1 /* $OpenBSD: cd9660_bmap.c,v 1.3 1997/11/08 17:21:05 niklas 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. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)cd9660_bmap.c 8.4 (Berkeley) 12/5/94 42 */ 43 44 #include <sys/param.h> 45 #include <sys/namei.h> 46 #include <sys/buf.h> 47 #include <sys/file.h> 48 #include <sys/vnode.h> 49 #include <sys/mount.h> 50 51 #include <isofs/cd9660/iso.h> 52 #include <isofs/cd9660/cd9660_extern.h> 53 #include <isofs/cd9660/cd9660_node.h> 54 55 /* 56 * Bmap converts a the logical block number of a file to its physical block 57 * number on the disk. The conversion is done by using the logical block 58 * number to index into the data block (extent) for the file. 59 */ 60 int 61 cd9660_bmap(v) 62 void *v; 63 { 64 struct vop_bmap_args /* { 65 struct vnode *a_vp; 66 daddr_t a_bn; 67 struct vnode **a_vpp; 68 daddr_t *a_bnp; 69 int *a_runp; 70 } */ *ap = v; 71 struct iso_node *ip = VTOI(ap->a_vp); 72 daddr_t lblkno = ap->a_bn; 73 int bshift; 74 75 /* 76 * Check for underlying vnode requests and ensure that logical 77 * to physical mapping is requested. 78 */ 79 if (ap->a_vpp != NULL) 80 *ap->a_vpp = ip->i_devvp; 81 if (ap->a_bnp == NULL) 82 return (0); 83 84 /* 85 * Compute the requested block number 86 */ 87 bshift = ip->i_mnt->im_bshift; 88 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT); 89 90 /* 91 * Determine maximum number of readahead blocks following the 92 * requested block. 93 */ 94 if (ap->a_runp) { 95 int nblk; 96 97 nblk = (ip->i_size >> bshift) - (lblkno + 1); 98 if (nblk <= 0) 99 *ap->a_runp = 0; 100 else if (nblk >= (MAXBSIZE >> bshift)) 101 *ap->a_runp = (MAXBSIZE >> bshift) - 1; 102 else 103 *ap->a_runp = nblk; 104 } 105 106 return (0); 107 } 108