source: MondoRescue/branches/stable/mindi-busybox/e2fsprogs/ext2fs/alloc.c @ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 14 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)

File size: 3.6 KB
Line 
1/*
2 * alloc.c --- allocate new inodes, blocks for ext2fs
3 *
4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
9 * %End-Header%
10 *
11 */
12
13#include <stdio.h>
14#if HAVE_UNISTD_H
15#include <unistd.h>
16#endif
17#include <time.h>
18#include <string.h>
19#if HAVE_SYS_STAT_H
20#include <sys/stat.h>
21#endif
22#if HAVE_SYS_TYPES_H
23#include <sys/types.h>
24#endif
25
26#include "ext2_fs.h"
27#include "ext2fs.h"
28
29/*
30 * Right now, just search forward from the parent directory's block
31 * group to find the next free inode.
32 *
33 * Should have a special policy for directories.
34 */
35errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
36               int mode EXT2FS_ATTR((unused)),
37               ext2fs_inode_bitmap map, ext2_ino_t *ret)
38{
39    ext2_ino_t  dir_group = 0;
40    ext2_ino_t  i;
41    ext2_ino_t  start_inode;
42
43    EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
44
45    if (!map)
46        map = fs->inode_map;
47    if (!map)
48        return EXT2_ET_NO_INODE_BITMAP;
49
50    if (dir > 0)
51        dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
52
53    start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
54    if (start_inode < EXT2_FIRST_INODE(fs->super))
55        start_inode = EXT2_FIRST_INODE(fs->super);
56    i = start_inode;
57
58    do {
59        if (!ext2fs_fast_test_inode_bitmap(map, i))
60            break;
61        i++;
62        if (i > fs->super->s_inodes_count)
63            i = EXT2_FIRST_INODE(fs->super);
64    } while (i != start_inode);
65
66    if (ext2fs_test_inode_bitmap(map, i))
67        return EXT2_ET_INODE_ALLOC_FAIL;
68    *ret = i;
69    return 0;
70}
71
72/*
73 * Stupid algorithm --- we now just search forward starting from the
74 * goal.  Should put in a smarter one someday....
75 */
76errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
77               ext2fs_block_bitmap map, blk_t *ret)
78{
79    blk_t   i;
80
81    EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
82
83    if (!map)
84        map = fs->block_map;
85    if (!map)
86        return EXT2_ET_NO_BLOCK_BITMAP;
87    if (!goal || (goal >= fs->super->s_blocks_count))
88        goal = fs->super->s_first_data_block;
89    i = goal;
90    do {
91        if (!ext2fs_fast_test_block_bitmap(map, i)) {
92            *ret = i;
93            return 0;
94        }
95        i++;
96        if (i >= fs->super->s_blocks_count)
97            i = fs->super->s_first_data_block;
98    } while (i != goal);
99    return EXT2_ET_BLOCK_ALLOC_FAIL;
100}
101
102/*
103 * This function zeros out the allocated block, and updates all of the
104 * appropriate filesystem records.
105 */
106errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
107                 char *block_buf, blk_t *ret)
108{
109    errcode_t   retval;
110    blk_t       block;
111    char        *buf = 0;
112
113    if (!block_buf) {
114        retval = ext2fs_get_mem(fs->blocksize, &buf);
115        if (retval)
116            return retval;
117        block_buf = buf;
118    }
119    memset(block_buf, 0, fs->blocksize);
120
121    if (!fs->block_map) {
122        retval = ext2fs_read_block_bitmap(fs);
123        if (retval)
124            goto fail;
125    }
126
127    retval = ext2fs_new_block(fs, goal, 0, &block);
128    if (retval)
129        goto fail;
130
131    retval = io_channel_write_blk(fs->io, block, 1, block_buf);
132    if (retval)
133        goto fail;
134
135    ext2fs_block_alloc_stats(fs, block, +1);
136    *ret = block;
137    return 0;
138
139fail:
140    if (buf)
141        ext2fs_free_mem(&buf);
142    return retval;
143}
144
145errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
146                 int num, ext2fs_block_bitmap map, blk_t *ret)
147{
148    blk_t   b = start;
149
150    EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
151
152    if (!map)
153        map = fs->block_map;
154    if (!map)
155        return EXT2_ET_NO_BLOCK_BITMAP;
156    if (!b)
157        b = fs->super->s_first_data_block;
158    if (!finish)
159        finish = start;
160    if (!num)
161        num = 1;
162    do {
163        if (b+num-1 > fs->super->s_blocks_count)
164            b = fs->super->s_first_data_block;
165        if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
166            *ret = b;
167            return 0;
168        }
169        b++;
170    } while (b != finish);
171    return EXT2_ET_BLOCK_ALLOC_FAIL;
172}
173
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