[mirror_ubuntu-bionic-kernel.git] / include / linux / buffer_head.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * 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,
		bool 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
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	/*
	3	* include/linux/buffer_head.h
	4	*
	5	* Everything to do with buffer_heads.
	6	*/
	7
	8	#ifndef _LINUX_BUFFER_HEAD_H
	9	#define _LINUX_BUFFER_HEAD_H
	10
	11	#include <linux/types.h>
	12	#include <linux/fs.h>
	13	#include <linux/linkage.h>
	14	#include <linux/pagemap.h>
	15	#include <linux/wait.h>
60063497	16	#include <linux/atomic.h>
1da177e4	17
9361401e DH	18	#ifdef CONFIG_BLOCK
9361401e DH	19
1da177e4 LT	20	enum bh_state_bits {
	21	BH_Uptodate, /* Contains valid data */
	22	BH_Dirty, /* Is dirty */
	23	BH_Lock, /* Is locked */
	24	BH_Req, /* Has been submitted for I/O */
a3972203 NP	25	BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise
	26	* IO completion of other buffers in the page
	27	*/
1da177e4 LT	28
	29	BH_Mapped, /* Has a disk mapping */
	30	BH_New, /* Disk mapping was newly created by get_block */
	31	BH_Async_Read, /* Is under end_buffer_async_read I/O */
	32	BH_Async_Write, /* Is under end_buffer_async_write I/O */
	33	BH_Delay, /* Buffer is not yet allocated on disk */
	34	BH_Boundary, /* Block is followed by a discontiguity */
	35	BH_Write_EIO, /* I/O error on write */
33a266dd	36	BH_Unwritten, /* Buffer is allocated on disk but not written */
08bafc03	37	BH_Quiet, /* Buffer Error Prinks to be quiet */
877f962c TT	38	BH_Meta, /* Buffer contains metadata */
877f962c TT	39	BH_Prio, /* Buffer should be submitted with REQ_PRIO */
7b7a8665	40	BH_Defer_Completion, /* Defer AIO completion to workqueue */
1da177e4 LT	41
	42	BH_PrivateStart,/* not a state bit, but the first bit available
	43	* for private allocation by other entities
	44	*/
	45	};
	46
09cbfeaf	47	#define MAX_BUF_PER_PAGE (PAGE_SIZE / 512)
1da177e4 LT	48
	49	struct page;
	50	struct buffer_head;
	51	struct address_space;
	52	typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);
	53
	54	/*
205f87f6 BP	55	* Historically, a buffer_head was used to map a single block
	56	* within a page, and of course as the unit of I/O through the
	57	* filesystem and block layers. Nowadays the basic I/O unit
	58	* is the bio, and buffer_heads are used for extracting block
	59	* mappings (via a get_block_t call), for tracking state within
	60	* a page (via a page_mapping) and for wrapping bio submission
	61	* for backward compatibility reasons (e.g. submit_bh).
1da177e4 LT	62	*/
1da177e4 LT	63	struct buffer_head {
1da177e4 LT	64	unsigned long b_state; /* buffer state bitmap (see above) */
	65	struct buffer_head b_this_page;/ circular list of page's buffers */
	66	struct page b_page; / the page this bh is mapped to */
1da177e4	67
205f87f6 BP	68	sector_t b_blocknr; /* start block number */
	69	size_t b_size; /* size of mapping */
	70	char b_data; / pointer to data within the page */
1da177e4 LT	71
	72	struct block_device *b_bdev;
	73	bh_end_io_t b_end_io; / I/O completion */
	74	void b_private; / reserved for b_end_io */
	75	struct list_head b_assoc_buffers; /* associated with another mapping */
58ff407b JK	76	struct address_space b_assoc_map; / mapping this buffer is
58ff407b JK	77	associated with */
205f87f6	78	atomic_t b_count; /* users using this buffer_head */
1da177e4 LT	79	};
	80
	81	/*
	82	* macro tricks to expand the set_buffer_foo(), clear_buffer_foo()
	83	* and buffer_foo() functions.
