[deliverable/linux.git] / fs / xfs / xfs_buf.h

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#ifndef __XFS_BUF_H__
#define __XFS_BUF_H__

#include <linux/list.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/buffer_head.h>
#include <linux/uio.h>

/*
 *	Base types
 */

#define XFS_BUF_DADDR_NULL	((xfs_daddr_t) (-1LL))

typedef enum {
	XBRW_READ = 1,			/* transfer into target memory */
	XBRW_WRITE = 2,			/* transfer from target memory */
	XBRW_ZERO = 3,			/* Zero target memory */
} xfs_buf_rw_t;

#define XBF_READ	 (1 << 0) /* buffer intended for reading from device */
#define XBF_WRITE	 (1 << 1) /* buffer intended for writing to device */
#define XBF_READ_AHEAD	 (1 << 2) /* asynchronous read-ahead */
#define XBF_ASYNC	 (1 << 4) /* initiator will not wait for completion */
#define XBF_DONE	 (1 << 5) /* all pages in the buffer uptodate */
#define XBF_STALE	 (1 << 6) /* buffer has been staled, do not find it */

/* I/O hints for the BIO layer */
#define XBF_SYNCIO	 (1 << 10)/* treat this buffer as synchronous I/O */
#define XBF_FUA		 (1 << 11)/* force cache write through mode */
#define XBF_FLUSH	 (1 << 12)/* flush the disk cache before a write */

/* flags used only as arguments to access routines */
#define XBF_TRYLOCK	 (1 << 16)/* lock requested, but do not wait */
#define XBF_UNMAPPED	 (1 << 17)/* do not map the buffer */

/* flags used only internally */
#define _XBF_PAGES	 (1 << 20)/* backed by refcounted pages */
#define _XBF_KMEM	 (1 << 21)/* backed by heap memory */
#define _XBF_DELWRI_Q	 (1 << 22)/* buffer on a delwri queue */
#define _XBF_COMPOUND	 (1 << 23)/* compound buffer */
#define _XBF_LRU_DISPOSE (1 << 24)/* buffer being discarded */

typedef unsigned int xfs_buf_flags_t;

#define XFS_BUF_FLAGS \
	{ XBF_READ,		"READ" }, \
	{ XBF_WRITE,		"WRITE" }, \
	{ XBF_READ_AHEAD,	"READ_AHEAD" }, \
	{ XBF_ASYNC,		"ASYNC" }, \
	{ XBF_DONE,		"DONE" }, \
	{ XBF_STALE,		"STALE" }, \
	{ XBF_SYNCIO,		"SYNCIO" }, \
	{ XBF_FUA,		"FUA" }, \
	{ XBF_FLUSH,		"FLUSH" }, \
	{ XBF_TRYLOCK,		"TRYLOCK" },	/* should never be set */\
	{ XBF_UNMAPPED,		"UNMAPPED" },	/* ditto */\
	{ _XBF_PAGES,		"PAGES" }, \
	{ _XBF_KMEM,		"KMEM" }, \
	{ _XBF_DELWRI_Q,	"DELWRI_Q" }, \
	{ _XBF_COMPOUND,	"COMPOUND" }, \
	{ _XBF_LRU_DISPOSE,	"LRU_DISPOSE" }

typedef struct xfs_buftarg {
	dev_t			bt_dev;
	struct block_device	*bt_bdev;
	struct backing_dev_info	*bt_bdi;
	struct xfs_mount	*bt_mount;
	unsigned int		bt_bsize;
	unsigned int		bt_sshift;
	size_t			bt_smask;

	/* LRU control structures */
	struct shrinker		bt_shrinker;
	struct list_head	bt_lru;
	spinlock_t		bt_lru_lock;
	unsigned int		bt_lru_nr;
} xfs_buftarg_t;

struct xfs_buf;
typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);


#define XB_PAGES	2

struct xfs_buf_map {
	xfs_daddr_t		bm_bn;	/* block number for I/O */
	int			bm_len;	/* size of I/O */
};

