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 | |