[mirror_ubuntu-artful-kernel.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 <linux/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_Unwritten,	/* Buffer is allocated on disk but not written */
	BH_Quiet,	/* Buffer Error Prinks to be quiet */
	BH_Meta,	/* Buffer contains metadata */
	BH_Prio,	/* Buffer should be submitted with REQ_PRIO */
	BH_Defer_Completion, /* Defer AIO completion to workqueue */

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

#define MAX_BUF_PER_PAGE (PAGE_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 __always_inline void set_buffer_##name(struct buffer_head *bh)	\
{									\
	set_bit(BH_##bit, &(bh)->b_state);				\
}									\
static __always_inline void clear_buffer_##name(struct buffer_head *bh)	\
{									\
	clear_bit(BH_##bit, &(bh)->b_state);				\
}									\
static __always_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 __always_inline int test_set_buffer_##name(struct buffer_head *bh) \
{									\
	return test_and_set_bit(BH_##bit, &(bh)->b_state);		\
}									\
static __always_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(Unwritten, unwritten)
BUFFER_FNS(Meta, meta)
BUFFER_FNS(Prio, prio)
BUFFER_FNS(Defer_Completion, defer_completion)

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

/* 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)

void buffer_check_dirty_writeback(struct page *page,
				     bool *dirty, bool *writeback);

/*
 * Declarations
 */

void mark_buffer_dirty(struct buffer_head *bh);
void mark_buffer_write_io_error(struct buffer_head *bh);
void init_buffer(struct buffer_head *, bh_end_io_t *, void *);
void touch_buffer(struct buffer_head *bh);
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 clean_bdev_aliases(struct block_device *bdev, sector_t block,
			sector_t len);
static inline void clean_bdev_bh_alias(struct buffer_head *bh)
{
	clean_bdev_aliases(bh->b_bdev, bh->b_blocknr, 1);
}

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_gfp(struct block_device *bdev, sector_t block,
				  unsigned size, gfp_t gfp);
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_gfp(struct block_device *,
				sector_t block, unsigned size, gfp_t gfp);
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, int, struct buffer_head * bh[]);
int sync_dirty_buffer(struct buffer_head *bh);
int __sync_dirty_buffer(struct buffer_head *bh, int op_flags);
void write_dirty_buffer(struct buffer_head *bh, int op_flags);
int submit_bh(int, 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);
loff_t page_cache_seek_hole_data(struct inode *inode, loff_t offset,
				 loff_t length, int whence);

extern int buffer_heads_over_limit;

/*
 * Generic address_space_operations implementations for buffer_head-backed
 * address_spaces.
 */
void block_invalidatepage(struct page *page, unsigned int offset,
			  unsigned int length);
int block_write_full_page(struct page *page, get_block_t *get_block,
				struct writeback_control *wbc);
int __block_write_full_page(struct inode *inode, 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, unsigned long from,
				unsigned long count);
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);
void clean_page_buffers(struct page *page);
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);
/* Convert errno to return value from ->page_mkwrite() call */
static inline int block_page_mkwrite_return(int err)
{
	if (err == 0)
		return VM_FAULT_LOCKED;
	if (err == -EFAULT || err == -EAGAIN)
		return VM_FAULT_NOPAGE;
	if (err == -ENOMEM)
		return VM_FAULT_OOM;
	/* -ENOSPC, -EDQUOT, -EIO ... */
	return VM_FAULT_SIGBUS;
}
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)
{
	get_page(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();
        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_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
}

static inline struct buffer_head *
sb_bread_unmovable(struct super_block *sb, sector_t block)
{
	return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0);
}

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_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
}


static inline struct buffer_head *
sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp)
{
	return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp);
}

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);
}

static inline struct buffer_head *getblk_unmovable(struct block_device *bdev,
						   sector_t block,
						   unsigned size)
{
	return __getblk_gfp(bdev, block, size, 0);
}

static inline struct buffer_head *__getblk(struct block_device *bdev,
					   sector_t block,
					   unsigned size)
{
	return __getblk_gfp(bdev, block, size, __GFP_MOVABLE);
}

/**
 *  __bread() - reads a specified block and returns the bh
 *  @bdev: the block_device to read from
 *  @block: number of block
 *  @size: size (in bytes) to read
 *
 *  Reads a specified block, and returns buffer head that contains it.
 *  The page cache is allocated from movable area so that it can be migrated.
 *  It returns NULL if the block was unreadable.
 */
static inline struct buffer_head *
__bread(struct block_device *bdev, sector_t block, unsigned size)
{
	return __bread_gfp(bdev, block, size, __GFP_MOVABLE);
}

