[deliverable/linux.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_Ordered,	/* ordered 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(Ordered, ordered)
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);

/* 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 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_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 file *, struct address_space *,
				loff_t, unsigned, unsigned,
				struct page **, void **, get_block_t*);
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 file_fsync(struct file *, struct dentry *, int);
int nobh_write_begin(struct file *, 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;
}

/*
 * Calling wait_on_buffer() for a zero-ref buffer is illegal, so we call into
 * __wait_on_buffer() just to trip a debug check.  Because debug code in inline
 * functions is bloaty.
 */
static inline void wait_on_buffer(struct buffer_head *bh)
{
	might_sleep();
	if (buffer_locked(bh) || atomic_read(&bh->b_count) == 0)
		__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 */
	35	BH_Ordered, /* ordered write */
	36	BH_Eopnotsupp, /* operation not supported (barrier) */
33a266dd	37	BH_Unwritten, /* Buffer is allocated on disk but not written */
08bafc03	38	BH_Quiet, /* Buffer Error Prinks to be quiet */
1da177e4 LT	39
	40	BH_PrivateStart,/* not a state bit, but the first bit available
	41	* for private allocation by other entities
	42	*/
	43	};
	44
	45	#define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512)
	46
	47	struct page;
	48	struct buffer_head;
	49	struct address_space;
	50	typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
	51
	52	/*
205f87f6 BP	53	* Historically, a buffer_head was used to map a single block
	54	* within a page, and of course as the unit of I/O through the
	55	* filesystem and block layers. Nowadays the basic I/O unit
	56	* is the bio, and buffer_heads are used for extracting block
	57	* mappings (via a get_block_t call), for tracking state within
	58	* a page (via a page_mapping) and for wrapping bio submission
	59	* for backward compatibility reasons (e.g. submit_bh).
1da177e4 LT	60	*/
1da177e4 LT	61	struct buffer_head {
1da177e4 LT	62	unsigned long b_state; /* buffer state bitmap (see above) */
	63	struct buffer_head b_this_page;/ circular list of page's buffers */
	64	struct page b_page; / the page this bh is mapped to */
1da177e4	65
205f87f6 BP	66	sector_t b_blocknr; /* start block number */
	67	size_t b_size; /* size of mapping */
	68	char b_data; / pointer to data within the page */
1da177e4 LT	69
	70	struct block_device *b_bdev;
	71	bh_end_io_t b_end_io; / I/O completion */
	72	void b_private; / reserved for b_end_io */
	73	struct list_head b_assoc_buffers; /* associated with another mapping */
58ff407b JK	74	struct address_space b_assoc_map; / mapping this buffer is
58ff407b JK	75	associated with */
205f87f6	76	atomic_t b_count; /* users using this buffer_head */
1da177e4 LT	77	};
	78
	79	/*
	80	* macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
	81	* and buffer_foo() functions.
	82	*/
	83	#define BUFFER_FNS(bit, name) \
	84	static inline void set_buffer_##name(struct buffer_head *bh) \
	85	{ \
	86	set_bit(BH_##bit, &(bh)->b_state); \
	87	} \
	88	static inline void clear_buffer_##name(struct buffer_head *bh) \
	89	{ \
	90	clear_bit(BH_##bit, &(bh)->b_state); \
	91	} \
	92	static inline int buffer_##name(const struct buffer_head *bh) \
	93	{ \
	94	return test_bit(BH_##bit, &(bh)->b_state); \
	95	}
	96
	97	/*
	98	* test_set_buffer_foo() and test_clear_buffer_foo()
	99	*/
	100	#define TAS_BUFFER_FNS(bit, name) \
	101	static inline int test_set_buffer_##name(struct buffer_head *bh) \
	102	{ \
	103	return test_and_set_bit(BH_##bit, &(bh)->b_state); \
	104	} \
	105	static inline int test_clear_buffer_##name(struct buffer_head *bh) \
	106	{ \
	107	return test_and_clear_bit(BH_##bit, &(bh)->b_state); \
	108	} \
	109
	110	/*
	111	* Emit the buffer bitops functions. Note that there are also functions
	112	* of the form "mark_buffer_foo()". These are higher-level functions which
	113	* do something in addition to setting a b_state bit.
