1 /* $OpenBSD: cd9660_bmap.c,v 1.10 2021/03/05 07:01:36 jsg Exp $ */ 2 /* $NetBSD: cd9660_bmap.c,v 1.7 1997/01/24 00:27:29 cgd Exp $ */ 3 4 /*- 5 * Copyright (c) 1994 6 * The Regents of the University of California. All rights reserved. 7 * 8 * This code is derived from software contributed to Berkeley 9 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension 10 * Support code is derived from software contributed to Berkeley 11 * by Atsushi Murai (amurai@spec.co.jp). 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)cd9660_bmap.c 8.4 (Berkeley) 12/5/94 38 */ 39 40 #include <sys/param.h> 41 #include <sys/namei.h> 42 #include <sys/buf.h> 43 #include <sys/vnode.h> 44 #include <sys/lock.h> 45 #include <sys/mount.h> 46 47 #include <isofs/cd9660/iso.h> 48 #include <isofs/cd9660/cd9660_extern.h> 49 #include <isofs/cd9660/cd9660_node.h> 50 51 /* 52 * Bmap converts a the logical block number of a file to its physical block 53 * number on the disk. The conversion is done by using the logical block 54 * number to index into the data block (extent) for the file. 55 */ 56 int 57 cd9660_bmap(void *v) 58 { 59 struct vop_bmap_args *ap = v; 60 struct iso_node *ip = VTOI(ap->a_vp); 61 daddr_t lblkno = ap->a_bn; 62 int bshift; 63 64 /* 65 * Check for underlying vnode requests and ensure that logical 66 * to physical mapping is requested. 67 */ 68 if (ap->a_vpp != NULL) 69 *ap->a_vpp = ip->i_devvp; 70 if (ap->a_bnp == NULL) 71 return (0); 72 73 /* 74 * Compute the requested block number 75 */ 76 bshift = ip->i_mnt->im_bshift; 77 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT); 78 79 /* 80 * Determine maximum number of readahead blocks following the 81 * requested block. 82 */ 83 if (ap->a_runp) { 84 int nblk; 85 86 nblk = (ip->i_size >> bshift) - (lblkno + 1); 87 if (nblk <= 0) 88 *ap->a_runp = 0; 89 else if (nblk >= (MAXBSIZE >> bshift)) 90 *ap->a_runp = (MAXBSIZE >> bshift) - 1; 91 else 92 *ap->a_runp = nblk; 93 } 94 95 return (0); 96 } 97