projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 40380a72 | 1 | /*- |
| 80409bdc KB |
2 | * Copyright (c) 1982, 1988, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. | |
| 40380a72 KB |
4 | * |
| 5 | * %sccs.include.proprietary.c% | |
| 6 | * | |
| 80409bdc | 7 | * @(#)bmap.c 8.1 (Berkeley) %G% |
| 40380a72 KB |
8 | */ |
| 9 | ||
| 10 | #include <sys/param.h> | |
| 61ef809e | 11 | #include <stand.att/saio.h> |
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12 | |
| 13 | #define NBUFS 4 | |
| 14 | static char b[NBUFS][MAXBSIZE]; | |
| 15 | static daddr_t blknos[NBUFS]; | |
| 16 | ||
| 17 | daddr_t | |
| 18 | bmap(io, bn) | |
| 19 | register struct iob *io; | |
| 20 | daddr_t bn; | |
| 21 | { | |
| 22 | register struct dinode *ip; | |
| 23 | int i, j, sh; | |
| 24 | daddr_t nb, *bap; | |
| 25 | ||
| 26 | ip = &io->i_ino; | |
| 27 | if (bn < 0) { | |
| 28 | printf("bn negative\n"); | |
| 29 | return ((daddr_t)0); | |
| 30 | } | |
| 31 | ||
| 32 | /* The first NDADDR blocks are direct blocks. */ | |
| 33 | if(bn < NDADDR) { | |
| 34 | nb = ip->di_db[bn]; | |
| 35 | return (nb); | |
| 36 | } | |
| 37 | ||
| 38 | /* Determine the number of levels of indirection. */ | |
| 39 | sh = 1; | |
| 40 | bn -= NDADDR; | |
| 41 | for (j = NIADDR; j > 0; j--) { | |
| 42 | sh *= NINDIR(&io->i_fs); | |
| 43 | if (bn < sh) | |
| 44 | break; | |
| 45 | bn -= sh; | |
| 46 | } | |
| 47 | if (j == 0) { | |
| de95853c | 48 | printf("bn ovf %ld\n", bn); |
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49 | return ((daddr_t)0); |
| 50 | } | |
| 51 | ||
| 52 | /* Get the first indirect block address. */ | |
| 53 | nb = ip->di_ib[NIADDR - j]; | |
| 54 | if (nb == 0) { | |
| de95853c | 55 | printf("bn void %ld\n",bn); |
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56 | return ((daddr_t)0); |
| 57 | } | |
| 58 | ||
| 59 | /* Get the indirect blocks. */ | |
| 60 | for (; j <= NIADDR; j++) { | |
| 61 | if (blknos[j] != nb) { | |
| 62 | io->i_bn = fsbtodb(&io->i_fs, nb) + io->i_boff; | |
| 63 | io->i_ma = b[j]; | |
| 64 | io->i_cc = io->i_fs.fs_bsize; | |
| 65 | if (devread(io) != io->i_fs.fs_bsize) { | |
| 66 | if (io->i_error) | |
| 67 | errno = io->i_error; | |
| de95853c | 68 | printf("bn %ld: read error\n", io->i_bn); |
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69 | return ((daddr_t)0); |
| 70 | } | |
| 71 | blknos[j] = nb; | |
| 72 | } | |
| 73 | bap = (daddr_t *)b[j]; | |
| 74 | sh /= NINDIR(&io->i_fs); | |
| 75 | i = (bn / sh) % NINDIR(&io->i_fs); | |
| 76 | nb = bap[i]; | |
| 77 | if(nb == 0) { | |
| de95853c | 78 | printf("bn void %ld\n",bn); |
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79 | return ((daddr_t)0); |
| 80 | } | |
| 81 | } | |
| 82 | return (nb); | |
| 83 | } |