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>
60063497	15	#include <linux/atomic.h>
1da177e4	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 */
33a266dd	35	BH_Unwritten, /* Buffer is allocated on disk but not written */
08bafc03	36	BH_Quiet, /* Buffer Error Prinks to be quiet */
877f962c TT	37	BH_Meta, /* Buffer contains metadata */
877f962c TT	38	BH_Prio, /* Buffer should be submitted with REQ_PRIO */
7b7a8665	39	BH_Defer_Completion, /* Defer AIO completion to workqueue */
1da177e4 LT	40
	41	BH_PrivateStart,/* not a state bit, but the first bit available
	42	* for private allocation by other entities
	43	*/
	44	};
	45
09cbfeaf	46	#define MAX_BUF_PER_PAGE (PAGE_SIZE / 512)
1da177e4 LT	47
	48	struct page;
	49	struct buffer_head;
	50	struct address_space;
	51	typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
	52
	53	/*
205f87f6 BP	54	* Historically, a buffer_head was used to map a single block
	55	* within a page, and of course as the unit of I/O through the
	56	* filesystem and block layers. Nowadays the basic I/O unit
	57	* is the bio, and buffer_heads are used for extracting block
	58	* mappings (via a get_block_t call), for tracking state within
	59	* a page (via a page_mapping) and for wrapping bio submission
	60	* for backward compatibility reasons (e.g. submit_bh).
1da177e4 LT	61	*/
1da177e4 LT	62	struct buffer_head {
1da177e4 LT	63	unsigned long b_state; /* buffer state bitmap (see above) */
	64	struct buffer_head b_this_page;/ circular list of page's buffers */
	65	struct page b_page; / the page this bh is mapped to */
1da177e4	66
205f87f6 BP	67	sector_t b_blocknr; /* start block number */
	68	size_t b_size; /* size of mapping */
	69	char b_data; / pointer to data within the page */
1da177e4 LT	70
	71	struct block_device *b_bdev;
	72	bh_end_io_t b_end_io; / I/O completion */
	73	void b_private; / reserved for b_end_io */
	74	struct list_head b_assoc_buffers; /* associated with another mapping */
58ff407b JK	75	struct address_space b_assoc_map; / mapping this buffer is
58ff407b JK	76	associated with */
205f87f6	77	atomic_t b_count; /* users using this buffer_head */
1da177e4 LT	78	};
	79
	80	/*
	81	* macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
	82	* and buffer_foo() functions.
	83	*/
	84	#define BUFFER_FNS(bit, name) \
ee91ef61	85	static __always_inline void set_buffer_##name(struct buffer_head *bh) \
1da177e4 LT	86	{ \
	87	set_bit(BH_##bit, &(bh)->b_state); \
	88	} \
ee91ef61	89	static __always_inline void clear_buffer_##name(struct buffer_head *bh) \
1da177e4 LT	90	{ \
	91	clear_bit(BH_##bit, &(bh)->b_state); \
	92	} \
ee91ef61	93	static __always_inline int buffer_##name(const struct buffer_head *bh) \
1da177e4 LT	94	{ \
	95	return test_bit(BH_##bit, &(bh)->b_state); \
	96	}
	97
	98	/*
	99	* test_set_buffer_foo() and test_clear_buffer_foo()
	100	*/
	101	#define TAS_BUFFER_FNS(bit, name) \
ee91ef61	102	static __always_inline int test_set_buffer_##name(struct buffer_head *bh) \
1da177e4 LT	103	{ \
	104	return test_and_set_bit(BH_##bit, &(bh)->b_state); \
	105	} \
ee91ef61	106	static __always_inline int test_clear_buffer_##name(struct buffer_head *bh) \
1da177e4 LT	107	{ \
	108	return test_and_clear_bit(BH_##bit, &(bh)->b_state); \
	109	} \
	110
	111	/*
	112	* Emit the buffer bitops functions. Note that there are also functions
	113	* of the form "mark_buffer_foo()". These are higher-level functions which
	114	* do something in addition to setting a b_state bit.
	115	*/
	116	BUFFER_FNS(Uptodate, uptodate)
	117	BUFFER_FNS(Dirty, dirty)
	118	TAS_BUFFER_FNS(Dirty, dirty)
	119	BUFFER_FNS(Lock, locked)
1da177e4 LT	120	BUFFER_FNS(Req, req)
	121	TAS_BUFFER_FNS(Req, req)
	122	BUFFER_FNS(Mapped, mapped)
	123	BUFFER_FNS(New, new)
	124	BUFFER_FNS(Async_Read, async_read)
	125	BUFFER_FNS(Async_Write, async_write)
