[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>

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 */
	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.
 */
int try_to_release_page(struct page * page, gfp_t gfp_mask);
void block_invalidatepage(struct page *page, unsigned long offset);
void do_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);
}

#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
	17	enum bh_state_bits {
	18	BH_Uptodate, /* Contains valid data */
	19	BH_Dirty, /* Is dirty */
	20	BH_Lock, /* Is locked */
	21	BH_Req, /* Has been submitted for I/O */
a3972203 NP	22	BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise
	23	* IO completion of other buffers in the page
	24	*/
1da177e4 LT	25
	26	BH_Mapped, /* Has a disk mapping */
	27	BH_New, /* Disk mapping was newly created by get_block */
	28	BH_Async_Read, /* Is under end_buffer_async_read I/O */
	29	BH_Async_Write, /* Is under end_buffer_async_write I/O */
	30	BH_Delay, /* Buffer is not yet allocated on disk */
	31	BH_Boundary, /* Block is followed by a discontiguity */
	32	BH_Write_EIO, /* I/O error on write */
	33	BH_Ordered, /* ordered write */
	34	BH_Eopnotsupp, /* operation not supported (barrier) */
	35
	36	BH_PrivateStart,/* not a state bit, but the first bit available
	37	* for private allocation by other entities
	38	*/
	39	};
	40
	41	#define MAX_BUF_PER_PAGE (PAGE_CACHE_SIZE / 512)
	42
	43	struct page;
	44	struct buffer_head;
	45	struct address_space;
	46	typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
	47
	48	/*
205f87f6 BP	49	* Historically, a buffer_head was used to map a single block
	50	* within a page, and of course as the unit of I/O through the
	51	* filesystem and block layers. Nowadays the basic I/O unit
	52	* is the bio, and buffer_heads are used for extracting block
	53	* mappings (via a get_block_t call), for tracking state within
	54	* a page (via a page_mapping) and for wrapping bio submission
	55	* for backward compatibility reasons (e.g. submit_bh).
1da177e4 LT	56	*/
1da177e4 LT	57	struct buffer_head {
1da177e4 LT	58	unsigned long b_state; /* buffer state bitmap (see above) */
	59	struct buffer_head b_this_page;/ circular list of page's buffers */
	60	struct page b_page; / the page this bh is mapped to */
1da177e4	61
205f87f6 BP	62	sector_t b_blocknr; /* start block number */
	63	size_t b_size; /* size of mapping */
	64	char b_data; / pointer to data within the page */
1da177e4 LT	65
	66	struct block_device *b_bdev;
	67	bh_end_io_t b_end_io; / I/O completion */
	68	void b_private; / reserved for b_end_io */
	69	struct list_head b_assoc_buffers; /* associated with another mapping */
205f87f6	70	atomic_t b_count; /* users using this buffer_head */
1da177e4 LT	71	};
	72
	73	/*
	74	* macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
	75	* and buffer_foo() functions.
	76	*/
	77	#define BUFFER_FNS(bit, name) \
	78	static inline void set_buffer_##name(struct buffer_head *bh) \
	79	{ \
	80	set_bit(BH_##bit, &(bh)->b_state); \
	81	} \
	82	static inline void clear_buffer_##name(struct buffer_head *bh) \
	83	{ \
	84	clear_bit(BH_##bit, &(bh)->b_state); \
	85	} \
	86	static inline int buffer_##name(const struct buffer_head *bh) \
	87	{ \
	88	return test_bit(BH_##bit, &(bh)->b_state); \
	89	}
	90
	91	/*
	92	* test_set_buffer_foo() and test_clear_buffer_foo()
	93	*/
	94	#define TAS_BUFFER_FNS(bit, name) \
	95	static inline int test_set_buffer_##name(struct buffer_head *bh) \
	96	{ \
	97	return test_and_set_bit(BH_##bit, &(bh)->b_state); \
	98	} \
	99	static inline int test_clear_buffer_##name(struct buffer_head *bh) \
	100	{ \
	101	return test_and_clear_bit(BH_##bit, &(bh)->b_state); \
	102	} \
	103
	104	/*
	105	* Emit the buffer bitops functions. Note that there are also functions
	106	* of the form "mark_buffer_foo()". These are higher-level functions which
	107	* do something in addition to setting a b_state bit.
