[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_Ordered,	/* ordered write */
	BH_Eopnotsupp,	/* operation not supported (barrier) */

	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)
TAS_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)

#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 FASTCALL(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 invalidate_bdev(struct block_device *, int);
int sync_blockdev(struct block_device *bdev);
void __wait_on_buffer(struct buffer_head *);
wait_queue_head_t *bh_waitq_head(struct buffer_head *bh);
int fsync_bdev(struct block_device *);
struct super_block *freeze_bdev(struct block_device *);
void thaw_bdev(struct block_device *, struct super_block *);
int fsync_super(struct super_block *);
int fsync_no_super(struct block_device *);
struct buffer_head *__find_get_block(struct block_device *, sector_t, int);
struct buffer_head * __getblk(struct block_device *, sector_t, int);
void __brelse(struct buffer_head *);
void __bforget(struct buffer_head *);
void __breadahead(struct block_device *, sector_t block, int size);
struct buffer_head *__bread(struct block_device *, sector_t block, int size);
struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
void free_buffer_head(struct buffer_head * bh);
void FASTCALL(unlock_buffer(struct buffer_head *bh));
void FASTCALL(__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);

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_prepare_write(struct page*, unsigned, unsigned, get_block_t*);
int cont_prepare_write(struct page*, unsigned, unsigned, get_block_t*,
				loff_t *);
int generic_cont_expand(struct inode *inode, loff_t size);
int generic_cont_expand_simple(struct inode *inode, loff_t size);
int block_commit_write(struct page *page, unsigned from, unsigned to);
void block_sync_page(struct page *);
sector_t generic_block_bmap(struct address_space *, sector_t, get_block_t *);
int generic_commit_write(struct file *, struct page *, unsigned, unsigned);
int block_truncate_page(struct address_space *, loff_t, get_block_t *);
int file_fsync(struct file *, struct dentry *, int);
int nobh_prepare_write(struct page*, unsigned, unsigned, get_block_t*);
int nobh_commit_write(struct file *, struct page *, unsigned, unsigned);
int nobh_truncate_page(struct address_space *, loff_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 void lock_buffer(struct buffer_head *bh)
{
	might_sleep();
	if (test_set_buffer_locked(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 sync_blockdev(struct block_device *bdev) { return 0; }
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; }
static inline void invalidate_bdev(struct block_device *bdev, int destroy_dirty_buffers) {}


#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) */
	37
	38	BH_PrivateStart,/* not a state bit, but the first bit available
	39	* for private allocation by other entities
	40	*/
	41	};
	42
	43	#define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512)
	44
	45	struct page;
	46	struct buffer_head;
	47	struct address_space;
	48	typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
	49
	50	/*
205f87f6 BP	51	* Historically, a buffer_head was used to map a single block
	52	* within a page, and of course as the unit of I/O through the
	53	* filesystem and block layers. Nowadays the basic I/O unit
	54	* is the bio, and buffer_heads are used for extracting block
	55	* mappings (via a get_block_t call), for tracking state within
	56	* a page (via a page_mapping) and for wrapping bio submission
	57	* for backward compatibility reasons (e.g. submit_bh).
1da177e4 LT	58	*/
1da177e4 LT	59	struct buffer_head {
1da177e4 LT	60	unsigned long b_state; /* buffer state bitmap (see above) */
	61	struct buffer_head b_this_page;/ circular list of page's buffers */
	62	struct page b_page; / the page this bh is mapped to */
1da177e4	63
205f87f6 BP	64	sector_t b_blocknr; /* start block number */
	65	size_t b_size; /* size of mapping */
	66	char b_data; / pointer to data within the page */
1da177e4 LT	67
	68	struct block_device *b_bdev;
	69	bh_end_io_t b_end_io; / I/O completion */
	70	void b_private; / reserved for b_end_io */
	71	struct list_head b_assoc_buffers; /* associated with another mapping */
58ff407b JK	72	struct address_space b_assoc_map; / mapping this buffer is
58ff407b JK	73	associated with */
205f87f6	74	atomic_t b_count; /* users using this buffer_head */
1da177e4 LT	75	};
	76
	77	/*
	78	* macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
	79	* and buffer_foo() functions.