	126	BUFFER_FNS(Delay, delay)
	127	BUFFER_FNS(Boundary, boundary)
	128	BUFFER_FNS(Write_EIO, write_io_error)
33a266dd	129	BUFFER_FNS(Unwritten, unwritten)
877f962c TT	130	BUFFER_FNS(Meta, meta)
877f962c TT	131	BUFFER_FNS(Prio, prio)
7b7a8665	132	BUFFER_FNS(Defer_Completion, defer_completion)
1da177e4 LT	133
1da177e4 LT	134	#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK)
1da177e4 LT	135
	136	/* If we know page->private refers to buffer_heads */
	137	#define page_buffers(page) \
	138	({ \
4c21e2f2 HD	139	BUG_ON(!PagePrivate(page)); \
4c21e2f2 HD	140	((struct buffer_head *)page_private(page)); \
1da177e4 LT	141	})
	142	#define page_has_buffers(page) PagePrivate(page)
	143
b4597226 MG	144	void buffer_check_dirty_writeback(struct page *page,
	145	bool dirty, bool writeback);
	146
1da177e4 LT	147	/*
	148	* Declarations
	149	*/
	150
b3c97528	151	void mark_buffer_dirty(struct buffer_head *bh);
87354e5d	152	void mark_buffer_write_io_error(struct buffer_head *bh);
1da177e4	153	void init_buffer(struct buffer_head , bh_end_io_t , void *);
f0059afd	154	void touch_buffer(struct buffer_head *bh);
1da177e4 LT	155	void set_bh_page(struct buffer_head *bh,
	156	struct page *page, unsigned long offset);
	157	int try_to_free_buffers(struct page *);
	158	struct buffer_head alloc_page_buffers(struct page page, unsigned long size,
	159	int retry);
	160	void create_empty_buffers(struct page *, unsigned long,
	161	unsigned long b_state);
	162	void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
	163	void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
35c80d5f	164	void end_buffer_async_write(struct buffer_head *bh, int uptodate);
1da177e4 LT	165
	166	/* Things to do with buffers at mapping->private_list */
	167	void mark_buffer_dirty_inode(struct buffer_head bh, struct inode inode);
	168	int inode_has_buffers(struct inode *);
	169	void invalidate_inode_buffers(struct inode *);
	170	int remove_inode_buffers(struct inode *inode);
	171	int sync_mapping_buffers(struct address_space *mapping);
29f3ad7d JK	172	void clean_bdev_aliases(struct block_device *bdev, sector_t block,
29f3ad7d JK	173	sector_t len);
e64855c6 JK	174	static inline void clean_bdev_bh_alias(struct buffer_head *bh)
	175	{
	176	clean_bdev_aliases(bh->b_bdev, bh->b_blocknr, 1);
	177	}
1da177e4 LT	178
1da177e4 LT	179	void mark_buffer_async_write(struct buffer_head *bh);
1da177e4 LT	180	void __wait_on_buffer(struct buffer_head *);
1da177e4 LT	181	wait_queue_head_t bh_waitq_head(struct buffer_head bh);
3991d3bd TK	182	struct buffer_head __find_get_block(struct block_device bdev, sector_t block,
3991d3bd TK	183	unsigned size);
3b5e6454 GK	184	struct buffer_head __getblk_gfp(struct block_device bdev, sector_t block,
3b5e6454 GK	185	unsigned size, gfp_t gfp);
1da177e4 LT	186	void __brelse(struct buffer_head *);
1da177e4 LT	187	void __bforget(struct buffer_head *);
3991d3bd	188	void __breadahead(struct block_device *, sector_t block, unsigned int size);
3b5e6454 GK	189	struct buffer_head __bread_gfp(struct block_device ,
3b5e6454 GK	190	sector_t block, unsigned size, gfp_t gfp);
f9a14399	191	void invalidate_bh_lrus(void);
dd0fc66f	192	struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
1da177e4	193	void free_buffer_head(struct buffer_head * bh);
b3c97528 HH	194	void unlock_buffer(struct buffer_head *bh);
b3c97528 HH	195	void __lock_buffer(struct buffer_head *bh);
dfec8a14	196	void ll_rw_block(int, int, int, struct buffer_head * bh[]);
1da177e4	197	int sync_dirty_buffer(struct buffer_head *bh);
2a222ca9 MC	198	int __sync_dirty_buffer(struct buffer_head *bh, int op_flags);
2a222ca9 MC	199	void write_dirty_buffer(struct buffer_head *bh, int op_flags);
2a222ca9	200	int submit_bh(int, int, struct buffer_head *);
1da177e4 LT	201	void write_boundary_block(struct block_device *bdev,