	84	*/
	85	#define BUFFER_FNS(bit, name) \
ee91ef61	86	static __always_inline void set_buffer_##name(struct buffer_head *bh) \
1da177e4 LT	87	{ \
	88	set_bit(BH_##bit, &(bh)->b_state); \
	89	} \
ee91ef61	90	static __always_inline void clear_buffer_##name(struct buffer_head *bh) \
1da177e4 LT	91	{ \
	92	clear_bit(BH_##bit, &(bh)->b_state); \
	93	} \
ee91ef61	94	static __always_inline int buffer_##name(const struct buffer_head *bh) \
1da177e4 LT	95	{ \
	96	return test_bit(BH_##bit, &(bh)->b_state); \
	97	}
	98
	99	/*
	100	* test_set_buffer_foo() and test_clear_buffer_foo()
	101	*/
	102	#define TAS_BUFFER_FNS(bit, name) \
ee91ef61	103	static __always_inline int test_set_buffer_##name(struct buffer_head *bh) \
1da177e4 LT	104	{ \
	105	return test_and_set_bit(BH_##bit, &(bh)->b_state); \
	106	} \
ee91ef61	107	static __always_inline int test_clear_buffer_##name(struct buffer_head *bh) \
1da177e4 LT	108	{ \
	109	return test_and_clear_bit(BH_##bit, &(bh)->b_state); \
	110	} \
	111
	112	/*
	113	* Emit the buffer bitops functions. Note that there are also functions
	114	* of the form "mark_buffer_foo()". These are higher-level functions which
	115	* do something in addition to setting a b_state bit.
	116	*/
	117	BUFFER_FNS(Uptodate, uptodate)
	118	BUFFER_FNS(Dirty, dirty)
	119	TAS_BUFFER_FNS(Dirty, dirty)
	120	BUFFER_FNS(Lock, locked)
1da177e4 LT	121	BUFFER_FNS(Req, req)
	122	TAS_BUFFER_FNS(Req, req)
	123	BUFFER_FNS(Mapped, mapped)
	124	BUFFER_FNS(New, new)
	125	BUFFER_FNS(Async_Read, async_read)
	126	BUFFER_FNS(Async_Write, async_write)
	127	BUFFER_FNS(Delay, delay)
	128	BUFFER_FNS(Boundary, boundary)
	129	BUFFER_FNS(Write_EIO, write_io_error)
33a266dd	130	BUFFER_FNS(Unwritten, unwritten)
877f962c TT	131	BUFFER_FNS(Meta, meta)
877f962c TT	132	BUFFER_FNS(Prio, prio)
7b7a8665	133	BUFFER_FNS(Defer_Completion, defer_completion)
1da177e4 LT	134
1da177e4 LT	135	#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK)
1da177e4 LT	136
	137	/* If we know page->private refers to buffer_heads */
	138	#define page_buffers(page) \
	139	({ \
4c21e2f2 HD	140	BUG_ON(!PagePrivate(page)); \
4c21e2f2 HD	141	((struct buffer_head *)page_private(page)); \
1da177e4 LT	142	})
	143	#define page_has_buffers(page) PagePrivate(page)
	144
b4597226 MG	145	void buffer_check_dirty_writeback(struct page *page,
	146	bool dirty, bool writeback);
	147
1da177e4 LT	148	/*
	149	* Declarations
	150	*/
	151
b3c97528	152	void mark_buffer_dirty(struct buffer_head *bh);
87354e5d	153	void mark_buffer_write_io_error(struct buffer_head *bh);
1da177e4	154	void init_buffer(struct buffer_head , bh_end_io_t , void *);
f0059afd	155	void touch_buffer(struct buffer_head *bh);
1da177e4 LT	156	void set_bh_page(struct buffer_head *bh,
	157	struct page *page, unsigned long offset);
	158	int try_to_free_buffers(struct page *);
	159	struct buffer_head alloc_page_buffers(struct page page, unsigned long size,
640ab98f	160	bool retry);
