1 /* $NetBSD: cd9660_bmap.c,v 1.1 2002/12/23 17:52:08 jdolecek 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. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Berkeley and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#)cd9660_bmap.c 8.4 (Berkeley) 12/5/94 41 */ 42 43 #include <sys/cdefs.h> 44 __KERNEL_RCSID(0, "$NetBSD: cd9660_bmap.c,v 1.1 2002/12/23 17:52:08 jdolecek Exp $"); 45 46 #include <sys/param.h> 47 #include <sys/namei.h> 48 #include <sys/buf.h> 49 #include <sys/file.h> 50 #include <sys/vnode.h> 51 #include <sys/mount.h> 52 53 #include <fs/cd9660/iso.h> 54 #include <fs/cd9660/cd9660_extern.h> 55 #include <fs/cd9660/cd9660_node.h> 56 57 /* 58 * Bmap converts a the logical block number of a file to its physical block 59 * number on the disk. The conversion is done by using the logical block 60 * number to index into the data block (extent) for the file. 61 */ 62 int 63 cd9660_bmap(v) 64 void *v; 65 { 66 struct vop_bmap_args /* { 67 struct vnode *a_vp; 68 daddr_t a_bn; 69 struct vnode **a_vpp; 70 daddr_t *a_bnp; 71 int *a_runp; 72 } */ *ap = v; 73 struct iso_node *ip = VTOI(ap->a_vp); 74 daddr_t lblkno = ap->a_bn; 75 int bshift; 76 77 /* 78 * Check for underlying vnode requests and ensure that logical 79 * to physical mapping is requested. 80 */ 81 if (ap->a_vpp != NULL) 82 *ap->a_vpp = ip->i_devvp; 83 if (ap->a_bnp == NULL) 84 return (0); 85 86 /* 87 * Compute the requested block number 88 */ 89 bshift = ip->i_mnt->im_bshift; 90 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT); 91 92 /* 93 * Determine maximum number of readahead blocks following the 94 * requested block. 95 */ 96 if (ap->a_runp) { 97 int nblk; 98 99 nblk = (ip->i_size >> bshift) - (lblkno + 1); 100 if (nblk <= 0) 101 *ap->a_runp = 0; 102 else if (nblk >= (MAXBSIZE >> bshift)) 103 *ap->a_runp = (MAXBSIZE >> bshift) - 1; 104 else 105 *ap->a_runp = nblk; 106 } 107 108 return (0); 109 } 110