aboutsummaryrefslogtreecommitdiff
path: root/e2fsprogs/old_e2fsprogs/ext2fs/alloc.c
blob: 5021d72c9f91509ad44eb6380fe2b4020735e710 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
/* vi: set sw=4 ts=4: */
/*
 * alloc.c --- allocate new inodes, blocks for ext2fs
 *
 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
 *
 * %Begin-Header%
 * This file may be redistributed under the terms of the GNU Public
 * License.
 * %End-Header%
 *
 */

#include <stdio.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#include <time.h>
#include <string.h>
#if HAVE_SYS_STAT_H
#include <sys/stat.h>
#endif
#if HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

#include "ext2_fs.h"
#include "ext2fs.h"

/*
 * Right now, just search forward from the parent directory's block
 * group to find the next free inode.
 *
 * Should have a special policy for directories.
 */
errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
			   int mode EXT2FS_ATTR((unused)),
			   ext2fs_inode_bitmap map, ext2_ino_t *ret)
{
	ext2_ino_t	dir_group = 0;
	ext2_ino_t	i;
	ext2_ino_t	start_inode;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!map)
		map = fs->inode_map;
	if (!map)
		return EXT2_ET_NO_INODE_BITMAP;

	if (dir > 0)
		dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);

	start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
	if (start_inode < EXT2_FIRST_INODE(fs->super))
		start_inode = EXT2_FIRST_INODE(fs->super);
	i = start_inode;

	do {
		if (!ext2fs_fast_test_inode_bitmap(map, i))
			break;
		i++;
		if (i > fs->super->s_inodes_count)
			i = EXT2_FIRST_INODE(fs->super);
	} while (i != start_inode);

	if (ext2fs_test_inode_bitmap(map, i))
		return EXT2_ET_INODE_ALLOC_FAIL;
	*ret = i;
	return 0;
}

/*
 * Stupid algorithm --- we now just search forward starting from the
 * goal.  Should put in a smarter one someday....
 */
errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
			   ext2fs_block_bitmap map, blk_t *ret)
{
	blk_t	i;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!map)
		map = fs->block_map;
	if (!map)
		return EXT2_ET_NO_BLOCK_BITMAP;
	if (!goal || (goal >= fs->super->s_blocks_count))
		goal = fs->super->s_first_data_block;
	i = goal;
	do {
		if (!ext2fs_fast_test_block_bitmap(map, i)) {
			*ret = i;
			return 0;
		}
		i++;
		if (i >= fs->super->s_blocks_count)
			i = fs->super->s_first_data_block;
	} while (i != goal);
	return EXT2_ET_BLOCK_ALLOC_FAIL;
}

/*
 * This function zeros out the allocated block, and updates all of the
 * appropriate filesystem records.
 */
errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
			     char *block_buf, blk_t *ret)
{
	errcode_t	retval;
	blk_t		block;
	char		*buf = NULL;

	if (!block_buf) {
		retval = ext2fs_get_mem(fs->blocksize, &buf);
		if (retval)
			return retval;
		block_buf = buf;
	}
	memset(block_buf, 0, fs->blocksize);

	if (!fs->block_map) {
		retval = ext2fs_read_block_bitmap(fs);
		if (retval)
			goto fail;
	}

	retval = ext2fs_new_block(fs, goal, 0, &block);
	if (retval)
		goto fail;

	retval = io_channel_write_blk(fs->io, block, 1, block_buf);
	if (retval)
		goto fail;

	ext2fs_block_alloc_stats(fs, block, +1);
	*ret = block;
	return 0;

fail:
	if (buf)
		ext2fs_free_mem(&buf);
	return retval;
}

errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
				 int num, ext2fs_block_bitmap map, blk_t *ret)
{
	blk_t	b = start;

	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);

	if (!map)
		map = fs->block_map;
	if (!map)
		return EXT2_ET_NO_BLOCK_BITMAP;
	if (!b)
		b = fs->super->s_first_data_block;
	if (!finish)
		finish = start;
	if (!num)
		num = 1;
	do {
		if (b+num-1 > fs->super->s_blocks_count)
			b = fs->super->s_first_data_block;
		if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
			*ret = b;
			return 0;
		}
		b++;
	} while (b != finish);
	return EXT2_ET_BLOCK_ALLOC_FAIL;
}