[mirror_ubuntu-zesty-kernel.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>
#include <linux/list_lru.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_lru		bt_lru;
} 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) };

struct xfs_buf_ops {
	void (*verify_read)(struct xfs_buf *);
	void (*verify_write)(struct xfs_buf *);
};

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 */
	const struct xfs_buf_ops	*b_ops;

#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,
			       const struct xfs_buf_ops *ops);
void xfs_buf_readahead_map(struct xfs_buftarg *target,
			       struct xfs_buf_map *map, int nmaps,
			       const struct xfs_buf_ops *ops);

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,
	const struct xfs_buf_ops *ops)
{
	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	return xfs_buf_read_map(target, &map, 1, flags, ops);
}

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

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,
				const struct xfs_buf_ops *ops);
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_maps[0].bm_bn)
#define XFS_BUF_SET_ADDR(bp, bno)	((bp)->b_maps[0].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
1da177e4	1	/*
7b718769 NS	2	* Copyright (c) 2000-2005 Silicon Graphics, Inc.
7b718769 NS	3	* All Rights Reserved.
1da177e4	4	*
7b718769 NS	5	* This program is free software; you can redistribute it and/or
7b718769 NS	6	* modify it under the terms of the GNU General Public License as
1da177e4 LT	7	* published by the Free Software Foundation.
1da177e4 LT	8	*
7b718769 NS	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.
1da177e4	13	*
7b718769 NS	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
1da177e4	17	*/
1da177e4 LT	18	#ifndef __XFS_BUF_H__
	19	#define __XFS_BUF_H__
	20
1da177e4 LT	21	#include <linux/list.h>
	22	#include <linux/types.h>
	23	#include <linux/spinlock.h>
1da177e4 LT	24	#include <linux/mm.h>
	25	#include <linux/fs.h>
	26	#include <linux/buffer_head.h>
	27	#include <linux/uio.h>
e80dfa19	28	#include <linux/list_lru.h>
1da177e4 LT	29
	30	/*
	31	* Base types
	32	*/
	33
ce8e922c NS	34	#define XFS_BUF_DADDR_NULL ((xfs_daddr_t) (-1LL))
ce8e922c NS	35
ce8e922c NS	36	typedef enum {
	37	XBRW_READ = 1, /* transfer into target memory */
	38	XBRW_WRITE = 2, /* transfer from target memory */
	39	XBRW_ZERO = 3, /* Zero target memory */
	40	} xfs_buf_rw_t;
	41
6fb8a90a CM	42	#define XBF_READ (1 << 0) /* buffer intended for reading from device */
	43	#define XBF_WRITE (1 << 1) /* buffer intended for writing to device */
	44	#define XBF_READ_AHEAD (1 << 2) /* asynchronous read-ahead */
	45	#define XBF_ASYNC (1 << 4) /* initiator will not wait for completion */
	46	#define XBF_DONE (1 << 5) /* all pages in the buffer uptodate */
	47	#define XBF_STALE (1 << 6) /* buffer has been staled, do not find it */
1d5ae5df CH	48
1d5ae5df CH	49	/* I/O hints for the BIO layer */
6fb8a90a CM	50	#define XBF_SYNCIO (1 << 10)/* treat this buffer as synchronous I/O */
