746 lines
16 KiB
C
746 lines
16 KiB
C
/*
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* Copyright (c) 1994 John S. Dyson
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* All rights reserved.
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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 immediately at the beginning of the file, without modification,
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* 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. Absolutely no warranty of function or purpose is made by the author
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* John S. Dyson.
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* 4. Modifications may be freely made to this file if the above conditions
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* are met.
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*
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* $Id: vfs_bio.c,v 1.15 1994/10/18 06:55:40 davidg Exp $
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/vnode.h>
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#include <sys/buf.h>
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#include <sys/mount.h>
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#include <sys/malloc.h>
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#include <sys/resourcevar.h>
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#include <sys/proc.h>
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#include <vm/vm.h>
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#include <vm/vm_pageout.h>
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#include <miscfs/specfs/specdev.h>
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struct buf *buf; /* buffer header pool */
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int nbuf; /* number of buffer headers calculated elsewhere */
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struct swqueue bswlist;
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extern vm_map_t buffer_map, io_map;
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void vm_hold_free_pages(vm_offset_t from, vm_offset_t to);
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void vm_hold_load_pages(vm_offset_t from, vm_offset_t to);
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int needsbuffer;
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/*
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* Internal update daemon, process 3
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* The variable vfs_update_wakeup allows for internal syncs.
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*/
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int vfs_update_wakeup;
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/*
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* Initialize buffer headers and related structures.
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*/
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void
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bufinit()
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{
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struct buf *bp;
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int i;
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caddr_t baddr;
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TAILQ_INIT(&bswlist);
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LIST_INIT(&invalhash);
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/* first, make a null hash table */
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for(i=0;i<BUFHSZ;i++)
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LIST_INIT(&bufhashtbl[i]);
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/* next, make a null set of free lists */
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for(i=0;i<BUFFER_QUEUES;i++)
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TAILQ_INIT(&bufqueues[i]);
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baddr = (caddr_t)kmem_alloc_pageable(buffer_map, MAXBSIZE * nbuf);
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/* finally, initialize each buffer header and stick on empty q */
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for(i=0;i<nbuf;i++) {
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bp = &buf[i];
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bzero(bp, sizeof *bp);
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bp->b_flags = B_INVAL; /* we're just an empty header */
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bp->b_dev = NODEV;
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bp->b_vp = NULL;
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bp->b_rcred = NOCRED;
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bp->b_wcred = NOCRED;
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bp->b_qindex = QUEUE_EMPTY;
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bp->b_vnbufs.le_next = NOLIST;
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bp->b_data = baddr + i * MAXBSIZE;
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TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist);
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LIST_INSERT_HEAD(&invalhash, bp, b_hash);
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}
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}
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/*
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* remove the buffer from the appropriate free list
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*/
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void
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bremfree(struct buf *bp)
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{
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int s = splbio();
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if( bp->b_qindex != QUEUE_NONE) {
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TAILQ_REMOVE(&bufqueues[bp->b_qindex], bp, b_freelist);
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bp->b_qindex = QUEUE_NONE;
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} else {
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panic("bremfree: removing a buffer when not on a queue");
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}
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splx(s);
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}
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/*
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* Get a buffer with the specified data. Look in the cache first.
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*/
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int
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bread(struct vnode *vp, daddr_t blkno, int size, struct ucred *cred,
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struct buf **bpp)
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{
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struct buf *bp;
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bp = getblk (vp, blkno, size, 0, 0);
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*bpp = bp;
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/* if not found in cache, do some I/O */
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if ((bp->b_flags & B_CACHE) == 0) {
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if (curproc && curproc->p_stats) /* count block I/O */
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curproc->p_stats->p_ru.ru_inblock++;
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bp->b_flags |= B_READ;
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bp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL);
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if( bp->b_rcred == NOCRED) {
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if (cred != NOCRED)
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crhold(cred);
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bp->b_rcred = cred;
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}
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VOP_STRATEGY(bp);
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return( biowait (bp));
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}
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return (0);
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}
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/*
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* Operates like bread, but also starts asynchronous I/O on
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* read-ahead blocks.