1da177e4 LT	161	void create_empty_buffers(struct page *, unsigned long,
	162	unsigned long b_state);
	163	void end_buffer_read_sync(struct buffer_head *bh, int uptodate);
	164	void end_buffer_write_sync(struct buffer_head *bh, int uptodate);
35c80d5f	165	void end_buffer_async_write(struct buffer_head *bh, int uptodate);
1da177e4 LT	166
	167	/* Things to do with buffers at mapping->private_list */
	168	void mark_buffer_dirty_inode(struct buffer_head bh, struct inode inode);
	169	int inode_has_buffers(struct inode *);
	170	void invalidate_inode_buffers(struct inode *);
	171	int remove_inode_buffers(struct inode *inode);
	172	int sync_mapping_buffers(struct address_space *mapping);
29f3ad7d JK	173	void clean_bdev_aliases(struct block_device *bdev, sector_t block,
29f3ad7d JK	174	sector_t len);
e64855c6 JK	175	static inline void clean_bdev_bh_alias(struct buffer_head *bh)
	176	{
	177	clean_bdev_aliases(bh->b_bdev, bh->b_blocknr, 1);
	178	}
1da177e4 LT	179
1da177e4 LT	180	void mark_buffer_async_write(struct buffer_head *bh);
1da177e4 LT	181	void __wait_on_buffer(struct buffer_head *);
1da177e4 LT	182	wait_queue_head_t bh_waitq_head(struct buffer_head bh);
3991d3bd TK	183	struct buffer_head __find_get_block(struct block_device bdev, sector_t block,
3991d3bd TK	184	unsigned size);
3b5e6454 GK	185	struct buffer_head __getblk_gfp(struct block_device bdev, sector_t block,
3b5e6454 GK	186	unsigned size, gfp_t gfp);
1da177e4 LT	187	void __brelse(struct buffer_head *);
1da177e4 LT	188	void __bforget(struct buffer_head *);
3991d3bd	189	void __breadahead(struct block_device *, sector_t block, unsigned int size);
3b5e6454 GK	190	struct buffer_head __bread_gfp(struct block_device ,
3b5e6454 GK	191	sector_t block, unsigned size, gfp_t gfp);
f9a14399	192	void invalidate_bh_lrus(void);
dd0fc66f	193	struct buffer_head *alloc_buffer_head(gfp_t gfp_flags);
1da177e4	194	void free_buffer_head(struct buffer_head * bh);
b3c97528 HH	195	void unlock_buffer(struct buffer_head *bh);
b3c97528 HH	196	void __lock_buffer(struct buffer_head *bh);
dfec8a14	197	void ll_rw_block(int, int, int, struct buffer_head * bh[]);
1da177e4	198	int sync_dirty_buffer(struct buffer_head *bh);
2a222ca9 MC	199	int __sync_dirty_buffer(struct buffer_head *bh, int op_flags);
2a222ca9 MC	200	void write_dirty_buffer(struct buffer_head *bh, int op_flags);
2a222ca9	201	int submit_bh(int, int, struct buffer_head *);
1da177e4 LT	202	void write_boundary_block(struct block_device *bdev,
1da177e4 LT	203	sector_t bblock, unsigned blocksize);
389d1b08 AK	204	int bh_uptodate_or_lock(struct buffer_head *bh);
389d1b08 AK	205	int bh_submit_read(struct buffer_head *bh);
334fd34d AG	206	loff_t page_cache_seek_hole_data(struct inode *inode, loff_t offset,
334fd34d AG	207	loff_t length, int whence);
1da177e4 LT	208
	209	extern int buffer_heads_over_limit;
	210
	211	/*
	212	* Generic address_space_operations implementations for buffer_head-backed
	213	* address_spaces.
