fs/xfs/linux-2.6/xfs_buf.h - kernel/msm-4.9 - Gitiles

 /*
  * 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 <asm/system.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))

 #define xfs_buf_ctob(pp)	((pp) * PAGE_CACHE_SIZE)
 #define xfs_buf_btoc(dd)	(((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT)
 #define xfs_buf_btoct(dd)	((dd) >> PAGE_CACHE_SHIFT)
 #define xfs_buf_poff(aa)	((aa) & ~PAGE_CACHE_MASK)

 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;

 typedef enum {
 	XBF_READ = (1 << 0),	/* buffer intended for reading from device */
 	XBF_WRITE = (1 << 1),	/* buffer intended for writing to device   */
 	XBF_MAPPED = (1 << 2),  /* buffer mapped (b_addr valid)            */
 	XBF_ASYNC = (1 << 4),   /* initiator will not wait for completion  */
 	XBF_DONE = (1 << 5),    /* all pages in the buffer uptodate	   */
 	XBF_DELWRI = (1 << 6),  /* buffer has dirty pages                  */
 	XBF_STALE = (1 << 7),	/* buffer has been staled, do not find it  */
 	XBF_FS_MANAGED = (1 << 8),  /* filesystem controls freeing memory  */
  	XBF_ORDERED = (1 << 11),    /* use ordered writes		   */
 	XBF_READ_AHEAD = (1 << 12), /* asynchronous read-ahead		   */

 	/* flags used only as arguments to access routines */
 	XBF_LOCK = (1 << 14),       /* lock requested			   */
 	XBF_TRYLOCK = (1 << 15),    /* lock requested, but do not wait	   */
 	XBF_DONT_BLOCK = (1 << 16), /* do not block in current thread	   */

 	/* flags used only internally */
 	_XBF_PAGE_CACHE = (1 << 17),/* backed by pagecache		   */
 	_XBF_KMEM_ALLOC = (1 << 18),/* backed by kmem_alloc()		   */
 	_XBF_RUN_QUEUES = (1 << 19),/* run block device task queue	   */
 	_XBF_DELWRI_Q = (1 << 21),   /* buffer on delwri queue		   */
 } xfs_buf_flags_t;

 typedef enum {
 	XBT_FORCE_SLEEP = 0,
 	XBT_FORCE_FLUSH = 1,
 } xfs_buftarg_flags_t;

 typedef struct xfs_bufhash {
 	struct list_head	bh_list;
 	spinlock_t		bh_lock;
 } xfs_bufhash_t;

 typedef struct xfs_buftarg {
 	dev_t			bt_dev;
 	struct block_device	*bt_bdev;
 	struct address_space	*bt_mapping;
 	unsigned int		bt_bsize;
 	unsigned int		bt_sshift;
 	size_t			bt_smask;

 	/* per device buffer hash table */
 	uint			bt_hashmask;
 	uint			bt_hashshift;
 	xfs_bufhash_t		*bt_hash;

 	/* per device delwri queue */
 	struct task_struct	*bt_task;
 	struct list_head	bt_list;
 	struct list_head	bt_delwrite_queue;
 	spinlock_t		bt_delwrite_lock;
 	unsigned long		bt_flags;
 } xfs_buftarg_t;

 /*
  *	xfs_buf_t:  Buffer structure for pagecache-based buffers
  *
  * This buffer structure is used by the pagecache buffer management routines
  * to refer to an assembly of pages forming a logical buffer.
  *
  * The buffer structure is used on a temporary basis only, and discarded when
  * released.  The real data storage is recorded in the pagecache. Buffers are
  * hashed to the block device on which the file system resides.
  */

 struct xfs_buf;
 typedef void (*xfs_buf_iodone_t)(struct xfs_buf *);
 typedef void (*xfs_buf_relse_t)(struct xfs_buf *);
 typedef int (*xfs_buf_bdstrat_t)(struct xfs_buf *);

