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

/*
 * include/linux/buffer_head.h
 *
 * Everything to do with buffer_heads.
 */

#ifndef _LINUX_BUFFER_HEAD_H
#define _LINUX_BUFFER_HEAD_H

#include <linux/types.h>
#include <linux/fs.h>
#include <linux/linkage.h>
#include <linux/pagemap.h>
#include <linux/wait.h>
#include <asm/atomic.h>

#ifdef CONFIG_BLOCK

enum bh_state_bits {
	BH_Uptodate,	/* Contains valid data */
	BH_Dirty,	/* Is dirty */
	BH_Lock,	/* Is locked */
	BH_Req,		/* Has been submitted for I/O */
	BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise
			  * IO completion of other buffers in the page
			  */

	BH_Mapped,	/* Has a disk mapping */
	BH_New,		/* Disk mapping was newly created by get_block */
	BH_Async_Read,	/* Is under end_buffer_async_read I/O */
	BH_Async_Write,	/* Is under end_buffer_async_write I/O */
	BH_Delay,	/* Buffer is not yet allocated on disk */
	BH_Boundary,	/* Block is followed by a discontiguity */
	BH_Write_EIO,	/* I/O error on write */
	BH_Eopnotsupp,	/* operation not supported (barrier) */
	BH_Unwritten,	/* Buffer is allocated on disk but not written */
	BH_Quiet,	/* Buffer Error Prinks to be quiet */

	BH_PrivateStart,/* not a state bit, but the first bit available
			 * for private allocation by other entities
			 */
};

#define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512)

struct page;
struct buffer_head;
struct address_space;
typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);

/*
 * Historically, a buffer_head was used to map a single block
 * within a page, and of course as the unit of I/O through the
 * filesystem and block layers.  Nowadays the basic I/O unit
 * is the bio, and buffer_heads are used for extracting block
 * mappings (via a get_block_t call), for tracking state within
 * a page (via a page_mapping) and for wrapping bio submission
 * for backward compatibility reasons (e.g. submit_bh).
 */
struct buffer_head {
	unsigned long b_state;		/* buffer state bitmap (see above) */
	struct buffer_head *b_this_page;/* circular list of page's buffers */
	struct page *b_page;		/* the page this bh is mapped to */

	sector_t b_blocknr;		/* start block number */
	size_t b_size;			/* size of mapping */
	char *b_data;			/* pointer to data within the page */

	struct block_device *b_bdev;
	bh_end_io_t *b_end_io;		/* I/O completion */
 	void *b_private;		/* reserved for b_end_io */
	struct list_head b_assoc_buffers; /* associated with another mapping */
	struct address_space *b_assoc_map;	/* mapping this buffer is
						   associated with */
	atomic_t b_count;		/* users using this buffer_head */
};

/*
 * macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
 * and buffer_foo() functions.
 */
#define BUFFER_FNS(bit, name)						\
static inline void set_buffer_##name(struct buffer_head *bh)		\
{									\
	set_bit(BH_##bit, &(bh)->b_state);				\
}									\
static inline void clear_buffer_##name(struct buffer_head *bh)		\
{									\
	clear_bit(BH_##bit, &(bh)->b_state);				\
}									\
static inline int buffer_##name(const struct buffer_head *bh)		\
{									\
	return test_bit(BH_##bit, &(bh)->b_state);			\
}

/*
 * test_set_buffer_foo() and test_clear_buffer_foo()
 */
#define TAS_BUFFER_FNS(bit, name)					\
static inline int test_set_buffer_##name(struct buffer_head *bh)	\
{									\
	return test_and_set_bit(BH_##bit, &(bh)->b_state);		\
}									\
static inline int test_clear_buffer_##name(struct buffer_head *bh)	\
{									\
	return test_and_clear_bit(BH_##bit, &(bh)->b_state);		\
}									\