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*/
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int
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breadn(struct vnode *vp, daddr_t blkno, int size,
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daddr_t *rablkno, int *rabsize,
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int cnt, struct ucred *cred, struct buf **bpp)
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{
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struct buf *bp, *rabp;
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int i;
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int rv = 0, readwait = 0;
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*bpp = bp = getblk (vp, blkno, size, 0, 0);
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/* if not found in cache, do some I/O */
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if ((bp->b_flags & B_CACHE) == 0) {
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if (curproc && curproc->p_stats) /* count block I/O */
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curproc->p_stats->p_ru.ru_inblock++;
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bp->b_flags |= B_READ;
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bp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL);
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if( bp->b_rcred == NOCRED) {
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if (cred != NOCRED)
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crhold(cred);
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bp->b_rcred = cred;
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}
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VOP_STRATEGY(bp);
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++readwait;
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}
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for(i=0;i<cnt;i++, rablkno++, rabsize++) {
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if( incore(vp, *rablkno)) {
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continue;
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}
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rabp = getblk (vp, *rablkno, *rabsize, 0, 0);
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if ((rabp->b_flags & B_CACHE) == 0) {
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if (curproc && curproc->p_stats)
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curproc->p_stats->p_ru.ru_inblock++;
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rabp->b_flags |= B_READ | B_ASYNC;
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rabp->b_flags &= ~(B_DONE|B_ERROR|B_INVAL);
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if( rabp->b_rcred == NOCRED) {
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if (cred != NOCRED)
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crhold(cred);
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rabp->b_rcred = cred;
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}
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VOP_STRATEGY(rabp);
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} else {
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brelse(rabp);
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}
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}
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if( readwait) {
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rv = biowait (bp);
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}
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return (rv);
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}
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/*
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* Write, release buffer on completion. (Done by iodone
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* if async.)
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*/
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int
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bwrite(struct buf *bp)
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{
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int oldflags = bp->b_flags;
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if(bp->b_flags & B_INVAL) {
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brelse(bp);
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return (0);
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}
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if(!(bp->b_flags & B_BUSY))
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panic("bwrite: buffer is not busy???");
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bp->b_flags &= ~(B_READ|B_DONE|B_ERROR|B_DELWRI);
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bp->b_flags |= B_WRITEINPROG;
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if (oldflags & B_ASYNC) {
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if (oldflags & B_DELWRI) {
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reassignbuf(bp, bp->b_vp);
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} else if( curproc) {
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++curproc->p_stats->p_ru.ru_oublock;
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}
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}
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bp->b_vp->v_numoutput++;
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VOP_STRATEGY(bp);
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if( (oldflags & B_ASYNC) == 0) {
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int rtval = biowait(bp);
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if (oldflags & B_DELWRI) {
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reassignbuf(bp, bp->b_vp);
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} else if( curproc) {
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++curproc->p_stats->p_ru.ru_oublock;
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}
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brelse(bp);
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return (rtval);
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}
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return(0);
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}
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int
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vn_bwrite(ap)
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struct vop_bwrite_args *ap;
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{
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return (bwrite(ap->a_bp));
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}
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/*
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* Delayed write. (Buffer is marked dirty).
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*/
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void
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bdwrite(struct buf *bp)
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{
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if((bp->b_flags & B_BUSY) == 0) {
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panic("bdwrite: buffer is not busy");
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}
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if(bp->b_flags & B_INVAL) {
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brelse(bp);
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return;
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}
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if(bp->b_flags & B_TAPE) {
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bawrite(bp);
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return;
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}
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bp->b_flags &= ~B_READ;
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if( (bp->b_flags & B_DELWRI) == 0) {
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if( curproc)
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++curproc->p_stats->p_ru.ru_oublock;
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bp->b_flags |= B_DONE|B_DELWRI;
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reassignbuf(bp, bp->b_vp);
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}
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brelse(bp);
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return;
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}
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/*
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* Asynchronous write.
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* Start output on a buffer, but do not wait for it to complete.
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* The buffer is released when the output completes.
