2eb24859bc
Bowrite guarantees that buffers queued after a call to bowrite will be written after the specified buffer (to a particular device). Bowrite does this either by taking advantage of hardware ordering support (e.g. tagged queueing on SCSI devices) or by resorting to a synchronous write.
251 lines
10 KiB
C
251 lines
10 KiB
C
/*
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)buf.h 8.9 (Berkeley) 3/30/95
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* $Id: buf.h,v 1.32 1996/05/03 20:56:09 phk Exp $
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*/
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#ifndef _SYS_BUF_H_
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#define _SYS_BUF_H_
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#include <sys/queue.h>
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#define NOLIST ((struct buf *)0x87654321)
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struct buf;
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struct iodone_chain {
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long ic_prev_flags;
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void (*ic_prev_iodone) __P((struct buf *));
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void *ic_prev_iodone_chain;
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struct {
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long ia_long;
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void *ia_ptr;
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} ic_args[5];
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};
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typedef TAILQ_HEAD(buf_queue_head, buf) buf_queue_head, *buf_queue_head_t;
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/*
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* The buffer header describes an I/O operation in the kernel.
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*/
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struct buf {
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LIST_ENTRY(buf) b_hash; /* Hash chain. */
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LIST_ENTRY(buf) b_vnbufs; /* Buffer's associated vnode. */
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TAILQ_ENTRY(buf) b_freelist; /* Free list position if not active. */
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TAILQ_ENTRY(buf) b_act; /* Device driver queue when active. *new* */
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struct proc *b_proc; /* Associated proc; NULL if kernel. */
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long b_flags; /* B_* flags. */
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unsigned short b_qindex; /* buffer queue index */
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unsigned char b_usecount; /* buffer use count */
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int b_error; /* Errno value. */
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long b_bufsize; /* Allocated buffer size. */
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long b_bcount; /* Valid bytes in buffer. */
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long b_resid; /* Remaining I/O. */
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dev_t b_dev; /* Device associated with buffer. */
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struct {
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caddr_t b_addr; /* Memory, superblocks, indirect etc. */
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} b_un;
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void *b_saveaddr; /* Original b_addr for physio. */
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daddr_t b_lblkno; /* Logical block number. */
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daddr_t b_blkno; /* Underlying physical block number. */
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/* Function to call upon completion. */
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void (*b_iodone) __P((struct buf *));
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/* For nested b_iodone's. */
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struct iodone_chain *b_iodone_chain;
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struct vnode *b_vp; /* Device vnode. */
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int b_dirtyoff; /* Offset in buffer of dirty region. */
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int b_dirtyend; /* Offset of end of dirty region. */
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struct ucred *b_rcred; /* Read credentials reference. */
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struct ucred *b_wcred; /* Write credentials reference. */
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int b_validoff; /* Offset in buffer of valid region. */
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int b_validend; /* Offset of end of valid region. */
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daddr_t b_pblkno; /* physical block number */
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caddr_t b_savekva; /* saved kva for transfer while bouncing */
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void *b_driver1; /* for private use by the driver */
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void *b_driver2; /* for private use by the driver */
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void *b_spc;
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union cluster_info {
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TAILQ_HEAD(cluster_list_head, buf) cluster_head;
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TAILQ_ENTRY(buf) cluster_entry;
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} b_cluster;
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struct vm_page *b_pages[btoc(MAXPHYS)];
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int b_npages;
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};
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/* Device driver compatibility definitions. */
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#define b_active b_bcount /* Driver queue head: drive active. */
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#define b_data b_un.b_addr /* b_un.b_addr is not changeable. */
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#define b_errcnt b_resid /* Retry count while I/O in progress. */
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#define iodone biodone /* Old name for biodone. */
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#define iowait biowait /* Old name for biowait. */
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/*
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* These flags are kept in b_flags.
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*/
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#define B_AGE 0x00000001 /* Move to age queue when I/O done. */
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#define B_NEEDCOMMIT 0x00000002 /* Append-write in progress. */
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#define B_ASYNC 0x00000004 /* Start I/O, do not wait. */
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#define B_BAD 0x00000008 /* Bad block revectoring in progress. */
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#define B_BUSY 0x00000010 /* I/O in progress. */
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#define B_CACHE 0x00000020 /* Bread found us in the cache. */
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#define B_CALL 0x00000040 /* Call b_iodone from biodone. */
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#define B_DELWRI 0x00000080 /* Delay I/O until buffer reused. */
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#define B_DIRTY 0x00000100 /* Dirty page to be pushed out async. */
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#define B_DONE 0x00000200 /* I/O completed. */
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#define B_EINTR 0x00000400 /* I/O was interrupted */
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#define B_ERROR 0x00000800 /* I/O error occurred. */
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#define B_GATHERED 0x00001000 /* LFS: already in a segment. */
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#define B_INVAL 0x00002000 /* Does not contain valid info. */
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#define B_LOCKED 0x00004000 /* Locked in core (not reusable). */
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#define B_NOCACHE 0x00008000 /* Do not cache block after use. */
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#define B_MALLOC 0x00010000 /* malloced b_data */
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#define B_CLUSTEROK 0x00020000 /* Pagein op, so swap() can count it. */
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#define B_PHYS 0x00040000 /* I/O to user memory. */
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#define B_RAW 0x00080000 /* Set by physio for raw transfers. */
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#define B_READ 0x00100000 /* Read buffer. */
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#define B_TAPE 0x00200000 /* Magnetic tape I/O. */
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#define B_RELBUF 0x00400000 /* Release VMIO buffer. */
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#define B_WANTED 0x00800000 /* Process wants this buffer. */
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#define B_WRITE 0x00000000 /* Write buffer (pseudo flag). */
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#define B_WRITEINPROG 0x01000000 /* Write in progress. */
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#define B_XXX 0x02000000 /* Debugging flag. */
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#define B_PAGING 0x04000000 /* volatile paging I/O -- bypass VMIO */
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#define B_ORDERED 0x08000000 /* Must guarantee I/O ordering */
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#define B_VMIO 0x20000000 /* VMIO flag */
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#define B_CLUSTER 0x40000000 /* pagein op, so swap() can count it */
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#define B_BOUNCE 0x80000000 /* bounce buffer flag */
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/*
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* number of buffer hash entries
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*/
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#define BUFHSZ 512
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/*
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* buffer hash table calculation, originally by David Greenman
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*/
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#define BUFHASH(vnp, bn) \
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(&bufhashtbl[(((unsigned long)(vnp) >> 7)+(int)(bn)) % BUFHSZ])
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/*
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* Definitions for the buffer free lists.