	114	*/
	115	BUFFER_FNS(Uptodate, uptodate)
	116	BUFFER_FNS(Dirty, dirty)
	117	TAS_BUFFER_FNS(Dirty, dirty)
	118	BUFFER_FNS(Lock, locked)
1da177e4 LT	119	BUFFER_FNS(Req, req)
	120	TAS_BUFFER_FNS(Req, req)
	121	BUFFER_FNS(Mapped, mapped)
	122	BUFFER_FNS(New, new)
	123	BUFFER_FNS(Async_Read, async_read)
	124	BUFFER_FNS(Async_Write, async_write)
	125	BUFFER_FNS(Delay, delay)
	126	BUFFER_FNS(Boundary, boundary)
	127	BUFFER_FNS(Write_EIO, write_io_error)
	128	BUFFER_FNS(Ordered, ordered)
	129	BUFFER_FNS(Eopnotsupp, eopnotsupp)
33a266dd	130	BUFFER_FNS(Unwritten, unwritten)
1da177e4 LT	131
	132	#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK)
	133	#define touch_buffer(bh) mark_page_accessed(bh->b_page)
	134
	135	/* If we know page->private refers to buffer_heads */
	136	#define page_buffers(page) \
	137	({ \
4c21e2f2 HD	138	BUG_ON(!PagePrivate(page)); \
4c21e2f2 HD	139	((struct buffer_head *)page_private(page)); \
1da177e4 LT	140	})
	141	#define page_has_buffers(page) PagePrivate(page)
	142
	143	/*
	144	* Declarations
	145	*/
	146
b3c97528	147	void mark_buffer_dirty(struct buffer_head *bh);
1da177e4 LT	148	void init_buffer(struct buffer_head , bh_end_io_t , void *);
	149	void set_bh_page(struct buffer_head *bh,
	150	struct page *page, unsigned long offset);
	151	int try_to_free_buffers(struct page *);
	152	struct buffer_head alloc_page_buffers(struct page page, unsigned long size,
	153	int retry);
	154	void create_empty_buffers(struct page *, unsigned long,
	155	unsigned long b_state);
	156	void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
	157	void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
1da177e4 LT	158
	159	/* Things to do with buffers at mapping->private_list */
	160	void mark_buffer_dirty_inode(struct buffer_head bh, struct inode inode);
	161	int inode_has_buffers(struct inode *);
	162	void invalidate_inode_buffers(struct inode *);
	163	int remove_inode_buffers(struct inode *inode);
	164	int sync_mapping_buffers(struct address_space *mapping);
	165	void unmap_underlying_metadata(struct block_device *bdev, sector_t block);
	166
	167	void mark_buffer_async_write(struct buffer_head *bh);
1da177e4 LT	168	void __wait_on_buffer(struct buffer_head *);
1da177e4 LT	169	wait_queue_head_t bh_waitq_head(struct buffer_head bh);
3991d3bd TK	170	struct buffer_head __find_get_block(struct block_device bdev, sector_t block,
	171	unsigned size);
	172	struct buffer_head __getblk(struct block_device bdev, sector_t block,
	173	unsigned size);
1da177e4 LT	174	void __brelse(struct buffer_head *);
1da177e4 LT	175	void __bforget(struct buffer_head *);
3991d3bd TK	176	void __breadahead(struct block_device *, sector_t block, unsigned int size);
3991d3bd TK	177	struct buffer_head __bread(struct block_device , sector_t block, unsigned size);
f9a14399	178	void invalidate_bh_lrus(void);
dd0fc66f	179	struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
1da177e4	180	void free_buffer_head(struct buffer_head * bh);
b3c97528 HH	181	void unlock_buffer(struct buffer_head *bh);
b3c97528 HH	182	void __lock_buffer(struct buffer_head *bh);
1da177e4 LT	183	void ll_rw_block(int, int, struct buffer_head * bh[]);
	184	int sync_dirty_buffer(struct buffer_head *bh);
	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,
	199	struct writeback_control *wbc);
	200	int block_read_full_page(struct page, get_block_t);
8ab22b9a HH	201	int block_is_partially_uptodate(struct page page, read_descriptor_t desc,
8ab22b9a HH	202	unsigned long from);
afddba49 NP	203	int block_write_begin(struct file , struct address_space ,
	204	loff_t, unsigned, unsigned,
	205	struct page , void , get_block_t*);
	206	int block_write_end(struct file , struct address_space ,
	207	loff_t, unsigned, unsigned,
	208	struct page , void );
	209	int generic_write_end(struct file , struct address_space ,
	210	loff_t, unsigned, unsigned,
	211	struct page , void );
	212	void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
1da177e4	213	int block_prepare_write(struct page, unsigned, unsigned, get_block_t);
89e10787 NP	214	int cont_write_begin(struct file , struct address_space , loff_t,
	215	unsigned, unsigned, struct page , void ,
	216	get_block_t , loff_t );