 #define XB_PAGES	2

 typedef struct xfs_buf {
 	struct semaphore	b_sema;		/* semaphore for lockables */
 	unsigned long		b_queuetime;	/* time buffer was queued */
 	atomic_t		b_pin_count;	/* pin count */
 	wait_queue_head_t	b_waiters;	/* unpin waiters */
 	struct list_head	b_list;
 	xfs_buf_flags_t		b_flags;	/* status flags */
 	struct list_head	b_hash_list;	/* hash table list */
 	xfs_bufhash_t		*b_hash;	/* hash table list start */
 	xfs_buftarg_t		*b_target;	/* buffer target (device) */
 	atomic_t		b_hold;		/* reference count */
 	xfs_daddr_t		b_bn;		/* block number for I/O */
 	xfs_off_t		b_file_offset;	/* offset in file */
 	size_t			b_buffer_length;/* size of buffer in bytes */
 	size_t			b_count_desired;/* desired transfer size */
 	void			*b_addr;	/* virtual address of buffer */
 	struct work_struct	b_iodone_work;
 	atomic_t		b_io_remaining;	/* #outstanding I/O requests */
 	xfs_buf_iodone_t	b_iodone;	/* I/O completion function */
 	xfs_buf_relse_t		b_relse;	/* releasing function */
 	xfs_buf_bdstrat_t	b_strat;	/* pre-write function */
 	struct semaphore	b_iodonesema;	/* Semaphore for I/O waiters */
 	void			*b_fspriv;
 	void			*b_fspriv2;
 	void			*b_fspriv3;
 	unsigned short		b_error;	/* error code on I/O */
 	unsigned short		b_locked;	/* page array is locked */
 	unsigned int		b_page_count;	/* size of page array */
 	unsigned int		b_offset;	/* page offset in first page */
 	struct page		**b_pages;	/* array of page pointers */
 	struct page		*b_page_array[XB_PAGES]; /* inline pages */
 #ifdef XFS_BUF_LOCK_TRACKING
 	int			b_last_holder;
 #endif
 } xfs_buf_t;


 /* Finding and Reading Buffers */
 extern xfs_buf_t *_xfs_buf_find(xfs_buftarg_t *, xfs_off_t, size_t,
 				xfs_buf_flags_t, xfs_buf_t *);
 #define xfs_incore(buftarg,blkno,len,lockit) \
 	_xfs_buf_find(buftarg, blkno ,len, lockit, NULL)

 extern xfs_buf_t *xfs_buf_get_flags(xfs_buftarg_t *, xfs_off_t, size_t,
 				xfs_buf_flags_t);
 #define xfs_buf_get(target, blkno, len, flags) \
 	xfs_buf_get_flags((target), (blkno), (len), XBF_LOCK | XBF_MAPPED)

 extern xfs_buf_t *xfs_buf_read_flags(xfs_buftarg_t *, xfs_off_t, size_t,
 				xfs_buf_flags_t);
 #define xfs_buf_read(target, blkno, len, flags) \
 	xfs_buf_read_flags((target), (blkno), (len), XBF_LOCK | XBF_MAPPED)

 extern xfs_buf_t *xfs_buf_get_empty(size_t, xfs_buftarg_t *);
 extern xfs_buf_t *xfs_buf_get_noaddr(size_t, xfs_buftarg_t *);
 extern int xfs_buf_associate_memory(xfs_buf_t *, void *, size_t);
 extern void xfs_buf_hold(xfs_buf_t *);
 extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t,
 				xfs_buf_flags_t);

 /* 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_cond_lock(xfs_buf_t *);
 extern int xfs_buf_lock_value(xfs_buf_t *);
 extern void xfs_buf_lock(xfs_buf_t *);
 extern void xfs_buf_unlock(xfs_buf_t *);

 /* Buffer Read and Write Routines */
 extern void xfs_buf_ioend(xfs_buf_t *,	int);
 extern void xfs_buf_ioerror(xfs_buf_t *, int);
 extern int xfs_buf_iostart(xfs_buf_t *, xfs_buf_flags_t);
 extern int 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, xfs_caddr_t,
 				xfs_buf_rw_t);

 static inline int xfs_buf_iostrategy(xfs_buf_t *bp)
 {
 	return bp->b_strat ? bp->b_strat(bp) : xfs_buf_iorequest(bp);
 }

 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);

 /* Pinning Buffer Storage in Memory */
 extern void xfs_buf_pin(xfs_buf_t *);
 extern void xfs_buf_unpin(xfs_buf_t *);
 extern int xfs_buf_ispin(xfs_buf_t *);

 /* Delayed Write Buffer Routines */
 extern void xfs_buf_delwri_dequeue(xfs_buf_t *);

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

 #ifdef XFS_BUF_TRACE
 extern ktrace_t *xfs_buf_trace_buf;
 extern void xfs_buf_trace(xfs_buf_t *, char *, void *, void *);
 #else
 #define xfs_buf_trace(bp,id,ptr,ra)	do { } while (0)
 #endif

 #define xfs_buf_target_name(target)	\
 	({ char __b[BDEVNAME_SIZE]; bdevname((target)->bt_bdev, __b); __b; })


