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63e4f22a2a
DE_UPDATE was confused with DE_MODIFIED in some places (they do have confusing names). Handle them exactly the same as IN_UPDATE and IN_MODIFIED. This fixes chmod() and chown() clobbering the mtime and other bugs. DE_MODIFIED was set but not used. Parenthesize macro args. DE_TIMES() now takes a timeval arg instead of a timespec arg. It was stupid to use a macro for speed and do unused conversions to prepare for the macro. Restore the left shifting of the DOS seconds count by 1. It got lost among the shifts for the bitfields, so DOS seconds counts appeared to range from 0 to 29 seconds (step 1) instead of 0 to 58 seconds (step 2). Actually use the passed-in mtime in deupdat() as documented so that utimes() works. Change `extern __inline's to `static inline's so that msdosfs_fat.o can be linked when it is compiled without -O. Remove faking of directory mtimes to always be the current time. It's more surprising for directory mtimes to change when you read the directories than for them not to change when you write the directories. This should be controlled by a mount-time option if at all.
985 lines
24 KiB
C
985 lines
24 KiB
C
/* $Id: msdosfs_fat.c,v 1.3 1994/10/10 07:57:33 phk Exp $ */
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/* $NetBSD: msdosfs_fat.c,v 1.12 1994/08/21 18:44:04 ws Exp $ */
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/*-
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* Copyright (C) 1994 Wolfgang Solfrank.
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* Copyright (C) 1994 TooLs GmbH.
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* All rights reserved.
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* Original code by Paul Popelka (paulp@uts.amdahl.com) (see below).
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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 TooLs GmbH.
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* 4. The name of TooLs GmbH may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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* Written by Paul Popelka (paulp@uts.amdahl.com)
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*
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* You can do anything you want with this software, just don't say you wrote
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* it, and don't remove this notice.
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*
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* This software is provided "as is".
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*
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* The author supplies this software to be publicly redistributed on the
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* understanding that the author is not responsible for the correct
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* functioning of this software in any circumstances and is not liable for
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* any damages caused by this software.
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*
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* October 1992
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*/
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/*
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* kernel include files.
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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/buf.h>
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#include <sys/file.h>
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#include <sys/namei.h>
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#include <sys/mount.h> /* to define statfs structure */
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#include <sys/vnode.h> /* to define vattr structure */
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#include <sys/errno.h>
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/*
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* msdosfs include files.
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*/
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#include <msdosfs/bpb.h>
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#include <msdosfs/msdosfsmount.h>
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#include <msdosfs/direntry.h>
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#include <msdosfs/denode.h>
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#include <msdosfs/fat.h>
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/*
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* Fat cache stats.
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*/
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int fc_fileextends; /* # of file extends */
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int fc_lfcempty; /* # of time last file cluster cache entry
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* was empty */
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int fc_bmapcalls; /* # of times pcbmap was called */
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#define LMMAX 20
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int fc_lmdistance[LMMAX]; /* counters for how far off the last
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* cluster mapped entry was. */
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int fc_largedistance; /* off by more than LMMAX */
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/* Byte offset in FAT on filesystem pmp, cluster cn */
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#define FATOFS(pmp, cn) (FAT12(pmp) ? (cn) * 3 / 2 : (cn) * 2)
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static void
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fatblock(pmp, ofs, bnp, sizep, bop)
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struct msdosfsmount *pmp;
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u_long ofs;
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u_long *bnp;
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u_long *sizep;
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u_long *bop;
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{
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u_long bn, size;
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bn = ofs / pmp->pm_fatblocksize * pmp->pm_fatblocksec;
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size = min(pmp->pm_fatblocksec, pmp->pm_FATsecs - bn)
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* pmp->pm_BytesPerSec;
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bn += pmp->pm_fatblk;
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if (bnp)
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*bnp = bn;
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if (sizep)
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*sizep = size;
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if (bop)
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*bop = ofs % pmp->pm_fatblocksize;
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}
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/*
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* Map the logical cluster number of a file into a physical disk sector
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* that is filesystem relative.
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*
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* dep - address of denode representing the file of interest
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* findcn - file relative cluster whose filesystem relative cluster number
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* and/or block number are/is to be found
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* bnp - address of where to place the file system relative block number.
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* If this pointer is null then don't return this quantity.