	80	*/
	81	#define BUFFER_FNS(bit, name) \
	82	static inline void set_buffer_##name(struct buffer_head *bh) \
	83	{ \
	84	set_bit(BH_##bit, &(bh)->b_state); \
	85	} \
	86	static inline void clear_buffer_##name(struct buffer_head *bh) \
	87	{ \
	88	clear_bit(BH_##bit, &(bh)->b_state); \
	89	} \
	90	static inline int buffer_##name(const struct buffer_head *bh) \
	91	{ \
	92	return test_bit(BH_##bit, &(bh)->b_state); \
	93	}
	94
	95	/*
	96	* test_set_buffer_foo() and test_clear_buffer_foo()
	97	*/
	98	#define TAS_BUFFER_FNS(bit, name) \
	99	static inline int test_set_buffer_##name(struct buffer_head *bh) \
	100	{ \
	101	return test_and_set_bit(BH_##bit, &(bh)->b_state); \
	102	} \
	103	static inline int test_clear_buffer_##name(struct buffer_head *bh) \
	104	{ \
	105	return test_and_clear_bit(BH_##bit, &(bh)->b_state); \
	106	} \
	107
	108	/*
	109	* Emit the buffer bitops functions. Note that there are also functions
	110	* of the form "mark_buffer_foo()". These are higher-level functions which
	111	* do something in addition to setting a b_state bit.
	112	*/
	113	BUFFER_FNS(Uptodate, uptodate)
	114	BUFFER_FNS(Dirty, dirty)
	115	TAS_BUFFER_FNS(Dirty, dirty)
	116	BUFFER_FNS(Lock, locked)
	117	TAS_BUFFER_FNS(Lock, locked)
	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)
	127	BUFFER_FNS(Ordered, ordered)
	128	BUFFER_FNS(Eopnotsupp, eopnotsupp)
	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
	145	void FASTCALL(mark_buffer_dirty(struct buffer_head *bh));
	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);
1da177e4 LT	156
	157	/* Things to do with buffers at mapping->private_list */
	158	void mark_buffer_dirty_inode(struct buffer_head bh, struct inode inode);
	159	int inode_has_buffers(struct inode *);
	160	void invalidate_inode_buffers(struct inode *);
	161	int remove_inode_buffers(struct inode *inode);
	162	int sync_mapping_buffers(struct address_space *mapping);
	163	void unmap_underlying_metadata(struct block_device *bdev, sector_t block);
	164
	165	void mark_buffer_async_write(struct buffer_head *bh);
	166	void invalidate_bdev(struct block_device *, int);
	167	int sync_blockdev(struct block_device *bdev);
	168	void __wait_on_buffer(struct buffer_head *);
	169	wait_queue_head_t bh_waitq_head(struct buffer_head bh);
	170	int fsync_bdev(struct block_device *);
	171	struct super_block freeze_bdev(struct block_device );
	172	void thaw_bdev(struct block_device , struct super_block );
	173	int fsync_super(struct super_block *);
	174	int fsync_no_super(struct block_device *);
	175	struct buffer_head __find_get_block(struct block_device , sector_t, int);
	176	struct buffer_head * __getblk(struct block_device *, sector_t, int);
	177	void __brelse(struct buffer_head *);
	178	void __bforget(struct buffer_head *);
	179	void __breadahead(struct block_device *, sector_t block, int size);
	180	struct buffer_head __bread(struct block_device , sector_t block, int size);
dd0fc66f	181	struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
1da177e4 LT	182	void free_buffer_head(struct buffer_head * bh);
	183	void FASTCALL(unlock_buffer(struct buffer_head *bh));
	184	void FASTCALL(__lock_buffer(struct buffer_head *bh));
	185	void ll_rw_block(int, int, struct buffer_head * bh[]);
	186	int sync_dirty_buffer(struct buffer_head *bh);
	187	int submit_bh(int, struct buffer_head *);
	188	void write_boundary_block(struct block_device *bdev,
	189	sector_t bblock, unsigned blocksize);
	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);
	201	int block_prepare_write(struct page, unsigned, unsigned, get_block_t);
	202	int cont_prepare_write(struct page, unsigned, unsigned, get_block_t,
	203	loff_t *);
05eb0b51 OH	204	int generic_cont_expand(struct inode *inode, loff_t size);
05eb0b51 OH	205	int generic_cont_expand_simple(struct inode *inode, loff_t size);
