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buf.h
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buf.h
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/* $NetBSD: buf.h,v 1.49 2002/05/12 23:06:28 matt Exp $ */
/*-
* Copyright (c) 1999, 2000 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
* NASA Ames Research Center.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the NetBSD
* Foundation, Inc. and its contributors.
* 4. Neither the name of The NetBSD Foundation nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)buf.h 8.9 (Berkeley) 3/30/95
*/
#ifndef _SYS_BUF_H_
#define _SYS_BUF_H_
#include <sys/pool.h>
#include <sys/queue.h>
#define NOLIST ((struct buf *)0x87654321)
/*
* To avoid including <ufs/ffs/softdep.h>
*/
LIST_HEAD(workhead, worklist);
/*
* Device driver buffer queue.
*/
struct buf_queue {
TAILQ_HEAD(bufq_head, buf) bq_head; /* actual list of buffers */
struct buf *bq_barrier; /* last B_ORDERED request */
};
#ifdef _KERNEL
#define BUFQ_FIRST(bufq) TAILQ_FIRST(&(bufq)->bq_head)
#define BUFQ_NEXT(bp) TAILQ_NEXT((bp), b_actq)
#define BUFQ_INIT(bufq) \
do { \
TAILQ_INIT(&(bufq)->bq_head); \
(bufq)->bq_barrier = NULL; \
} while (/*CONSTCOND*/0)
#define BUFQ_INSERT_HEAD(bufq, bp) \
do { \
TAILQ_INSERT_HEAD(&(bufq)->bq_head, (bp), b_actq); \
if (((bp)->b_flags & B_ORDERED) != 0 && \
(bufq)->bq_barrier == NULL) \
(bufq)->bq_barrier = (bp); \
} while (/*CONSTCOND*/0)
#define BUFQ_INSERT_TAIL(bufq, bp) \
do { \
TAILQ_INSERT_TAIL(&(bufq)->bq_head, (bp), b_actq); \
if (((bp)->b_flags & B_ORDERED) != 0) \
(bufq)->bq_barrier = (bp); \
} while (/*CONSTCOND*/0)
#define BUFQ_INSERT_AFTER(bufq, lbp, bp) \
do { \
KASSERT((bufq)->bq_barrier == NULL); \
KASSERT(((bp)->b_flags & B_ORDERED) == 0); \
TAILQ_INSERT_AFTER(&(bufq)->bq_head, (lbp), (bp), b_actq); \
} while (/*CONSTCOND*/0)
#define BUFQ_INSERT_BEFORE(bufq, lbp, bp) \
do { \
KASSERT((bufq)->bq_barrier == NULL); \
KASSERT(((bp)->b_flags & B_ORDERED) == 0); \
TAILQ_INSERT_BEFORE((lbp), (bp), b_actq); \
} while (/*CONSTCOND*/0)
#define BUFQ_REMOVE(bufq, bp) \
do { \
if ((bufq)->bq_barrier == (bp)) \
(bufq)->bq_barrier = TAILQ_PREV((bp), bufq_head, b_actq); \
TAILQ_REMOVE(&(bufq)->bq_head, (bp), b_actq); \
} while (/*CONSTCOND*/0)
#endif /* _KERNEL */
/*
* These are currently used only by the soft dependency code, hence
* are stored once in a global variable. If other subsystems wanted
* to use these hooks, a pointer to a set of bio_ops could be added
* to each buffer.
*/
struct buf;
struct mount;
struct vnode;
struct bio_ops {
void (*io_start) __P((struct buf *));
void (*io_complete) __P((struct buf *));
void (*io_deallocate) __P((struct buf *));
int (*io_fsync) __P((struct vnode *));
int (*io_sync) __P((struct mount *));
void (*io_movedeps) __P((struct buf *, struct buf *));
int (*io_countdeps) __P((struct buf *, int));
void (*io_pageiodone) __P((struct buf *));
};
/*
* The buffer header describes an I/O operation in the kernel.
*/
struct buf {
LIST_ENTRY(buf) b_hash; /* Hash chain. */
LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */
TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
TAILQ_ENTRY(buf) b_actq; /* Device driver queue when active. */
struct proc *b_proc; /* Associated proc if B_PHYS set. */
volatile long b_flags; /* B_* flags. */
int b_error; /* Errno value. */
long b_bufsize; /* Allocated buffer size. */
long b_bcount; /* Valid bytes in buffer. */
long b_resid; /* Remaining I/O. */
dev_t b_dev; /* Device associated with buffer. */
struct {
caddr_t b_addr; /* Memory, superblocks, indirect etc. */
} b_un;
void *b_saveaddr; /* Original b_addr for physio. */
daddr_t b_lblkno; /* Logical block number. */
daddr_t b_blkno; /* Underlying physical block number
(partition relative) */
daddr_t b_rawblkno; /* Raw underlying physical block
number (not partition relative) */
/* Function to call upon completion. */
void (*b_iodone) __P((struct buf *));
struct vnode *b_vp; /* File vnode. */
void *b_private; /* Private data for owner */
off_t b_dcookie; /* Offset cookie if dir block */
struct workhead b_dep; /* List of filesystem dependencies. */
};
/*
* For portability with historic industry practice, the cylinder number has
* to be maintained in the `b_resid' field.
