| 1 | /* $NetBSD: cd9660_bmap.c,v 1.5 2014/06/14 07:39:28 hannken 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 1.5 2014/06/14 07:39:28 hannken 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(void *v) |
| 60 | { |
| 61 | struct vop_bmap_args /* { |
| 62 | struct vnode *a_vp; |
| 63 | daddr_t a_bn; |
| 64 | struct vnode **a_vpp; |
| 65 | daddr_t *a_bnp; |
| 66 | int *a_runp; |
| 67 | } */ *ap = v; |
| 68 | struct iso_node *ip = VTOI(ap->a_vp); |
| 69 | daddr_t lblkno = ap->a_bn; |
| 70 | int bshift; |
| 71 | |
| 72 | /* |
| 73 | * Check for underlying vnode requests and ensure that logical |
| 74 | * to physical mapping is requested. |
| 75 | */ |
| 76 | if (ap->a_vpp != NULL) |
| 77 | *ap->a_vpp = ip->i_mnt->im_devvp; |
| 78 | if (ap->a_bnp == NULL) |
| 79 | return (0); |
| 80 | |
| 81 | /* |
| 82 | * Compute the requested block number |
| 83 | */ |
| 84 | bshift = ip->i_mnt->im_bshift; |
| 85 | *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT); |
| 86 | |
| 87 | /* |
| 88 | * Determine maximum number of readahead blocks following the |
| 89 | * requested block. |
| 90 | */ |
| 91 | if (ap->a_runp) { |
| 92 | int nblk; |
| 93 | |
| 94 | nblk = (ip->i_size >> bshift) - (lblkno + 1); |
| 95 | if (nblk <= 0) |
| 96 | *ap->a_runp = 0; |
| 97 | else if (nblk >= (MAXBSIZE >> bshift)) |
| 98 | *ap->a_runp = (MAXBSIZE >> bshift) - 1; |
| 99 | else |
| 100 | *ap->a_runp = nblk; |
| 101 | } |
| 102 | |
| 103 | return (0); |
| 104 | } |
| 105 | |