05eb0b51	217	int generic_cont_expand_simple(struct inode *inode, loff_t size);
1da177e4	218	int block_commit_write(struct page *page, unsigned from, unsigned to);
c2ec175c	219	int block_page_mkwrite(struct vm_area_struct vma, struct vm_fault vmf,
54171690	220	get_block_t get_block);
3978d717	221	void block_sync_page(struct page *);
1da177e4	222	sector_t generic_block_bmap(struct address_space , sector_t, get_block_t );
1da177e4 LT	223	int block_truncate_page(struct address_space , loff_t, get_block_t );
1da177e4 LT	224	int file_fsync(struct file , struct dentry , int);
03158cd7 NP	225	int nobh_write_begin(struct file , struct address_space ,
	226	loff_t, unsigned, unsigned,
	227	struct page , void , get_block_t*);
	228	int nobh_write_end(struct file , struct address_space ,
	229	loff_t, unsigned, unsigned,
	230	struct page , void );
	231	int nobh_truncate_page(struct address_space , loff_t, get_block_t );
1da177e4 LT	232	int nobh_writepage(struct page page, get_block_t get_block,
	233	struct writeback_control *wbc);
	234
b6cd0b77	235	void buffer_init(void);
1da177e4 LT	236
	237	/*
	238	* inline definitions
	239	*/
	240
	241	static inline void attach_page_buffers(struct page *page,
	242	struct buffer_head *head)
	243	{
	244	page_cache_get(page);
	245	SetPagePrivate(page);
4c21e2f2	246	set_page_private(page, (unsigned long)head);
1da177e4 LT	247	}
	248
	249	static inline void get_bh(struct buffer_head *bh)
	250	{
	251	atomic_inc(&bh->b_count);
	252	}
	253
	254	static inline void put_bh(struct buffer_head *bh)
	255	{
	256	smp_mb__before_atomic_dec();
	257	atomic_dec(&bh->b_count);
	258	}
	259
	260	static inline void brelse(struct buffer_head *bh)
	261	{
	262	if (bh)
	263	__brelse(bh);
	264	}
	265
	266	static inline void bforget(struct buffer_head *bh)
	267	{
	268	if (bh)
	269	__bforget(bh);
	270	}
	271
	272	static inline struct buffer_head *
	273	sb_bread(struct super_block *sb, sector_t block)
	274	{
	275	return __bread(sb->s_bdev, block, sb->s_blocksize);
	276	}
	277
	278	static inline void
	279	sb_breadahead(struct super_block *sb, sector_t block)
	280	{
	281	__breadahead(sb->s_bdev, block, sb->s_blocksize);
	282	}
	283
	284	static inline struct buffer_head *
	285	sb_getblk(struct super_block *sb, sector_t block)
	286	{
	287	return __getblk(sb->s_bdev, block, sb->s_blocksize);
	288	}
	289
	290	static inline struct buffer_head *
	291	sb_find_get_block(struct super_block *sb, sector_t block)
	292	{
	293	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
	294	}
	295
	296	static inline void
	297	map_bh(struct buffer_head bh, struct super_block sb, sector_t block)
	298	{
	299	set_buffer_mapped(bh);
	300	bh->b_bdev = sb->s_bdev;
	301	bh->b_blocknr = block;
b0cf2321	302	bh->b_size = sb->s_blocksize;
1da177e4 LT	303	}
	304
	305	/*
	306	* Calling wait_on_buffer() for a zero-ref buffer is illegal, so we call into
	307	* __wait_on_buffer() just to trip a debug check. Because debug code in inline
	308	* functions is bloaty.
	309	*/
	310	static inline void wait_on_buffer(struct buffer_head *bh)
	311	{
	312	might_sleep();
	313	if (buffer_locked(bh) \|\| atomic_read(&bh->b_count) == 0)
	314	__wait_on_buffer(bh);
	315	}
	316
ca5de404 NP	317	static inline int trylock_buffer(struct buffer_head *bh)
ca5de404 NP	318	{
51b07fc3	319	return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
ca5de404 NP	320	}
ca5de404 NP	321
1da177e4 LT	322	static inline void lock_buffer(struct buffer_head *bh)
	323	{
	324	might_sleep();
ca5de404	325	if (!trylock_buffer(bh))
1da177e4 LT	326	__lock_buffer(bh);
	327	}
	328
cf9a2ae8	329	extern int __set_page_dirty_buffers(struct page *page);
9361401e DH	330
	331	#else /* CONFIG_BLOCK */
	332
	333	static inline void buffer_init(void) {}
	334	static inline int try_to_free_buffers(struct page *page) { return 1; }
9361401e DH	335	static inline int inode_has_buffers(struct inode *inode) { return 0; }
	336	static inline void invalidate_inode_buffers(struct inode *inode) {}
	337	static inline int remove_inode_buffers(struct inode *inode) { return 1; }
	338	static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
9361401e DH	339
9361401e DH	340	#endif /* CONFIG_BLOCK */
1da177e4	341	#endif /* _LINUX_BUFFER_HEAD_H */