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*/
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void
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bawrite(struct buf *bp)
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{
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bp->b_flags |= B_ASYNC;
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(void) bwrite(bp);
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}
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/*
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* Release a buffer.
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*/
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void
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brelse(struct buf *bp)
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{
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int x;
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/* anyone need a "free" block? */
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x=splbio();
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if (needsbuffer) {
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needsbuffer = 0;
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wakeup((caddr_t)&needsbuffer);
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}
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/* anyone need this block? */
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if (bp->b_flags & B_WANTED) {
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bp->b_flags &= ~(B_WANTED|B_AGE);
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wakeup((caddr_t)bp);
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}
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if (bp->b_flags & B_LOCKED)
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bp->b_flags &= ~B_ERROR;
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if ((bp->b_flags & (B_NOCACHE|B_INVAL|B_ERROR)) ||
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(bp->b_bufsize <= 0)) {
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bp->b_flags |= B_INVAL;
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bp->b_flags &= ~(B_DELWRI|B_CACHE);
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if(bp->b_vp)
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brelvp(bp);
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}
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if( bp->b_qindex != QUEUE_NONE)
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panic("brelse: free buffer onto another queue???");
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/* enqueue */
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/* buffers with no memory */
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if(bp->b_bufsize == 0) {
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bp->b_qindex = QUEUE_EMPTY;
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TAILQ_INSERT_HEAD(&bufqueues[QUEUE_EMPTY], bp, b_freelist);
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LIST_REMOVE(bp, b_hash);
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LIST_INSERT_HEAD(&invalhash, bp, b_hash);
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bp->b_dev = NODEV;
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/* buffers with junk contents */
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} else if(bp->b_flags & (B_ERROR|B_INVAL|B_NOCACHE)) {
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bp->b_qindex = QUEUE_AGE;
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TAILQ_INSERT_HEAD(&bufqueues[QUEUE_AGE], bp, b_freelist);
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LIST_REMOVE(bp, b_hash);
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LIST_INSERT_HEAD(&invalhash, bp, b_hash);
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bp->b_dev = NODEV;
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/* buffers that are locked */
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} else if(bp->b_flags & B_LOCKED) {
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bp->b_qindex = QUEUE_LOCKED;
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TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LOCKED], bp, b_freelist);
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/* buffers with stale but valid contents */
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} else if(bp->b_flags & B_AGE) {
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bp->b_qindex = QUEUE_AGE;
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TAILQ_INSERT_TAIL(&bufqueues[QUEUE_AGE], bp, b_freelist);
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/* buffers with valid and quite potentially reuseable contents */
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} else {
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bp->b_qindex = QUEUE_LRU;
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TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist);
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}
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|
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/* unlock */
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bp->b_flags &= ~(B_WANTED|B_BUSY|B_ASYNC|B_NOCACHE|B_AGE);
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splx(x);
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}
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int freebufspace;
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int allocbufspace;
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/*
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* Find a buffer header which is available for use.