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* cnp - address of where to place the file system relative cluster number.
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* If this pointer is null then don't return this quantity.
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*
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* NOTE: Either bnp or cnp must be non-null.
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* This function has one side effect. If the requested file relative cluster
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* is beyond the end of file, then the actual number of clusters in the file
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* is returned in *cnp. This is useful for determining how long a directory is.
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* If cnp is null, nothing is returned.
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*/
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int
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pcbmap(dep, findcn, bnp, cnp)
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struct denode *dep;
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u_long findcn; /* file relative cluster to get */
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daddr_t *bnp; /* returned filesys relative blk number */
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u_long *cnp; /* returned cluster number */
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{
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int error;
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u_long i;
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u_long cn;
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u_long prevcn;
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u_long byteoffset;
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u_long bn;
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u_long bo;
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struct buf *bp = NULL;
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u_long bp_bn = -1;
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struct msdosfsmount *pmp = dep->de_pmp;
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u_long bsize;
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int fat12 = FAT12(pmp); /* 12 bit fat */
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fc_bmapcalls++;
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/*
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* If they don't give us someplace to return a value then don't
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* bother doing anything.
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*/
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if (bnp == NULL && cnp == NULL)
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return 0;
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cn = dep->de_StartCluster;
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/*
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* The "file" that makes up the root directory is contiguous,
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* permanently allocated, of fixed size, and is not made up of
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* clusters. If the cluster number is beyond the end of the root
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* directory, then return the number of clusters in the file.
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*/
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if (cn == MSDOSFSROOT) {
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if (dep->de_Attributes & ATTR_DIRECTORY) {
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if (findcn * pmp->pm_SectPerClust > pmp->pm_rootdirsize) {
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if (cnp)
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*cnp = pmp->pm_rootdirsize / pmp->pm_SectPerClust;
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return E2BIG;
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}
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if (bnp)
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*bnp = pmp->pm_rootdirblk + (findcn * pmp->pm_SectPerClust);
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if (cnp)
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*cnp = MSDOSFSROOT;
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return 0;
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} else { /* just an empty file */
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if (cnp)
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*cnp = 0;
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return E2BIG;
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}
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}
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/*
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* Rummage around in the fat cache, maybe we can avoid tromping
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* thru every fat entry for the file. And, keep track of how far
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* off the cache was from where we wanted to be.
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*/
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i = 0;
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fc_lookup(dep, findcn, &i, &cn);
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if ((bn = findcn - i) >= LMMAX)
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fc_largedistance++;
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else
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fc_lmdistance[bn]++;
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/*
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* Handle all other files or directories the normal way.
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*/
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prevcn = 0;
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for (; i < findcn; i++) {
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if (MSDOSFSEOF(cn))
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goto hiteof;
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byteoffset = FATOFS(pmp, cn);
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fatblock(pmp, byteoffset, &bn, &bsize, &bo);
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if (bn != bp_bn) {
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if (bp)
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brelse(bp);
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error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
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if (error)
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return error;
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bp_bn = bn;
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}
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prevcn = cn;
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cn = getushort(&bp->b_data[bo]);
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if (fat12) {
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if (prevcn & 1)
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cn >>= 4;
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cn &= 0x0fff;
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/*
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* Force the special cluster numbers in the range
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* 0x0ff0-0x0fff to be the same as for 16 bit
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* cluster numbers to let the rest of msdosfs think
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* it is always dealing with 16 bit fats.
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*/
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if ((cn & 0x0ff0) == 0x0ff0)
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cn |= 0xf000;
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}
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}
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if (!MSDOSFSEOF(cn)) {
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if (bp)
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brelse(bp);
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if (bnp)
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*bnp = cntobn(pmp, cn);
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if (cnp)
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*cnp = cn;
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fc_setcache(dep, FC_LASTMAP, i, cn);
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return 0;
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}
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hiteof:;
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if (cnp)
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*cnp = i;
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if (bp)
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brelse(bp);
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/* update last file cluster entry in the fat cache */
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fc_setcache(dep, FC_LASTFC, i - 1, prevcn);
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return E2BIG;
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}
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/*
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* Find the closest entry in the fat cache to the cluster we are looking
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* for.
