alloc.c revision d1154eb460efe588eaed3d439c1caaca149fa362 
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 "config.h"
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 * Check for uninit block bitmaps and deal with them appropriately
31 */
32static void check_block_uninit(ext2_filsys fs, ext2fs_block_bitmap map,
33			       dgrp_t group)
34{
35	blk_t		i;
36	blk64_t		blk, super_blk, old_desc_blk, new_desc_blk;
37	int		old_desc_blocks;
38
39	if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
40					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
41	    !(ext2fs_bg_flags_test(fs, group, EXT2_BG_BLOCK_UNINIT)))
42		return;
43
44	blk = (group * fs->super->s_blocks_per_group) +
45		fs->super->s_first_data_block;
46
47	ext2fs_super_and_bgd_loc2(fs, group, &super_blk,
48				  &old_desc_blk, &new_desc_blk, 0);
49
50	if (fs->super->s_feature_incompat &
51	    EXT2_FEATURE_INCOMPAT_META_BG)
52		old_desc_blocks = fs->super->s_first_meta_bg;
53	else
54		old_desc_blocks = fs->desc_blocks + fs->super->s_reserved_gdt_blocks;
55
56	for (i=0; i < fs->super->s_blocks_per_group; i++, blk++)
57		ext2fs_fast_unmark_block_bitmap2(map, blk);
58
59	blk = (group * fs->super->s_blocks_per_group) +
60		fs->super->s_first_data_block;
61	for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
62		if ((blk == super_blk) ||
63		    (old_desc_blk && old_desc_blocks &&
64		     (blk >= old_desc_blk) &&
65		     (blk < old_desc_blk + old_desc_blocks)) ||
66		    (new_desc_blk && (blk == new_desc_blk)) ||
67		    (blk == ext2fs_block_bitmap_loc(fs, group)) ||
68		    (blk == ext2fs_inode_bitmap_loc(fs, group)) ||
69		    (blk >= ext2fs_inode_table_loc(fs, group) &&
70		     (blk < ext2fs_inode_table_loc(fs, group)
71		      + fs->inode_blocks_per_group)))
72			ext2fs_fast_mark_block_bitmap2(map, blk);
73	}
74	ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
75	ext2fs_group_desc_csum_set(fs, group);
76}
77
78/*
79 * Check for uninit inode bitmaps and deal with them appropriately
80 */
81static void check_inode_uninit(ext2_filsys fs, ext2fs_inode_bitmap map,
82			  dgrp_t group)
83{
84	ext2_ino_t	i, ino;
85
86	if (!(EXT2_HAS_RO_COMPAT_FEATURE(fs->super,
87					 EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) ||
88	    !(ext2fs_bg_flags_test(fs, group, EXT2_BG_INODE_UNINIT)))
89		return;
90
91	ino = (group * fs->super->s_inodes_per_group) + 1;
92	for (i=0; i < fs->super->s_inodes_per_group; i++, ino++)
93		ext2fs_fast_unmark_inode_bitmap2(map, ino);
94
95	ext2fs_bg_flags_clear(fs, group, EXT2_BG_INODE_UNINIT);
96	check_block_uninit(fs, fs->block_map, group);
97}
98
99/*
100 * Right now, just search forward from the parent directory's block
101 * group to find the next free inode.
102 *
103 * Should have a special policy for directories.
104 */
105errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
106			   int mode EXT2FS_ATTR((unused)),
107			   ext2fs_inode_bitmap map, ext2_ino_t *ret)
108{
109	ext2_ino_t	dir_group = 0;
110	ext2_ino_t	i;
111	ext2_ino_t	start_inode;
112
113	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
114
115	if (!map)
116		map = fs->inode_map;
117	if (!map)
118		return EXT2_ET_NO_INODE_BITMAP;
119
120	if (dir > 0)
121		dir_group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
122
123	start_inode = (dir_group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
124	if (start_inode < EXT2_FIRST_INODE(fs->super))
125		start_inode = EXT2_FIRST_INODE(fs->super);
126	if (start_inode > fs->super->s_inodes_count)
127		return EXT2_ET_INODE_ALLOC_FAIL;
128	i = start_inode;
129
130	do {
131		if (((i - 1) % EXT2_INODES_PER_GROUP(fs->super)) == 0)
132			check_inode_uninit(fs, map, (i - 1) /
133					   EXT2_INODES_PER_GROUP(fs->super));
134
135		if (!ext2fs_fast_test_inode_bitmap2(map, i))
136			break;
137		i++;
138		if (i > fs->super->s_inodes_count)
139			i = EXT2_FIRST_INODE(fs->super);
140	} while (i != start_inode);
141
142	if (ext2fs_test_inode_bitmap2(map, i))
143		return EXT2_ET_INODE_ALLOC_FAIL;
144	*ret = i;
145	return 0;
146}
147
148/*
149 * Stupid algorithm --- we now just search forward starting from the
150 * goal.  Should put in a smarter one someday....
