alloc.c revision b0ecb787ef9fde414791b644fa074450b28d4060 
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 Library
8 * General Public License, version 2.
9 * %End-Header%
10 */
11
12#include <stdio.h>
13#if HAVE_UNISTD_H
14#include <unistd.h>
15#endif
16#include <time.h>
17#include <string.h>
18#if HAVE_SYS_STAT_H
19#include <sys/stat.h>
20#endif
21#if HAVE_SYS_TYPES_H
22#include <sys/types.h>
23#endif
24
25#include "ext2_fs.h"
26#include "ext2fs.h"
27
28/*
29 * Check for uninit block bitmaps and deal with them appropriately
30 */
31static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map,
32			       dgrp_t group)
33{
34	blk_t		i;
35	blk64_t		blk, super_blk, old_desc_blk, new_desc_blk;
36	int		old_desc_blocks;
37
38	if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
39					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
40	    !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
41		return;
42
43	blk = (group * fs->super->s_blocks_per_group) +
44		fs->super->s_first_data_block;
45
46	ext2fs_super_and_bgd_loc2(fs, group, &super_blk,
47				  &old_desc_blk, &new_desc_blk, 0);
48
49	if (fs->super->s_feature_incompat &
50	    EXT2_FEATURE_INCOMPAT_META_BG)
51		old_desc_blocks = fs->super->s_first_meta_bg;
52	else
53		old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
54
55	for (i=0; i < fs->super->s_blocks_per_group; i++, blk++)
56		ext2fs_fast_unmark_block_bitmap2(map, blk);
57
58	for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
59		if ((blk == super_blk) ||
60		    (old_desc_blk && old_desc_blocks &&
61		     (blk >= old_desc_blk) &&
62		     (blk < old_desc_blk + old_desc_blocks)) ||
63		    (new_desc_blk && (blk == new_desc_blk)) ||
64		    (blk == ext2fs_block_bitmap_loc(fs, group)) ||
65		    (blk == ext2fs_inode_bitmap_loc(fs, group)) ||
66		    (blk >= ext2fs_inode_table_loc(fs, group) &&
67		     (blk < ext2fs_inode_table_loc(fs, group)
68		      + fs->inode_blocks_per_group)))
69			ext2fs_fast_mark_block_bitmap2(map, blk);
70	}
71	ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
72	ext2fs_group_desc_csum_set(fs, group);
73}
74
75/*
76 * Check for uninit inode bitmaps and deal with them appropriately
77 */
78static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
79			  dgrp_t group)
80{
81	ext2_ino_t	i, ino;
82
83	if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
84					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
85	    !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
86		return;
87
88	ino = (group * fs->super->s_inodes_per_group) + 1;
89	for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
90		ext2fs_fast_unmark_inode_bitmap2(map, ino);
91
92	ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
93	check_block_uninit(fs, fs->block_map, group);
94}
95
96/*
97 * Right now, just search forward from the parent directory's block
98 * group to find the next free inode.
99 *
100 * Should have a special policy for directories.
101 */
102errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
103			   int mode EXT2FS_ATTR((unused)),
104			   ext2fs_inode_bitmap map, ext2_ino_t *ret)
105{
106	ext2_ino_t	dir_group = 0;
107	ext2_ino_t	i;
108	ext2_ino_t	start_inode;
109
110	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
111
112	if (!map)
113		map = fs->inode_map;
114	if (!map)
115		return EXT2_ET_NO_INODE_BITMAP;
116
117	if (dir > 0)
118		dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
119
120	start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
121	if (start_inode < EXT2_FIRST_INODE(fs->super))
122		start_inode = EXT2_FIRST_INODE(fs->super);
123	if (start_inode > fs->super->s_inodes_count)
124		return EXT2_ET_INODE_ALLOC_FAIL;
125	i = start_inode;
126
127	do {
128		if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
129			check_inode_uninit(fs, map, (i - 1) /
130					   EXT2_INODES_PER_GROUP(fs->super));
131
132		if (!ext2fs_fast_test_inode_bitmap2(map, i))
133			break;
134		i++;
135		if (i > fs->super->s_inodes_count)
136			i = EXT2_FIRST_INODE(fs->super);
137	} while (i != start_inode);
138
139	if (ext2fs_test_inode_bitmap2(map, i))
140		return EXT2_ET_INODE_ALLOC_FAIL;
141	*ret = i;
142	return 0;
143}
144
145/*
146 * Stupid algorithm --- we now just search forward starting from the
147 * goal.  Should put in a smarter one someday....