#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
	struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };

typedef struct xfs_buf {
	/*
	 * first cacheline holds all the fields needed for an uncontended cache
	 * hit to be fully processed. The semaphore straddles the cacheline
	 * boundary, but the counter and lock sits on the first cacheline,
	 * which is the only bit that is touched if we hit the semaphore
	 * fast-path on locking.
	 */
	struct rb_node		b_rbnode;	/* rbtree node */
	xfs_daddr_t		b_bn;		/* block number of buffer */
	int			b_length;	/* size of buffer in BBs */
	atomic_t		b_hold;		/* reference count */
	atomic_t		b_lru_ref;	/* lru reclaim ref count */
	xfs_buf_flags_t		b_flags;	/* status flags */
	struct semaphore	b_sema;		/* semaphore for lockables */

	/*
	 * concurrent access to b_lru and b_lru_flags are protected by
	 * bt_lru_lock and not by b_sema
	 */
	struct list_head	b_lru;		/* lru list */
	xfs_buf_flags_t		b_lru_flags;	/* internal lru status flags */
	wait_queue_head_t	b_waiters;	/* unpin waiters */
	struct list_head	b_list;
	struct xfs_perag	*b_pag;		/* contains rbtree root */
	xfs_buftarg_t		*b_target;	/* buffer target (device) */
	void			*b_addr;	/* virtual address of buffer */
	struct work_struct	b_iodone_work;
	xfs_buf_iodone_t	b_iodone;	/* I/O completion function */
	struct completion	b_iowait;	/* queue for I/O waiters */
	void			*b_fspriv;
	struct xfs_trans	*b_transp;
	struct page		**b_pages;	/* array of page pointers */
	struct page		*b_page_array[XB_PAGES]; /* inline pages */
	struct xfs_buf_map	*b_maps;	/* compound buffer map */
	struct xfs_buf_map	b_map;		/* inline compound buffer map */
	int			b_map_count;
	int			b_io_length;	/* IO size in BBs */
	atomic_t		b_pin_count;	/* pin count */
	atomic_t		b_io_remaining;	/* #outstanding I/O requests */
	unsigned int		b_page_count;	/* size of page array */
	unsigned int		b_offset;	/* page offset in first page */
	unsigned short		b_error;	/* error code on I/O */

#ifdef XFS_BUF_LOCK_TRACKING
	int			b_last_holder;
#endif
} xfs_buf_t;

/* Finding and Reading Buffers */
struct xfs_buf *_xfs_buf_find(struct xfs_buftarg *target,
			      struct xfs_buf_map *map, int nmaps,
			      xfs_buf_flags_t flags, struct xfs_buf *new_bp);

static inline struct xfs_buf *
xfs_incore(
	struct xfs_buftarg	*target,
	xfs_daddr_t		blkno,
	size_t			numblks,
	xfs_buf_flags_t		flags)
{
	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	return _xfs_buf_find(target, &map, 1, flags, NULL);
}

struct xfs_buf *_xfs_buf_alloc(struct xfs_buftarg *target,
			       struct xfs_buf_map *map, int nmaps,
			       xfs_buf_flags_t flags);

static inline struct xfs_buf *
xfs_buf_alloc(
	struct xfs_buftarg	*target,
	xfs_daddr_t		blkno,
	size_t			numblks,
	xfs_buf_flags_t		flags)
{
	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	return _xfs_buf_alloc(target, &map, 1, flags);
}

struct xfs_buf *xfs_buf_get_map(struct xfs_buftarg *target,
			       struct xfs_buf_map *map, int nmaps,
			       xfs_buf_flags_t flags);
struct xfs_buf *xfs_buf_read_map(struct xfs_buftarg *target,
			       struct xfs_buf_map *map, int nmaps,
			       xfs_buf_flags_t flags, xfs_buf_iodone_t verify);
void xfs_buf_readahead_map(struct xfs_buftarg *target,
			       struct xfs_buf_map *map, int nmaps,
			       xfs_buf_iodone_t verify);

static inline struct xfs_buf *
xfs_buf_get(
	struct xfs_buftarg	*target,
	xfs_daddr_t		blkno,
	size_t			numblks,
	xfs_buf_flags_t		flags)
{
	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	return xfs_buf_get_map(target, &map, 1, flags);
}

