1 /* $NetBSD: ufs_bmap.c,v 1.14 2004/06/20 22:20:18 jmc Exp $ */
2 /* From: NetBSD: ufs_bmap.c,v 1.14 2001/11/08 05:00:51 chs Exp */
3
4 /*-
5 * SPDX-License-Identifier: BSD-3-Clause
6 *
7 * Copyright (c) 1989, 1991, 1993
8 * The Regents of the University of California. All rights reserved.
9 * (c) UNIX System Laboratories, Inc.
10 * All or some portions of this file are derived from material licensed
11 * to the University of California by American Telephone and Telegraph
12 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
13 * the permission of UNIX System Laboratories, Inc.
14 *
15 * Redistribution and use in source and binary forms, with or without
16 * modification, are permitted provided that the following conditions
17 * are met:
18 * 1. Redistributions of source code must retain the above copyright
19 * notice, this list of conditions and the following disclaimer.
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in the
22 * documentation and/or other materials provided with the distribution.
23 * 3. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95
40 * $FreeBSD: head/usr.sbin/makefs/ffs/ufs_bmap.c 326025 2017-11-20 19:49:47Z pfg $
41 */
42
43 #include <sys/param.h>
44 #include <sys/time.h>
45
46 #include <assert.h>
47 #include <errno.h>
48 #include <strings.h>
49
50 #include "makefs.h"
51
52 #include <vfs/ufs/dinode.h>
53 #include <vfs/ufs/fs.h>
54
55 #include "ffs/ufs_bswap.h"
56 #include "ffs/ufs_inode.h"
57 #include "ffs/ffs_extern.h"
58
59 /*
60 * Create an array of logical block number/offset pairs which represent the
61 * path of indirect blocks required to access a data block. The first "pair"
62 * contains the logical block number of the appropriate single, double or
63 * triple indirect block and the offset into the inode indirect block array.
64 * Note, the logical block number of the inode single/double/triple indirect
65 * block appears twice in the array, once with the offset into the i_ffs_ib and
66 * once with the offset into the page itself.
67 */
68 int
ufs_getlbns(struct inode * ip,makefs_daddr_t bn,struct indir * ap,int * nump)69 ufs_getlbns(struct inode *ip, makefs_daddr_t bn, struct indir *ap, int *nump)
70 {
71 makefs_daddr_t metalbn, realbn;
72 int64_t blockcnt;
73 int lbc;
74 int i, numlevels, off;
75 u_long lognindir;
76
77 lognindir = ffs(NINDIR(ip->i_fs)) - 1;
78 if (nump)
79 *nump = 0;
80 numlevels = 0;
81 realbn = bn;
82 if ((long)bn < 0)
83 bn = -(long)bn;
84
85 assert (bn >= UFS_NDADDR);
86
87 /*
88 * Determine the number of levels of indirection. After this loop
89 * is done, blockcnt indicates the number of data blocks possible
90 * at the given level of indirection, and UFS_NIADDR - i is the number
91 * of levels of indirection needed to locate the requested block.
92 */
93
94 bn -= UFS_NDADDR;
95 for (lbc = 0, i = UFS_NIADDR;; i--, bn -= blockcnt) {
96 if (i == 0)
97 return (EFBIG);
98
99 lbc += lognindir;
100 blockcnt = (int64_t)1 << lbc;
101
102 if (bn < blockcnt)
103 break;
104 }
105
106 /* Calculate the address of the first meta-block. */
107 if (realbn >= 0)
108 metalbn = -(realbn - bn + UFS_NIADDR - i);
109 else
110 metalbn = -(-realbn - bn + UFS_NIADDR - i);
111
112 /*
113 * At each iteration, off is the offset into the bap array which is
114 * an array of disk addresses at the current level of indirection.
115 * The logical block number and the offset in that block are stored
116 * into the argument array.
117 */
118 ap->in_lbn = metalbn;
119 ap->in_off = off = UFS_NIADDR - i;
120 ap++;
121 for (++numlevels; i <= UFS_NIADDR; i++) {
122 /* If searching for a meta-data block, quit when found. */
123 if (metalbn == realbn)
124 break;
125
126 lbc -= lognindir;
127 blockcnt = (int64_t)1 << lbc;
128 off = (bn >> lbc) & (NINDIR(ip->i_fs) - 1);
129
130 ++numlevels;
131 ap->in_lbn = metalbn;
132 ap->in_off = off;
133 ++ap;
134
135 metalbn -= -1 + (off << lbc);
136 }
137 if (nump)
138 *nump = numlevels;
139 return (0);
140 }
141