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*/
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struct buf *
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getnewbuf(int slpflag, int slptimeo)
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{
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struct buf *bp;
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int s;
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s = splbio();
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start:
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/* can we constitute a new buffer? */
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if ((bp = bufqueues[QUEUE_EMPTY].tqh_first)) {
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if( bp->b_qindex != QUEUE_EMPTY)
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panic("getnewbuf: inconsistent EMPTY queue");
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bremfree(bp);
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goto fillbuf;
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}
|
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if ((bp = bufqueues[QUEUE_AGE].tqh_first)) {
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if( bp->b_qindex != QUEUE_AGE)
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panic("getnewbuf: inconsistent AGE queue");
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bremfree(bp);
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} else if ((bp = bufqueues[QUEUE_LRU].tqh_first)) {
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if( bp->b_qindex != QUEUE_LRU)
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panic("getnewbuf: inconsistent LRU queue");
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bremfree(bp);
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} else {
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/* wait for a free buffer of any kind */
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needsbuffer = 1;
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tsleep((caddr_t)&needsbuffer, PRIBIO, "newbuf", 0);
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splx(s);
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return (0);
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}
|
|
|
|
|
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/* if we are a delayed write, convert to an async write */
|
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if (bp->b_flags & B_DELWRI) {
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bp->b_flags |= B_BUSY;
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bawrite (bp);
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goto start;
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}
|
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|
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if(bp->b_vp)
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brelvp(bp);
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|
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/* we are not free, nor do we contain interesting data */
|
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if (bp->b_rcred != NOCRED)
|
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crfree(bp->b_rcred);
|
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if (bp->b_wcred != NOCRED)
|
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crfree(bp->b_wcred);
|
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fillbuf:
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bp->b_flags = B_BUSY;
|
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LIST_REMOVE(bp, b_hash);
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LIST_INSERT_HEAD(&invalhash, bp, b_hash);
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splx(s);
|
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bp->b_dev = NODEV;
|
|
bp->b_vp = NULL;
|
|
bp->b_blkno = bp->b_lblkno = 0;
|
|
bp->b_iodone = 0;
|
|
bp->b_error = 0;
|
|
bp->b_resid = 0;
|
|
bp->b_bcount = 0;
|
|
bp->b_wcred = bp->b_rcred = NOCRED;
|
|
bp->b_dirtyoff = bp->b_dirtyend = 0;
|
|
bp->b_validoff = bp->b_validend = 0;
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* Check to see if a block is currently memory resident.
|
|
*/
|
|
struct buf *
|
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incore(struct vnode *vp, daddr_t blkno)
|
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{
|
|
struct buf *bp;
|
|
struct bufhashhdr *bh;
|
|
|
|
int s = splbio();
|
|
|
|
bh = BUFHASH(vp, blkno);
|
|
bp = bh->lh_first;
|
|
|
|
/* Search hash chain */
|
|
while (bp) {
|
|
#ifdef DEBUG
|
|
if( (bp < buf) || (bp >= buf + nbuf)) {
|
|
printf("incore: buf out of range: %p, hash: %d\n",
|
|
bp, bh - bufhashtbl);
|
|
panic("incore: buf fault");
|
|
}
|
|
#endif
|
|
/* hit */
|
|
if (bp->b_lblkno == blkno && bp->b_vp == vp
|
|
&& (bp->b_flags & B_INVAL) == 0) {
|
|
splx(s);
|
|
return (bp);
|
|
}
|
|
bp = bp->b_hash.le_next;
|
|
}
|
|
splx(s);
|
|
|
|
return(0);
|
|
}
|
|
|
|
/*
|
|
* Get a block given a specified block and offset into a file/device.
|
|
*/
|
|
struct buf *
|
|
getblk(struct vnode *vp, daddr_t blkno, int size, int slpflag, int slptimeo)
|
|
{
|
|
struct buf *bp;
|
|
int s;
|
|
struct bufhashhdr *bh;
|
|
|
|
s = splbio();
|
|
loop:
|
|
if ((bp = incore(vp, blkno))) {
|
|
if (bp->b_flags & B_BUSY) {
|
|
bp->b_flags |= B_WANTED;
|
|
tsleep ((caddr_t)bp, PRIBIO, "getblk", 0);
|
|
goto loop;
|
|
}
|
|
bp->b_flags |= B_BUSY | B_CACHE;
|
|
bremfree(bp);
|
|
/*
|
|
* check for size inconsistancies
|
|
*/
|
|
if (bp->b_bcount != size) {
|
|
printf("getblk: invalid buffer size: %ld\n", bp->b_bcount);
|
|
bp->b_flags |= B_INVAL;
|
|
bwrite(bp);
|
|
goto loop;
|
|
}
|
|
} else {
|
|
if ((bp = getnewbuf(0, 0)) == 0)
|
|
goto loop;
|
|
bp->b_blkno = bp->b_lblkno = blkno;
|
|
bgetvp(vp, bp);
|
|
LIST_REMOVE(bp, b_hash);
|
|
bh = BUFHASH(vp, blkno);
|
|
LIST_INSERT_HEAD(bh, bp, b_hash);
|
|
allocbuf(bp, size);
|
|
}
|
|
splx(s);
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* Get an empty, disassociated buffer of given size.