/*
 * Emit the buffer bitops functions.   Note that there are also functions
 * of the form "mark_buffer_foo()".  These are higher-level functions which
 * do something in addition to setting a b_state bit.
 */
BUFFER_FNS(Uptodate, uptodate)
BUFFER_FNS(Dirty, dirty)
TAS_BUFFER_FNS(Dirty, dirty)
BUFFER_FNS(Lock, locked)
BUFFER_FNS(Req, req)
TAS_BUFFER_FNS(Req, req)
BUFFER_FNS(Mapped, mapped)
BUFFER_FNS(New, new)
BUFFER_FNS(Async_Read, async_read)
BUFFER_FNS(Async_Write, async_write)
BUFFER_FNS(Delay, delay)
BUFFER_FNS(Boundary, boundary)
BUFFER_FNS(Write_EIO, write_io_error)
BUFFER_FNS(Eopnotsupp, eopnotsupp)
BUFFER_FNS(Unwritten, unwritten)

#define bh_offset(bh)		((unsigned long)(bh)->b_data & ~PAGE_MASK)
#define touch_buffer(bh)	mark_page_accessed(bh->b_page)

/* If we *know* page->private refers to buffer_heads */
#define page_buffers(page)					\
	({							\
		BUG_ON(!PagePrivate(page));			\
		((struct buffer_head *)page_private(page));	\
	})
#define page_has_buffers(page)	PagePrivate(page)

/*
 * Declarations
 */

void mark_buffer_dirty(struct buffer_head *bh);
void init_buffer(struct buffer_head *, bh_end_io_t *, void *);
void set_bh_page(struct buffer_head *bh,
		struct page *page, unsigned long offset);
int try_to_free_buffers(struct page *);
struct buffer_head *alloc_page_buffers(struct page *page, unsigned long size,
		int retry);
void create_empty_buffers(struct page *, unsigned long,
			unsigned long b_state);
void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
void end_buffer_async_write(struct buffer_head *bh, int uptodate);

/* Things to do with buffers at mapping->private_list */
void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode);
int inode_has_buffers(struct inode *);
void invalidate_inode_buffers(struct inode *);
int remove_inode_buffers(struct inode *inode);
int sync_mapping_buffers(struct address_space *mapping);
void unmap_underlying_metadata(struct block_device *bdev, sector_t block);

void mark_buffer_async_write(struct buffer_head *bh);
void __wait_on_buffer(struct buffer_head *);
wait_queue_head_t *bh_waitq_head(struct buffer_head *bh);
struct buffer_head *__find_get_block(struct block_device *bdev, sector_t block,
			unsigned size);
struct buffer_head *__getblk(struct block_device *bdev, sector_t block,
			unsigned size);
void __brelse(struct buffer_head *);
void __bforget(struct buffer_head *);
void __breadahead(struct block_device *, sector_t block, unsigned int size);
struct buffer_head *__bread(struct block_device *, sector_t block, unsigned size);
void invalidate_bh_lrus(void);
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
void free_buffer_head(struct buffer_head * bh);
void unlock_buffer(struct buffer_head *bh);
void __lock_buffer(struct buffer_head *bh);
void ll_rw_block(int, int, struct buffer_head * bh[]);
int sync_dirty_buffer(struct buffer_head *bh);
int __sync_dirty_buffer(struct buffer_head *bh, int rw);
int submit_bh(int, struct buffer_head *);
void write_boundary_block(struct block_device *bdev,
			sector_t bblock, unsigned blocksize);
int bh_uptodate_or_lock(struct buffer_head *bh);
int bh_submit_read(struct buffer_head *bh);

extern int buffer_heads_over_limit;

