alloc.c revision f5c562e2324a8950d659ebfc8db4356121d6104e 
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->get_alloc_block) {
122		blk64_t	new;
123
124		retval = (fs->get_alloc_block)(fs, (blk64_t) goal, &new);
125		if (retval)
126			goto fail;
127		block = (blk_t) new;
128	} else {
129		if (!fs->block_map) {
130			retval = ext2fs_read_block_bitmap(fs);
131			if (retval)
132				goto fail;
133		}
134
135		retval = ext2fs_new_block(fs, goal, 0, &block);
136		if (retval)
137			goto fail;
138	}
139
140	retval = io_channel_write_blk(fs->io, block, 1, block_buf);
141	if (retval)
142		goto fail;
143
144	ext2fs_block_alloc_stats(fs, block, +1);
145	*ret = block;
146
147fail:
148	if (buf)
149		ext2fs_free_mem(&buf);
150	return retval;
151}
152
153errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
154				 int num, ext2fs_block_bitmap map, blk_t *ret)
155{
156	blk_t	b = start;
157
158	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
159
160	if (!map)
161		map = fs->block_map;
162	if (!map)
163		return EXT2_ET_NO_BLOCK_BITMAP;
164	if (!b)
165		b = fs->super->s_first_data_block;
166	if (!finish)
167		finish = start;
168	if (!num)
169		num = 1;
170	do {
171		if (b+num-1 > fs->super->s_blocks_count)
172			b = fs->super->s_first_data_block;
173		if (ext2fs_fast_test_block_bitmap_range(map, b, num)) {
174			*ret = b;
175			return 0;
176		}
177		b++;
178	} while (b != finish);
179	return EXT2_ET_BLOCK_ALLOC_FAIL;
180}
181
182void ext2fs_set_alloc_block_callback(ext2_filsys fs,
183				     errcode_t (*func)(ext2_filsys fs,
184						       blk64_t goal,
185						       blk64_t *ret),
186				     errcode_t (**old)(ext2_filsys fs,
187						       blk64_t goal,
188						       blk64_t *ret))
189{
190	if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
191		return;
192
193	if (old)
194		*old = fs->get_alloc_block;
195
196	fs->get_alloc_block = func;
197}
198