|
|
*/
|
|
struct buf *
|
|
geteblk(int size)
|
|
{
|
|
struct buf *bp;
|
|
while ((bp = getnewbuf(0, 0)) == 0)
|
|
;
|
|
allocbuf(bp, size);
|
|
bp->b_flags |= B_INVAL;
|
|
return (bp);
|
|
}
|
|
|
|
/*
|
|
* Modify the length of a buffer's underlying buffer storage without
|
|
* destroying information (unless, of course the buffer is shrinking).
|
|
*/
|
|
void
|
|
allocbuf(struct buf *bp, int size)
|
|
{
|
|
|
|
int newbsize = round_page(size);
|
|
|
|
if( newbsize == bp->b_bufsize) {
|
|
bp->b_bcount = size;
|
|
return;
|
|
} else if( newbsize < bp->b_bufsize) {
|
|
vm_hold_free_pages(
|
|
(vm_offset_t) bp->b_data + newbsize,
|
|
(vm_offset_t) bp->b_data + bp->b_bufsize);
|
|
} else if( newbsize > bp->b_bufsize) {
|
|
vm_hold_load_pages(
|
|
(vm_offset_t) bp->b_data + bp->b_bufsize,
|
|
(vm_offset_t) bp->b_data + newbsize);
|
|
}
|
|
|
|
/* adjust buffer cache's idea of memory allocated to buffer contents */
|
|
freebufspace -= newbsize - bp->b_bufsize;
|
|
allocbufspace += newbsize - bp->b_bufsize;
|
|
|
|
bp->b_bufsize = newbsize;
|
|
bp->b_bcount = size;
|
|
}
|
|
|
|
/*
|
|
* Wait for buffer I/O completion, returning error status.
|
|
*/
|
|
int
|
|
biowait(register struct buf *bp)
|
|
{
|
|
int s;
|
|
|
|
s = splbio();
|
|
while ((bp->b_flags & B_DONE) == 0)
|
|
tsleep((caddr_t)bp, PRIBIO, "biowait", 0);
|
|
if((bp->b_flags & B_ERROR) || bp->b_error) {
|
|
if ((bp->b_flags & B_INVAL) == 0) {
|
|
bp->b_flags |= B_INVAL;
|
|
bp->b_dev = NODEV;
|
|
LIST_REMOVE(bp, b_hash);
|
|
LIST_INSERT_HEAD(&invalhash, bp, b_hash);
|
|
}
|
|
if (!bp->b_error)
|
|
bp->b_error = EIO;
|
|
else
|
|
bp->b_flags |= B_ERROR;
|
|
splx(s);
|
|
return (bp->b_error);
|
|
} else {
|
|
splx(s);
|
|
return (0);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Finish I/O on a buffer, calling an optional function.
|
|
* This is usually called from interrupt level, so process blocking
|
|
* is not *a good idea*.
|
|
*/
|
|
void
|
|
biodone(register struct buf *bp)
|
|
{
|
|
int s;
|
|
s = splbio();
|
|
bp->b_flags |= B_DONE;
|
|
|
|
if ((bp->b_flags & B_READ) == 0) {
|
|
vwakeup(bp);
|
|
}
|
|
|
|
#ifdef BOUNCE_BUFFERS
|
|
if (bp->b_flags & B_BOUNCE)
|
|
vm_bounce_free(bp);
|
|
#endif
|
|
|
|
/* call optional completion function if requested */
|
|
if (bp->b_flags & B_CALL) {
|
|
bp->b_flags &= ~B_CALL;
|
|
(*bp->b_iodone)(bp);
|
|
splx(s);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* For asynchronous completions, release the buffer now. The brelse
|
|
* checks for B_WANTED and will do the wakeup there if necessary -
|
|
* so no need to do a wakeup here in the async case.