static inline struct xfs_buf *
xfs_buf_read(
	struct xfs_buftarg	*target,
	xfs_daddr_t		blkno,
	size_t			numblks,
	xfs_buf_flags_t		flags,
	xfs_buf_iodone_t	verify)
{
	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	return xfs_buf_read_map(target, &map, 1, flags, verify);
}

static inline void
xfs_buf_readahead(
	struct xfs_buftarg	*target,
	xfs_daddr_t		blkno,
	size_t			numblks,
	xfs_buf_iodone_t	verify)
{
	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	return xfs_buf_readahead_map(target, &map, 1, verify);
}

struct xfs_buf *xfs_buf_get_empty(struct xfs_buftarg *target, size_t numblks);
void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
int xfs_buf_associate_memory(struct xfs_buf *bp, void *mem, size_t length);

struct xfs_buf *xfs_buf_get_uncached(struct xfs_buftarg *target, size_t numblks,
				int flags);
struct xfs_buf *xfs_buf_read_uncached(struct xfs_buftarg *target,
				xfs_daddr_t daddr, size_t numblks, int flags,
				xfs_buf_iodone_t verify);
void xfs_buf_hold(struct xfs_buf *bp);

/* Releasing Buffers */
extern void xfs_buf_free(xfs_buf_t *);
extern void xfs_buf_rele(xfs_buf_t *);

/* Locking and Unlocking Buffers */
extern int xfs_buf_trylock(xfs_buf_t *);
extern void xfs_buf_lock(xfs_buf_t *);
extern void xfs_buf_unlock(xfs_buf_t *);
#define xfs_buf_islocked(bp) \
	((bp)->b_sema.count <= 0)

/* Buffer Read and Write Routines */
extern int xfs_bwrite(struct xfs_buf *bp);

extern void xfsbdstrat(struct xfs_mount *, struct xfs_buf *);

extern void xfs_buf_ioend(xfs_buf_t *,	int);
extern void xfs_buf_ioerror(xfs_buf_t *, int);
extern void xfs_buf_ioerror_alert(struct xfs_buf *, const char *func);
extern void xfs_buf_iorequest(xfs_buf_t *);
extern int xfs_buf_iowait(xfs_buf_t *);
extern void xfs_buf_iomove(xfs_buf_t *, size_t, size_t, void *,
				xfs_buf_rw_t);
#define xfs_buf_zero(bp, off, len) \
	    xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)

static inline int xfs_buf_geterror(xfs_buf_t *bp)
{
	return bp ? bp->b_error : ENOMEM;
}

/* Buffer Utility Routines */
extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);

/* Delayed Write Buffer Routines */
extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
extern int xfs_buf_delwri_submit(struct list_head *);
extern int xfs_buf_delwri_submit_nowait(struct list_head *);

/* Buffer Daemon Setup Routines */
extern int xfs_buf_init(void);
extern void xfs_buf_terminate(void);

#define XFS_BUF_ZEROFLAGS(bp) \
	((bp)->b_flags &= ~(XBF_READ|XBF_WRITE|XBF_ASYNC| \
			    XBF_SYNCIO|XBF_FUA|XBF_FLUSH))

void xfs_buf_stale(struct xfs_buf *bp);
#define XFS_BUF_UNSTALE(bp)	((bp)->b_flags &= ~XBF_STALE)
#define XFS_BUF_ISSTALE(bp)	((bp)->b_flags & XBF_STALE)

#define XFS_BUF_DONE(bp)	((bp)->b_flags |= XBF_DONE)
#define XFS_BUF_UNDONE(bp)	((bp)->b_flags &= ~XBF_DONE)
#define XFS_BUF_ISDONE(bp)	((bp)->b_flags & XBF_DONE)

#define XFS_BUF_ASYNC(bp)	((bp)->b_flags |= XBF_ASYNC)
#define XFS_BUF_UNASYNC(bp)	((bp)->b_flags &= ~XBF_ASYNC)
#define XFS_BUF_ISASYNC(bp)	((bp)->b_flags & XBF_ASYNC)

#define XFS_BUF_READ(bp)	((bp)->b_flags |= XBF_READ)
#define XFS_BUF_UNREAD(bp)	((bp)->b_flags &= ~XBF_READ)
#define XFS_BUF_ISREAD(bp)	((bp)->b_flags & XBF_READ)

