/* $FreeBSD$ */ /* $NetBSD: msdosfs_vnops.c,v 1.68 1998/02/10 14:10:04 mrg Exp $ */ /*- * SPDX-License-Identifier: BSD-4-Clause * * Copyright (C) 1994, 1995, 1997 Wolfgang Solfrank. * Copyright (C) 1994, 1995, 1997 TooLs GmbH. * All rights reserved. * Original code by Paul Popelka (paulp@uts.amdahl.com) (see below). * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by TooLs GmbH. * 4. The name of TooLs GmbH may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /*- * Written by Paul Popelka (paulp@uts.amdahl.com) * * You can do anything you want with this software, just don't say you wrote * it, and don't remove this notice. * * This software is provided "as is". * * The author supplies this software to be publicly redistributed on the * understanding that the author is not responsible for the correct * functioning of this software in any circumstances and is not liable for * any damages caused by this software. * * October 1992 */ // Modified to support the Haiku FAT driver. #include "sys/param.h" #include "sys/systm.h" #include "sys/buf.h" #include "sys/vnode.h" #include "fs/msdosfs/bpb.h" #include "fs/msdosfs/denode.h" #include "fs/msdosfs/direntry.h" #include "fs/msdosfs/fat.h" #include "fs/msdosfs/msdosfsmount.h" int msdosfs_bmap(struct vnode* a_vp, daddr_t a_bn, struct bufobj** a_bop, daddr_t* a_bnp, int* a_runp, int* a_runb); /* * Some general notes: * * In the ufs filesystem the inodes, superblocks, and indirect blocks are * read/written using the vnode for the filesystem. Blocks that represent * the contents of a file are read/written using the vnode for the file * (including directories when they are read/written as files). This * presents problems for the dos filesystem because data that should be in * an inode (if dos had them) resides in the directory itself. Since we * must update directory entries without the benefit of having the vnode * for the directory we must use the vnode for the filesystem. This means * that when a directory is actually read/written (via read, write, or * readdir, or seek) we must use the vnode for the filesystem instead of * the vnode for the directory as would happen in ufs. */ /*! @param a_vp pointer to the file's vnode @param a_bn logical block number within the file (cluster number for us) @param a_bop where to return the bufobj of the special file containing the fs @param a_bnp where to return the "physical" block number corresponding to a_bn (relative to the special file; units are blocks of size DEV_BSIZE) @param a_runp where to return the "run past" a_bn. This is the count of logical blocks whose physical blocks (together with a_bn's physical block) are contiguous. @param a_runb where to return the "run before" a_bn. */ int msdosfs_bmap(struct vnode* a_vp, daddr_t a_bn, struct bufobj** a_bop, daddr_t* a_bnp, int* a_runp, int* a_runb) { struct fatcache savefc; struct denode* dep; struct mount* mp; struct msdosfsmount* pmp; struct vnode* vp; daddr_t runbn; u_long cn; int bnpercn, error, maxio, maxrun, run; vp = a_vp; dep = VTODE(vp); pmp = dep->de_pmp; if (a_bop != NULL) *a_bop = &pmp->pm_devvp->v_bufobj; if (a_bnp == NULL) return 0; if (a_runp != NULL) *a_runp = 0; if (a_runb != NULL) *a_runb = 0; cn = a_bn; if (cn != (u_long)a_bn) return EFBIG; error = pcbmap(dep, cn, a_bnp, NULL, NULL); if (error != 0 || (a_runp == NULL && a_runb == NULL)) return error; /* * Prepare to back out updates of the fatchain cache after the one * for the first block done by pcbmap() above. Without the backout, * then whenever the caller doesn't do i/o to all of the blocks that * we find, the single useful cache entry would be too far in advance * of the actual i/o to work for the next sequential i/o. Then the * FAT would be searched from the beginning. With the backout, the * FAT is searched starting at most a few blocks early. This wastes * much less time. Time is also wasted finding more blocks than the * caller will do i/o to. This is necessary because the runlength * parameters are output-only. */ savefc = dep->de_fc[FC_LASTMAP]; mp = vp->v_mount; maxio = mp->mnt_iosize_max / mp->mnt_stat.f_iosize; bnpercn = de_cn2bn(pmp, 1); if (a_runp != NULL) { maxrun = ulmin(maxio - 1, pmp->pm_maxcluster - cn); for (run = 1; run <= maxrun; run++) { if (pcbmap(dep, cn + run, &runbn, NULL, NULL) != 0 || runbn != *a_bnp + run * bnpercn) break; } *a_runp = run - 1; } if (a_runb != NULL) { maxrun = ulmin(maxio - 1, cn); for (run = 1; run < maxrun; run++) { if (pcbmap(dep, cn - run, &runbn, NULL, NULL) != 0 || runbn != *a_bnp - run * bnpercn) break; } *a_runb = run - 1; } dep->de_fc[FC_LASTMAP] = savefc; return 0; } /* Global vfs data structures for msdosfs */ struct vop_vector msdosfs_vnodeops;
