1 /* $NetBSD: cd9660_bmap.c,v 1.3 2005/12/11 12:24:25 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley 8 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension 9 * Support code is derived from software contributed to Berkeley 10 * by Atsushi Murai (amurai@spec.co.jp). 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 * 36 * @(#)cd9660_bmap.c 8.4 (Berkeley) 12/5/94 37 */ 38 39 #include <sys/cdefs.h> 40 __KERNEL_RCSID(0, "$NetBSD: cd9660_bmap.c,v 1.3 2005/12/11 12:24:25 christos Exp $"); 41 42 #include <sys/param.h> 43 #include <sys/namei.h> 44 #include <sys/buf.h> 45 #include <sys/file.h> 46 #include <sys/vnode.h> 47 #include <sys/mount.h> 48 49 #include <fs/cd9660/iso.h> 50 #include <fs/cd9660/cd9660_extern.h> 51 #include <fs/cd9660/cd9660_node.h> 52 53 /* 54 * Bmap converts a the logical block number of a file to its physical block 55 * number on the disk. The conversion is done by using the logical block 56 * number to index into the data block (extent) for the file. 57 */ 58 int 59 cd9660_bmap(v) 60 void *v; 61 { 62 struct vop_bmap_args /* { 63 struct vnode *a_vp; 64 daddr_t a_bn; 65 struct vnode **a_vpp; 66 daddr_t *a_bnp; 67 int *a_runp; 68 } */ *ap = v; 69 struct iso_node *ip = VTOI(ap->a_vp); 70 daddr_t lblkno = ap->a_bn; 71 int bshift; 72 73 /* 74 * Check for underlying vnode requests and ensure that logical 75 * to physical mapping is requested. 76 */ 77 if (ap->a_vpp != NULL) 78 *ap->a_vpp = ip->i_devvp; 79 if (ap->a_bnp == NULL) 80 return (0); 81 82 /* 83 * Compute the requested block number 84 */ 85 bshift = ip->i_mnt->im_bshift; 86 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT); 87 88 /* 89 * Determine maximum number of readahead blocks following the 90 * requested block. 91 */ 92 if (ap->a_runp) { 93 int nblk; 94 95 nblk = (ip->i_size >> bshift) - (lblkno + 1); 96 if (nblk <= 0) 97 *ap->a_runp = 0; 98 else if (nblk >= (MAXBSIZE >> bshift)) 99 *ap->a_runp = (MAXBSIZE >> bshift) - 1; 100 else 101 *ap->a_runp = nblk; 102 } 103 104 return (0); 105 } 106