1 /*- 2 * Copyright (c) 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley 6 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension 7 * Support code is derived from software contributed to Berkeley 8 * by Atsushi Murai (amurai@spec.co.jp). 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)cd9660_bmap.c 8.3 (Berkeley) 1/23/94 39 * $FreeBSD: src/sys/isofs/cd9660/cd9660_bmap.c,v 1.8 1999/08/28 00:46:06 peter Exp $ 40 * $DragonFly: src/sys/vfs/isofs/cd9660/cd9660_bmap.c,v 1.3 2003/08/07 21:17:41 dillon Exp $ 41 */ 42 43 #include <sys/param.h> 44 #include <sys/vnode.h> 45 #include <sys/mount.h> 46 47 #include "iso.h" 48 #include "cd9660_node.h" 49 50 /* 51 * Bmap converts a the logical block number of a file to its physical block 52 * number on the disk. The conversion is done by using the logical block 53 * number to index into the data block (extent) for the file. 54 */ 55 int 56 cd9660_bmap(ap) 57 struct vop_bmap_args /* { 58 struct vnode *a_vp; 59 daddr_t a_bn; 60 struct vnode **a_vpp; 61 daddr_t *a_bnp; 62 int *a_runp; 63 int *a_runb; 64 } */ *ap; 65 { 66 struct iso_node *ip = VTOI(ap->a_vp); 67 daddr_t lblkno = ap->a_bn; 68 int bshift; 69 70 /* 71 * Check for underlying vnode requests and ensure that logical 72 * to physical mapping is requested. 73 */ 74 if (ap->a_vpp != NULL) 75 *ap->a_vpp = ip->i_devvp; 76 if (ap->a_bnp == NULL) 77 return (0); 78 79 /* 80 * Compute the requested block number 81 */ 82 bshift = ip->i_mnt->im_bshift; 83 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT); 84 85 /* 86 * Determine maximum number of readahead blocks following the 87 * requested block. 88 */ 89 if (ap->a_runp) { 90 int nblk; 91 92 nblk = (ip->i_size >> bshift) - (lblkno + 1); 93 if (nblk <= 0) 94 *ap->a_runp = 0; 95 else if (nblk >= (MAXBSIZE >> bshift)) 96 *ap->a_runp = (MAXBSIZE >> bshift) - 1; 97 else 98 *ap->a_runp = nblk; 99 } 100 101 if (ap->a_runb) { 102 *ap->a_runb = 0; 103 } 104 105 return 0; 106 } 107