148 */
149errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
150			   ext2fs_block_bitmap map, blk64_t *ret)
151{
152	blk64_t	i;
153	int	c_ratio;
154
155	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
156
157	if (!map)
158		map = fs->block_map;
159	if (!map)
160		return EXT2_ET_NO_BLOCK_BITMAP;
161	if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
162		goal = fs->super->s_first_data_block;
163	i = goal;
164	c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
165	check_block_uninit(fs, map,
166			   (i - fs->super->s_first_data_block) /
167			   EXT2_BLOCKS_PER_GROUP(fs->super));
168	do {
169		if (((i - fs->super->s_first_data_block) %
170		     EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
171			check_block_uninit(fs, map,
172					   (i - fs->super->s_first_data_block) /
173					   EXT2_BLOCKS_PER_GROUP(fs->super));
174
175		if (!ext2fs_fast_test_block_bitmap2(map, i)) {
176			*ret = i;
177			return 0;
178		}
179		i = (i + c_ratio) & ~(c_ratio - 1);
180		if (i >= ext2fs_blocks_count(fs->super))
181			i = fs->super->s_first_data_block;
182	} while (i != goal);
183	return EXT2_ET_BLOCK_ALLOC_FAIL;
184}
185
186errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
187			   ext2fs_block_bitmap map, blk_t *ret)
188{
189	errcode_t retval;
190	blk64_t val;
191	retval = ext2fs_new_block2(fs, goal, map, &val);
192	if (!retval)
193		*ret = (blk_t) val;
194	return retval;
195}
196
197/*
198 * This function zeros out the allocated block, and updates all of the
199 * appropriate filesystem records.
200 */
201errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
202			     char *block_buf, blk64_t *ret)
203{
204	errcode_t	retval;
205	blk64_t		block;
206	char		*buf = 0;
207
208	if (!block_buf) {
209		retval = ext2fs_get_mem(fs->blocksize, &buf);
210		if (retval)
211			return retval;
212		block_buf = buf;
213	}
214	memset(block_buf, 0, fs->blocksize);
215
216	if (fs->get_alloc_block) {
217		retval = (fs->get_alloc_block)(fs, goal, &block);
218		if (retval)
219			goto fail;
220	} else {
221		if (!fs->block_map) {
222			retval = ext2fs_read_block_bitmap(fs);
223			if (retval)
224				goto fail;
225		}
226
227		retval = ext2fs_new_block2(fs, goal, 0, &block);
228		if (retval)
229			goto fail;
230	}
231
232	retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
233	if (retval)
234		goto fail;
235
236	ext2fs_block_alloc_stats2(fs, block, +1);
237	*ret = block;
238
239fail:
240	if (buf)
241		ext2fs_free_mem(&buf);
242	return retval;
243}
244
245errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
246			     char *block_buf, blk_t *ret)
247{
248	errcode_t retval;
249	blk64_t	val;
250	retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
251	if (!retval)
252		*ret = (blk_t) val;
253	return retval;
254}
255
256errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
257				 int num, ext2fs_block_bitmap map, blk64_t *ret)
258{
259	blk64_t	b = start, c = 0;
260	int	c_ratio;
261
262	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
263
264	if (!map)
265		map = fs->block_map;
266	if (!map)
267		return EXT2_ET_NO_BLOCK_BITMAP;
268	if (!b)
269		b = fs->super->s_first_data_block;
270	if (!finish)
271		finish = start;
272	if (!num)
273		num = 1;
274	c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
275	b &= ~(c_ratio - 1);
276	finish &= ~(c_ratio -1);
277	do {
278		if (b+num-1 > ext2fs_blocks_count(fs->super))
279			b = fs->super->s_first_data_block;
280		if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
281			*ret = b;
282			return 0;
283		}
284		b += c_ratio;
285	} while (b != finish);
286	return EXT2_ET_BLOCK_ALLOC_FAIL;
287}
288
289errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
290				 int num, ext2fs_block_bitmap map, blk_t *ret)
291{
292	errcode_t retval;
293	blk64_t val;
294	retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
295	if(!retval)
296		*ret = (blk_t) val;
297	return retval;
298}
299
300void ext2fs_set_alloc_block_callback(ext2_filsys fs,
301				     errcode_t (*func)(ext2_filsys fs,
302						       blk64_t goal,
303						       blk64_t *ret),
304				     errcode_t (**old)(ext2_filsys fs,
305						       blk64_t goal,
306						       blk64_t *ret))
307{
308	if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
309		return;
310
311	if (old)
312		*old = fs->get_alloc_block;
313
314	fs->get_alloc_block = func;
315}
316