	51	#define XBF_FUA (1 << 11)/* force cache write through mode */
	52	#define XBF_FLUSH (1 << 12)/* flush the disk cache before a write */
1da177e4	53
807cbbdb	54	/* flags used only as arguments to access routines */
6fb8a90a CM	55	#define XBF_TRYLOCK (1 << 16)/* lock requested, but do not wait */
6fb8a90a CM	56	#define XBF_UNMAPPED (1 << 17)/* do not map the buffer */
1da177e4	57
807cbbdb	58	/* flags used only internally */
6fb8a90a CM	59	#define _XBF_PAGES (1 << 20)/* backed by refcounted pages */
	60	#define _XBF_KMEM (1 << 21)/* backed by heap memory */
	61	#define _XBF_DELWRI_Q (1 << 22)/* buffer on a delwri queue */
	62	#define _XBF_COMPOUND (1 << 23)/* compound buffer */
	63	#define _XBF_LRU_DISPOSE (1 << 24)/* buffer being discarded */
6ab455ee	64
807cbbdb	65	typedef unsigned int xfs_buf_flags_t;
1da177e4	66
0b1b213f CH	67	#define XFS_BUF_FLAGS \
	68	{ XBF_READ, "READ" }, \
	69	{ XBF_WRITE, "WRITE" }, \
1d5ae5df	70	{ XBF_READ_AHEAD, "READ_AHEAD" }, \
0b1b213f CH	71	{ XBF_ASYNC, "ASYNC" }, \
0b1b213f CH	72	{ XBF_DONE, "DONE" }, \
0b1b213f	73	{ XBF_STALE, "STALE" }, \
1d5ae5df CH	74	{ XBF_SYNCIO, "SYNCIO" }, \
	75	{ XBF_FUA, "FUA" }, \
	76	{ XBF_FLUSH, "FLUSH" }, \
6fb8a90a	77	{ XBF_TRYLOCK, "TRYLOCK" }, /* should never be set */\
611c9946	78	{ XBF_UNMAPPED, "UNMAPPED" }, /* ditto */\
0b1b213f	79	{ _XBF_PAGES, "PAGES" }, \
0e6e847f	80	{ _XBF_KMEM, "KMEM" }, \
cbb7baab	81	{ _XBF_DELWRI_Q, "DELWRI_Q" }, \
6fb8a90a CM	82	{ _XBF_COMPOUND, "COMPOUND" }, \
6fb8a90a CM	83	{ _XBF_LRU_DISPOSE, "LRU_DISPOSE" }
0b1b213f	84
1da177e4	85	typedef struct xfs_buftarg {
ce8e922c NS	86	dev_t bt_dev;
ce8e922c NS	87	struct block_device *bt_bdev;
0e6e847f	88	struct backing_dev_info *bt_bdi;
ebad861b	89	struct xfs_mount *bt_mount;
ce8e922c NS	90	unsigned int bt_bsize;
	91	unsigned int bt_sshift;
	92	size_t bt_smask;
	93
ff57ab21 DC	94	/* LRU control structures */
ff57ab21 DC	95	struct shrinker bt_shrinker;
e80dfa19	96	struct list_lru bt_lru;
1da177e4 LT	97	} xfs_buftarg_t;
1da177e4 LT	98
1da177e4	99	struct xfs_buf;
ce8e922c	100	typedef void (xfs_buf_iodone_t)(struct xfs_buf );
1da177e4	101
c3f8fc73	102
ce8e922c	103	#define XB_PAGES 2
1da177e4	104
cbb7baab DC	105	struct xfs_buf_map {
	106	xfs_daddr_t bm_bn; /* block number for I/O */
	107	int bm_len; /* size of I/O */
	108	};
	109
3e85c868 DC	110	#define DEFINE_SINGLE_BUF_MAP(map, blkno, numblk) \
	111	struct xfs_buf_map (map) = { .bm_bn = (blkno), .bm_len = (numblk) };
	112
1813dd64 DC	113	struct xfs_buf_ops {
	114	void (verify_read)(struct xfs_buf );
	115	void (verify_write)(struct xfs_buf );
	116	};
	117
1da177e4	118	typedef struct xfs_buf {
50f59e8e DC	119	/*
	120	* first cacheline holds all the fields needed for an uncontended cache
	121	* hit to be fully processed. The semaphore straddles the cacheline
	122	* boundary, but the counter and lock sits on the first cacheline,
	123	* which is the only bit that is touched if we hit the semaphore
	124	* fast-path on locking.