|
|
*/
|
|
|
|
if (bp->b_flags & B_ASYNC) {
|
|
brelse(bp);
|
|
} else {
|
|
bp->b_flags &= ~B_WANTED;
|
|
wakeup((caddr_t) bp);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
int
|
|
count_lock_queue()
|
|
{
|
|
int count;
|
|
struct buf *bp;
|
|
|
|
count = 0;
|
|
for(bp = bufqueues[QUEUE_LOCKED].tqh_first;
|
|
bp != NULL;
|
|
bp = bp->b_freelist.tqe_next)
|
|
count++;
|
|
return(count);
|
|
}
|
|
|
|
int vfs_update_interval = 30;
|
|
|
|
void
|
|
vfs_update() {
|
|
(void) spl0();
|
|
while(1) {
|
|
tsleep((caddr_t)&vfs_update_wakeup, PRIBIO, "update",
|
|
hz * vfs_update_interval);
|
|
vfs_update_wakeup = 0;
|
|
sync(curproc, NULL, NULL);
|
|
}
|
|
}
|
|
|
|
#if 0
|
|
#define MAXFREEBP 128
|
|
#define LDFREE_BUSY 1
|
|
#define LDFREE_WANT 2
|
|
int loadfreeing;
|
|
struct buf *freebp[MAXFREEBP];
|
|
#endif
|
|
/*
|
|
* these routines are not in the correct place (yet)
|
|
* also they work *ONLY* for kernel_pmap!!!
|
|
*/
|
|
void
|
|
vm_hold_load_pages(vm_offset_t froma, vm_offset_t toa) {
|
|
vm_offset_t pg;
|
|
vm_page_t p;
|
|
vm_offset_t from = round_page(froma);
|
|
vm_offset_t to = round_page(toa);
|
|
|
|
for(pg = from ; pg < to ; pg += PAGE_SIZE) {
|
|
|
|
tryagain:
|
|
#if 0
|
|
/*
|
|
* don't allow buffer cache to cause VM paging
|
|
*/
|
|
if ( cnt.v_free_count < cnt.v_free_min) {
|
|
if( !loadfreeing ) {
|
|
int n=0;
|
|
struct buf *bp;
|
|
loadfreeing = LDFREE_BUSY;
|
|
while( (cnt.v_free_count <= cnt.v_free_min) &&
|
|
(n < MAXFREEBP)) {
|
|
bp = geteblk(0);
|
|
if( bp)
|
|
freebp[n++] = bp;
|
|
else
|
|
break;
|
|
}
|
|
while(--n >= 0) {
|
|
brelse(freebp[n]);
|
|
}
|
|
if( loadfreeing & LDFREE_WANT)
|
|
wakeup((caddr_t) &loadfreeing);
|
|
loadfreeing = 0;
|
|
} else {
|
|
loadfreeing |= LDFREE_WANT;
|
|
tsleep(&loadfreeing, PRIBIO, "biofree", 0);
|
|
}
|
|
}
|
|
#endif
|
|
if ((curproc != pageproc) && (cnt.v_free_count <=
|
|
cnt.v_free_reserved + (toa-froma) / PAGE_SIZE)) {
|
|
VM_WAIT;
|
|
goto tryagain;
|
|
}
|
|
|
|
p = vm_page_alloc(kernel_object, pg - VM_MIN_KERNEL_ADDRESS);
|
|
if( !p) {
|
|
VM_WAIT;
|
|
goto tryagain;
|
|
}
|
|
|
|
vm_page_wire(p);
|
|
pmap_kenter( pg, VM_PAGE_TO_PHYS(p));
|
|
}
|
|
}
|
|
|
|
void
|
|
vm_hold_free_pages(vm_offset_t froma, vm_offset_t toa)
|
|
{
|
|
vm_offset_t pg;
|
|
vm_page_t p;
|
|
vm_offset_t from = round_page(froma);
|
|
vm_offset_t to = round_page(toa);
|
|
|
|
for(pg = from ; pg < to ; pg += PAGE_SIZE) {
|
|
p = PHYS_TO_VM_PAGE( pmap_kextract( pg));
|
|
pmap_kremove( pg);
|
|
vm_page_free(p);
|
|
}
|
|
}
|
|
|
|
void
|
|
bufstats()
|
|
{
|
|
}
|
|
|