/*
 * Generic address_space_operations implementations for buffer_head-backed
 * address_spaces.
 */
void block_invalidatepage(struct page *page, unsigned long offset);
int block_write_full_page(struct page *page, get_block_t *get_block,
				struct writeback_control *wbc);
int block_write_full_page_endio(struct page *page, get_block_t *get_block,
			struct writeback_control *wbc, bh_end_io_t *handler);
int block_read_full_page(struct page*, get_block_t*);
int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc,
				unsigned long from);
int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
		unsigned flags, struct page **pagep, get_block_t *get_block);
int __block_write_begin(struct page *page, loff_t pos, unsigned len,
		get_block_t *get_block);
int block_write_end(struct file *, struct address_space *,
				loff_t, unsigned, unsigned,
				struct page *, void *);
int generic_write_end(struct file *, struct address_space *,
				loff_t, unsigned, unsigned,
				struct page *, void *);
void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
int block_prepare_write(struct page*, unsigned, unsigned, get_block_t*);
int cont_write_begin(struct file *, struct address_space *, loff_t,
			unsigned, unsigned, struct page **, void **,
			get_block_t *, loff_t *);
int generic_cont_expand_simple(struct inode *inode, loff_t size);
int block_commit_write(struct page *page, unsigned from, unsigned to);
int block_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf,
				get_block_t get_block);
void block_sync_page(struct page *);
sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *);
int block_truncate_page(struct address_space *, loff_t, get_block_t *);
int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned,
				struct page **, void **, get_block_t*);
int nobh_write_end(struct file *, struct address_space *,
				loff_t, unsigned, unsigned,
				struct page *, void *);
int nobh_truncate_page(struct address_space *, loff_t, get_block_t *);
int nobh_writepage(struct page *page, get_block_t *get_block,
                        struct writeback_control *wbc);

void buffer_init(void);

/*
 * inline definitions
 */

static inline void attach_page_buffers(struct page *page,
		struct buffer_head *head)
{
	page_cache_get(page);
	SetPagePrivate(page);
	set_page_private(page, (unsigned long)head);
}

static inline void get_bh(struct buffer_head *bh)
{
        atomic_inc(&bh->b_count);
}

static inline void put_bh(struct buffer_head *bh)
{
        smp_mb__before_atomic_dec();
        atomic_dec(&bh->b_count);
}

static inline void brelse(struct buffer_head *bh)
{
	if (bh)
		__brelse(bh);
}

static inline void bforget(struct buffer_head *bh)
{
	if (bh)
		__bforget(bh);
}

static inline struct buffer_head *
sb_bread(struct super_block *sb, sector_t block)
{
	return __bread(sb->s_bdev, block, sb->s_blocksize);
}

static inline void
sb_breadahead(struct super_block *sb, sector_t block)
{
	__breadahead(sb->s_bdev, block, sb->s_blocksize);
}

static inline struct buffer_head *
sb_getblk(struct super_block *sb, sector_t block)
{
	return __getblk(sb->s_bdev, block, sb->s_blocksize);
}

static inline struct buffer_head *
sb_find_get_block(struct super_block *sb, sector_t block)
{
	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
}

static inline void
map_bh(struct buffer_head *bh, struct super_block *sb, sector_t block)
{
	set_buffer_mapped(bh);
	bh->b_bdev = sb->s_bdev;
	bh->b_blocknr = block;
	bh->b_size = sb->s_blocksize;
}

static inline void wait_on_buffer(struct buffer_head *bh)
{
	might_sleep();
	if (buffer_locked(bh))
		__wait_on_buffer(bh);
}

static inline int trylock_buffer(struct buffer_head *bh)
{
	return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
}

static inline void lock_buffer(struct buffer_head *bh)
{
	might_sleep();
	if (!trylock_buffer(bh))
		__lock_buffer(bh);
}

extern int __set_page_dirty_buffers(struct page *page);

#else /* CONFIG_BLOCK */

static inline void buffer_init(void) {}
static inline int try_to_free_buffers(struct page *page) { return 1; }
static inline int inode_has_buffers(struct inode *inode) { return 0; }
static inline void invalidate_inode_buffers(struct inode *inode) {}
static inline int remove_inode_buffers(struct inode *inode) { return 1; }
static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }

