[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 */
};

/*
 * 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);
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 unsigned long dirty_background_bytes;
extern int vm_dirty_ratio;
extern unsigned long vm_dirty_bytes;
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 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 *);
	81	void sync_inodes_sb(struct super_block *, int wait);
	82	void sync_inodes(int wait);
	83
	84	/* writeback.h requires fs.h; it, too, is not included from here. */
	85	static inline void wait_on_inode(struct inode *inode)
	86	{
	87	might_sleep();
	88	wait_on_bit(&inode->i_state, __I_LOCK, inode_wait,
	89	TASK_UNINTERRUPTIBLE);
	90	}
1c0eeaf5 JE	91	static inline void inode_sync_wait(struct inode *inode)
	92	{
	93	might_sleep();
	94	wait_on_bit(&inode->i_state, __I_SYNC, inode_wait,
	95	TASK_UNINTERRUPTIBLE);
	96	}
	97
1da177e4 LT	98
	99	/*
	100	* mm/page-writeback.c
	101	*/
687a21ce	102	int wakeup_pdflush(long nr_pages);
1da177e4 LT	103	void laptop_io_completion(void);
1da177e4 LT	104	void laptop_sync_completion(void);
232ea4d6	105	void throttle_vm_writeout(gfp_t gfp_mask);
1da177e4 LT	106
	107	/* These are exported to sysctl. */
	108	extern int dirty_background_ratio;
2da02997	109	extern unsigned long dirty_background_bytes;
1da177e4	110	extern int vm_dirty_ratio;
2da02997	111	extern unsigned long vm_dirty_bytes;
f6ef9438 BS	112	extern int dirty_writeback_interval;
f6ef9438 BS	113	extern int dirty_expire_interval;
195cf453	114	extern int vm_highmem_is_dirtyable;
1da177e4 LT	115	extern int block_dump;
	116	extern int laptop_mode;
	117
3eefae99 SR	118	extern unsigned long determine_dirtyable_memory(void);
3eefae99 SR	119
2da02997 DR	120	extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
	121	struct file filp, void __user buffer, size_t *lenp,
	122	loff_t *ppos);
	123	extern int dirty_background_bytes_handler(struct ctl_table *table, int write,
	124	struct file filp, void __user buffer, size_t *lenp,
	125	loff_t *ppos);
04fbfdc1 PZ	126	extern int dirty_ratio_handler(struct ctl_table *table, int write,
	127	struct file filp, void __user buffer, size_t *lenp,
	128	loff_t *ppos);
2da02997 DR	129	extern int dirty_bytes_handler(struct ctl_table *table, int write,
	130	struct file filp, void __user buffer, size_t *lenp,
	131	loff_t *ppos);
04fbfdc1	132
1da177e4 LT	133	struct ctl_table;
	134	struct file;
	135	int dirty_writeback_centisecs_handler(struct ctl_table , int, struct file ,
	136	void __user , size_t , loff_t *);
	137
364aeb28 DR	138	void get_dirty_limits(unsigned long pbackground, unsigned long pdirty,
364aeb28 DR	139	unsigned long pbdi_dirty, struct backing_dev_info bdi);
cf0ca9fe	140
1da177e4	141	void page_writeback_init(void);
fa5a734e AM	142	void balance_dirty_pages_ratelimited_nr(struct address_space *mapping,
	143	unsigned long nr_pages_dirtied);
	144
	145	static inline void
	146	balance_dirty_pages_ratelimited(struct address_space *mapping)
	147	{
	148	balance_dirty_pages_ratelimited_nr(mapping, 1);
	149	}
	150
0ea97180 MS	151	typedef int (writepage_t)(struct page page, struct writeback_control *wbc,
	152	void *data);
	153
1da177e4	154	int pdflush_operation(void (*fn)(unsigned long), unsigned long arg0);
0ea97180 MS	155	int generic_writepages(struct address_space *mapping,
	156	struct writeback_control *wbc);
	157	int write_cache_pages(struct address_space *mapping,
	158	struct writeback_control *wbc, writepage_t writepage,
	159	void *data);
1da177e4 LT	160	int do_writepages(struct address_space mapping, struct writeback_control wbc);
1da177e4 LT	161	int sync_page_range(struct inode inode, struct address_space mapping,
268fc16e OH	162	loff_t pos, loff_t count);
	163	int sync_page_range_nolock(struct inode inode, struct address_space mapping,
	164	loff_t pos, loff_t count);
a200ee18	165	void set_page_dirty_balance(struct page *page, int page_mkwrite);
2d1d43f6	166	void writeback_set_ratelimit(void);
1da177e4 LT	167
	168	/* pdflush.c */
	169	extern int nr_pdflush_threads; /* Global so it can be exported to sysctl
	170	read-only. */
	171
	172
	173	#endif /* WRITEBACK_H */