1da177e4 LT	202	sector_t bblock, unsigned blocksize);
389d1b08 AK	203	int bh_uptodate_or_lock(struct buffer_head *bh);
389d1b08 AK	204	int bh_submit_read(struct buffer_head *bh);
334fd34d AG	205	loff_t page_cache_seek_hole_data(struct inode *inode, loff_t offset,
334fd34d AG	206	loff_t length, int whence);
1da177e4 LT	207
	208	extern int buffer_heads_over_limit;
	209
	210	/*
	211	* Generic address_space_operations implementations for buffer_head-backed
	212	* address_spaces.
	213	*/
d47992f8 LC	214	void block_invalidatepage(struct page *page, unsigned int offset,
d47992f8 LC	215	unsigned int length);
1da177e4 LT	216	int block_write_full_page(struct page page, get_block_t get_block,
1da177e4 LT	217	struct writeback_control *wbc);
b4bba389 BM	218	int __block_write_full_page(struct inode inode, struct page page,
	219	get_block_t get_block, struct writeback_control wbc,
	220	bh_end_io_t *handler);
1da177e4	221	int block_read_full_page(struct page, get_block_t);
c186afb4 AV	222	int block_is_partially_uptodate(struct page *page, unsigned long from,
c186afb4 AV	223	unsigned long count);
155130a4 CH	224	int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
155130a4 CH	225	unsigned flags, struct page *pagep, get_block_t get_block);
6e1db88d CH	226	int __block_write_begin(struct page *page, loff_t pos, unsigned len,
6e1db88d CH	227	get_block_t *get_block);
afddba49 NP	228	int block_write_end(struct file , struct address_space ,
	229	loff_t, unsigned, unsigned,
	230	struct page , void );
	231	int generic_write_end(struct file , struct address_space ,
	232	loff_t, unsigned, unsigned,
	233	struct page , void );
	234	void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
5330704d	235	void clean_page_buffers(struct page *page);
89e10787 NP	236	int cont_write_begin(struct file , struct address_space , loff_t,
	237	unsigned, unsigned, struct page , void ,
	238	get_block_t , loff_t );
05eb0b51	239	int generic_cont_expand_simple(struct inode *inode, loff_t size);
1da177e4	240	int block_commit_write(struct page *page, unsigned from, unsigned to);
c2ec175c	241	int block_page_mkwrite(struct vm_area_struct vma, struct vm_fault vmf,
54171690	242	get_block_t get_block);
24da4fab JK	243	/* Convert errno to return value from ->page_mkwrite() call */
	244	static inline int block_page_mkwrite_return(int err)
	245	{
	246	if (err == 0)
	247	return VM_FAULT_LOCKED;
0911d004	248	if (err == -EFAULT \|\| err == -EAGAIN)
24da4fab JK	249	return VM_FAULT_NOPAGE;
	250	if (err == -ENOMEM)
	251	return VM_FAULT_OOM;
	252	/* -ENOSPC, -EDQUOT, -EIO ... */
	253	return VM_FAULT_SIGBUS;
	254	}
1da177e4	255	sector_t generic_block_bmap(struct address_space , sector_t, get_block_t );
1da177e4	256	int block_truncate_page(struct address_space , loff_t, get_block_t );
ea0f04e5	257	int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned,
03158cd7 NP	258	struct page , void , get_block_t*);
	259	int nobh_write_end(struct file , struct address_space ,
	260	loff_t, unsigned, unsigned,
	261	struct page , void );
	262	int nobh_truncate_page(struct address_space , loff_t, get_block_t );
1da177e4 LT	263	int nobh_writepage(struct page page, get_block_t get_block,
	264	struct writeback_control *wbc);
	265
b6cd0b77	266	void buffer_init(void);
1da177e4 LT	267
	268	/*
	269	* inline definitions
	270	*/
	271
	272	static inline void attach_page_buffers(struct page *page,
	273	struct buffer_head *head)
	274	{
09cbfeaf	275	get_page(page);
1da177e4	276	SetPagePrivate(page);
4c21e2f2	277	set_page_private(page, (unsigned long)head);
1da177e4 LT	278	}
	279
	280	static inline void get_bh(struct buffer_head *bh)
	281	{
	282	atomic_inc(&bh->b_count);
	283	}
	284
	285	static inline void put_bh(struct buffer_head *bh)
	286	{
4e857c58	287	smp_mb__before_atomic();
1da177e4 LT	288	atomic_dec(&bh->b_count);
	289	}
	290