#endif /* CONFIG_BLOCK */
#endif /* _LINUX_BUFFER_HEAD_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* include/linux/buffer_head.h
	3	*
	4	* Everything to do with buffer_heads.
	5	*/
	6
	7	#ifndef _LINUX_BUFFER_HEAD_H
	8	#define _LINUX_BUFFER_HEAD_H
	9
	10	#include <linux/types.h>
	11	#include <linux/fs.h>
	12	#include <linux/linkage.h>
	13	#include <linux/pagemap.h>
	14	#include <linux/wait.h>
	15	#include <asm/atomic.h>
	16
9361401e DH	17	#ifdef CONFIG_BLOCK
9361401e DH	18
1da177e4 LT	19	enum bh_state_bits {
	20	BH_Uptodate, /* Contains valid data */
	21	BH_Dirty, /* Is dirty */
	22	BH_Lock, /* Is locked */
	23	BH_Req, /* Has been submitted for I/O */
a3972203 NP	24	BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise
	25	* IO completion of other buffers in the page
	26	*/
1da177e4 LT	27
	28	BH_Mapped, /* Has a disk mapping */
	29	BH_New, /* Disk mapping was newly created by get_block */
	30	BH_Async_Read, /* Is under end_buffer_async_read I/O */
	31	BH_Async_Write, /* Is under end_buffer_async_write I/O */
	32	BH_Delay, /* Buffer is not yet allocated on disk */
	33	BH_Boundary, /* Block is followed by a discontiguity */
	34	BH_Write_EIO, /* I/O error on write */
1da177e4	35	BH_Eopnotsupp, /* operation not supported (barrier) */
33a266dd	36	BH_Unwritten, /* Buffer is allocated on disk but not written */
08bafc03	37	BH_Quiet, /* Buffer Error Prinks to be quiet */
1da177e4 LT	38
	39	BH_PrivateStart,/* not a state bit, but the first bit available
	40	* for private allocation by other entities
	41	*/
	42	};
	43
	44	#define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512)
	45
	46	struct page;
	47	struct buffer_head;
	48	struct address_space;
	49	typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
	50
	51	/*
205f87f6 BP	52	* Historically, a buffer_head was used to map a single block
	53	* within a page, and of course as the unit of I/O through the
	54	* filesystem and block layers. Nowadays the basic I/O unit
	55	* is the bio, and buffer_heads are used for extracting block
	56	* mappings (via a get_block_t call), for tracking state within
	57	* a page (via a page_mapping) and for wrapping bio submission
	58	* for backward compatibility reasons (e.g. submit_bh).
1da177e4 LT	59	*/
1da177e4 LT	60	struct buffer_head {
1da177e4 LT	61	unsigned long b_state; /* buffer state bitmap (see above) */
	62	struct buffer_head b_this_page;/ circular list of page's buffers */
	63	struct page b_page; / the page this bh is mapped to */
1da177e4	64
205f87f6 BP	65	sector_t b_blocknr; /* start block number */
	66	size_t b_size; /* size of mapping */
	67	char b_data; / pointer to data within the page */
1da177e4 LT	68
	69	struct block_device *b_bdev;
	70	bh_end_io_t b_end_io; / I/O completion */
	71	void b_private; / reserved for b_end_io */
	72	struct list_head b_assoc_buffers; /* associated with another mapping */
58ff407b JK	73	struct address_space b_assoc_map; / mapping this buffer is
58ff407b JK	74	associated with */
205f87f6	75	atomic_t b_count; /* users using this buffer_head */
1da177e4 LT	76	};
	77
	78	/*
	79	* macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
	80	* and buffer_foo() functions.
	81	*/
	82	#define BUFFER_FNS(bit, name) \
	83	static inline void set_buffer_##name(struct buffer_head *bh) \
	84	{ \
	85	set_bit(BH_##bit, &(bh)->b_state); \
	86	} \