 #define XFS_B_ASYNC		XBF_ASYNC
 #define XFS_B_DELWRI		XBF_DELWRI
 #define XFS_B_READ		XBF_READ
 #define XFS_B_WRITE		XBF_WRITE
 #define XFS_B_STALE		XBF_STALE

 #define XFS_BUF_TRYLOCK		XBF_TRYLOCK
 #define XFS_INCORE_TRYLOCK	XBF_TRYLOCK
 #define XFS_BUF_LOCK		XBF_LOCK
 #define XFS_BUF_MAPPED		XBF_MAPPED

 #define BUF_BUSY		XBF_DONT_BLOCK

 #define XFS_BUF_BFLAGS(bp)	((bp)->b_flags)
 #define XFS_BUF_ZEROFLAGS(bp)	((bp)->b_flags &= \
 		~(XBF_READ|XBF_WRITE|XBF_ASYNC|XBF_DELWRI|XBF_ORDERED))

 #define XFS_BUF_STALE(bp)	((bp)->b_flags |= XFS_B_STALE)
 #define XFS_BUF_UNSTALE(bp)	((bp)->b_flags &= ~XFS_B_STALE)
 #define XFS_BUF_ISSTALE(bp)	((bp)->b_flags & XFS_B_STALE)
 #define XFS_BUF_SUPER_STALE(bp)	do {				\
 					XFS_BUF_STALE(bp);	\
 					xfs_buf_delwri_dequeue(bp);	\
 					XFS_BUF_DONE(bp);	\
 				} while (0)

 #define XFS_BUF_MANAGE		XBF_FS_MANAGED
 #define XFS_BUF_UNMANAGE(bp)	((bp)->b_flags &= ~XBF_FS_MANAGED)

 #define XFS_BUF_DELAYWRITE(bp)		((bp)->b_flags |= XBF_DELWRI)
 #define XFS_BUF_UNDELAYWRITE(bp)	xfs_buf_delwri_dequeue(bp)
 #define XFS_BUF_ISDELAYWRITE(bp)	((bp)->b_flags & XBF_DELWRI)

 #define XFS_BUF_ERROR(bp,no)	xfs_buf_ioerror(bp,no)
 #define XFS_BUF_GETERROR(bp)	xfs_buf_geterror(bp)
 #define XFS_BUF_ISERROR(bp)	(xfs_buf_geterror(bp) ? 1 : 0)

 #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_BUSY(bp)	do { } while (0)
 #define XFS_BUF_UNBUSY(bp)	do { } while (0)
 #define XFS_BUF_ISBUSY(bp)	(1)

 #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_ORDERED(bp)	((bp)->b_flags |= XBF_ORDERED)
 #define XFS_BUF_UNORDERED(bp)	((bp)->b_flags &= ~XBF_ORDERED)
 #define XFS_BUF_ISORDERED(bp)	((bp)->b_flags & XBF_ORDERED)

 #define XFS_BUF_SHUT(bp)	do { } while (0)
 #define XFS_BUF_UNSHUT(bp)	do { } while (0)
 #define XFS_BUF_ISSHUT(bp)	(0)

 #define XFS_BUF_HOLD(bp)	xfs_buf_hold(bp)
 #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)

 #define XFS_BUF_IODONE_FUNC(bp)			((bp)->b_iodone)
 #define XFS_BUF_SET_IODONE_FUNC(bp, func)	((bp)->b_iodone = (func))
 #define XFS_BUF_CLR_IODONE_FUNC(bp)		((bp)->b_iodone = NULL)
 #define XFS_BUF_SET_BDSTRAT_FUNC(bp, func)	((bp)->b_strat = (func))
 #define XFS_BUF_CLR_BDSTRAT_FUNC(bp)		((bp)->b_strat = NULL)

 #define XFS_BUF_FSPRIVATE(bp, type)		((type)(bp)->b_fspriv)
 #define XFS_BUF_SET_FSPRIVATE(bp, val)		((bp)->b_fspriv = (void*)(val))
 #define XFS_BUF_FSPRIVATE2(bp, type)		((type)(bp)->b_fspriv2)
 #define XFS_BUF_SET_FSPRIVATE2(bp, val)		((bp)->b_fspriv2 = (void*)(val))
 #define XFS_BUF_FSPRIVATE3(bp, type)		((type)(bp)->b_fspriv3)
 #define XFS_BUF_SET_FSPRIVATE3(bp, val)		((bp)->b_fspriv3 = (void*)(val))
 #define XFS_BUF_SET_START(bp)			do { } while (0)
 #define XFS_BUF_SET_BRELSE_FUNC(bp, func)	((bp)->b_relse = (func))