	125	*/
	126	struct rb_node b_rbnode; /* rbtree node */
cbb7baab	127	xfs_daddr_t b_bn; /* block number of buffer */
4e94b71b	128	int b_length; /* size of buffer in BBs */
50f59e8e	129	atomic_t b_hold; /* reference count */
430cbeb8	130	atomic_t b_lru_ref; /* lru reclaim ref count */
50f59e8e	131	xfs_buf_flags_t b_flags; /* status flags */
ce8e922c	132	struct semaphore b_sema; /* semaphore for lockables */
50f59e8e	133
6fb8a90a CM	134	/*
	135	* concurrent access to b_lru and b_lru_flags are protected by
	136	* bt_lru_lock and not by b_sema
	137	*/
430cbeb8	138	struct list_head b_lru; /* lru list */
6fb8a90a	139	xfs_buf_flags_t b_lru_flags; /* internal lru status flags */
ce8e922c NS	140	wait_queue_head_t b_waiters; /* unpin waiters */
ce8e922c NS	141	struct list_head b_list;
74f75a0c	142	struct xfs_perag b_pag; / contains rbtree root */
ce8e922c	143	xfs_buftarg_t b_target; / buffer target (device) */
ce8e922c NS	144	void b_addr; / virtual address of buffer */
ce8e922c NS	145	struct work_struct b_iodone_work;
ce8e922c	146	xfs_buf_iodone_t b_iodone; /* I/O completion function */
b4dd330b	147	struct completion b_iowait; /* queue for I/O waiters */
ce8e922c	148	void *b_fspriv;
bf9d9013	149	struct xfs_trans *b_transp;
ce8e922c NS	150	struct page *b_pages; / array of page pointers */
ce8e922c NS	151	struct page b_page_array[XB_PAGES]; / inline pages */
3e85c868	152	struct xfs_buf_map b_maps; / compound buffer map */
d44d9bc6	153	struct xfs_buf_map __b_map; /* inline compound buffer map */
3e85c868	154	int b_map_count;
aa0e8833	155	int b_io_length; /* IO size in BBs */
50f59e8e DC	156	atomic_t b_pin_count; /* pin count */
	157	atomic_t b_io_remaining; /* #outstanding I/O requests */
	158	unsigned int b_page_count; /* size of page array */
	159	unsigned int b_offset; /* page offset in first page */
	160	unsigned short b_error; /* error code on I/O */
1813dd64	161	const struct xfs_buf_ops *b_ops;
cfb02852	162
ce8e922c NS	163	#ifdef XFS_BUF_LOCK_TRACKING
ce8e922c NS	164	int b_last_holder;
1da177e4 LT	165	#endif
	166	} xfs_buf_t;
	167
1da177e4	168	/* Finding and Reading Buffers */
3e85c868 DC	169	struct xfs_buf _xfs_buf_find(struct xfs_buftarg target,
	170	struct xfs_buf_map *map, int nmaps,
	171	xfs_buf_flags_t flags, struct xfs_buf *new_bp);
	172
	173	static inline struct xfs_buf *
	174	xfs_incore(
	175	struct xfs_buftarg *target,
	176	xfs_daddr_t blkno,
	177	size_t numblks,
	178	xfs_buf_flags_t flags)
	179	{
	180	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	181	return _xfs_buf_find(target, &map, 1, flags, NULL);
	182	}
	183
	184	struct xfs_buf _xfs_buf_alloc(struct xfs_buftarg target,
	185	struct xfs_buf_map *map, int nmaps,
	186	xfs_buf_flags_t flags);
	187
	188	static inline struct xfs_buf *
	189	xfs_buf_alloc(
	190	struct xfs_buftarg *target,
	191	xfs_daddr_t blkno,
	192	size_t numblks,
	193	xfs_buf_flags_t flags)
	194	{
	195	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	196	return _xfs_buf_alloc(target, &map, 1, flags);
	197	}
1da177e4	198
6dde2707 DC	199	struct xfs_buf xfs_buf_get_map(struct xfs_buftarg target,
	200	struct xfs_buf_map *map, int nmaps,
	201	xfs_buf_flags_t flags);
	202	struct xfs_buf xfs_buf_read_map(struct xfs_buftarg target,
	203	struct xfs_buf_map *map, int nmaps,
1813dd64 DC	204	xfs_buf_flags_t flags,
1813dd64 DC	205	const struct xfs_buf_ops *ops);
