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
cd9660_bmap(void * v)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