	87	static inline void clear_buffer_##name(struct buffer_head *bh) \
	88	{ \
	89	clear_bit(BH_##bit, &(bh)->b_state); \
	90	} \
	91	static inline int buffer_##name(const struct buffer_head *bh) \
	92	{ \
	93	return test_bit(BH_##bit, &(bh)->b_state); \
	94	}
	95
	96	/*
	97	* test_set_buffer_foo() and test_clear_buffer_foo()
	98	*/
	99	#define TAS_BUFFER_FNS(bit, name) \
	100	static inline int test_set_buffer_##name(struct buffer_head *bh) \
	101	{ \
	102	return test_and_set_bit(BH_##bit, &(bh)->b_state); \
	103	} \
	104	static inline int test_clear_buffer_##name(struct buffer_head *bh) \
	105	{ \
	106	return test_and_clear_bit(BH_##bit, &(bh)->b_state); \
	107	} \
	108
	109	/*
	110	* Emit the buffer bitops functions. Note that there are also functions
	111	* of the form "mark_buffer_foo()". These are higher-level functions which
	112	* do something in addition to setting a b_state bit.
	113	*/
	114	BUFFER_FNS(Uptodate, uptodate)
	115	BUFFER_FNS(Dirty, dirty)
	116	TAS_BUFFER_FNS(Dirty, dirty)
	117	BUFFER_FNS(Lock, locked)
1da177e4 LT	118	BUFFER_FNS(Req, req)
	119	TAS_BUFFER_FNS(Req, req)
	120	BUFFER_FNS(Mapped, mapped)
	121	BUFFER_FNS(New, new)
	122	BUFFER_FNS(Async_Read, async_read)
	123	BUFFER_FNS(Async_Write, async_write)
	124	BUFFER_FNS(Delay, delay)
	125	BUFFER_FNS(Boundary, boundary)
	126	BUFFER_FNS(Write_EIO, write_io_error)
1da177e4	127	BUFFER_FNS(Eopnotsupp, eopnotsupp)
33a266dd	128	BUFFER_FNS(Unwritten, unwritten)
1da177e4 LT	129
	130	#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK)
	131	#define touch_buffer(bh) mark_page_accessed(bh->b_page)
	132
	133	/* If we know page->private refers to buffer_heads */
	134	#define page_buffers(page) \
	135	({ \
4c21e2f2 HD	136	BUG_ON(!PagePrivate(page)); \
4c21e2f2 HD	137	((struct buffer_head *)page_private(page)); \
1da177e4 LT	138	})
	139	#define page_has_buffers(page) PagePrivate(page)
	140
	141	/*
	142	* Declarations
	143	*/
	144
b3c97528	145	void mark_buffer_dirty(struct buffer_head *bh);
1da177e4 LT	146	void init_buffer(struct buffer_head , bh_end_io_t , void *);
	147	void set_bh_page(struct buffer_head *bh,
	148	struct page *page, unsigned long offset);
	149	int try_to_free_buffers(struct page *);
	150	struct buffer_head alloc_page_buffers(struct page page, unsigned long size,
	151	int retry);
	152	void create_empty_buffers(struct page *, unsigned long,
	153	unsigned long b_state);
	154	void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
	155	void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
35c80d5f	156	void end_buffer_async_write(struct buffer_head *bh, int uptodate);
1da177e4 LT	157
	158	/* Things to do with buffers at mapping->private_list */
	159	void mark_buffer_dirty_inode(struct buffer_head bh, struct inode inode);
	160	int inode_has_buffers(struct inode *);
	161	void invalidate_inode_buffers(struct inode *);
	162	int remove_inode_buffers(struct inode *inode);
	163	int sync_mapping_buffers(struct address_space *mapping);
	164	void unmap_underlying_metadata(struct block_device *bdev, sector_t block);
	165
	166	void mark_buffer_async_write(struct buffer_head *bh);
1da177e4 LT	167	void __wait_on_buffer(struct buffer_head *);
1da177e4 LT	168	wait_queue_head_t bh_waitq_head(struct buffer_head bh);
3991d3bd TK	169	struct buffer_head __find_get_block(struct block_device bdev, sector_t block,