 #define XFS_BUF_PTR(bp)			(xfs_caddr_t)((bp)->b_addr)
 #define XFS_BUF_SET_PTR(bp, val, cnt)	xfs_buf_associate_memory(bp, val, cnt)
 #define XFS_BUF_ADDR(bp)		((bp)->b_bn)
 #define XFS_BUF_SET_ADDR(bp, bno)	((bp)->b_bn = (xfs_daddr_t)(bno))
 #define XFS_BUF_OFFSET(bp)		((bp)->b_file_offset)
 #define XFS_BUF_SET_OFFSET(bp, off)	((bp)->b_file_offset = (off))
 #define XFS_BUF_COUNT(bp)		((bp)->b_count_desired)
 #define XFS_BUF_SET_COUNT(bp, cnt)	((bp)->b_count_desired = (cnt))
 #define XFS_BUF_SIZE(bp)		((bp)->b_buffer_length)
 #define XFS_BUF_SET_SIZE(bp, cnt)	((bp)->b_buffer_length = (cnt))

 #define XFS_BUF_SET_VTYPE_REF(bp, type, ref)	do { } while (0)
 #define XFS_BUF_SET_VTYPE(bp, type)		do { } while (0)
 #define XFS_BUF_SET_REF(bp, ref)		do { } while (0)

 #define XFS_BUF_ISPINNED(bp)	xfs_buf_ispin(bp)

 #define XFS_BUF_VALUSEMA(bp)	xfs_buf_lock_value(bp)
 #define XFS_BUF_CPSEMA(bp)	(xfs_buf_cond_lock(bp) == 0)
 #define XFS_BUF_VSEMA(bp)	xfs_buf_unlock(bp)
 #define XFS_BUF_PSEMA(bp,x)	xfs_buf_lock(bp)
 #define XFS_BUF_V_IODONESEMA(bp) up(&bp->b_iodonesema);

 #define XFS_BUF_SET_TARGET(bp, target)	((bp)->b_target = (target))
 #define XFS_BUF_TARGET(bp)		((bp)->b_target)
 #define XFS_BUFTARG_NAME(target)	xfs_buf_target_name(target)

 static inline int xfs_bawrite(void *mp, xfs_buf_t *bp)
 {
 	bp->b_fspriv3 = mp;
 	bp->b_strat = xfs_bdstrat_cb;
 	xfs_buf_delwri_dequeue(bp);
 	return xfs_buf_iostart(bp, XBF_WRITE | XBF_ASYNC | _XBF_RUN_QUEUES);
 }

 static inline void xfs_buf_relse(xfs_buf_t *bp)
 {
 	if (!bp->b_relse)
 		xfs_buf_unlock(bp);
 	xfs_buf_rele(bp);
 }

 #define xfs_bpin(bp)		xfs_buf_pin(bp)
 #define xfs_bunpin(bp)		xfs_buf_unpin(bp)

 #define xfs_buftrace(id, bp)	\
 	    xfs_buf_trace(bp, id, NULL, (void *)__builtin_return_address(0))

 #define xfs_biodone(bp)		xfs_buf_ioend(bp, 0)

 #define xfs_biomove(bp, off, len, data, rw) \
 	    xfs_buf_iomove((bp), (off), (len), (data), \
 		((rw) == XFS_B_WRITE) ? XBRW_WRITE : XBRW_READ)

 #define xfs_biozero(bp, off, len) \
 	    xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)


 static inline int XFS_bwrite(xfs_buf_t *bp)
 {
 	int	iowait = (bp->b_flags & XBF_ASYNC) == 0;
 	int	error = 0;

 	if (!iowait)
 		bp->b_flags |= _XBF_RUN_QUEUES;

 	xfs_buf_delwri_dequeue(bp);
 	xfs_buf_iostrategy(bp);
 	if (iowait) {
 		error = xfs_buf_iowait(bp);
 		xfs_buf_relse(bp);
 	}
 	return error;
 }

 static inline int xfs_bdwrite(void *mp, xfs_buf_t *bp)
 {
 	bp->b_strat = xfs_bdstrat_cb;
 	bp->b_fspriv3 = mp;
 	return xfs_buf_iostart(bp, XBF_DELWRI | XBF_ASYNC);
 }

 #define XFS_bdstrat(bp) xfs_buf_iorequest(bp)