#define XFS_BUF_WRITE(bp)	((bp)->b_flags |= XBF_WRITE)
#define XFS_BUF_UNWRITE(bp)	((bp)->b_flags &= ~XBF_WRITE)
#define XFS_BUF_ISWRITE(bp)	((bp)->b_flags & XBF_WRITE)

/*
 * These macros use the IO block map rather than b_bn. b_bn is now really
 * just for the buffer cache index for cached buffers. As IO does not use b_bn
 * anymore, uncached buffers do not use b_bn at all and hence must modify the IO
 * map directly. Uncached buffers are not allowed to be discontiguous, so this
 * is safe to do.
 *
 * In future, uncached buffers will pass the block number directly to the io
 * request function and hence these macros will go away at that point.
 */
#define XFS_BUF_ADDR(bp)		((bp)->b_map.bm_bn)
#define XFS_BUF_SET_ADDR(bp, bno)	((bp)->b_map.bm_bn = (xfs_daddr_t)(bno))

static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
{
	atomic_set(&bp->b_lru_ref, lru_ref);
}

static inline int xfs_buf_ispinned(struct xfs_buf *bp)
{
	return atomic_read(&bp->b_pin_count);
}

static inline void xfs_buf_relse(xfs_buf_t *bp)
{
	xfs_buf_unlock(bp);
	xfs_buf_rele(bp);
}

/*
 *	Handling of buftargs.
 */
extern xfs_buftarg_t *xfs_alloc_buftarg(struct xfs_mount *,
			struct block_device *, int, const char *);
extern void xfs_free_buftarg(struct xfs_mount *, struct xfs_buftarg *);
extern void xfs_wait_buftarg(xfs_buftarg_t *);
extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);

#define xfs_getsize_buftarg(buftarg)	block_size((buftarg)->bt_bdev)
#define xfs_readonly_buftarg(buftarg)	bdev_read_only((buftarg)->bt_bdev)

