projects / unix-history / blame
| Commit | Line | Data |
|---|---|---|
| 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 | } |