*/
#define b_cylinder b_resid /* Cylinder number for disksort(). */
/* Device driver compatibility definitions. */
#define b_data b_un.b_addr /* b_un.b_addr is not changeable. */
/*
* These flags are kept in b_flags.
*/
#define B_AGE 0x00000001 /* Move to age queue when I/O done. */
#define B_NEEDCOMMIT 0x00000002 /* Needs committing to stable storage */
#define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
#define B_BAD 0x00000008 /* Bad block revectoring in progress. */
#define B_BUSY 0x00000010 /* I/O in progress. */
#define B_SCANNED 0x00000020 /* Block already pushed during sync */
#define B_CALL 0x00000040 /* Call b_iodone from biodone. */
#define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
#define B_DIRTY 0x00000100 /* Dirty page to be pushed out async. */
#define B_DONE 0x00000200 /* I/O completed. */
#define B_EINTR 0x00000400 /* I/O was interrupted */
#define B_ERROR 0x00000800 /* I/O error occurred. */
#define B_GATHERED 0x00001000 /* LFS: already in a segment. */
#define B_INVAL 0x00002000 /* Does not contain valid info. */
#define B_LOCKED 0x00004000 /* Locked in core (not reusable). */
#define B_NOCACHE 0x00008000 /* Do not cache block after use. */
#define B_ORDERED 0x00010000 /* ordered I/O request */
#define B_CACHE 0x00020000 /* Bread found us in the cache. */
#define B_PHYS 0x00040000 /* I/O to user memory. */
#define B_RAW 0x00080000 /* Set by physio for raw transfers. */
#define B_READ 0x00100000 /* Read buffer. */
#define B_TAPE 0x00200000 /* Magnetic tape I/O. */
#define B_WANTED 0x00800000 /* Process wants this buffer. */
#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
#define B_XXX 0x02000000 /* Debugging flag. */
#define B_VFLUSH 0x04000000 /* Buffer is being synced. */
/*
* This structure describes a clustered I/O. It is stored in the b_saveaddr
* field of the buffer on which I/O is done. At I/O completion, cluster
* callback uses the structure to parcel I/O's to individual buffers, and
* then free's this structure.
*/
struct cluster_save {
long bs_bcount; /* Saved b_bcount. */
long bs_bufsize; /* Saved b_bufsize. */
void *bs_saveaddr; /* Saved b_addr. */
int bs_nchildren; /* Number of associated buffers. */
struct buf **bs_children; /* List of associated buffers. */
};
/*
* Zero out the buffer's data area.
*/
#define clrbuf(bp) \
do { \
memset((bp)->b_data, 0, (u_int)(bp)->b_bcount); \
(bp)->b_resid = 0; \
} while (/* CONSTCOND */ 0)
/* Flags to low-level allocation routines. */
#define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */
#define B_SYNC 0x02 /* Do all allocations synchronously. */
#ifdef _KERNEL
extern struct bio_ops bioops;
extern int nbuf; /* The number of buffer headers */
extern struct buf *buf; /* The buffer headers. */
extern char *buffers; /* The buffer contents. */
extern int bufpages; /* Number of memory pages in the buffer pool. */
extern int nswbuf; /* Number of swap I/O buffer headers. */
extern struct pool bufpool; /* I/O buf pool */
__BEGIN_DECLS
void allocbuf __P((struct buf *, int));
void bawrite __P((struct buf *));
void bowrite __P((struct buf *));
void bdirty __P((struct buf *));
void bdwrite __P((struct buf *));
void biodone __P((struct buf *));
int biowait __P((struct buf *));
int bread __P((struct vnode *, daddr_t, int,
struct ucred *, struct buf **));
int breada __P((struct vnode *, daddr_t, int, daddr_t, int,
struct ucred *, struct buf **));
int breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int,
struct ucred *, struct buf **));
void brelse __P((struct buf *));
void bremfree __P((struct buf *));
void bufinit __P((void));
int bwrite __P((struct buf *));
void cluster_callback __P((struct buf *));
int cluster_read __P((struct vnode *, u_quad_t, daddr_t, long,
struct ucred *, struct buf **));
void cluster_write __P((struct buf *, u_quad_t));
struct buf *getblk __P((struct vnode *, daddr_t, int, int, int));
struct buf *geteblk __P((int));
struct buf *getnewbuf __P((int slpflag, int slptimeo));
struct buf *incore __P((struct vnode *, daddr_t));
void minphys __P((struct buf *bp));
int physio __P((void (*strategy)(struct buf *), struct buf *bp, dev_t dev,
int flags, void (*minphys)(struct buf *), struct uio *uio));
void brelvp __P((struct buf *));
void reassignbuf __P((struct buf *, struct vnode *));
void bgetvp __P((struct vnode *, struct buf *));
#ifdef DDB
void vfs_buf_print __P((struct buf *, int, void (*)(const char *, ...)));
#endif
__END_DECLS
#endif
#endif /* !_SYS_BUF_H_ */