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*/
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void
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fc_lookup(dep, findcn, frcnp, fsrcnp)
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struct denode *dep;
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u_long findcn;
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u_long *frcnp;
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u_long *fsrcnp;
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{
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int i;
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u_long cn;
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struct fatcache *closest = 0;
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for (i = 0; i < FC_SIZE; i++) {
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cn = dep->de_fc[i].fc_frcn;
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if (cn != FCE_EMPTY && cn <= findcn) {
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if (closest == 0 || cn > closest->fc_frcn)
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closest = &dep->de_fc[i];
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}
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}
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if (closest) {
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*frcnp = closest->fc_frcn;
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*fsrcnp = closest->fc_fsrcn;
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}
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}
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/*
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* Purge the fat cache in denode dep of all entries relating to file
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* relative cluster frcn and beyond.
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*/
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void fc_purge(dep, frcn)
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struct denode *dep;
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u_int frcn;
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{
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int i;
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struct fatcache *fcp;
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fcp = dep->de_fc;
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for (i = 0; i < FC_SIZE; i++, fcp++) {
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if (fcp->fc_frcn >= frcn)
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fcp->fc_frcn = FCE_EMPTY;
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}
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}
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/*
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* Update all copies of the fat. The first copy is updated last.
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*
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* pmp - msdosfsmount structure for filesystem to update
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* bp - addr of modified fat block
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* fatbn - block number relative to begin of filesystem of the modified fat block.
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*/
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void
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updatefats(pmp, bp, fatbn)
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struct msdosfsmount *pmp;
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struct buf *bp;
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u_long fatbn;
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{
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int i;
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struct buf *bpn;
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#ifdef MSDOSFS_DEBUG
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printf("updatefats(pmp %p, bp %p, fatbn %ld)\n", pmp, bp, fatbn);
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#endif
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/*
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* Now copy the block(s) of the modified fat to the other copies of
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* the fat and write them out. This is faster than reading in the
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* other fats and then writing them back out. This could tie up
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* the fat for quite a while. Preventing others from accessing it.
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* To prevent us from going after the fat quite so much we use
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* delayed writes, unless they specfied "synchronous" when the
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* filesystem was mounted. If synch is asked for then use
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* bwrite()'s and really slow things down.
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*/
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for (i = 1; i < pmp->pm_FATs; i++) {
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fatbn += pmp->pm_FATsecs;
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/* getblk() never fails */
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bpn = getblk(pmp->pm_devvp, fatbn, bp->b_bcount, 0, 0);
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bcopy(bp->b_data, bpn->b_data, bp->b_bcount);
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if (pmp->pm_waitonfat)
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bwrite(bpn);
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else
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bdwrite(bpn);
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}
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/*
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* Write out the first fat last.
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*/
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if (pmp->pm_waitonfat)
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bwrite(bp);
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else
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bdwrite(bp);
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}
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/*
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* Updating entries in 12 bit fats is a pain in the butt.
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*
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* The following picture shows where nibbles go when moving from a 12 bit
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* cluster number into the appropriate bytes in the FAT.
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*
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* byte m byte m+1 byte m+2
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* +----+----+ +----+----+ +----+----+
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* | 0 1 | | 2 3 | | 4 5 | FAT bytes
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* +----+----+ +----+----+ +----+----+
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*
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* +----+----+----+ +----+----+----+
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* | 3 0 1 | | 4 5 2 |
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* +----+----+----+ +----+----+----+
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* cluster n cluster n+1
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*
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* Where n is even. m = n + (n >> 2)
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*
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*/
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static inline void
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usemap_alloc(pmp, cn)
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struct msdosfsmount *pmp;
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u_long cn;
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{
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pmp->pm_inusemap[cn / N_INUSEBITS]
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|= 1 << (cn % N_INUSEBITS);
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pmp->pm_freeclustercount--;
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}
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static inline void
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usemap_free(pmp, cn)
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struct msdosfsmount *pmp;
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u_long cn;
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{
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pmp->pm_freeclustercount++;
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pmp->pm_inusemap[cn / N_INUSEBITS] &= ~(1 << (cn % N_INUSEBITS));
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}
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int
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clusterfree(pmp, cluster, oldcnp)
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struct msdosfsmount *pmp;
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u_long cluster;
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u_long *oldcnp;
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{
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int error;
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u_long oldcn;
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error = fatentry(FAT_GET_AND_SET, pmp, cluster, &oldcn, MSDOSFSFREE);
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if (error == 0) {
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/*
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* If the cluster was successfully marked free, then update
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* the count of free clusters, and turn off the "allocated"
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* bit in the "in use" cluster bit map.