#endif	/* __XFS_BUF_H__ */
Commit	Line	Data
	1	/*
	2	* Copyright (c) 2000-2005 Silicon Graphics, Inc.
	3	* All Rights Reserved.
	4	*
	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License as
	7	* published by the Free Software Foundation.
	8	*
	9	* This program is distributed in the hope that it would be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	* You should have received a copy of the GNU General Public License
	15	* along with this program; if not, write the Free Software Foundation,
	16	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
	17	*/
	18	#ifndef __XFS_BUF_H__
	19	#define __XFS_BUF_H__
	20
	21	#include <linux/list.h>
	22	#include <linux/types.h>
	23	#include <linux/spinlock.h>
	24	#include <linux/mm.h>
	25	#include <linux/fs.h>
	26	#include <linux/buffer_head.h>
	27	#include <linux/uio.h>
	28
	29	/*
	30	* Base types
	31	*/
	32
	33	#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
	34
	35	typedef enum {
	36	XBRW_READ = 1, /* transfer into target memory */
	37	XBRW_WRITE = 2, /* transfer from target memory */
	38	XBRW_ZERO = 3, /* Zero target memory */
	39	} xfs_buf_rw_t;
	40
	41	#define XBF_READ (1 << 0) /* buffer intended for reading from device */
	42	#define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
	43	#define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
	44	#define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
	45	#define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
	46	#define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
	47
	48	/* I/O hints for the BIO layer */
	49	#define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
	50	#define XBF_FUA (1 << 11)/* force cache write through mode */
	51	#define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
	52
	53	/* flags used only as arguments to access routines */
	54	#define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
	55	#define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
	56
	57	/* flags used only internally */
	58	#define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
	59	#define _XBF_KMEM (1 << 21)/* backed by heap memory */
	60	#define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
	61	#define _XBF_COMPOUND (1 << 23)/* compound buffer */
	62	#define _XBF_LRU_DISPOSE (1 << 24)/* buffer being discarded */
	63
	64	typedef unsigned int xfs_buf_flags_t;
	65
	66	#define XFS_BUF_FLAGS \
	67	{ XBF_READ, "READ" }, \
	68	{ XBF_WRITE, "WRITE" }, \
	69	{ XBF_READ_AHEAD, "READ_AHEAD" }, \
	70	{ XBF_ASYNC, "ASYNC" }, \
	71	{ XBF_DONE, "DONE" }, \
	72	{ XBF_STALE, "STALE" }, \
	73	{ XBF_SYNCIO, "SYNCIO" }, \
	74	{ XBF_FUA, "FUA" }, \
	75	{ XBF_FLUSH, "FLUSH" }, \
	76	{ XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
	77	{ XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
	78	{ _XBF_PAGES, "PAGES" }, \
	79	{ _XBF_KMEM, "KMEM" }, \
	80	{ _XBF_DELWRI_Q, "DELWRI_Q" }, \
	81	{ _XBF_COMPOUND, "COMPOUND" }, \
	82	{ _XBF_LRU_DISPOSE, "LRU_DISPOSE" }
	83
	84	typedef struct xfs_buftarg {
	85	dev_t bt_dev;
	86	struct block_device *bt_bdev;
	87	struct backing_dev_info *bt_bdi;
	88	struct xfs_mount *bt_mount;
	89	unsigned int bt_bsize;
	90	unsigned int bt_sshift;
	91	size_t bt_smask;
	92
	93	/* LRU control structures */
	94	struct shrinker bt_shrinker;
	95	struct list_head bt_lru;
	96	spinlock_t bt_lru_lock;
	97	unsigned int bt_lru_nr;
	98	} xfs_buftarg_t;
	99
	100	struct xfs_buf;
	101	typedef void (xfs_buf_iodone_t)(struct xfs_buf );
	102
	103
	104	#define XB_PAGES 2
	105
	106	struct xfs_buf_map {
	107	xfs_daddr_t bm_bn; /* block number for I/O */
	108	int bm_len; /* size of I/O */
	109	};
	110
	111	#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
	112	struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
	113
	114	typedef struct xfs_buf {
	115	/*
	116	* first cacheline holds all the fields needed for an uncontended cache
	117	* hit to be fully processed. The semaphore straddles the cacheline
	118	* boundary, but the counter and lock sits on the first cacheline,
	119	* which is the only bit that is touched if we hit the semaphore
	120	* fast-path on locking.
	121	*/
	122	struct rb_node b_rbnode; /* rbtree node */
	123	xfs_daddr_t b_bn; /* block number of buffer */
	124	int b_length; /* size of buffer in BBs */
	125	atomic_t b_hold; /* reference count */
