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 * 3. 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 * $FreeBSD: src/sys/isofs/cd9660/cd9660_bmap.c,v 1.8 1999/08/28 00:46:06 peter Exp $
36 */
37
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/vnode.h>
41 #include <sys/mount.h>
42
43 #include "iso.h"
44 #include "cd9660_node.h"
45
46 /*
47 * Bmap converts the logical block number of a file to its physical block
48 * number on the disk. The conversion is done by using the logical block
49 * number to index into the data block (extent) for the file.
50 *
51 * cd9660_bmap(struct vnode *a_vp, off_t a_loffset,
52 * off_t *a_doffsetp, int *a_runp, int *a_runb)
53 */
54 int
cd9660_bmap(struct vop_bmap_args * ap)55 cd9660_bmap(struct vop_bmap_args *ap)
56 {
57 struct iso_node *ip = VTOI(ap->a_vp);
58 off_t loffset = ap->a_loffset;
59 int bshift;
60 int bsize;
61
62 /*
63 * Check for underlying vnode requests and ensure that logical
64 * to physical mapping is requested.
65 */
66 if (ap->a_doffsetp == NULL)
67 return (0);
68
69 /*
70 * Compute the requested block number
71 */
72 bshift = ip->i_mnt->im_bshift;
73 bsize = 1 << bshift;
74 *ap->a_doffsetp = loffset + ((off_t)ip->iso_start << bshift);
75
76 KKASSERT((loffset & (bsize - 1)) == 0);
77
78 /*
79 * Determine maximum number of readahead bytes following the
80 * requested offset. Align the result to the nearest block
81 * boundary. Do not count any non-full blocks(?)
82 */
83 if (ap->a_runp) {
84 off_t nbytes;
85
86 nbytes = (off_t)ip->i_size - loffset;
87 if (nbytes < bsize)
88 *ap->a_runp = 0;
89 else if (nbytes > MAXBSIZE)
90 *ap->a_runp = MAXBSIZE;
91 else
92 *ap->a_runp = rounddown2((int)nbytes, bsize);
93 }
94
95 if (ap->a_runb) {
96 *ap->a_runb = 0;
97 }
98
99 return 0;
100 }
101