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*/
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usemap_free(pmp, cluster);
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if (oldcnp)
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*oldcnp = oldcn;
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}
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return error;
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}
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/*
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* Get or Set or 'Get and Set' the cluster'th entry in the fat.
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*
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* function - whether to get or set a fat entry
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* pmp - address of the msdosfsmount structure for the filesystem
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* whose fat is to be manipulated.
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* cn - which cluster is of interest
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* oldcontents - address of a word that is to receive the contents of the
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* cluster'th entry if this is a get function
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* newcontents - the new value to be written into the cluster'th element of
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* the fat if this is a set function.
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*
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* This function can also be used to free a cluster by setting the fat entry
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* for a cluster to 0.
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*
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* All copies of the fat are updated if this is a set function. NOTE: If
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* fatentry() marks a cluster as free it does not update the inusemap in
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* the msdosfsmount structure. This is left to the caller.
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*/
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int
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fatentry(function, pmp, cn, oldcontents, newcontents)
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int function;
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struct msdosfsmount *pmp;
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u_long cn;
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u_long *oldcontents;
|
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u_long newcontents;
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{
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int error;
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u_long readcn;
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u_long bn, bo, bsize, byteoffset;
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struct buf *bp;
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|
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/*
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* printf("fatentry(func %d, pmp %08x, clust %d, oldcon %08x, newcon %d)\n",
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* function, pmp, cluster, oldcontents, newcontents);
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*/
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|
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#ifdef DIAGNOSTIC
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/*
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* Be sure they asked us to do something.
|
|
*/
|
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if ((function & (FAT_SET | FAT_GET)) == 0) {
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printf("fatentry(): function code doesn't specify get or set\n");
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return EINVAL;
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}
|
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|
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/*
|
|
* If they asked us to return a cluster number but didn't tell us
|
|
* where to put it, give them an error.
|
|
*/
|
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if ((function & FAT_GET) && oldcontents == NULL) {
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printf("fatentry(): get function with no place to put result\n");
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return EINVAL;
|
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}
|
|
#endif
|
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|
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/*
|
|
* Be sure the requested cluster is in the filesystem.
|
|
*/
|
|
if (cn < CLUST_FIRST || cn > pmp->pm_maxcluster)
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return EINVAL;
|
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|
|
byteoffset = FATOFS(pmp, cn);
|
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fatblock(pmp, byteoffset, &bn, &bsize, &bo);
|
|
error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
|
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if (error)
|
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return error;
|
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|
|
if (function & FAT_GET) {
|
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readcn = getushort(&bp->b_data[bo]);
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if (FAT12(pmp)) {
|
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if (cn & 1)
|
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readcn >>= 4;
|
|
readcn &= 0x0fff;
|
|
/* map certain 12 bit fat entries to 16 bit */
|
|
if ((readcn & 0x0ff0) == 0x0ff0)
|
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readcn |= 0xf000;
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}
|
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*oldcontents = readcn;
|
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}
|
|
if (function & FAT_SET) {
|
|
if (FAT12(pmp)) {
|
|
readcn = getushort(&bp->b_data[bo]);
|
|
if (cn & 1) {
|
|
readcn &= 0x000f;
|
|
readcn |= newcontents << 4;
|
|
} else {
|
|
readcn &= 0xf000;
|
|
readcn |= newcontents & 0xfff;
|
|
}
|
|
putushort(&bp->b_data[bo], readcn);
|
|
} else
|
|
putushort(&bp->b_data[bo], newcontents);
|
|
updatefats(pmp, bp, bn);
|
|
bp = NULL;
|
|
pmp->pm_fmod = 1;
|
|
}
|
|
if (bp)
|
|
brelse(bp);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Update a contiguous cluster chain
|
|
*
|
|
* pmp - mount point
|
|
* start - first cluster of chain
|
|
* count - number of clusters in chain
|
|
* fillwith - what to write into fat entry of last cluster
|
|
*/
|
|
static int
|
|
fatchain(pmp, start, count, fillwith)
|
|
struct msdosfsmount *pmp;
|
|
u_long start;
|
|
u_long count;
|
|
u_long fillwith;
|
|
{
|
|
int error;
|
|
u_long bn, bo, bsize, byteoffset, readcn, newc;
|
|
struct buf *bp;
|
|
|
|
#ifdef MSDOSFS_DEBUG
|
|
printf("fatchain(pmp %p, start %ld, count %ld, fillwith %ld)\n",
|
|
pmp, start, count, fillwith);
|
|
#endif
|
|
/*
|
|
* Be sure the clusters are in the filesystem.
