1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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 ([email protected]). The Rock Ridge Extension
9 * Support code is derived from software contributed to Berkeley
10 * by Atsushi Murai ([email protected]).
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 8.3 (Berkeley) 1/23/94
37 */
38
39 #include <sys/cdefs.h>
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
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 daddr_t lblkno = ap->a_bn;
59 int bshift;
60
61 /*
62 * Check for underlying vnode requests and ensure that logical
63 * to physical mapping is requested.
64 */
65 if (ap->a_bop != NULL)
66 *ap->a_bop = &ip->i_mnt->im_devvp->v_bufobj;
67 if (ap->a_bnp == NULL)
68 return (0);
69
70 /*
71 * Compute the requested block number
72 */
73 bshift = ip->i_mnt->im_bshift;
74 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT);
75
76 /*
77 * Determine maximum number of readahead blocks following the
78 * requested block.
79 */
80 if (ap->a_runp) {
81 int nblk;
82
83 nblk = (ip->i_size >> bshift) - (lblkno + 1);
84 if (nblk <= 0)
85 *ap->a_runp = 0;
86 else if (nblk >= (MAXBSIZE >> bshift))
87 *ap->a_runp = (MAXBSIZE >> bshift) - 1;
88 else
89 *ap->a_runp = nblk;
90 }
91
92 if (ap->a_runb) {
93 *ap->a_runb = 0;
94 }
95
96 return 0;
97 }
98