6dde2707	206	void xfs_buf_readahead_map(struct xfs_buftarg *target,
c3f8fc73	207	struct xfs_buf_map *map, int nmaps,
1813dd64	208	const struct xfs_buf_ops *ops);
6dde2707 DC	209
	210	static inline struct xfs_buf *
	211	xfs_buf_get(
	212	struct xfs_buftarg *target,
	213	xfs_daddr_t blkno,
	214	size_t numblks,
	215	xfs_buf_flags_t flags)
	216	{
	217	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
	218	return xfs_buf_get_map(target, &map, 1, flags);
	219	}
	220
	221	static inline struct xfs_buf *
	222	xfs_buf_read(
	223	struct xfs_buftarg *target,
	224	xfs_daddr_t blkno,
	225	size_t numblks,
c3f8fc73	226	xfs_buf_flags_t flags,
1813dd64	227	const struct xfs_buf_ops *ops)
6dde2707 DC	228	{
6dde2707 DC	229	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
1813dd64	230	return xfs_buf_read_map(target, &map, 1, flags, ops);
6dde2707 DC	231	}
	232
	233	static inline void
	234	xfs_buf_readahead(
	235	struct xfs_buftarg *target,
	236	xfs_daddr_t blkno,
c3f8fc73	237	size_t numblks,
1813dd64	238	const struct xfs_buf_ops *ops)
6dde2707 DC	239	{
6dde2707 DC	240	DEFINE_SINGLE_BUF_MAP(map, blkno, numblks);
1813dd64	241	return xfs_buf_readahead_map(target, &map, 1, ops);
6dde2707	242	}
e70b73f8 DC	243
e70b73f8 DC	244	struct xfs_buf xfs_buf_get_empty(struct xfs_buftarg target, size_t numblks);
e70b73f8 DC	245	void xfs_buf_set_empty(struct xfs_buf *bp, size_t numblks);
	246	int xfs_buf_associate_memory(struct xfs_buf bp, void mem, size_t length);
	247
	248	struct xfs_buf xfs_buf_get_uncached(struct xfs_buftarg target, size_t numblks,
	249	int flags);
	250	struct xfs_buf xfs_buf_read_uncached(struct xfs_buftarg target,
c3f8fc73	251	xfs_daddr_t daddr, size_t numblks, int flags,
1813dd64	252	const struct xfs_buf_ops *ops);
e70b73f8	253	void xfs_buf_hold(struct xfs_buf *bp);
1da177e4 LT	254
1da177e4 LT	255	/* Releasing Buffers */
ce8e922c NS	256	extern void xfs_buf_free(xfs_buf_t *);
ce8e922c NS	257	extern void xfs_buf_rele(xfs_buf_t *);
1da177e4 LT	258
1da177e4 LT	259	/* Locking and Unlocking Buffers */
0c842ad4	260	extern int xfs_buf_trylock(xfs_buf_t *);
ce8e922c NS	261	extern void xfs_buf_lock(xfs_buf_t *);
ce8e922c NS	262	extern void xfs_buf_unlock(xfs_buf_t *);
0c842ad4 CH	263	#define xfs_buf_islocked(bp) \
0c842ad4 CH	264	((bp)->b_sema.count <= 0)
1da177e4 LT	265
1da177e4 LT	266	/* Buffer Read and Write Routines */
c2b006c1	267	extern int xfs_bwrite(struct xfs_buf *bp);
4e23471a CH	268
4e23471a CH	269	extern void xfsbdstrat(struct xfs_mount , struct xfs_buf );
4e23471a	270
ce8e922c NS	271	extern void xfs_buf_ioend(xfs_buf_t *, int);
ce8e922c NS	272	extern void xfs_buf_ioerror(xfs_buf_t *, int);
901796af	273	extern void xfs_buf_ioerror_alert(struct xfs_buf , const char func);
0e95f19a	274	extern void xfs_buf_iorequest(xfs_buf_t *);
ce8e922c	275	extern int xfs_buf_iowait(xfs_buf_t *);
b9c48649	276	extern void xfs_buf_iomove(xfs_buf_t , size_t, size_t, void ,
ce8e922c	277	xfs_buf_rw_t);
1a1a3e97 CH	278	#define xfs_buf_zero(bp, off, len) \
1a1a3e97 CH	279	xfs_buf_iomove((bp), (off), (len), NULL, XBRW_ZERO)
ce8e922c	280
ce8e922c	281	static inline int xfs_buf_geterror(xfs_buf_t *bp)
1da177e4	282	{
ce8e922c	283	return bp ? bp->b_error : ENOMEM;
1da177e4 LT	284	}
	285
	286	/* Buffer Utility Routines */
ce8e922c	287	extern xfs_caddr_t xfs_buf_offset(xfs_buf_t *, size_t);
1da177e4	288
1da177e4	289	/* Delayed Write Buffer Routines */