	170	unsigned size);
	171	struct buffer_head __getblk(struct block_device bdev, sector_t block,
	172	unsigned size);
1da177e4 LT	173	void __brelse(struct buffer_head *);
1da177e4 LT	174	void __bforget(struct buffer_head *);
3991d3bd TK	175	void __breadahead(struct block_device *, sector_t block, unsigned int size);
3991d3bd TK	176	struct buffer_head __bread(struct block_device , sector_t block, unsigned size);
f9a14399	177	void invalidate_bh_lrus(void);
dd0fc66f	178	struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
1da177e4	179	void free_buffer_head(struct buffer_head * bh);
b3c97528 HH	180	void unlock_buffer(struct buffer_head *bh);
b3c97528 HH	181	void __lock_buffer(struct buffer_head *bh);
1da177e4 LT	182	void ll_rw_block(int, int, struct buffer_head * bh[]);
1da177e4 LT	183	int sync_dirty_buffer(struct buffer_head *bh);
87e99511	184	int __sync_dirty_buffer(struct buffer_head *bh, int rw);
1da177e4 LT	185	int submit_bh(int, struct buffer_head *);
	186	void write_boundary_block(struct block_device *bdev,
	187	sector_t bblock, unsigned blocksize);
389d1b08 AK	188	int bh_uptodate_or_lock(struct buffer_head *bh);
389d1b08 AK	189	int bh_submit_read(struct buffer_head *bh);
1da177e4 LT	190
	191	extern int buffer_heads_over_limit;
	192
	193	/*
	194	* Generic address_space_operations implementations for buffer_head-backed
	195	* address_spaces.
	196	*/
2ff28e22	197	void block_invalidatepage(struct page *page, unsigned long offset);
1da177e4 LT	198	int block_write_full_page(struct page page, get_block_t get_block,
1da177e4 LT	199	struct writeback_control *wbc);
35c80d5f CM	200	int block_write_full_page_endio(struct page page, get_block_t get_block,
35c80d5f CM	201	struct writeback_control wbc, bh_end_io_t handler);
1da177e4	202	int block_read_full_page(struct page, get_block_t);
8ab22b9a HH	203	int block_is_partially_uptodate(struct page page, read_descriptor_t desc,
8ab22b9a HH	204	unsigned long from);
155130a4 CH	205	int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
155130a4 CH	206	unsigned flags, struct page *pagep, get_block_t get_block);
6e1db88d CH	207	int __block_write_begin(struct page *page, loff_t pos, unsigned len,
6e1db88d CH	208	get_block_t *get_block);
afddba49 NP	209	int block_write_end(struct file , struct address_space ,
	210	loff_t, unsigned, unsigned,
	211	struct page , void );
	212	int generic_write_end(struct file , struct address_space ,
	213	loff_t, unsigned, unsigned,
	214	struct page , void );
	215	void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
1da177e4	216	int block_prepare_write(struct page, unsigned, unsigned, get_block_t);
89e10787 NP	217	int cont_write_begin(struct file , struct address_space , loff_t,
	218	unsigned, unsigned, struct page , void ,
	219	get_block_t , loff_t );
05eb0b51	220	int generic_cont_expand_simple(struct inode *inode, loff_t size);
1da177e4	221	int block_commit_write(struct page *page, unsigned from, unsigned to);
c2ec175c	222	int block_page_mkwrite(struct vm_area_struct vma, struct vm_fault vmf,
54171690	223	get_block_t get_block);
3978d717	224	void block_sync_page(struct page *);
1da177e4	225	sector_t generic_block_bmap(struct address_space , sector_t, get_block_t );
1da177e4	226	int block_truncate_page(struct address_space , loff_t, get_block_t );
ea0f04e5	227	int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned,
