2 * SPDX-License-Identifier: BSD-3-Clause
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7 * This code is derived from software contributed to Berkeley
8 * by Pace Willisson (pace@blitz.com). The Rock Ridge Extension
9 * Support code is derived from software contributed to Berkeley
10 * by Atsushi Murai (amurai@spec.co.jp).
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36 * @(#)cd9660_bmap.c 8.3 (Berkeley) 1/23/94
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>
45 #include <fs/cd9660/iso.h>
46 #include <fs/cd9660/cd9660_node.h>
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
55 cd9660_bmap(struct vop_bmap_args *ap)
57 struct iso_node *ip = VTOI(ap->a_vp);
58 daddr_t lblkno = ap->a_bn;
62 * Check for underlying vnode requests and ensure that logical
63 * to physical mapping is requested.
65 if (ap->a_bop != NULL)
66 *ap->a_bop = &ip->i_mnt->im_devvp->v_bufobj;
67 if (ap->a_bnp == NULL)
71 * Compute the requested block number
73 bshift = ip->i_mnt->im_bshift;
74 *ap->a_bnp = (ip->iso_start + lblkno) << (bshift - DEV_BSHIFT);
77 * Determine maximum number of readahead blocks following the
83 nblk = (ip->i_size >> bshift) - (lblkno + 1);
86 else if (nblk >= (MAXBSIZE >> bshift))
87 *ap->a_runp = (MAXBSIZE >> bshift) - 1;