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. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)cd9660_bmap.c 8.3 (Berkeley) 1/23/94 39 * $FreeBSD: src/sys/isofs/cd9660/cd9660_bmap.c,v 1.8 1999/08/28 00:46:06 peter Exp $ 40 * $DragonFly: src/sys/vfs/isofs/cd9660/cd9660_bmap.c,v 1.6 2007/08/13 17:31:56 dillon Exp $ 41 */ 42 43 #include <sys/param.h> 44 #include <sys/systm.h> 45 #include <sys/vnode.h> 46 #include <sys/mount.h> 47 48 #include "iso.h" 49 #include "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 * cd9660_bmap(struct vnode *a_vp, off_t a_loffset, 57 * off_t *a_doffsetp, int *a_runp, int *a_runb) 58 */ 59 int 60 cd9660_bmap(struct vop_bmap_args *ap) 61 { 62 struct iso_node *ip = VTOI(ap->a_vp); 63 off_t loffset = ap->a_loffset; 64 int bshift; 65 int bsize; 66 67 /* 68 * Check for underlying vnode requests and ensure that logical 69 * to physical mapping is requested. 70 */ 71 if (ap->a_doffsetp == NULL) 72 return (0); 73 74 /* 75 * Compute the requested block number 76 */ 77 bshift = ip->i_mnt->im_bshift; 78 bsize = 1 << bshift; 79 *ap->a_doffsetp = loffset + ((off_t)ip->iso_start << bshift); 80 81 KKASSERT((loffset & (bsize - 1)) == 0); 82 83 /* 84 * Determine maximum number of readahead bytes following the 85 * requested offset. Align the result to the nearest block 86 * boundary. Do not count any non-full blocks(?) 87 */ 88 if (ap->a_runp) { 89 off_t nbytes; 90 91 nbytes = (off_t)ip->i_size - loffset; 92 if (nbytes < bsize) 93 *ap->a_runp = 0; 94 else if (nbytes > MAXBSIZE) 95 *ap->a_runp = MAXBSIZE; 96 else 97 *ap->a_runp = (int)nbytes & ~(bsize - 1); 98 } 99 if (ap->a_runb) { 100 *ap->a_runb = 0; 101 } 102 return 0; 103 } 104