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effabf81 WJ |
1 | /* |
2 | * Copyright (c) 1982, 1986, 1989 Regents of the University of California. | |
3 | * All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * 3. All advertising materials mentioning features or use of this software | |
14 | * must display the following acknowledgement: | |
15 | * This product includes software developed by the University of | |
16 | * California, Berkeley and its contributors. | |
17 | * 4. Neither the name of the University nor the names of its contributors | |
18 | * may be used to endorse or promote products derived from this software | |
19 | * without specific prior written permission. | |
20 | * | |
21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | * SUCH DAMAGE. | |
32 | * | |
33 | * derived from: @(#)ufs_bmap.c 7.13 (Berkeley) 5/8/91 | |
34 | */ | |
35 | ||
36 | #include "param.h" | |
37 | #include "dinode.h" | |
38 | #include "fs.h" | |
39 | #include "errno.h" | |
40 | ||
41 | /* | |
42 | * Bmap converts a the logical block number of a file | |
43 | * to its physical block number on the disk. The conversion | |
44 | * is done by using the logical block number to index into | |
45 | * the array of block pointers described by the dinode. | |
46 | */ | |
47 | extern struct fs *fs; | |
48 | extern int bdev; | |
49 | ||
50 | static daddr_t bap[2*1024]; | |
51 | static daddr_t bnobap; | |
52 | ||
53 | bmap(dip, bn, bnp) | |
54 | register struct dinode *dip; | |
55 | register daddr_t bn; | |
56 | daddr_t *bnp; | |
57 | { | |
58 | register daddr_t nb; | |
59 | int i, j, sh; | |
60 | int error; | |
61 | ||
62 | /*fprintf(stderr, "bmap %d ", bn);*/ | |
63 | if (bn < 0) | |
64 | return (EFBIG); | |
65 | ||
66 | /* | |
67 | * The first NDADDR blocks are direct blocks | |
68 | */ | |
69 | if (bn < NDADDR) { | |
70 | nb = dip->di_db[bn]; | |
71 | if (nb == 0) { | |
72 | *bnp = (daddr_t)-1; | |
73 | /*fprintf(stderr, "%d\n", *bnp);*/ | |
74 | return (0); | |
75 | } | |
76 | *bnp = fsbtodb(fs, nb); | |
77 | /*fprintf(stderr, "%d\n", *bnp);*/ | |
78 | return (0); | |
79 | } | |
80 | /* | |
81 | * Determine the number of levels of indirection. | |
82 | */ | |
83 | sh = 1; | |
84 | bn -= NDADDR; | |
85 | for (j = NIADDR; j > 0; j--) { | |
86 | sh *= NINDIR(fs); | |
87 | if (bn < sh) | |
88 | break; | |
89 | bn -= sh; | |
90 | } | |
91 | if (j == 0) | |
92 | return (EFBIG); | |
93 | /* | |
94 | * Fetch through the indirect blocks. | |
95 | */ | |
96 | nb = dip->di_ib[NIADDR - j]; | |
97 | if (nb == 0) { | |
98 | *bnp = (daddr_t)-1; | |
99 | /*fprintf(stderr, "%d\n", *bnp);*/ | |
100 | return (0); | |
101 | } | |
102 | for (; j <= NIADDR; j++) { | |
103 | daddr_t bno = fsbtodb(fs, nb); | |
104 | ||
105 | if (bnobap != bno && | |
106 | (error = bread(bdev, bno, &bap, | |
107 | (int)fs->fs_bsize))) { | |
108 | return (error); | |
109 | } | |
110 | bnobap = bno; | |
111 | sh /= NINDIR(fs); | |
112 | i = (bn / sh) % NINDIR(fs); | |
113 | nb = bap[i]; | |
114 | if (nb == 0) { | |
115 | *bnp = (daddr_t)-1; | |
116 | /*fprintf(stderr, "%d\n", *bnp);*/ | |
117 | return (0); | |
118 | } | |
119 | } | |
120 | *bnp = fsbtodb(fs, nb); | |
121 | /*fprintf(stderr, "%d\n", *bnp);*/ | |
122 | return (0); | |
123 | } |