alloc.c revision 027b0577d4e5081a4d28dff9289559d38a36d533 
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 = ext2fs_group_first_block2(fs, group);
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	blk = ext2fs_group_first_block2(fs, group);
59	for (i=0; i < fs->super->s_blocks_per_group; i++, blk++) {
60		if ((blk == super_blk) ||
61		    (old_desc_blk && old_desc_blocks &&
62		     (blk >= old_desc_blk) &&
63		     (blk < old_desc_blk + old_desc_blocks)) ||
64		    (new_desc_blk && (blk == new_desc_blk)) ||
65		    (blk == ext2fs_block_bitmap_loc(fs, group)) ||
66		    (blk == ext2fs_inode_bitmap_loc(fs, group)) ||
67		    (blk >= ext2fs_inode_table_loc(fs, group) &&
68		     (blk < ext2fs_inode_table_loc(fs, group)
69		      + fs->inode_blocks_per_group)))
70			ext2fs_fast_mark_block_bitmap2(map, blk);
71	}
72	ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
73	ext2fs_group_desc_csum_set(fs, group);
74	ext2fs_mark_super_dirty(fs);
75	ext2fs_mark_bb_dirty(fs);
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	ext2fs_group_desc_csum_set(fs, group);
97	ext2fs_mark_ib_dirty(fs);
98	ext2fs_mark_super_dirty(fs);
99	check_block_uninit(fs, fs->block_map, group);
100}
101
102/*
103 * Right now, just search forward from the parent directory's block
104 * group to find the next free inode.
105 *
106 * Should have a special policy for directories.
107 */
108errcode_t ext2fs_new_inode(ext2_filsys fs, ext2_ino_t dir,
109			   int mode EXT2FS_ATTR((unused)),
110			   ext2fs_inode_bitmap map, ext2_ino_t *ret)
111{
112	ext2_ino_t	start_inode = 0;
113	ext2_ino_t	i, ino_in_group, upto, first_zero;
114	errcode_t	retval;
115	dgrp_t		group;
116
117	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
118
119	if (!map)
120		map = fs->inode_map;
121	if (!map)
122		return EXT2_ET_NO_INODE_BITMAP;
123
124	if (dir > 0) {
125		group = (dir - 1) / EXT2_INODES_PER_GROUP(fs->super);
126		start_inode = (group * EXT2_INODES_PER_GROUP(fs->super)) + 1;
127	}
128	if (start_inode < EXT2_FIRST_INODE(fs->super))
129		start_inode = EXT2_FIRST_INODE(fs->super);
130	if (start_inode > fs->super->s_inodes_count)
131		return EXT2_ET_INODE_ALLOC_FAIL;
132	i = start_inode;
133	do {
134		ino_in_group = (i - 1) % EXT2_INODES_PER_GROUP(fs->super);
135		group = (i - 1) / EXT2_INODES_PER_GROUP(fs->super);
136
137		check_inode_uninit(fs, map, group);
138		upto = i + (EXT2_INODES_PER_GROUP(fs->super) - ino_in_group);
139		if (i < start_inode && upto >= start_inode)
140			upto = start_inode - 1;
141		if (upto > fs->super->s_inodes_count)
142			upto = fs->super->s_inodes_count;
143
144		retval = ext2fs_find_first_zero_inode_bitmap2(map, i, upto,
145							      &first_zero);
146		if (retval == 0) {
147			i = first_zero;
148			break;
149		}
150		if (retval != ENOENT)
151			return EXT2_ET_INODE_ALLOC_FAIL;
152		i = upto + 1;
153		if (i > fs->super->s_inodes_count)
154			i = EXT2_FIRST_INODE(fs->super);
155	} while (i != start_inode);
156
157	if (ext2fs_test_inode_bitmap2(map, i))
158		return EXT2_ET_INODE_ALLOC_FAIL;
159	*ret = i;
160	return 0;
161}
162
163/*
164 * Stupid algorithm --- we now just search forward starting from the
165 * goal.  Should put in a smarter one someday....