	291	static inline void brelse(struct buffer_head *bh)
	292	{
	293	if (bh)
	294	__brelse(bh);
	295	}
	296
	297	static inline void bforget(struct buffer_head *bh)
	298	{
	299	if (bh)
	300	__bforget(bh);
	301	}
	302
	303	static inline struct buffer_head *
	304	sb_bread(struct super_block *sb, sector_t block)
	305	{
3b5e6454 GK	306	return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
	307	}
	308
	309	static inline struct buffer_head *
	310	sb_bread_unmovable(struct super_block *sb, sector_t block)
	311	{
	312	return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0);
1da177e4 LT	313	}
	314
	315	static inline void
	316	sb_breadahead(struct super_block *sb, sector_t block)
	317	{
	318	__breadahead(sb->s_bdev, block, sb->s_blocksize);
	319	}
	320
	321	static inline struct buffer_head *
	322	sb_getblk(struct super_block *sb, sector_t block)
	323	{
3b5e6454	324	return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
1da177e4 LT	325	}
1da177e4 LT	326
bd7ade3c NB	327
	328	static inline struct buffer_head *
	329	sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp)
	330	{
	331	return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp);
	332	}
	333
1da177e4 LT	334	static inline struct buffer_head *
	335	sb_find_get_block(struct super_block *sb, sector_t block)
	336	{
	337	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
	338	}
	339
	340	static inline void
	341	map_bh(struct buffer_head bh, struct super_block sb, sector_t block)
	342	{
	343	set_buffer_mapped(bh);
	344	bh->b_bdev = sb->s_bdev;
	345	bh->b_blocknr = block;
b0cf2321	346	bh->b_size = sb->s_blocksize;
1da177e4 LT	347	}
1da177e4 LT	348
1da177e4 LT	349	static inline void wait_on_buffer(struct buffer_head *bh)
	350	{
	351	might_sleep();
a9877cc2	352	if (buffer_locked(bh))
1da177e4 LT	353	__wait_on_buffer(bh);
	354	}
	355
ca5de404 NP	356	static inline int trylock_buffer(struct buffer_head *bh)
ca5de404 NP	357	{
51b07fc3	358	return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
ca5de404 NP	359	}
ca5de404 NP	360
1da177e4 LT	361	static inline void lock_buffer(struct buffer_head *bh)
	362	{
	363	might_sleep();
ca5de404	364	if (!trylock_buffer(bh))
1da177e4 LT	365	__lock_buffer(bh);
	366	}
	367
3b5e6454 GK	368	static inline struct buffer_head getblk_unmovable(struct block_device bdev,
	369	sector_t block,
	370	unsigned size)
	371	{
	372	return __getblk_gfp(bdev, block, size, 0);
	373	}
	374
	375	static inline struct buffer_head __getblk(struct block_device bdev,
	376	sector_t block,
	377	unsigned size)
	378	{
	379	return __getblk_gfp(bdev, block, size, __GFP_MOVABLE);
	380	}
	381
	382	/**
	383	* __bread() - reads a specified block and returns the bh
	384	* @bdev: the block_device to read from
	385	* @block: number of block
	386	* @size: size (in bytes) to read
	387	*
	388	* Reads a specified block, and returns buffer head that contains it.
	389	* The page cache is allocated from movable area so that it can be migrated.
	390	* It returns NULL if the block was unreadable.
	391	*/
	392	static inline struct buffer_head *
	393	__bread(struct block_device *bdev, sector_t block, unsigned size)
	394	{
	395	return __bread_gfp(bdev, block, size, __GFP_MOVABLE);
	396	}
	397
cf9a2ae8	398	extern int __set_page_dirty_buffers(struct page *page);
9361401e DH	399
	400	#else /* CONFIG_BLOCK */
	401
	402	static inline void buffer_init(void) {}
	403	static inline int try_to_free_buffers(struct page *page) { return 1; }
9361401e DH	404	static inline int inode_has_buffers(struct inode *inode) { return 0; }
	405	static inline void invalidate_inode_buffers(struct inode *inode) {}
	406	static inline int remove_inode_buffers(struct inode *inode) { return 1; }
	407	static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
9361401e DH	408
9361401e DH	409	#endif /* CONFIG_BLOCK */
1da177e4	410	#endif /* _LINUX_BUFFER_HEAD_H */