	108	*/
	109	BUFFER_FNS(Uptodate, uptodate)
	110	BUFFER_FNS(Dirty, dirty)
	111	TAS_BUFFER_FNS(Dirty, dirty)
	112	BUFFER_FNS(Lock, locked)
	113	TAS_BUFFER_FNS(Lock, locked)
	114	BUFFER_FNS(Req, req)
	115	TAS_BUFFER_FNS(Req, req)
	116	BUFFER_FNS(Mapped, mapped)
	117	BUFFER_FNS(New, new)
	118	BUFFER_FNS(Async_Read, async_read)
	119	BUFFER_FNS(Async_Write, async_write)
	120	BUFFER_FNS(Delay, delay)
	121	BUFFER_FNS(Boundary, boundary)
	122	BUFFER_FNS(Write_EIO, write_io_error)
	123	BUFFER_FNS(Ordered, ordered)
	124	BUFFER_FNS(Eopnotsupp, eopnotsupp)
	125
	126	#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK)
	127	#define touch_buffer(bh) mark_page_accessed(bh->b_page)
	128
	129	/* If we know page->private refers to buffer_heads */
	130	#define page_buffers(page) \
	131	({ \
4c21e2f2 HD	132	BUG_ON(!PagePrivate(page)); \
4c21e2f2 HD	133	((struct buffer_head *)page_private(page)); \
1da177e4 LT	134	})
	135	#define page_has_buffers(page) PagePrivate(page)
	136
	137	/*
	138	* Declarations
	139	*/
	140
	141	void FASTCALL(mark_buffer_dirty(struct buffer_head *bh));
	142	void init_buffer(struct buffer_head , bh_end_io_t , void *);
	143	void set_bh_page(struct buffer_head *bh,
	144	struct page *page, unsigned long offset);
	145	int try_to_free_buffers(struct page *);
	146	struct buffer_head alloc_page_buffers(struct page page, unsigned long size,
	147	int retry);
	148	void create_empty_buffers(struct page *, unsigned long,
	149	unsigned long b_state);
	150	void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
	151	void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
1da177e4 LT	152
	153	/* Things to do with buffers at mapping->private_list */
	154	void mark_buffer_dirty_inode(struct buffer_head bh, struct inode inode);
	155	int inode_has_buffers(struct inode *);
	156	void invalidate_inode_buffers(struct inode *);
	157	int remove_inode_buffers(struct inode *inode);
	158	int sync_mapping_buffers(struct address_space *mapping);
	159	void unmap_underlying_metadata(struct block_device *bdev, sector_t block);
	160
	161	void mark_buffer_async_write(struct buffer_head *bh);
	162	void invalidate_bdev(struct block_device *, int);
	163	int sync_blockdev(struct block_device *bdev);
	164	void __wait_on_buffer(struct buffer_head *);
	165	wait_queue_head_t bh_waitq_head(struct buffer_head bh);
	166	int fsync_bdev(struct block_device *);
	167	struct super_block freeze_bdev(struct block_device );
	168	void thaw_bdev(struct block_device , struct super_block );
	169	int fsync_super(struct super_block *);
	170	int fsync_no_super(struct block_device *);
	171	struct buffer_head __find_get_block(struct block_device , sector_t, int);
	172	struct buffer_head * __getblk(struct block_device *, sector_t, int);
	173	void __brelse(struct buffer_head *);
	174	void __bforget(struct buffer_head *);
	175	void __breadahead(struct block_device *, sector_t block, int size);
	176	struct buffer_head __bread(struct block_device , sector_t block, int size);
dd0fc66f	177	struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
1da177e4 LT	178	void free_buffer_head(struct buffer_head * bh);
	179	void FASTCALL(unlock_buffer(struct buffer_head *bh));
	180	void FASTCALL(__lock_buffer(struct buffer_head *bh));
	181	void ll_rw_block(int, int, struct buffer_head * bh[]);
	182	int sync_dirty_buffer(struct buffer_head *bh);
	183	int submit_bh(int, struct buffer_head *);
	184	void write_boundary_block(struct block_device *bdev,
	185	sector_t bblock, unsigned blocksize);
	186
	187	extern int buffer_heads_over_limit;
	188
	189	/*
	190	* Generic address_space_operations implementations for buffer_head-backed
	191	* address_spaces.