151 */
152errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
153			   ext2fs_block_bitmap map, blk64_t *ret)
154{
155	blk64_t	i;
156	int	c_ratio;
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 (!goal || (goal >= ext2fs_blocks_count(fs->super)))
165		goal = fs->super->s_first_data_block;
166	i = goal;
167	c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
168	if (c_ratio > 1)
169		goal &= ~EXT2FS_CLUSTER_MASK(fs);
170	check_block_uninit(fs, map,
171			   (i - fs->super->s_first_data_block) /
172			   EXT2_BLOCKS_PER_GROUP(fs->super));
173	do {
174		if (((i - fs->super->s_first_data_block) %
175		     EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
176			check_block_uninit(fs, map,
177					   (i - fs->super->s_first_data_block) /
178					   EXT2_BLOCKS_PER_GROUP(fs->super));
179
180		if (!ext2fs_fast_test_block_bitmap2(map, i)) {
181			*ret = i;
182			return 0;
183		}
184		i = (i + c_ratio) & ~(c_ratio - 1);
185		if (i >= ext2fs_blocks_count(fs->super))
186			i = fs->super->s_first_data_block;
187	} while (i != goal);
188	return EXT2_ET_BLOCK_ALLOC_FAIL;
189}
190
191errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
192			   ext2fs_block_bitmap map, blk_t *ret)
193{
194	errcode_t retval;
195	blk64_t val;
196	retval = ext2fs_new_block2(fs, goal, map, &val);
197	if (!retval)
198		*ret = (blk_t) val;
199	return retval;
200}
201
202/*
203 * This function zeros out the allocated block, and updates all of the
204 * appropriate filesystem records.
205 */
206errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
207			     char *block_buf, blk64_t *ret)
208{
209	errcode_t	retval;
210	blk64_t		block;
211	char		*buf = 0;
212
213	if (!block_buf) {
214		retval = ext2fs_get_mem(fs->blocksize, &buf);
215		if (retval)
216			return retval;
217		block_buf = buf;
218	}
219	memset(block_buf, 0, fs->blocksize);
220
221	if (fs->get_alloc_block) {
222		retval = (fs->get_alloc_block)(fs, goal, &block);
223		if (retval)
224			goto fail;
225	} else {
226		if (!fs->block_map) {
227			retval = ext2fs_read_block_bitmap(fs);
228			if (retval)
229				goto fail;
230		}
231
232		retval = ext2fs_new_block2(fs, goal, 0, &block);
233		if (retval)
234			goto fail;
235	}
236
237	retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
238	if (retval)
239		goto fail;
240
241	ext2fs_block_alloc_stats2(fs, block, +1);
242	*ret = block;
243
244fail:
245	if (buf)
246		ext2fs_free_mem(&buf);
247	return retval;
248}
249
250errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
251			     char *block_buf, blk_t *ret)
252{
253	errcode_t retval;
254	blk64_t	val;
255	retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
256	if (!retval)
257		*ret = (blk_t) val;
258	return retval;
259}
260
261errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
262				 int num, ext2fs_block_bitmap map, blk64_t *ret)
263{
264	blk64_t	b = start;
265	int	c_ratio;
266
267	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
268
269	if (!map)
270		map = fs->block_map;
271	if (!map)
272		return EXT2_ET_NO_BLOCK_BITMAP;
273	if (!b)
274		b = fs->super->s_first_data_block;
275	if (!finish)
276		finish = start;
277	if (!num)
278		num = 1;
279	c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
280	b &= ~(c_ratio - 1);
281	finish &= ~(c_ratio -1);
282	do {
283		if (b+num-1 > ext2fs_blocks_count(fs->super))
284			b = fs->super->s_first_data_block;
285		if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
286			*ret = b;
287			return 0;
288		}
289		b += c_ratio;
290	} while (b != finish);
291	return EXT2_ET_BLOCK_ALLOC_FAIL;
292}
293
294errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
295				 int num, ext2fs_block_bitmap map, blk_t *ret)
296{
297	errcode_t retval;
298	blk64_t val;
299	retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
300	if(!retval)
301		*ret = (blk_t) val;
302	return retval;
303}
304
305void ext2fs_set_alloc_block_callback(ext2_filsys fs,
306				     errcode_t (*func)(ext2_filsys fs,
307						       blk64_t goal,
308						       blk64_t *ret),
309				     errcode_t (**old)(ext2_filsys fs,
310						       blk64_t goal,
311						       blk64_t *ret))
312{
313	if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
314		return;
315
316	if (old)
317		*old = fs->get_alloc_block;
318
319	fs->get_alloc_block = func;
320}
321