166 */
167errcode_t ext2fs_new_block2(ext2_filsys fs, blk64_t goal,
168			   ext2fs_block_bitmap map, blk64_t *ret)
169{
170	blk64_t	i;
171	int	c_ratio;
172
173	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
174
175	if (!map)
176		map = fs->block_map;
177	if (!map)
178		return EXT2_ET_NO_BLOCK_BITMAP;
179	if (!goal || (goal >= ext2fs_blocks_count(fs->super)))
180		goal = fs->super->s_first_data_block;
181	i = goal;
182	c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
183	if (c_ratio > 1)
184		goal &= ~EXT2FS_CLUSTER_MASK(fs);
185	check_block_uninit(fs, map,
186			   (i - fs->super->s_first_data_block) /
187			   EXT2_BLOCKS_PER_GROUP(fs->super));
188	do {
189		if (((i - fs->super->s_first_data_block) %
190		     EXT2_BLOCKS_PER_GROUP(fs->super)) == 0)
191			check_block_uninit(fs, map,
192					   (i - fs->super->s_first_data_block) /
193					   EXT2_BLOCKS_PER_GROUP(fs->super));
194
195		if (!ext2fs_fast_test_block_bitmap2(map, i)) {
196			*ret = i;
197			return 0;
198		}
199		i = (i + c_ratio) & ~(c_ratio - 1);
200		if (i >= ext2fs_blocks_count(fs->super))
201			i = fs->super->s_first_data_block;
202	} while (i != goal);
203	return EXT2_ET_BLOCK_ALLOC_FAIL;
204}
205
206errcode_t ext2fs_new_block(ext2_filsys fs, blk_t goal,
207			   ext2fs_block_bitmap map, blk_t *ret)
208{
209	errcode_t retval;
210	blk64_t val;
211	retval = ext2fs_new_block2(fs, goal, map, &val);
212	if (!retval)
213		*ret = (blk_t) val;
214	return retval;
215}
216
217/*
218 * This function zeros out the allocated block, and updates all of the
219 * appropriate filesystem records.
220 */
221errcode_t ext2fs_alloc_block2(ext2_filsys fs, blk64_t goal,
222			     char *block_buf, blk64_t *ret)
223{
224	errcode_t	retval;
225	blk64_t		block;
226	char		*buf = 0;
227
228	if (!block_buf) {
229		retval = ext2fs_get_mem(fs->blocksize, &buf);
230		if (retval)
231			return retval;
232		block_buf = buf;
233	}
234	memset(block_buf, 0, fs->blocksize);
235
236	if (fs->get_alloc_block) {
237		retval = (fs->get_alloc_block)(fs, goal, &block);
238		if (retval)
239			goto fail;
240	} else {
241		if (!fs->block_map) {
242			retval = ext2fs_read_block_bitmap(fs);
243			if (retval)
244				goto fail;
245		}
246
247		retval = ext2fs_new_block2(fs, goal, 0, &block);
248		if (retval)
249			goto fail;
250	}
251
252	retval = io_channel_write_blk64(fs->io, block, 1, block_buf);
253	if (retval)
254		goto fail;
255
256	ext2fs_block_alloc_stats2(fs, block, +1);
257	*ret = block;
258
259fail:
260	if (buf)
261		ext2fs_free_mem(&buf);
262	return retval;
263}
264
265errcode_t ext2fs_alloc_block(ext2_filsys fs, blk_t goal,
266			     char *block_buf, blk_t *ret)
267{
268	errcode_t retval;
269	blk64_t	val;
270	retval = ext2fs_alloc_block2(fs, goal, block_buf, &val);
271	if (!retval)
272		*ret = (blk_t) val;
273	return retval;
274}
275
276errcode_t ext2fs_get_free_blocks2(ext2_filsys fs, blk64_t start, blk64_t finish,
277				 int num, ext2fs_block_bitmap map, blk64_t *ret)
278{
279	blk64_t	b = start;
280	int	c_ratio;
281
282	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
283
284	if (!map)
285		map = fs->block_map;
286	if (!map)
287		return EXT2_ET_NO_BLOCK_BITMAP;
288	if (!b)
289		b = fs->super->s_first_data_block;
290	if (!finish)
291		finish = start;
292	if (!num)
293		num = 1;
294	c_ratio = 1 << ext2fs_get_bitmap_granularity(map);
295	b &= ~(c_ratio - 1);
296	finish &= ~(c_ratio -1);
297	do {
298		if (b+num-1 > ext2fs_blocks_count(fs->super))
299			b = fs->super->s_first_data_block;
300		if (ext2fs_fast_test_block_bitmap_range2(map, b, num)) {
301			*ret = b;
302			return 0;
303		}
304		b += c_ratio;
305	} while (b != finish);
306	return EXT2_ET_BLOCK_ALLOC_FAIL;
307}
308
309errcode_t ext2fs_get_free_blocks(ext2_filsys fs, blk_t start, blk_t finish,
310				 int num, ext2fs_block_bitmap map, blk_t *ret)
311{
312	errcode_t retval;
313	blk64_t val;
314	retval = ext2fs_get_free_blocks2(fs, start, finish, num, map, &val);
315	if(!retval)
316		*ret = (blk_t) val;
317	return retval;
318}
319
320void ext2fs_set_alloc_block_callback(ext2_filsys fs,
321				     errcode_t (*func)(ext2_filsys fs,
322						       blk64_t goal,
323						       blk64_t *ret),
324				     errcode_t (**old)(ext2_filsys fs,
325						       blk64_t goal,
326						       blk64_t *ret))
327{
328	if (!fs || fs->magic != EXT2_ET_MAGIC_EXT2FS_FILSYS)
329		return;
330
331	if (old)
332		*old = fs->get_alloc_block;
333
334	fs->get_alloc_block = func;
335}
336