43ff2122 CH	290	extern bool xfs_buf_delwri_queue(struct xfs_buf , struct list_head );
	291	extern int xfs_buf_delwri_submit(struct list_head *);
	292	extern int xfs_buf_delwri_submit_nowait(struct list_head *);
1da177e4 LT	293
1da177e4 LT	294	/* Buffer Daemon Setup Routines */
ce8e922c NS	295	extern int xfs_buf_init(void);
ce8e922c NS	296	extern void xfs_buf_terminate(void);
1da177e4	297
1d5ae5df	298	#define XFS_BUF_ZEROFLAGS(bp) \
43ff2122	299	((bp)->b_flags &= ~(XBF_READ\|XBF_WRITE\|XBF_ASYNC\| \
1d5ae5df	300	XBF_SYNCIO\|XBF_FUA\|XBF_FLUSH))
ce8e922c	301
430cbeb8	302	void xfs_buf_stale(struct xfs_buf *bp);
0cadda1c CH	303	#define XFS_BUF_UNSTALE(bp) ((bp)->b_flags &= ~XBF_STALE)
0cadda1c CH	304	#define XFS_BUF_ISSTALE(bp) ((bp)->b_flags & XBF_STALE)
1da177e4	305
ce8e922c NS	306	#define XFS_BUF_DONE(bp) ((bp)->b_flags \|= XBF_DONE)
	307	#define XFS_BUF_UNDONE(bp) ((bp)->b_flags &= ~XBF_DONE)
	308	#define XFS_BUF_ISDONE(bp) ((bp)->b_flags & XBF_DONE)
	309
ce8e922c NS	310	#define XFS_BUF_ASYNC(bp) ((bp)->b_flags \|= XBF_ASYNC)
	311	#define XFS_BUF_UNASYNC(bp) ((bp)->b_flags &= ~XBF_ASYNC)
	312	#define XFS_BUF_ISASYNC(bp) ((bp)->b_flags & XBF_ASYNC)
	313
ce8e922c NS	314	#define XFS_BUF_READ(bp) ((bp)->b_flags \|= XBF_READ)
	315	#define XFS_BUF_UNREAD(bp) ((bp)->b_flags &= ~XBF_READ)
	316	#define XFS_BUF_ISREAD(bp) ((bp)->b_flags & XBF_READ)
	317
	318	#define XFS_BUF_WRITE(bp) ((bp)->b_flags \|= XBF_WRITE)
	319	#define XFS_BUF_UNWRITE(bp) ((bp)->b_flags &= ~XBF_WRITE)
	320	#define XFS_BUF_ISWRITE(bp) ((bp)->b_flags & XBF_WRITE)
	321
cbb7baab DC	322	/*
	323	* These macros use the IO block map rather than b_bn. b_bn is now really
	324	* just for the buffer cache index for cached buffers. As IO does not use b_bn
	325	* anymore, uncached buffers do not use b_bn at all and hence must modify the IO
	326	* map directly. Uncached buffers are not allowed to be discontiguous, so this
	327	* is safe to do.
	328	*
	329	* In future, uncached buffers will pass the block number directly to the io
	330	* request function and hence these macros will go away at that point.
	331	*/
d44d9bc6 MT	332	#define XFS_BUF_ADDR(bp) ((bp)->b_maps[0].bm_bn)
d44d9bc6 MT	333	#define XFS_BUF_SET_ADDR(bp, bno) ((bp)->b_maps[0].bm_bn = (xfs_daddr_t)(bno))
ce8e922c	334
38f23232	335	static inline void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref)
821eb21d DC	336	{
	337	atomic_set(&bp->b_lru_ref, lru_ref);
	338	}
ce8e922c	339
811e64c7 CS	340	static inline int xfs_buf_ispinned(struct xfs_buf *bp)
	341	{
	342	return atomic_read(&bp->b_pin_count);
	343	}
ce8e922c	344
ce8e922c	345	static inline void xfs_buf_relse(xfs_buf_t *bp)
1da177e4	346	{
bfc60177	347	xfs_buf_unlock(bp);
ce8e922c	348	xfs_buf_rele(bp);
1da177e4 LT	349	}
1da177e4 LT	350
1da177e4 LT	351	/*
	352	* Handling of buftargs.
	353	*/
ebad861b DC	354	extern xfs_buftarg_t xfs_alloc_buftarg(struct xfs_mount ,
ebad861b DC	355	struct block_device , int, const char );
c141b292	356	extern void xfs_free_buftarg(struct xfs_mount , struct xfs_buftarg );
1da177e4 LT	357	extern void xfs_wait_buftarg(xfs_buftarg_t *);
1da177e4 LT	358	extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int, unsigned int);
d808f617	359
ce8e922c NS	360	#define xfs_getsize_buftarg(buftarg) block_size((buftarg)->bt_bdev)
	361	#define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev)
	362
1da177e4	363	#endif /* __XFS_BUF_H__ */