	126	atomic_t b_lru_ref; /* lru reclaim ref count */
	127	xfs_buf_flags_t b_flags; /* status flags */
	128	struct semaphore b_sema; /* semaphore for lockables */
	129
	130	/*
	131	* concurrent access to b_lru and b_lru_flags are protected by
	132	* bt_lru_lock and not by b_sema
	133	*/
	134	struct list_head b_lru; /* lru list */
	135	xfs_buf_flags_t b_lru_flags; /* internal lru status flags */
	136	wait_queue_head_t b_waiters; /* unpin waiters */
	137	struct list_head b_list;
	138	struct xfs_perag b_pag; / contains rbtree root */
	139	xfs_buftarg_t b_target; / buffer target (device) */
	140	void b_addr; / virtual address of buffer */
	141	struct work_struct b_iodone_work;
	142	xfs_buf_iodone_t b_iodone; /* I/O completion function */
	143	struct completion b_iowait; /* queue for I/O waiters */
	144	void *b_fspriv;
	145	struct xfs_trans *b_transp;
	146	struct page *b_pages; / array of page pointers */
	147	struct page b_page_array[XB_PAGES]; / inline pages */
	148	struct xfs_buf_map b_maps; / compound buffer map */
	149	struct xfs_buf_map b_map; /* inline compound buffer map */
	150	int b_map_count;
	151	int b_io_length; /* IO size in BBs */
	152	atomic_t b_pin_count; /* pin count */
	153	atomic_t b_io_remaining; /* #outstanding I/O requests */
	154	unsigned int b_page_count; /* size of page array */
	155	unsigned int b_offset; /* page offset in first page */
	156	unsigned short b_error; /* error code on I/O */
	157
	158	#ifdef XFS_BUF_LOCK_TRACKING
	159	int b_last_holder;
	160	#endif
	161	} xfs_buf_t;
	162
	163	/* Finding and Reading Buffers */
	164	struct xfs_buf _xfs_buf_find(struct xfs_buftarg target,
	165	struct xfs_buf_map *map, int nmaps,
	166	xfs_buf_flags_t flags, struct xfs_buf *new_bp);
	167
	168	static inline struct xfs_buf *
	169	xfs_incore(
	170	struct xfs_buftarg *target,
	171	xfs_daddr_t blkno,
	172	size_t numblks,
	173	xfs_buf_flags_t flags)
	174	{
	175	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	176	return _xfs_buf_find(target, &map, 1, flags, NULL);
	177	}
	178
	179	struct xfs_buf _xfs_buf_alloc(struct xfs_buftarg target,
	180	struct xfs_buf_map *map, int nmaps,
	181	xfs_buf_flags_t flags);
	182
	183	static inline struct xfs_buf *
	184	xfs_buf_alloc(
	185	struct xfs_buftarg *target,
	186	xfs_daddr_t blkno,
	187	size_t numblks,
	188	xfs_buf_flags_t flags)
	189	{
	190	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	191	return _xfs_buf_alloc(target, &map, 1, flags);
	192	}
	193
	194	struct xfs_buf xfs_buf_get_map(struct xfs_buftarg target,
	195	struct xfs_buf_map *map, int nmaps,
	196	xfs_buf_flags_t flags);
	197	struct xfs_buf xfs_buf_read_map(struct xfs_buftarg target,
	198	struct xfs_buf_map *map, int nmaps,
	199	xfs_buf_flags_t flags, xfs_buf_iodone_t verify);
	200	void xfs_buf_readahead_map(struct xfs_buftarg *target,
	201	struct xfs_buf_map *map, int nmaps,
	202	xfs_buf_iodone_t verify);
	203
	204	static inline struct xfs_buf *
	205	xfs_buf_get(
	206	struct xfs_buftarg *target,
	207	xfs_daddr_t blkno,
	208	size_t numblks,
	209	xfs_buf_flags_t flags)
	210	{
	211	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	212	return xfs_buf_get_map(target, &map, 1, flags);
	213	}
	214
	215	static inline struct xfs_buf *
	216	xfs_buf_read(
	217	struct xfs_buftarg *target,
	218	xfs_daddr_t blkno,
	219	size_t numblks,
	220	xfs_buf_flags_t flags,
	221	xfs_buf_iodone_t verify)
	222	{
	223	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	224	return xfs_buf_read_map(target, &map, 1, flags, verify);
	225	}
	226
	227	static inline void
	228	xfs_buf_readahead(
	229	struct xfs_buftarg *target,
	230	xfs_daddr_t blkno,
	231	size_t numblks,
	232	xfs_buf_iodone_t verify)
	233	{
	234	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	235	return xfs_buf_readahead_map(target, &map, 1, verify);
	236	}
	237
	238	struct xfs_buf xfs_buf_get_empty(struct xfs_buftarg target, size_t numblks);
	239	void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
	240	int xfs_buf_associate_memory(struct xfs_buf bp, void mem, size_t length);
	241
	242	struct xfs_buf xfs_buf_get_uncached(struct xfs_buftarg target, size_t numblks,
	243	int flags);
	244	struct xfs_buf xfs_buf_read_uncached(struct xfs_buftarg target,
	245	xfs_daddr_t daddr, size_t numblks, int flags,
	246	xfs_buf_iodone_t verify);