	214	*/
d47992f8 LC	215	void block_invalidatepage(struct page *page, unsigned int offset,
d47992f8 LC	216	unsigned int length);
1da177e4 LT	217	int block_write_full_page(struct page page, get_block_t get_block,
1da177e4 LT	218	struct writeback_control *wbc);
b4bba389 BM	219	int __block_write_full_page(struct inode inode, struct page page,
	220	get_block_t get_block, struct writeback_control wbc,
	221	bh_end_io_t *handler);
1da177e4	222	int block_read_full_page(struct page, get_block_t);
c186afb4 AV	223	int block_is_partially_uptodate(struct page *page, unsigned long from,
c186afb4 AV	224	unsigned long count);
155130a4 CH	225	int block_write_begin(struct address_space *mapping, loff_t pos, unsigned len,
155130a4 CH	226	unsigned flags, struct page *pagep, get_block_t get_block);
6e1db88d CH	227	int __block_write_begin(struct page *page, loff_t pos, unsigned len,
6e1db88d CH	228	get_block_t *get_block);
afddba49 NP	229	int block_write_end(struct file , struct address_space ,
	230	loff_t, unsigned, unsigned,
	231	struct page , void );
	232	int generic_write_end(struct file , struct address_space ,
	233	loff_t, unsigned, unsigned,
	234	struct page , void );
	235	void page_zero_new_buffers(struct page *page, unsigned from, unsigned to);
f892760a	236	void clean_page_buffers(struct page *page);
89e10787 NP	237	int cont_write_begin(struct file , struct address_space , loff_t,
	238	unsigned, unsigned, struct page , void ,
	239	get_block_t , loff_t );
05eb0b51	240	int generic_cont_expand_simple(struct inode *inode, loff_t size);
1da177e4	241	int block_commit_write(struct page *page, unsigned from, unsigned to);
c2ec175c	242	int block_page_mkwrite(struct vm_area_struct vma, struct vm_fault vmf,
54171690	243	get_block_t get_block);
24da4fab JK	244	/* Convert errno to return value from ->page_mkwrite() call */
	245	static inline int block_page_mkwrite_return(int err)
	246	{
	247	if (err == 0)
	248	return VM_FAULT_LOCKED;
0911d004	249	if (err == -EFAULT \|\| err == -EAGAIN)
24da4fab JK	250	return VM_FAULT_NOPAGE;
	251	if (err == -ENOMEM)
	252	return VM_FAULT_OOM;
	253	/* -ENOSPC, -EDQUOT, -EIO ... */
	254	return VM_FAULT_SIGBUS;
	255	}
1da177e4	256	sector_t generic_block_bmap(struct address_space , sector_t, get_block_t );
1da177e4	257	int block_truncate_page(struct address_space , loff_t, get_block_t );
ea0f04e5	258	int nobh_write_begin(struct address_space *, loff_t, unsigned, unsigned,
03158cd7 NP	259	struct page , void , get_block_t*);
	260	int nobh_write_end(struct file , struct address_space ,
	261	loff_t, unsigned, unsigned,
	262	struct page , void );
	263	int nobh_truncate_page(struct address_space , loff_t, get_block_t );
1da177e4 LT	264	int nobh_writepage(struct page page, get_block_t get_block,
	265	struct writeback_control *wbc);
	266
b6cd0b77	267	void buffer_init(void);
1da177e4 LT	268
	269	/*
	270	* inline definitions
	271	*/
	272
	273	static inline void attach_page_buffers(struct page *page,
	274	struct buffer_head *head)
	275	{
09cbfeaf	276	get_page(page);
1da177e4	277	SetPagePrivate(page);
4c21e2f2	278	set_page_private(page, (unsigned long)head);
1da177e4 LT	279	}
	280
	281	static inline void get_bh(struct buffer_head *bh)
	282	{
	283	atomic_inc(&bh->b_count);
	284	}
	285
	286	static inline void put_bh(struct buffer_head *bh)
	287	{
4e857c58	288	smp_mb__before_atomic();
1da177e4 LT	289	atomic_dec(&bh->b_count);
	290	}
	291
	292	static inline void brelse(struct buffer_head *bh)
	293	{
	294	if (bh)
	295	__brelse(bh);
	296	}
	297
	298	static inline void bforget(struct buffer_head *bh)
	299	{
	300	if (bh)
	301	__bforget(bh);
	302	}
	303
	304	static inline struct buffer_head *