|
|
*/
|
|
if (start < CLUST_FIRST || start + count - 1 > pmp->pm_maxcluster)
|
|
return EINVAL;
|
|
|
|
while (count > 0) {
|
|
byteoffset = FATOFS(pmp, start);
|
|
fatblock(pmp, byteoffset, &bn, &bsize, &bo);
|
|
error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
|
|
if (error)
|
|
return error;
|
|
while (count > 0) {
|
|
start++;
|
|
newc = --count > 0 ? start : fillwith;
|
|
if (FAT12(pmp)) {
|
|
readcn = getushort(&bp->b_data[bo]);
|
|
if (start & 1) {
|
|
readcn &= 0xf000;
|
|
readcn |= newc & 0xfff;
|
|
} else {
|
|
readcn &= 0x000f;
|
|
readcn |= newc << 4;
|
|
}
|
|
putushort(&bp->b_data[bo], readcn);
|
|
bo++;
|
|
if (!(start & 1))
|
|
bo++;
|
|
} else {
|
|
putushort(&bp->b_data[bo], newc);
|
|
bo += 2;
|
|
}
|
|
if (bo >= bsize)
|
|
break;
|
|
}
|
|
updatefats(pmp, bp, bn);
|
|
}
|
|
pmp->pm_fmod = 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Check the length of a free cluster chain starting at start.
|
|
*
|
|
* pmp - mount point
|
|
* start - start of chain
|
|
* count - maximum interesting length
|
|
*/
|
|
int
|
|
chainlength(pmp, start, count)
|
|
struct msdosfsmount *pmp;
|
|
u_long start;
|
|
u_long count;
|
|
{
|
|
u_long idx, max_idx;
|
|
u_int map;
|
|
u_long len;
|
|
|
|
max_idx = pmp->pm_maxcluster / N_INUSEBITS;
|
|
idx = start / N_INUSEBITS;
|
|
start %= N_INUSEBITS;
|
|
map = pmp->pm_inusemap[idx];
|
|
map &= ~((1 << start) - 1);
|
|
if (map) {
|
|
len = ffs(map) - 1 - start;
|
|
return len > count ? count : len;
|
|
}
|
|
len = N_INUSEBITS - start;
|
|
if (len >= count)
|
|
return count;
|
|
while (++idx <= max_idx) {
|
|
if (len >= count)
|
|
break;
|
|
map = pmp->pm_inusemap[idx];
|
|
if (map) {
|
|
len += ffs(map) - 1;
|
|
break;
|
|
}
|
|
len += N_INUSEBITS;
|
|
}
|
|
return len > count ? count : len;
|
|
}
|
|
|
|
/*
|
|
* Allocate contigous free clusters.
|
|
*
|
|
* pmp - mount point.
|
|
* start - start of cluster chain.
|
|
* count - number of clusters to allocate.
|
|
* fillwith - put this value into the fat entry for the
|
|
* last allocated cluster.
|
|
* retcluster - put the first allocated cluster's number here.
|
|
* got - how many clusters were actually allocated.
|
|
*/
|
|
int
|
|
chainalloc(pmp, start, count, fillwith, retcluster, got)
|
|
struct msdosfsmount *pmp;
|
|
u_long start;
|
|
u_long count;
|
|
u_long fillwith;
|
|
u_long *retcluster;
|
|
u_long *got;
|
|
{
|
|
int error;
|
|
|
|
error = fatchain(pmp, start, count, fillwith);
|
|
if (error == 0) {
|
|
#ifdef MSDOSFS_DEBUG
|
|
printf("clusteralloc(): allocated cluster chain at %ld (%ld clusters)\n",
|
|
start, count);
|
|
#endif
|
|
if (retcluster)
|
|
*retcluster = start;
|
|
if (got)
|
|
*got = count;
|
|
while (count-- > 0)
|
|
usemap_alloc(pmp, start++);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Allocate contiguous free clusters.
