1 /*-
2 * Copyright (c) 1994
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley
6 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension
7 * Support code is derived from software contributed to Berkeley
8 * by Atsushi Murai (amurai@spec.co.jp).
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 4. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 * @(#)cd9660_bmap.c 8.3 (Berkeley) 1/23/94
35 */
36
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD: releng/9.0/sys/fs/cd9660/cd9660_bmap.c 185071 2008-11-18 23:19:43Z jhb $");
39
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/vnode.h>
43 #include <sys/mount.h>
44
45 #include <fs/cd9660/iso.h>
46 #include <fs/cd9660/cd9660_node.h>
47
48 /*
49 * Bmap converts the logical block number of a file to its physical
50 * block number on the disk. The conversion is done by using the
51 * logical block number to index into the data block (extent) for the
52 * file.
53 */
54 int
55 cd9660_bmap(ap)
56 struct vop_bmap_args /* {
57 struct vnode *a_vp;
58 daddr_t a_bn;
59 struct bufobj **a_bop;
60 daddr_t *a_bnp;
61 int *a_runp;
62 int *a_runb;
63 } */ *ap;
64 {
65 struct iso_node *ip = VTOI(ap->a_vp);
66 daddr_t lblkno = ap->a_bn;
67 int bshift;
68
69 /*
70 * Check for underlying vnode requests and ensure that logical
71 * to physical mapping is requested.
72 */
73 if (ap->a_bop != NULL)
74 *ap->a_bop = &ip->i_mnt->im_devvp->v_bufobj;
75 if (ap->a_bnp == NULL)
76 return (0);
77
78 /*
79 * Compute the requested block number
80 */
81 bshift = ip->i_mnt->im_bshift;
82 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT);
83
84 /*
85 * Determine maximum number of readahead blocks following the
86 * requested block.
87 */
88 if (ap->a_runp) {
89 int nblk;
90
91 nblk = (ip->i_size >> bshift) - (lblkno + 1);
92 if (nblk <= 0)
93 *ap->a_runp = 0;
94 else if (nblk >= (MAXBSIZE >> bshift))
95 *ap->a_runp = (MAXBSIZE >> bshift) - 1;
96 else
97 *ap->a_runp = nblk;
98 }
99
100 if (ap->a_runb) {
101 *ap->a_runb = 0;
102 }
103
104 return 0;
105 }
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