	305	sb_bread(struct super_block *sb, sector_t block)
	306	{
3b5e6454 GK	307	return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
	308	}
	309
	310	static inline struct buffer_head *
	311	sb_bread_unmovable(struct super_block *sb, sector_t block)
	312	{
	313	return __bread_gfp(sb->s_bdev, block, sb->s_blocksize, 0);
1da177e4 LT	314	}
	315
	316	static inline void
	317	sb_breadahead(struct super_block *sb, sector_t block)
	318	{
	319	__breadahead(sb->s_bdev, block, sb->s_blocksize);
	320	}
	321
	322	static inline struct buffer_head *
	323	sb_getblk(struct super_block *sb, sector_t block)
	324	{
3b5e6454	325	return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, __GFP_MOVABLE);
1da177e4 LT	326	}
1da177e4 LT	327
bd7ade3c NB	328
	329	static inline struct buffer_head *
	330	sb_getblk_gfp(struct super_block *sb, sector_t block, gfp_t gfp)
	331	{
	332	return __getblk_gfp(sb->s_bdev, block, sb->s_blocksize, gfp);
	333	}
	334
1da177e4 LT	335	static inline struct buffer_head *
	336	sb_find_get_block(struct super_block *sb, sector_t block)
	337	{
	338	return __find_get_block(sb->s_bdev, block, sb->s_blocksize);
	339	}
	340
	341	static inline void
	342	map_bh(struct buffer_head bh, struct super_block sb, sector_t block)
	343	{
	344	set_buffer_mapped(bh);
	345	bh->b_bdev = sb->s_bdev;
	346	bh->b_blocknr = block;
b0cf2321	347	bh->b_size = sb->s_blocksize;
1da177e4 LT	348	}
1da177e4 LT	349
1da177e4 LT	350	static inline void wait_on_buffer(struct buffer_head *bh)
	351	{
	352	might_sleep();
a9877cc2	353	if (buffer_locked(bh))
1da177e4 LT	354	__wait_on_buffer(bh);
	355	}
	356
ca5de404 NP	357	static inline int trylock_buffer(struct buffer_head *bh)
ca5de404 NP	358	{
51b07fc3	359	return likely(!test_and_set_bit_lock(BH_Lock, &bh->b_state));
ca5de404 NP	360	}
ca5de404 NP	361
1da177e4 LT	362	static inline void lock_buffer(struct buffer_head *bh)
	363	{
	364	might_sleep();
ca5de404	365	if (!trylock_buffer(bh))
1da177e4 LT	366	__lock_buffer(bh);
	367	}
	368
3b5e6454 GK	369	static inline struct buffer_head getblk_unmovable(struct block_device bdev,
	370	sector_t block,
	371	unsigned size)
	372	{
	373	return __getblk_gfp(bdev, block, size, 0);
	374	}
	375
	376	static inline struct buffer_head __getblk(struct block_device bdev,
	377	sector_t block,
	378	unsigned size)
	379	{
	380	return __getblk_gfp(bdev, block, size, __GFP_MOVABLE);
	381	}
	382
	383	/**
	384	* __bread() - reads a specified block and returns the bh
	385	* @bdev: the block_device to read from
	386	* @block: number of block
	387	* @size: size (in bytes) to read
	388	*
	389	* Reads a specified block, and returns buffer head that contains it.
	390	* The page cache is allocated from movable area so that it can be migrated.
	391	* It returns NULL if the block was unreadable.
	392	*/
	393	static inline struct buffer_head *
	394	__bread(struct block_device *bdev, sector_t block, unsigned size)
	395	{
	396	return __bread_gfp(bdev, block, size, __GFP_MOVABLE);
	397	}
	398
cf9a2ae8	399	extern int __set_page_dirty_buffers(struct page *page);
9361401e DH	400
	401	#else /* CONFIG_BLOCK */
	402
	403	static inline void buffer_init(void) {}
	404	static inline int try_to_free_buffers(struct page *page) { return 1; }
9361401e DH	405	static inline int inode_has_buffers(struct inode *inode) { return 0; }
	406	static inline void invalidate_inode_buffers(struct inode *inode) {}
	407	static inline int remove_inode_buffers(struct inode *inode) { return 1; }
	408	static inline int sync_mapping_buffers(struct address_space *mapping) { return 0; }
9361401e DH	409
9361401e DH	410	#endif /* CONFIG_BLOCK */
1da177e4	411	#endif /* _LINUX_BUFFER_HEAD_H */