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79c0c4b77f
vfs_cache.c: Fix a very rare probelm in the vnode-cache. Submitted by: Terry Lambert <terry@lambert.org>
159 lines
4.3 KiB
C
159 lines
4.3 KiB
C
/*-
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* Parts Copyright (c) 1995 Terrence R. Lambert
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* Copyright (c) 1995 Julian R. Elischer
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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, 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 Terrence R. Lambert.
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* 4. The name Terrence R. Lambert may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY
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* 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 TERRENCE R. LAMBERT 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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* $Id: kern_conf.c,v 1.8 1995/12/21 20:09:39 julian Exp $
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*/
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#include <sys/param.h>
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#include <sys/types.h>
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#include <sys/systm.h>
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#include <sys/conf.h>
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#include <sys/vnode.h>
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#define NUMCDEV 96
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#define NUMBDEV 32
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struct bdevsw *bdevsw[NUMBDEV];
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int nblkdev = NUMBDEV;
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struct cdevsw *cdevsw[NUMCDEV];
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int nchrdev = NUMCDEV;
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/*
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* Routine to determine if a device is a disk.
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*
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* KLUDGE XXX add flags to cdevsw entries for disks XXX
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* A minimal stub routine can always return 0.
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*/
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int
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isdisk(dev, type)
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dev_t dev;
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int type;
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{
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switch (major(dev)) {
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case 15: /* VBLK: vn, VCHR: cd */
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return (1);
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case 0: /* wd */
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case 2: /* fd */
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case 4: /* sd */
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case 6: /* cd */
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case 7: /* mcd */
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case 16: /* scd */
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case 17: /* matcd */
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case 18: /* ata */
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case 19: /* wcd */
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case 20: /* od */
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if (type == VBLK)
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return (1);
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return (0);
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case 3: /* wd */
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case 9: /* fd */
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case 13: /* sd */
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case 29: /* mcd */
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case 43: /* vn */
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case 45: /* scd */
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case 46: /* matcd */
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case 69: /* wcd */
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case 70: /* od */
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if (type == VCHR)
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return (1);
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/* fall through */
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default:
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return (0);
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}
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/* NOTREACHED */
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}
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/*
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* Routine to convert from character to block device number.
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*
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* A minimal stub routine can always return NODEV.
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*/
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dev_t
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chrtoblk(dev_t dev)
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{
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struct bdevsw *bd;
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struct cdevsw *cd;
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if(cd = cdevsw[major(dev)]) {
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if ( (bd = cd->d_bdev) )
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return(makedev(bd->d_maj,minor(dev)));
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}
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return(NODEV);
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}
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/*
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* (re)place an entry in the bdevsw or cdevsw table
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* return the slot used in major(*descrip)
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*/
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#define ADDENTRY(TTYPE,NXXXDEV) \
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int TTYPE##_add(dev_t *descrip, \
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struct TTYPE *newentry, \
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struct TTYPE **oldentry) \
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{ \
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int i ; \
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if ( (int)*descrip == -1) { /* auto (0 is valid) */ \
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/* \
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* Search the table looking for a slot... \
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*/ \
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for (i = 0; i < NXXXDEV; i++) \
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if (TTYPE[i] == NULL) \
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break; /* found one! */ \
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/* out of allocable slots? */ \
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if (i == NXXXDEV) { \
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return ENFILE; \
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} \
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} else { /* assign */ \
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i = major(*descrip); \
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if (i < 0 || i >= NXXXDEV) { \
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return EINVAL; \
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} \
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} \
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\
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/* maybe save old */ \
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if (oldentry) { \
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*oldentry = TTYPE[i]; \
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} \
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newentry->d_maj = i; \
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/* replace with new */ \
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TTYPE[i] = newentry; \
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\
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/* done! let them know where we put it */ \
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*descrip = makedev(i,0); \
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return 0; \
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} \
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ADDENTRY(bdevsw, nblkdev)
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ADDENTRY(cdevsw, nchrdev)
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