 #define xfs_iowait(bp)	xfs_buf_iowait(bp)

 #define xfs_baread(target, rablkno, ralen)  \
 	xfs_buf_readahead((target), (rablkno), (ralen), XBF_DONT_BLOCK)


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

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

 #define xfs_binval(buftarg)		xfs_flush_buftarg(buftarg, 1)
 #define XFS_bflush(buftarg)		xfs_flush_buftarg(buftarg, 1)

 #endif	/* __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 <asm/system.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))

	#define xfs_buf_ctob(pp) ((pp) * PAGE_CACHE_SIZE)
	#define xfs_buf_btoc(dd) (((dd) + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT)
	#define xfs_buf_btoct(dd) ((dd) >> PAGE_CACHE_SHIFT)
	#define xfs_buf_poff(aa) ((aa) & ~PAGE_CACHE_MASK)

	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;

	typedef enum {
	XBF_READ = (1 << 0), /* buffer intended for reading from device */
	XBF_WRITE = (1 << 1), /* buffer intended for writing to device */
	XBF_MAPPED = (1 << 2), /* buffer mapped (b_addr valid) */
	XBF_ASYNC = (1 << 4), /* initiator will not wait for completion */
	XBF_DONE = (1 << 5), /* all pages in the buffer uptodate */
	XBF_DELWRI = (1 << 6), /* buffer has dirty pages */
	XBF_STALE = (1 << 7), /* buffer has been staled, do not find it */
	XBF_FS_MANAGED = (1 << 8), /* filesystem controls freeing memory */
	XBF_ORDERED = (1 << 11), /* use ordered writes */
	XBF_READ_AHEAD = (1 << 12), /* asynchronous read-ahead */

	/* flags used only as arguments to access routines */
	XBF_LOCK = (1 << 14), /* lock requested */
	XBF_TRYLOCK = (1 << 15), /* lock requested, but do not wait */
	XBF_DONT_BLOCK = (1 << 16), /* do not block in current thread */

	/* flags used only internally */
	_XBF_PAGE_CACHE = (1 << 17),/* backed by pagecache */
	_XBF_KMEM_ALLOC = (1 << 18),/* backed by kmem_alloc() */
	_XBF_RUN_QUEUES = (1 << 19),/* run block device task queue */
	_XBF_DELWRI_Q = (1 << 21), /* buffer on delwri queue */
	} xfs_buf_flags_t;

	typedef enum {
	XBT_FORCE_SLEEP = 0,
	XBT_FORCE_FLUSH = 1,
	} xfs_buftarg_flags_t;

	typedef struct xfs_bufhash {
	struct list_head bh_list;
	spinlock_t bh_lock;
	} xfs_bufhash_t;

	typedef struct xfs_buftarg {
	dev_t bt_dev;
	struct block_device *bt_bdev;
	struct address_space *bt_mapping;
	unsigned int bt_bsize;
	unsigned int bt_sshift;
	size_t bt_smask;

	/* per device buffer hash table */
	uint bt_hashmask;
	uint bt_hashshift;
	xfs_bufhash_t *bt_hash;

	/* per device delwri queue */
	struct task_struct *bt_task;
	struct list_head bt_list;
	struct list_head bt_delwrite_queue;
	spinlock_t bt_delwrite_lock;
	unsigned long bt_flags;
	} xfs_buftarg_t;

	/*
	* xfs_buf_t: Buffer structure for pagecache-based buffers
	*
	* This buffer structure is used by the pagecache buffer management routines
	* to refer to an assembly of pages forming a logical buffer.
	*
	* The buffer structure is used on a temporary basis only, and discarded when
	* released. The real data storage is recorded in the pagecache. Buffers are
	* hashed to the block device on which the file system resides.
	*/

	struct xfs_buf;
	typedef void (xfs_buf_iodone_t)(struct xfs_buf );
	typedef void (xfs_buf_relse_t)(struct xfs_buf );
	typedef int (xfs_buf_bdstrat_t)(struct xfs_buf );