|
|
*
|
|
* pmp - mount point.
|
|
* start - preferred start of cluster chain.
|
|
* count - number of clusters requested.
|
|
* fillwith - put this value into the fat entry for the
|
|
* last allocated cluster.
|
|
* retcluster - put the first allocated cluster's number here.
|
|
* got - how many clusters were actually allocated.
|
|
*/
|
|
int
|
|
clusteralloc(pmp, start, count, fillwith, retcluster, got)
|
|
struct msdosfsmount *pmp;
|
|
u_long start;
|
|
u_long count;
|
|
u_long fillwith;
|
|
u_long *retcluster;
|
|
u_long *got;
|
|
{
|
|
u_long idx;
|
|
u_long len, newst, foundcn, foundl, cn, l;
|
|
u_int map;
|
|
|
|
#ifdef MSDOSFS_DEBUG
|
|
printf("clusteralloc(): find %d clusters\n",count);
|
|
#endif
|
|
if (start) {
|
|
if ((len = chainlength(pmp, start, count)) >= count)
|
|
return chainalloc(pmp, start, count, fillwith, retcluster, got);
|
|
} else {
|
|
/*
|
|
* This is a new file, initialize start
|
|
*/
|
|
struct timeval tv;
|
|
|
|
microtime(&tv);
|
|
start = (tv.tv_usec >> 10)|tv.tv_usec;
|
|
len = 0;
|
|
}
|
|
|
|
/*
|
|
* Start at a (pseudo) random place to maximize cluster runs
|
|
* under multiple writers.
|
|
*/
|
|
foundcn = newst = (start * 1103515245 + 12345) % (pmp->pm_maxcluster + 1);
|
|
foundl = 0;
|
|
|
|
for (cn = newst; cn <= pmp->pm_maxcluster;) {
|
|
idx = cn / N_INUSEBITS;
|
|
map = pmp->pm_inusemap[idx];
|
|
map |= (1 << (cn % N_INUSEBITS)) - 1;
|
|
if (map != (u_int)-1) {
|
|
cn = idx * N_INUSEBITS + ffs(map^(u_int)-1) - 1;
|
|
if ((l = chainlength(pmp, cn, count)) >= count)
|
|
return chainalloc(pmp, cn, count, fillwith, retcluster, got);
|
|
if (l > foundl) {
|
|
foundcn = cn;
|
|
foundl = l;
|
|
}
|
|
cn += l + 1;
|
|
continue;
|
|
}
|
|
cn += N_INUSEBITS - cn % N_INUSEBITS;
|
|
}
|
|
for (cn = 0; cn < newst;) {
|
|
idx = cn / N_INUSEBITS;
|
|
map = pmp->pm_inusemap[idx];
|
|
map |= (1 << (cn % N_INUSEBITS)) - 1;
|
|
if (map != (u_int)-1) {
|
|
cn = idx * N_INUSEBITS + ffs(map^(u_int)-1) - 1;
|
|
if ((l = chainlength(pmp, cn, count)) >= count)
|
|
return chainalloc(pmp, cn, count, fillwith, retcluster, got);
|
|
if (l > foundl) {
|
|
foundcn = cn;
|
|
foundl = l;
|
|
}
|
|
cn += l + 1;
|
|
continue;
|
|
}
|
|
cn += N_INUSEBITS - cn % N_INUSEBITS;
|
|
}
|
|
|
|
if (!foundl)
|
|
return ENOSPC;
|
|
|
|
if (len)
|
|
return chainalloc(pmp, start, len, fillwith, retcluster, got);
|
|
else
|
|
return chainalloc(pmp, foundcn, foundl, fillwith, retcluster, got);
|
|
}
|
|
|
|
|
|
/*
|
|
* Free a chain of clusters.
|
|
*
|
|
* pmp - address of the msdosfs mount structure for the filesystem
|
|
* containing the cluster chain to be freed.
|
|
* startcluster - number of the 1st cluster in the chain of clusters to be
|
|
* freed.