03158cd7 NP	228	struct page , void , get_block_t*);
	229	int nobh_write_end(struct file , struct address_space ,
	230	loff_t, unsigned, unsigned,
	231	struct page , void );
	232	int nobh_truncate_page(struct address_space , loff_t, get_block_t );
1da177e4 LT	233	int nobh_writepage(struct page page, get_block_t get_block,
	234	struct writeback_control *wbc);
	235
b6cd0b77	236	void buffer_init(void);
1da177e4 LT	237
	238	/*
	239	* inline definitions
	240	*/
	241
	242	static inline void attach_page_buffers(struct page *page,
	243	struct buffer_head *head)
	244	{
	245	page_cache_get(page);
	246	SetPagePrivate(page);
4c21e2f2	247	set_page_private(page, (unsigned long)head);
1da177e4 LT	248	}
	249
	250	static inline void get_bh(struct buffer_head *bh)
	251	{
	252	atomic_inc(&bh->b_count);
	253	}
	254
	255	static inline void put_bh(struct buffer_head *bh)
	256	{
	257	smp_mb__before_atomic_dec();
	258	atomic_dec(&bh->b_count);
	259	}
	260
	261	static inline void brelse(struct buffer_head *bh)
	262	{
	263	if (bh)
	264	__brelse(bh);
	265	}
	266
	267	static inline void bforget(struct buffer_head *bh)
	268	{
	269	if (bh)
	270	__bforget(bh);
	271	}
	272
	273	static inline struct buffer_head *
	274	sb_bread(struct super_block *sb, sector_t block)
	275	{
	276	return __bread(sb->s_bdev, block, sb->s_blocksize);
	277	}
	278
	279	static inline void
	280	sb_breadahead(struct super_block *sb, sector_t block)
	281	{
	282	__breadahead(sb->s_bdev, block, sb->s_blocksize);
	283	}
	284
	285	static inline struct buffer_head *
	286	sb_getblk(struct super_block *sb, sector_t block)
	287	{
	288	return __getblk(sb->s_bdev, block, sb->s_blocksize);
	289	}
	290
	291	static inline struct buffer_head *
	292	sb_find_get_block(struct super_block *sb, sector_t block)
	293	{
	294	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
	295	}
	296
	297	static inline void
	298	map_bh(struct buffer_head bh, struct super_block sb, sector_t block)
	299	{
	300	set_buffer_mapped(bh);
	301	bh->b_bdev = sb->s_bdev;
	302	bh->b_blocknr = block;
b0cf2321	303	bh->b_size = sb->s_blocksize;
1da177e4 LT	304	}
1da177e4 LT	305
1da177e4 LT	306	static inline void wait_on_buffer(struct buffer_head *bh)
	307	{
	308	might_sleep();
a9877cc2	309	if (buffer_locked(bh))
1da177e4 LT	310	__wait_on_buffer(bh);
	311	}
	312
ca5de404 NP	313	static inline int trylock_buffer(struct buffer_head *bh)
ca5de404 NP	314	{
51b07fc3	315	return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
ca5de404 NP	316	}
ca5de404 NP	317
1da177e4 LT	318	static inline void lock_buffer(struct buffer_head *bh)
	319	{
	320	might_sleep();
ca5de404	321	if (!trylock_buffer(bh))
1da177e4 LT	322	__lock_buffer(bh);
	323	}
	324
cf9a2ae8	325	extern int __set_page_dirty_buffers(struct page *page);
9361401e DH	326
	327	#else /* CONFIG_BLOCK */
	328
	329	static inline void buffer_init(void) {}
	330	static inline int try_to_free_buffers(struct page *page) { return 1; }
9361401e DH	331	static inline int inode_has_buffers(struct inode *inode) { return 0; }
	332	static inline void invalidate_inode_buffers(struct inode *inode) {}
	333	static inline int remove_inode_buffers(struct inode *inode) { return 1; }
	334	static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
9361401e DH	335
9361401e DH	336	#endif /* CONFIG_BLOCK */
1da177e4	337	#endif /* _LINUX_BUFFER_HEAD_H */