	#define XB_PAGES 2

	typedef struct xfs_buf {
	struct semaphore b_sema; /* semaphore for lockables */
	unsigned long b_queuetime; /* time buffer was queued */
	atomic_t b_pin_count; /* pin count */
	wait_queue_head_t b_waiters; /* unpin waiters */
	struct list_head b_list;
	xfs_buf_flags_t b_flags; /* status flags */
	struct list_head b_hash_list; /* hash table list */
	xfs_bufhash_t b_hash; / hash table list start */
	xfs_buftarg_t b_target; / buffer target (device) */
	atomic_t b_hold; /* reference count */
	xfs_daddr_t b_bn; /* block number for I/O */
	xfs_off_t b_file_offset; /* offset in file */
	size_t b_buffer_length;/* size of buffer in bytes */
	size_t b_count_desired;/* desired transfer size */
	void b_addr; / virtual address of buffer */
	struct work_struct b_iodone_work;
	atomic_t b_io_remaining; /* #outstanding I/O requests */
	xfs_buf_iodone_t b_iodone; /* I/O completion function */
	xfs_buf_relse_t b_relse; /* releasing function */
	xfs_buf_bdstrat_t b_strat; /* pre-write function */
	struct semaphore b_iodonesema; /* Semaphore for I/O waiters */
	void *b_fspriv;
	void *b_fspriv2;
	void *b_fspriv3;
	unsigned short b_error; /* error code on I/O */
	unsigned short b_locked; /* page array is locked */
	unsigned int b_page_count; /* size of page array */
	unsigned int b_offset; /* page offset in first page */
	struct page *b_pages; / array of page pointers */
	struct page b_page_array[XB_PAGES]; / inline pages */
	#ifdef XFS_BUF_LOCK_TRACKING
	int b_last_holder;
	#endif
	} xfs_buf_t;


	/* Finding and Reading Buffers */
	extern xfs_buf_t _xfs_buf_find(xfs_buftarg_t , xfs_off_t, size_t,
	xfs_buf_flags_t, xfs_buf_t *);
	#define xfs_incore(buftarg,blkno,len,lockit) \
	_xfs_buf_find(buftarg, blkno ,len, lockit, NULL)

	extern xfs_buf_t xfs_buf_get_flags(xfs_buftarg_t , xfs_off_t, size_t,
	xfs_buf_flags_t);
	#define xfs_buf_get(target, blkno, len, flags) \
	xfs_buf_get_flags((target), (blkno), (len), XBF_LOCK \| XBF_MAPPED)

	extern xfs_buf_t xfs_buf_read_flags(xfs_buftarg_t , xfs_off_t, size_t,
	xfs_buf_flags_t);
	#define xfs_buf_read(target, blkno, len, flags) \
	xfs_buf_read_flags((target), (blkno), (len), XBF_LOCK \| XBF_MAPPED)

	extern xfs_buf_t xfs_buf_get_empty(size_t, xfs_buftarg_t );
	extern xfs_buf_t xfs_buf_get_noaddr(size_t, xfs_buftarg_t );
	extern int xfs_buf_associate_memory(xfs_buf_t , void , size_t);
	extern void xfs_buf_hold(xfs_buf_t *);
	extern void xfs_buf_readahead(xfs_buftarg_t *, xfs_off_t, size_t,
	xfs_buf_flags_t);

	/* 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_cond_lock(xfs_buf_t *);
	extern int xfs_buf_lock_value(xfs_buf_t *);
	extern void xfs_buf_lock(xfs_buf_t *);
	extern void xfs_buf_unlock(xfs_buf_t *);

	/* Buffer Read and Write Routines */
	extern void xfs_buf_ioend(xfs_buf_t *, int);
	extern void xfs_buf_ioerror(xfs_buf_t *, int);
	extern int xfs_buf_iostart(xfs_buf_t *, xfs_buf_flags_t);
	extern int 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, xfs_caddr_t,
	xfs_buf_rw_t);

	static inline int xfs_buf_iostrategy(xfs_buf_t *bp)
	{
	return bp->b_strat ? bp->b_strat(bp) : xfs_buf_iorequest(bp);
	}

	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);

	/* Pinning Buffer Storage in Memory */
	extern void xfs_buf_pin(xfs_buf_t *);
	extern void xfs_buf_unpin(xfs_buf_t *);
	extern int xfs_buf_ispin(xfs_buf_t *);

	/* Delayed Write Buffer Routines */
	extern void xfs_buf_delwri_dequeue(xfs_buf_t *);

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

	#ifdef XFS_BUF_TRACE
	extern ktrace_t *xfs_buf_trace_buf;
	extern void xfs_buf_trace(xfs_buf_t , char , void , void );
	#else
	#define xfs_buf_trace(bp,id,ptr,ra) do { } while (0)
	#endif

	#define xfs_buf_target_name(target) \
	({ char __b[BDEVNAME_SIZE]; bdevname((target)->bt_bdev, __b); __b; })