	192	*/
27496a8c	193	int try_to_release_page(struct page * page, gfp_t gfp_mask);
2ff28e22 N	194	void block_invalidatepage(struct page *page, unsigned long offset);
2ff28e22 N	195	void do_invalidatepage(struct page *page, unsigned long offset);
1da177e4 LT	196	int block_write_full_page(struct page page, get_block_t get_block,
	197	struct writeback_control *wbc);
	198	int block_read_full_page(struct page, get_block_t);
	199	int block_prepare_write(struct page, unsigned, unsigned, get_block_t);
	200	int cont_prepare_write(struct page, unsigned, unsigned, get_block_t,
	201	loff_t *);
05eb0b51 OH	202	int generic_cont_expand(struct inode *inode, loff_t size);
05eb0b51 OH	203	int generic_cont_expand_simple(struct inode *inode, loff_t size);
1da177e4	204	int block_commit_write(struct page *page, unsigned from, unsigned to);
3978d717	205	void block_sync_page(struct page *);
1da177e4 LT	206	sector_t generic_block_bmap(struct address_space , sector_t, get_block_t );
	207	int generic_commit_write(struct file , struct page , unsigned, unsigned);
	208	int block_truncate_page(struct address_space , loff_t, get_block_t );
	209	int file_fsync(struct file , struct dentry , int);
	210	int nobh_prepare_write(struct page, unsigned, unsigned, get_block_t);
	211	int nobh_commit_write(struct file , struct page , unsigned, unsigned);
	212	int nobh_truncate_page(struct address_space *, loff_t);
	213	int nobh_writepage(struct page page, get_block_t get_block,
	214	struct writeback_control *wbc);
	215
b6cd0b77	216	void buffer_init(void);
1da177e4 LT	217
	218	/*
	219	* inline definitions
	220	*/
	221
	222	static inline void attach_page_buffers(struct page *page,
	223	struct buffer_head *head)
	224	{
	225	page_cache_get(page);
	226	SetPagePrivate(page);
4c21e2f2	227	set_page_private(page, (unsigned long)head);
1da177e4 LT	228	}
	229
	230	static inline void get_bh(struct buffer_head *bh)
	231	{
	232	atomic_inc(&bh->b_count);
	233	}
	234
	235	static inline void put_bh(struct buffer_head *bh)
	236	{
	237	smp_mb__before_atomic_dec();
	238	atomic_dec(&bh->b_count);
	239	}
	240
	241	static inline void brelse(struct buffer_head *bh)
	242	{
	243	if (bh)
	244	__brelse(bh);
	245	}
	246
	247	static inline void bforget(struct buffer_head *bh)
	248	{
	249	if (bh)
	250	__bforget(bh);
	251	}
	252
	253	static inline struct buffer_head *
	254	sb_bread(struct super_block *sb, sector_t block)
	255	{
	256	return __bread(sb->s_bdev, block, sb->s_blocksize);
	257	}
	258
	259	static inline void
	260	sb_breadahead(struct super_block *sb, sector_t block)
	261	{
	262	__breadahead(sb->s_bdev, block, sb->s_blocksize);
	263	}
	264
	265	static inline struct buffer_head *
	266	sb_getblk(struct super_block *sb, sector_t block)
	267	{
	268	return __getblk(sb->s_bdev, block, sb->s_blocksize);
	269	}
	270
	271	static inline struct buffer_head *
	272	sb_find_get_block(struct super_block *sb, sector_t block)
	273	{
	274	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
	275	}
	276
	277	static inline void
	278	map_bh(struct buffer_head bh, struct super_block sb, sector_t block)
	279	{
	280	set_buffer_mapped(bh);
	281	bh->b_bdev = sb->s_bdev;
	282	bh->b_blocknr = block;
b0cf2321	283	bh->b_size = sb->s_blocksize;
1da177e4 LT	284	}
	285
	286	/*
	287	* Calling wait_on_buffer() for a zero-ref buffer is illegal, so we call into
	288	* __wait_on_buffer() just to trip a debug check. Because debug code in inline
	289	* functions is bloaty.
	290	*/
	291	static inline void wait_on_buffer(struct buffer_head *bh)
	292	{
	293	might_sleep();
	294	if (buffer_locked(bh) \|\| atomic_read(&bh->b_count) == 0)
	295	__wait_on_buffer(bh);
	296	}
	297
	298	static inline void lock_buffer(struct buffer_head *bh)
	299	{
	300	might_sleep();
	301	if (test_set_buffer_locked(bh))
	302	__lock_buffer(bh);
	303	}
	304
	305	#endif /* _LINUX_BUFFER_HEAD_H */