|
|
*/
|
|
int
|
|
freeclusterchain(pmp, cluster)
|
|
struct msdosfsmount *pmp;
|
|
u_long cluster;
|
|
{
|
|
int error = 0;
|
|
struct buf *bp = NULL;
|
|
u_long bn, bo, bsize, byteoffset;
|
|
u_long readcn, lbn = -1;
|
|
|
|
while (cluster >= CLUST_FIRST && cluster <= pmp->pm_maxcluster) {
|
|
byteoffset = FATOFS(pmp, cluster);
|
|
fatblock(pmp, byteoffset, &bn, &bsize, &bo);
|
|
if (lbn != bn) {
|
|
if (bp)
|
|
updatefats(pmp, bp, bn);
|
|
error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
|
|
if (error)
|
|
return error;
|
|
lbn = bn;
|
|
}
|
|
usemap_free(pmp, cluster);
|
|
readcn = getushort(&bp->b_data[bo]);
|
|
if (FAT12(pmp)) {
|
|
if (cluster & 1) {
|
|
cluster = readcn >> 4;
|
|
readcn &= 0x000f;
|
|
readcn |= MSDOSFSFREE << 4;
|
|
} else {
|
|
cluster = readcn;
|
|
readcn &= 0xf000;
|
|
readcn |= MSDOSFSFREE & 0xfff;
|
|
}
|
|
putushort(&bp->b_data[bo], readcn);
|
|
cluster &= 0x0fff;
|
|
if ((cluster&0x0ff0) == 0x0ff0)
|
|
cluster |= 0xf000;
|
|
} else {
|
|
cluster = readcn;
|
|
putushort(&bp->b_data[bo], MSDOSFSFREE);
|
|
}
|
|
}
|
|
if (bp)
|
|
updatefats(pmp, bp, bn);
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Read in fat blocks looking for free clusters. For every free cluster
|
|
* found turn off its corresponding bit in the pm_inusemap.
|
|
*/
|
|
int
|
|
fillinusemap(pmp)
|
|
struct msdosfsmount *pmp;
|
|
{
|
|
struct buf *bp = NULL;
|
|
u_long cn, readcn;
|
|
int error;
|
|
int fat12 = FAT12(pmp);
|
|
u_long bn, bo, bsize, byteoffset;
|
|
|
|
/*
|
|
* Mark all clusters in use, we mark the free ones in the fat scan
|
|
* loop further down.
|
|
*/
|
|
for (cn = 0; cn < (pmp->pm_maxcluster + N_INUSEBITS) / N_INUSEBITS; cn++)
|
|
pmp->pm_inusemap[cn] = (u_int)-1;
|
|
|
|
/*
|
|
* Figure how many free clusters are in the filesystem by ripping
|
|
* through the fat counting the number of entries whose content is
|
|
* zero. These represent free clusters.
|
|
*/
|
|
pmp->pm_freeclustercount = 0;
|
|
for (cn = CLUST_FIRST; cn <= pmp->pm_maxcluster; cn++) {
|
|
byteoffset = FATOFS(pmp, cn);
|
|
bo = byteoffset % pmp->pm_fatblocksize;
|
|
if (!bo || !bp) {
|
|
/* Read new FAT block */
|
|
if (bp)
|
|
brelse(bp);
|
|
fatblock(pmp, byteoffset, &bn, &bsize, NULL);
|
|
error = bread(pmp->pm_devvp, bn, bsize, NOCRED, &bp);
|
|
if (error)
|
|
return error;
|
|
}
|
|
readcn = getushort(&bp->b_data[bo]);
|
|
if (fat12) {
|
|
if (cn & 1)
|
|
readcn >>= 4;
|
|
readcn &= 0x0fff;
|
|
}
|
|
|
|
if (readcn == 0)
|
|
usemap_free(pmp, cn);
|
|
}
|
|
brelse(bp);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Allocate a new cluster and chain it onto the end of the file.
|
|
*
|
|
* dep - the file to extend
|
|
* count - number of clusters to allocate
|
|
* bpp - where to return the address of the buf header for the first new
|
|
* file block
|
|
* ncp - where to put cluster number of the first newly allocated cluster
|
|
* If this pointer is 0, do not return the cluster number.
|
|
* flags - see fat.h
|
|
*
|
|
* NOTE: This function is not responsible for turning on the DE_UPDATE bit of
|
|
* the de_flag field of the denode and it does not change the de_FileSize
|
|
* field. This is left for the caller to do.