	#define XFS_B_ASYNC XBF_ASYNC
	#define XFS_B_DELWRI XBF_DELWRI
	#define XFS_B_READ XBF_READ
	#define XFS_B_WRITE XBF_WRITE
	#define XFS_B_STALE XBF_STALE

	#define XFS_BUF_TRYLOCK XBF_TRYLOCK
	#define XFS_INCORE_TRYLOCK XBF_TRYLOCK
	#define XFS_BUF_LOCK XBF_LOCK
	#define XFS_BUF_MAPPED XBF_MAPPED

	#define BUF_BUSY XBF_DONT_BLOCK

	#define XFS_BUF_BFLAGS(bp) ((bp)->b_flags)
	#define XFS_BUF_ZEROFLAGS(bp) ((bp)->b_flags &= \
	~(XBF_READ\|XBF_WRITE\|XBF_ASYNC\|XBF_DELWRI\|XBF_ORDERED))

	#define XFS_BUF_STALE(bp) ((bp)->b_flags \|= XFS_B_STALE)
	#define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XFS_B_STALE)
	#define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XFS_B_STALE)
	#define XFS_BUF_SUPER_STALE(bp) do { \
	XFS_BUF_STALE(bp); \
	xfs_buf_delwri_dequeue(bp); \
	XFS_BUF_DONE(bp); \
	} while (0)

	#define XFS_BUF_MANAGE XBF_FS_MANAGED
	#define XFS_BUF_UNMANAGE(bp) ((bp)->b_flags &= ~XBF_FS_MANAGED)

	#define XFS_BUF_DELAYWRITE(bp) ((bp)->b_flags \|= XBF_DELWRI)
	#define XFS_BUF_UNDELAYWRITE(bp) xfs_buf_delwri_dequeue(bp)
	#define XFS_BUF_ISDELAYWRITE(bp) ((bp)->b_flags & XBF_DELWRI)

	#define XFS_BUF_ERROR(bp,no) xfs_buf_ioerror(bp,no)
	#define XFS_BUF_GETERROR(bp) xfs_buf_geterror(bp)
	#define XFS_BUF_ISERROR(bp) (xfs_buf_geterror(bp) ? 1 : 0)

	#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_BUSY(bp) do { } while (0)
	#define XFS_BUF_UNBUSY(bp) do { } while (0)
	#define XFS_BUF_ISBUSY(bp) (1)

	#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_ORDERED(bp) ((bp)->b_flags \|= XBF_ORDERED)
	#define XFS_BUF_UNORDERED(bp) ((bp)->b_flags &= ~XBF_ORDERED)
	#define XFS_BUF_ISORDERED(bp) ((bp)->b_flags & XBF_ORDERED)

	#define XFS_BUF_SHUT(bp) do { } while (0)
	#define XFS_BUF_UNSHUT(bp) do { } while (0)
	#define XFS_BUF_ISSHUT(bp) (0)

	#define XFS_BUF_HOLD(bp) xfs_buf_hold(bp)
	#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)

	#define XFS_BUF_IODONE_FUNC(bp) ((bp)->b_iodone)
	#define XFS_BUF_SET_IODONE_FUNC(bp, func) ((bp)->b_iodone = (func))
	#define XFS_BUF_CLR_IODONE_FUNC(bp) ((bp)->b_iodone = NULL)
	#define XFS_BUF_SET_BDSTRAT_FUNC(bp, func) ((bp)->b_strat = (func))
	#define XFS_BUF_CLR_BDSTRAT_FUNC(bp) ((bp)->b_strat = NULL)

	#define XFS_BUF_FSPRIVATE(bp, type) ((type)(bp)->b_fspriv)
	#define XFS_BUF_SET_FSPRIVATE(bp, val) ((bp)->b_fspriv = (void*)(val))
	#define XFS_BUF_FSPRIVATE2(bp, type) ((type)(bp)->b_fspriv2)
	#define XFS_BUF_SET_FSPRIVATE2(bp, val) ((bp)->b_fspriv2 = (void*)(val))
	#define XFS_BUF_FSPRIVATE3(bp, type) ((type)(bp)->b_fspriv3)
	#define XFS_BUF_SET_FSPRIVATE3(bp, val) ((bp)->b_fspriv3 = (void*)(val))
	#define XFS_BUF_SET_START(bp) do { } while (0)
	#define XFS_BUF_SET_BRELSE_FUNC(bp, func) ((bp)->b_relse = (func))