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*/
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#define BUFFER_QUEUES 6 /* number of free buffer queues */
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extern LIST_HEAD(bufhashhdr, buf) bufhashtbl[BUFHSZ], invalhash;
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extern TAILQ_HEAD(bqueues, buf) bufqueues[BUFFER_QUEUES];
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#define QUEUE_NONE 0 /* on no queue */
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#define QUEUE_LOCKED 1 /* locked buffers */
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#define QUEUE_LRU 2 /* useful buffers */
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#define QUEUE_VMIO 3 /* VMIO buffers */
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#define QUEUE_AGE 4 /* not-useful buffers */
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#define QUEUE_EMPTY 5 /* empty buffer headers*/
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/*
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* Zero out the buffer's data area.
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*/
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#define clrbuf(bp) { \
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bzero((bp)->b_data, (u_int)(bp)->b_bcount); \
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(bp)->b_resid = 0; \
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}
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/* Flags to low-level allocation routines. */
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#define B_CLRBUF 0x01 /* Request allocated buffer be cleared. */
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#define B_SYNC 0x02 /* Do all allocations synchronously. */
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#ifdef KERNEL
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extern int nbuf; /* The number of buffer headers */
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extern struct buf *buf; /* The buffer headers. */
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extern char *buffers; /* The buffer contents. */
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extern int bufpages; /* Number of memory pages in the buffer pool. */
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extern struct buf *swbuf; /* Swap I/O buffer headers. */
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extern int nswbuf; /* Number of swap I/O buffer headers. */
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extern TAILQ_HEAD(swqueue, buf) bswlist;
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void bufinit __P((void));
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void bremfree __P((struct buf *));
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int bread __P((struct vnode *, daddr_t, int,
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struct ucred *, struct buf **));
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int breadn __P((struct vnode *, daddr_t, int, daddr_t *, int *, int,
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struct ucred *, struct buf **));
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int bwrite __P((struct buf *));
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void bdwrite __P((struct buf *));
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void bawrite __P((struct buf *));
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int bowrite __P((struct buf *));
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void brelse __P((struct buf *));
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void bqrelse __P((struct buf *));
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int vfs_bio_awrite __P((struct buf *));
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struct buf * getpbuf __P((void));
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struct buf *incore __P((struct vnode *, daddr_t));
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struct buf *gbincore __P((struct vnode *, daddr_t));
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int inmem __P((struct vnode *, daddr_t));
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struct buf *getblk __P((struct vnode *, daddr_t, int, int, int));
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struct buf *geteblk __P((int));
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int allocbuf __P((struct buf *, int));
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int biowait __P((struct buf *));
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void biodone __P((struct buf *));
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void cluster_callback __P((struct buf *));
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int cluster_read __P((struct vnode *, u_quad_t, daddr_t, long,
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struct ucred *, struct buf **));
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int cluster_wbuild __P((struct vnode *, long, daddr_t, int));
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void cluster_write __P((struct buf *, u_quad_t));
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int physio __P((void (*)(struct buf *), struct buf *, dev_t,
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int, u_int (*)(struct buf *), struct uio *));
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u_int minphys __P((struct buf *));
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void vfs_bio_clrbuf __P((struct buf *));
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void vfs_busy_pages __P((struct buf *, int clear_modify));
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void vfs_unbusy_pages(struct buf *);
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void vwakeup __P((struct buf *));
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void vmapbuf __P((struct buf *));
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void vunmapbuf __P((struct buf *));
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void relpbuf __P((struct buf *));
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void brelvp __P((struct buf *));
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void bgetvp __P((struct vnode *, struct buf *));
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void pbgetvp __P((struct vnode *, struct buf *));
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void pbrelvp __P((struct buf *));
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void reassignbuf __P((struct buf *, struct vnode *));
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struct buf *trypbuf __P((void));
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void vm_bounce_alloc __P((struct buf *));
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void vm_bounce_free __P((struct buf *));
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vm_offset_t vm_bounce_kva_alloc __P((int));
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void vm_bounce_kva_alloc_free __P((vm_offset_t, int));
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#endif /* KERNEL */
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#endif /* !_SYS_BUF_H_ */
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