	247	void xfs_buf_hold(struct xfs_buf *bp);
	248
	249	/* Releasing Buffers */
	250	extern void xfs_buf_free(xfs_buf_t *);
	251	extern void xfs_buf_rele(xfs_buf_t *);
	252
	253	/* Locking and Unlocking Buffers */
	254	extern int xfs_buf_trylock(xfs_buf_t *);
	255	extern void xfs_buf_lock(xfs_buf_t *);
	256	extern void xfs_buf_unlock(xfs_buf_t *);
	257	#define xfs_buf_islocked(bp) \
	258	((bp)->b_sema.count <= 0)
	259
	260	/* Buffer Read and Write Routines */
	261	extern int xfs_bwrite(struct xfs_buf *bp);
	262
	263	extern void xfsbdstrat(struct xfs_mount , struct xfs_buf );
	264
	265	extern void xfs_buf_ioend(xfs_buf_t *, int);
	266	extern void xfs_buf_ioerror(xfs_buf_t *, int);
	267	extern void xfs_buf_ioerror_alert(struct xfs_buf , const char func);
	268	extern void xfs_buf_iorequest(xfs_buf_t *);
	269	extern int xfs_buf_iowait(xfs_buf_t *);
	270	extern void xfs_buf_iomove(xfs_buf_t , size_t, size_t, void ,
	271	xfs_buf_rw_t);
	272	#define xfs_buf_zero(bp, off, len) \
	273	xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
	274
	275	static inline int xfs_buf_geterror(xfs_buf_t *bp)
	276	{
	277	return bp ? bp->b_error : ENOMEM;
	278	}
	279
	280	/* Buffer Utility Routines */
	281	extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
	282
	283	/* Delayed Write Buffer Routines */
	284	extern bool xfs_buf_delwri_queue(struct xfs_buf , struct list_head );
	285	extern int xfs_buf_delwri_submit(struct list_head *);
	286	extern int xfs_buf_delwri_submit_nowait(struct list_head *);
	287
	288	/* Buffer Daemon Setup Routines */
	289	extern int xfs_buf_init(void);
	290	extern void xfs_buf_terminate(void);
	291
	292	#define XFS_BUF_ZEROFLAGS(bp) \
	293	((bp)->b_flags &= ~(XBF_READ\|XBF_WRITE\|XBF_ASYNC\| \
	294	XBF_SYNCIO\|XBF_FUA\|XBF_FLUSH))
	295
	296	void xfs_buf_stale(struct xfs_buf *bp);
	297	#define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
	298	#define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
	299
	300	#define XFS_BUF_DONE(bp) ((bp)->b_flags \|= XBF_DONE)
	301	#define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
	302	#define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
	303
	304	#define XFS_BUF_ASYNC(bp) ((bp)->b_flags \|= XBF_ASYNC)
	305	#define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
	306	#define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
	307
	308	#define XFS_BUF_READ(bp) ((bp)->b_flags \|= XBF_READ)
	309	#define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
	310	#define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
	311
	312	#define XFS_BUF_WRITE(bp) ((bp)->b_flags \|= XBF_WRITE)
	313	#define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
	314	#define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
	315
	316	/*
	317	* These macros use the IO block map rather than b_bn. b_bn is now really
	318	* just for the buffer cache index for cached buffers. As IO does not use b_bn
	319	* anymore, uncached buffers do not use b_bn at all and hence must modify the IO
	320	* map directly. Uncached buffers are not allowed to be discontiguous, so this
	321	* is safe to do.
	322	*
	323	* In future, uncached buffers will pass the block number directly to the io
	324	* request function and hence these macros will go away at that point.
	325	*/
	326	#define XFS_BUF_ADDR(bp) ((bp)->b_map.bm_bn)
	327	#define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_map.bm_bn = (xfs_daddr_t)(bno))
	328
	329	static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
	330	{
	331	atomic_set(&bp->b_lru_ref, lru_ref);
	332	}
	333
	334	static inline int xfs_buf_ispinned(struct xfs_buf *bp)
	335	{
	336	return atomic_read(&bp->b_pin_count);
	337	}
	338
	339	static inline void xfs_buf_relse(xfs_buf_t *bp)
	340	{
	341	xfs_buf_unlock(bp);
	342	xfs_buf_rele(bp);
	343	}
	344
	345	/*
	346	* Handling of buftargs.
	347	*/
	348	extern xfs_buftarg_t xfs_alloc_buftarg(struct xfs_mount ,
	349	struct block_device , int, const char );
	350	extern void xfs_free_buftarg(struct xfs_mount , struct xfs_buftarg );
	351	extern void xfs_wait_buftarg(xfs_buftarg_t *);
	352	extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
	353
	354	#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
	355	#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
	356
	357	#endif /* __XFS_BUF_H__ */