Annotation of sys/isofs/cd9660/cd9660_bmap.c, Revision 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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