1da177e4	206	int block_commit_write(struct page *page, unsigned from, unsigned to);
3978d717	207	void block_sync_page(struct page *);
1da177e4 LT	208	sector_t generic_block_bmap(struct address_space , sector_t, get_block_t );
	209	int generic_commit_write(struct file , struct page , unsigned, unsigned);
	210	int block_truncate_page(struct address_space , loff_t, get_block_t );
	211	int file_fsync(struct file , struct dentry , int);
	212	int nobh_prepare_write(struct page, unsigned, unsigned, get_block_t);
	213	int nobh_commit_write(struct file , struct page , unsigned, unsigned);
	214	int nobh_truncate_page(struct address_space *, loff_t);
	215	int nobh_writepage(struct page page, get_block_t get_block,
	216	struct writeback_control *wbc);
	217
b6cd0b77	218	void buffer_init(void);
1da177e4 LT	219
	220	/*
	221	* inline definitions
	222	*/
	223
	224	static inline void attach_page_buffers(struct page *page,
	225	struct buffer_head *head)
	226	{
	227	page_cache_get(page);
	228	SetPagePrivate(page);
4c21e2f2	229	set_page_private(page, (unsigned long)head);
1da177e4 LT	230	}
	231
	232	static inline void get_bh(struct buffer_head *bh)
	233	{
	234	atomic_inc(&bh->b_count);
	235	}
	236
	237	static inline void put_bh(struct buffer_head *bh)
	238	{
	239	smp_mb__before_atomic_dec();
	240	atomic_dec(&bh->b_count);
	241	}
	242
	243	static inline void brelse(struct buffer_head *bh)
	244	{
	245	if (bh)
	246	__brelse(bh);
	247	}
	248
	249	static inline void bforget(struct buffer_head *bh)
	250	{
	251	if (bh)
	252	__bforget(bh);
	253	}
	254
	255	static inline struct buffer_head *
	256	sb_bread(struct super_block *sb, sector_t block)
	257	{
	258	return __bread(sb->s_bdev, block, sb->s_blocksize);
	259	}
	260
	261	static inline void
	262	sb_breadahead(struct super_block *sb, sector_t block)
	263	{
	264	__breadahead(sb->s_bdev, block, sb->s_blocksize);
	265	}
	266
	267	static inline struct buffer_head *
	268	sb_getblk(struct super_block *sb, sector_t block)
	269	{
	270	return __getblk(sb->s_bdev, block, sb->s_blocksize);
	271	}
	272
	273	static inline struct buffer_head *
	274	sb_find_get_block(struct super_block *sb, sector_t block)
	275	{
	276	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
	277	}
	278
	279	static inline void
	280	map_bh(struct buffer_head bh, struct super_block sb, sector_t block)
	281	{
	282	set_buffer_mapped(bh);
	283	bh->b_bdev = sb->s_bdev;
	284	bh->b_blocknr = block;
b0cf2321	285	bh->b_size = sb->s_blocksize;
1da177e4 LT	286	}
	287
	288	/*
	289	* Calling wait_on_buffer() for a zero-ref buffer is illegal, so we call into
	290	* __wait_on_buffer() just to trip a debug check. Because debug code in inline
	291	* functions is bloaty.
	292	*/
	293	static inline void wait_on_buffer(struct buffer_head *bh)
	294	{
	295	might_sleep();
	296	if (buffer_locked(bh) \|\| atomic_read(&bh->b_count) == 0)
	297	__wait_on_buffer(bh);
	298	}
	299
	300	static inline void lock_buffer(struct buffer_head *bh)
	301	{
	302	might_sleep();
	303	if (test_set_buffer_locked(bh))
	304	__lock_buffer(bh);
	305	}
	306
cf9a2ae8	307	extern int __set_page_dirty_buffers(struct page *page);
9361401e DH	308
	309	#else /* CONFIG_BLOCK */
	310
	311	static inline void buffer_init(void) {}
	312	static inline int try_to_free_buffers(struct page *page) { return 1; }
	313	static inline int sync_blockdev(struct block_device *bdev) { return 0; }
	314	static inline int inode_has_buffers(struct inode *inode) { return 0; }
	315	static inline void invalidate_inode_buffers(struct inode *inode) {}
	316	static inline int remove_inode_buffers(struct inode *inode) { return 1; }
	317	static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
	318	static inline void invalidate_bdev(struct block_device *bdev, int destroy_dirty_buffers) {}
	319
	320
	321	#endif /* CONFIG_BLOCK */
1da177e4	322	#endif /* _LINUX_BUFFER_HEAD_H */