	#define XFS_BUF_PTR(bp) (xfs_caddr_t)((bp)->b_addr)
	#define XFS_BUF_SET_PTR(bp, val, cnt) xfs_buf_associate_memory(bp, val, cnt)
	#define XFS_BUF_ADDR(bp) ((bp)->b_bn)
	#define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_bn = (xfs_daddr_t)(bno))
	#define XFS_BUF_OFFSET(bp) ((bp)->b_file_offset)
	#define XFS_BUF_SET_OFFSET(bp, off) ((bp)->b_file_offset = (off))
	#define XFS_BUF_COUNT(bp) ((bp)->b_count_desired)
	#define XFS_BUF_SET_COUNT(bp, cnt) ((bp)->b_count_desired = (cnt))
	#define XFS_BUF_SIZE(bp) ((bp)->b_buffer_length)
	#define XFS_BUF_SET_SIZE(bp, cnt) ((bp)->b_buffer_length = (cnt))

	#define XFS_BUF_SET_VTYPE_REF(bp, type, ref) do { } while (0)
	#define XFS_BUF_SET_VTYPE(bp, type) do { } while (0)
	#define XFS_BUF_SET_REF(bp, ref) do { } while (0)

	#define XFS_BUF_ISPINNED(bp) xfs_buf_ispin(bp)

	#define XFS_BUF_VALUSEMA(bp) xfs_buf_lock_value(bp)
	#define XFS_BUF_CPSEMA(bp) (xfs_buf_cond_lock(bp) == 0)
	#define XFS_BUF_VSEMA(bp) xfs_buf_unlock(bp)
	#define XFS_BUF_PSEMA(bp,x) xfs_buf_lock(bp)
	#define XFS_BUF_V_IODONESEMA(bp) up(&bp->b_iodonesema);

	#define XFS_BUF_SET_TARGET(bp, target) ((bp)->b_target = (target))
	#define XFS_BUF_TARGET(bp) ((bp)->b_target)
	#define XFS_BUFTARG_NAME(target) xfs_buf_target_name(target)

	static inline int xfs_bawrite(void mp, xfs_buf_t bp)
	{
	bp->b_fspriv3 = mp;
	bp->b_strat = xfs_bdstrat_cb;
	xfs_buf_delwri_dequeue(bp);
	return xfs_buf_iostart(bp, XBF_WRITE \| XBF_ASYNC \| _XBF_RUN_QUEUES);
	}

	static inline void xfs_buf_relse(xfs_buf_t *bp)
	{
	if (!bp->b_relse)
	xfs_buf_unlock(bp);
	xfs_buf_rele(bp);
	}

	#define xfs_bpin(bp) xfs_buf_pin(bp)
	#define xfs_bunpin(bp) xfs_buf_unpin(bp)

	#define xfs_buftrace(id, bp) \
	xfs_buf_trace(bp, id, NULL, (void *)__builtin_return_address(0))

	#define xfs_biodone(bp) xfs_buf_ioend(bp, 0)

	#define xfs_biomove(bp, off, len, data, rw) \
	xfs_buf_iomove((bp), (off), (len), (data), \
	((rw) == XFS_B_WRITE) ? XBRW_WRITE : XBRW_READ)

	#define xfs_biozero(bp, off, len) \
	xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)


	static inline int XFS_bwrite(xfs_buf_t *bp)
	{
	int iowait = (bp->b_flags & XBF_ASYNC) == 0;
	int error = 0;

	if (!iowait)
	bp->b_flags \|= _XBF_RUN_QUEUES;

	xfs_buf_delwri_dequeue(bp);
	xfs_buf_iostrategy(bp);
	if (iowait) {
	error = xfs_buf_iowait(bp);
	xfs_buf_relse(bp);
	}
	return error;
	}

	static inline int xfs_bdwrite(void mp, xfs_buf_t bp)
	{
	bp->b_strat = xfs_bdstrat_cb;
	bp->b_fspriv3 = mp;
	return xfs_buf_iostart(bp, XBF_DELWRI \| XBF_ASYNC);
	}

	#define XFS_bdstrat(bp) xfs_buf_iorequest(bp)

	#define xfs_iowait(bp) xfs_buf_iowait(bp)

	#define xfs_baread(target, rablkno, ralen) \
	xfs_buf_readahead((target), (rablkno), (ralen), XBF_DONT_BLOCK)


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

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

	#define xfs_binval(buftarg) xfs_flush_buftarg(buftarg, 1)
	#define XFS_bflush(buftarg) xfs_flush_buftarg(buftarg, 1)

	#endif /* __XFS_BUF_H__ */