Annotation of sys/isofs/cd9660/cd9660_bmap.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: cd9660_bmap.c,v 1.6 2007/06/06 17:15:13 deraadt Exp $ */
2: /* $NetBSD: cd9660_bmap.c,v 1.7 1997/01/24 00:27:29 cgd Exp $ */
3:
4: /*-
5: * Copyright (c) 1994
6: * The Regents of the University of California. All rights reserved.
7: *
8: * This code is derived from software contributed to Berkeley
9: * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension
10: * Support code is derived from software contributed to Berkeley
11: * by Atsushi Murai (amurai@spec.co.jp).
12: *
13: * Redistribution and use in source and binary forms, with or without
14: * modification, are permitted provided that the following conditions
15: * are met:
16: * 1. Redistributions of source code must retain the above copyright
17: * notice, this list of conditions and the following disclaimer.
18: * 2. Redistributions in binary form must reproduce the above copyright
19: * notice, this list of conditions and the following disclaimer in the
20: * documentation and/or other materials provided with the distribution.
21: * 3. Neither the name of the University nor the names of its contributors
22: * may be used to endorse or promote products derived from this software
23: * without specific prior written permission.
24: *
25: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35: * SUCH DAMAGE.
36: *
37: * @(#)cd9660_bmap.c 8.4 (Berkeley) 12/5/94
38: */
39:
40: #include <sys/param.h>
41: #include <sys/namei.h>
42: #include <sys/buf.h>
43: #include <sys/file.h>
44: #include <sys/vnode.h>
45: #include <sys/mount.h>
46:
47: #include <isofs/cd9660/iso.h>
48: #include <isofs/cd9660/cd9660_extern.h>
49: #include <isofs/cd9660/cd9660_node.h>
50:
51: /*
52: * Bmap converts a the logical block number of a file to its physical block
53: * number on the disk. The conversion is done by using the logical block
54: * number to index into the data block (extent) for the file.
55: */
56: int
57: cd9660_bmap(v)
58: void *v;
59: {
60: struct vop_bmap_args *ap = v;
61: struct iso_node *ip = VTOI(ap->a_vp);
62: daddr64_t lblkno = ap->a_bn;
63: int bshift;
64:
65: /*
66: * Check for underlying vnode requests and ensure that logical
67: * to physical mapping is requested.
68: */
69: if (ap->a_vpp != NULL)
70: *ap->a_vpp = ip->i_devvp;
71: if (ap->a_bnp == NULL)
72: return (0);
73:
74: /*
75: * Compute the requested block number
76: */
77: bshift = ip->i_mnt->im_bshift;
78: *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT);
79:
80: /*
81: * Determine maximum number of readahead blocks following the
82: * requested block.
83: */
84: if (ap->a_runp) {
85: int nblk;
86:
87: nblk = (ip->i_size >> bshift) - (lblkno + 1);
88: if (nblk <= 0)
89: *ap->a_runp = 0;
90: else if (nblk >= (MAXBSIZE >> bshift))
91: *ap->a_runp = (MAXBSIZE >> bshift) - 1;
92: else
93: *ap->a_runp = nblk;
94: }
95:
96: return (0);
97: }
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