|
|
*/
|
|
int
|
|
extendfile(dep, count, bpp, ncp, flags)
|
|
struct denode *dep;
|
|
u_long count;
|
|
struct buf **bpp;
|
|
u_long *ncp;
|
|
int flags;
|
|
{
|
|
int error = 0;
|
|
u_long frcn;
|
|
u_long cn, got;
|
|
struct msdosfsmount *pmp = dep->de_pmp;
|
|
struct buf *bp;
|
|
|
|
/*
|
|
* Don't try to extend the root directory
|
|
*/
|
|
if (DETOV(dep)->v_flag & VROOT) {
|
|
printf("extendfile(): attempt to extend root directory\n");
|
|
return ENOSPC;
|
|
}
|
|
|
|
/*
|
|
* If the "file's last cluster" cache entry is empty, and the file
|
|
* is not empty, then fill the cache entry by calling pcbmap().
|
|
*/
|
|
fc_fileextends++;
|
|
if (dep->de_fc[FC_LASTFC].fc_frcn == FCE_EMPTY &&
|
|
dep->de_StartCluster != 0) {
|
|
fc_lfcempty++;
|
|
error = pcbmap(dep, 0xffff, 0, &cn);
|
|
/* we expect it to return E2BIG */
|
|
if (error != E2BIG)
|
|
return error;
|
|
error = 0;
|
|
}
|
|
|
|
while (count > 0) {
|
|
/*
|
|
* Allocate a new cluster chain and cat onto the end of the file.
|
|
* If the file is empty we make de_StartCluster point to the new
|
|
* block. Note that de_StartCluster being 0 is sufficient to be
|
|
* sure the file is empty since we exclude attempts to extend the
|
|
* root directory above, and the root dir is the only file with a
|
|
* startcluster of 0 that has blocks allocated (sort of).
|
|
*/
|
|
if (dep->de_StartCluster == 0)
|
|
cn = 0;
|
|
else
|
|
cn = dep->de_fc[FC_LASTFC].fc_fsrcn + 1;
|
|
error = clusteralloc(pmp, cn, count, CLUST_EOFE, &cn, &got);
|
|
if (error)
|
|
return error;
|
|
|
|
count -= got;
|
|
|
|
/*
|
|
* Give them the filesystem relative cluster number if they want
|
|
* it.
|
|
*/
|
|
if (ncp) {
|
|
*ncp = cn;
|
|
ncp = NULL;
|
|
}
|
|
|
|
if (dep->de_StartCluster == 0) {
|
|
dep->de_StartCluster = cn;
|
|
frcn = 0;
|
|
} else {
|
|
error = fatentry(FAT_SET, pmp, dep->de_fc[FC_LASTFC].fc_fsrcn,
|
|
0, cn);
|
|
if (error) {
|
|
clusterfree(pmp, cn, NULL);
|
|
return error;
|
|
}
|
|
|
|
frcn = dep->de_fc[FC_LASTFC].fc_frcn + 1;
|
|
}
|
|
|
|
/*
|
|
* Update the "last cluster of the file" entry in the denode's fat
|
|
* cache.
|
|
*/
|
|
fc_setcache(dep, FC_LASTFC, frcn + got - 1, cn + got - 1);
|
|
|
|
if (flags & DE_CLEAR) {
|
|
while (got-- > 0) {
|
|
/*
|
|
* Get the buf header for the new block of the file.
|
|
*/
|
|
if (dep->de_Attributes & ATTR_DIRECTORY)
|
|
bp = getblk(pmp->pm_devvp, cntobn(pmp, cn++),
|
|
pmp->pm_bpcluster, 0, 0);
|
|
else {
|
|
bp = getblk(DETOV(dep), frcn++, pmp->pm_bpcluster, 0, 0);
|
|
/*
|
|
* Do the bmap now, as in msdosfs_write
|
|
*/
|
|
if (pcbmap(dep, bp->b_lblkno, &bp->b_blkno, 0))
|
|
bp->b_blkno = -1;
|
|
if (bp->b_blkno == -1)
|
|
panic("extendfile: pcbmap");
|
|
}
|
|
clrbuf(bp);
|
|
if (bpp) {
|
|
*bpp = bp;
|
|
bpp = NULL;
|
|
} else {
|
|
bp->b_flags |= B_AGE;
|
|
bawrite(bp);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|