1 /* $NetBSD: ufs_bmap.c,v 1.19 2022/04/09 10:05:35 riastradh Exp $ */
2 /* From: NetBSD: ufs_bmap.c,v 1.14 2001/11/08 05:00:51 chs Exp */
3
4 /*
5 * Copyright (c) 1989, 1991, 1993
6 * The Regents of the University of California. All rights reserved.
7 * (c) UNIX System Laboratories, Inc.
8 * All or some portions of this file are derived from material licensed
9 * to the University of California by American Telephone and Telegraph
10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11 * the permission of UNIX System Laboratories, Inc.
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 * @(#)ufs_bmap.c 8.8 (Berkeley) 8/11/95
38 */
39
40 #if HAVE_NBTOOL_CONFIG_H
41 #include "nbtool_config.h"
42 #endif
43
44 #include <sys/cdefs.h>
45 #if defined(__RCSID) && !defined(__lint)
46 __RCSID("$NetBSD: ufs_bmap.c,v 1.19 2022/04/09 10:05:35 riastradh Exp $");
47 #endif /* !__lint */
48
49 #include <sys/param.h>
50 #include <sys/time.h>
51
52 #include <assert.h>
53 #include <errno.h>
54 #include <strings.h>
55
56 #include "makefs.h"
57
58 #include <ufs/ufs/dinode.h>
59 #include <ufs/ufs/ufs_bswap.h>
60 #include <ufs/ffs/fs.h>
61
62 #include "ffs/ufs_inode.h"
63 #include "ffs/ffs_extern.h"
64
65 /*
66 * Create an array of logical block number/offset pairs which represent the
67 * path of indirect blocks required to access a data block. The first "pair"
68 * contains the logical block number of the appropriate single, double or
69 * triple indirect block and the offset into the inode indirect block array.
70 * Note, the logical block number of the inode single/double/triple indirect
71 * block appears twice in the array, once with the offset into the i_ffs_ib and
72 * once with the offset into the page itself.
73 */
74 int
ufs_getlbns(struct inode * ip,daddr_t bn,struct indir * ap,int * nump)75 ufs_getlbns(struct inode *ip, daddr_t bn, struct indir *ap, int *nump)
76 {
77 daddr_t metalbn, realbn;
78 int64_t blockcnt;
79 int lbc;
80 int i, numlevels, off;
81 u_long lognindir;
82
83 lognindir = ffs(FFS_NINDIR(ip->i_fs)) - 1;
84 if (nump)
85 *nump = 0;
86 numlevels = 0;
87 realbn = bn;
88 if ((long)bn < 0)
89 bn = -(long)bn;
90
91 assert (bn >= UFS_NDADDR);
92
93 /*
94 * Determine the number of levels of indirection. After this loop
95 * is done, blockcnt indicates the number of data blocks possible
96 * at the given level of indirection, and UFS_NIADDR - i is the number
97 * of levels of indirection needed to locate the requested block.
98 */
99
100 bn -= UFS_NDADDR;
101 for (lbc = 0, i = UFS_NIADDR;; i--, bn -= blockcnt) {
102 if (i == 0)
103 return (EFBIG);
104
105 lbc += lognindir;
106 blockcnt = (int64_t)1 << lbc;
107
108 if (bn < blockcnt)
109 break;
110 }
111
112 /* Calculate the address of the first meta-block. */
113 metalbn = -((realbn >= 0 ? realbn : -realbn) - bn + UFS_NIADDR - i);
114
115 /*
116 * At each iteration, off is the offset into the bap array which is
117 * an array of disk addresses at the current level of indirection.
118 * The logical block number and the offset in that block are stored
119 * into the argument array.
120 */
121 ap->in_lbn = metalbn;
122 ap->in_off = off = UFS_NIADDR - i;
123 ap->in_exists = 0;
124 ap++;
125 for (++numlevels; i <= UFS_NIADDR; i++) {
126 /* If searching for a meta-data block, quit when found. */
127 if (metalbn == realbn)
128 break;
129
130 lbc -= lognindir;
131 blockcnt = (int64_t)1 << lbc;
132 off = (bn >> lbc) & (FFS_NINDIR(ip->i_fs) - 1);
133
134 ++numlevels;
135 ap->in_lbn = metalbn;
136 ap->in_off = off;
137 ap->in_exists = 0;
138 ++ap;
139
140 metalbn -= -1 + (off << lbc);
141 }
142 if (nump)
143 *nump = numlevels;
144 return (0);
145 }
146