground, unsigned long pdirty,
364aeb28 DR	138	unsigned long pbdi_dirty, struct backing_dev_info bdi);
cf0ca9fe	139
1da177e4	140	void page_writeback_init(void);
fa5a734e AM	141	void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
	142	unsigned long nr_pages_dirtied);
	143
	144	static inline void
	145	balance_dirty_pages_ratelimited(struct address_space *mapping)
	146	{
	147	balance_dirty_pages_ratelimited_nr(mapping, 1);
	148	}
	149
0ea97180 MS	150	typedef int (writepage_t)(struct page page, struct writeback_control *wbc,
	151	void *data);
	152
1da177e4	153	int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
0ea97180 MS	154	int generic_writepages(struct address_space *mapping,
	155	struct writeback_control *wbc);
	156	int write_cache_pages(struct address_space *mapping,
	157	struct writeback_control *wbc, writepage_t writepage,
	158	void *data);
1da177e4 LT	159	int do_writepages(struct address_space mapping, struct writeback_control wbc);
1da177e4 LT	160	int sync_page_range(struct inode inode, struct address_space mapping,
268fc16e OH	161	loff_t pos, loff_t count);
	162	int sync_page_range_nolock(struct inode inode, struct address_space mapping,
	163	loff_t pos, loff_t count);
a200ee18	164	void set_page_dirty_balance(struct page *page, int page_mkwrite);
2d1d43f6	165	void writeback_set_ratelimit(void);
1da177e4 LT	166
	167	/* pdflush.c */
	168	extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
	169	read-only. */
	170
	171
	172	#endif /* WRITEBACK_H */