dblist.c revision 4c77fe50d97a773e32a4756c79dade3adbb6a601 
1/*
2 * dblist.c -- directory block list functions
3 *
4 * Copyright 1997 by 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 <string.h>
18#include <time.h>
19
20#if EXT2_FLAT_INCLUDES
21#include "ext2_fs.h"
22#else
23#include <linux/ext2_fs.h>
24#endif
25
26#include "ext2fsP.h"
27
28static EXT2_QSORT_TYPE dir_block_cmp(const void *a, const void *b);
29
30/*
31 * Returns the number of directories in the filesystem as reported by
32 * the group descriptors.  Of course, the group descriptors could be
33 * wrong!
34 */
35errcode_t ext2fs_get_num_dirs(ext2_filsys fs, ino_t *ret_num_dirs)
36{
37	int	i;
38	ino_t	num_dirs, max_dirs;
39
40	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
41
42	num_dirs = 0;
43	max_dirs = fs->super->s_inodes_per_group;
44	for (i = 0; i < fs->group_desc_count; i++) {
45		if (fs->group_desc[i].bg_used_dirs_count > max_dirs)
46			num_dirs += max_dirs / 8;
47		else
48			num_dirs += fs->group_desc[i].bg_used_dirs_count;
49	}
50	if (num_dirs > fs->super->s_inodes_count)
51		num_dirs = fs->super->s_inodes_count;
52
53	*ret_num_dirs = num_dirs;
54
55	return 0;
56}
57
58/*
59 * helper function for making a new directory block list (for
60 * initialize and copy).
61 */
62static errcode_t make_dblist(ext2_filsys fs, ino_t size, ino_t count,
63			     struct ext2_db_entry *list,
64			     ext2_dblist *ret_dblist)
65{
66	ext2_dblist	dblist;
67	errcode_t	retval;
68	size_t		len;
69
70	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
71
72	if ((ret_dblist == 0) && fs->dblist &&
73	    (fs->dblist->magic == EXT2_ET_MAGIC_DBLIST))
74		return 0;
75
76	retval = ext2fs_get_mem(sizeof(struct ext2_struct_dblist),
77				(void **) &dblist);
78	if (retval)
79		return retval;
80	memset(dblist, 0, sizeof(struct ext2_struct_dblist));
81
82	dblist->magic = EXT2_ET_MAGIC_DBLIST;
83	dblist->fs = fs;
84	if (size)
85		dblist->size = size;
86	else {
87		retval = ext2fs_get_num_dirs(fs, &dblist->size);
88		if (retval)
89			goto cleanup;
90		dblist->size = (dblist->size * 2) + 12;
91	}
92	len = (size_t) sizeof(struct ext2_db_entry) * dblist->size;
93	dblist->count = count;
94	retval = ext2fs_get_mem(len, (void **) &dblist->list);
95	if (retval)
96		goto cleanup;
97
98	if (list)
99		memcpy(dblist->list, list, len);
100	else
101		memset(dblist->list, 0, len);
102	*ret_dblist = dblist;
103	return 0;
104cleanup:
105	if (dblist)
106		ext2fs_free_mem((void **) &dblist);
107	return retval;
108}
109
110/*
111 * Initialize a directory block list
112 */
113errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
114{
115	ext2_dblist	dblist;
116	errcode_t	retval;
117
118	retval = make_dblist(fs, 0, 0, 0, &dblist);
119	if (retval)
120		return retval;
121
122	dblist->sorted = 1;
123	if (ret_dblist)
124		*ret_dblist = dblist;
125	else
126		fs->dblist = dblist;
127
128	return 0;
129}
130
131/*
132 * Copy a directory block list
133 */
134errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
135{
136	ext2_dblist	dblist;
137	errcode_t	retval;
138
139	retval = make_dblist(src->fs, src->size, src->count, src->list,
140			     &dblist);
141	if (retval)
142		return retval;
143	dblist->sorted = src->sorted;
144	*dest = dblist;
145	return 0;
146}
147
148/*
149 * Close a directory block list
150 *
151 * (moved to closefs.c)
152 */
153
154
155/*
156 * Add a directory block to the directory block list
157 */
158errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ino_t ino, blk_t blk,
159			       int blockcnt)
160{
161	struct ext2_db_entry 	*new_entry;
162	errcode_t		retval;
163	unsigned long		old_size;
164
165	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
166
167	if (dblist->count >= dblist->size) {
168		old_size = dblist->size * sizeof(struct ext2_db_entry);
169		dblist->size += 100;
170		retval = ext2fs_resize_mem(old_size, (size_t) dblist->size *
171					   sizeof(struct ext2_db_entry),
172					   (void **) &dblist->list);
173		if (retval) {
174			dblist->size -= 100;
175			return retval;
176		}
177	}
178	new_entry = dblist->list + ( (int) dblist->count++);
179	new_entry->blk = blk;
180	new_entry->ino = ino;
181	new_entry->blockcnt = blockcnt;
182
183	dblist->sorted = 0;
184
185	return 0;
186}
187
188/*
189 * Change the directory block to the directory block list
190 */
191errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ino_t ino, blk_t blk,
192			       int blockcnt)
193{
194	int			i;
195
196	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
197
198	for (i=0; i < dblist->count; i++) {
199		if ((dblist->list[i].ino != ino) ||
200		    (dblist->list[i].blockcnt != blockcnt))
201			continue;
202		dblist->list[i].blk = blk;
203		dblist->sorted = 0;
204		return 0;
205	}
206	return EXT2_ET_DB_NOT_FOUND;
207}
208
209/*
210 * This function iterates over the directory block list
211 */
212errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
213				int (*func)(ext2_filsys fs,
214					    struct ext2_db_entry *db_info,
215					    void	*priv_data),
216				void *priv_data)
217{
218	ino_t	i;
219	int	ret;
220
221	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
222
223	if (!dblist->sorted) {
224		qsort(dblist->list, (size_t) dblist->count,
225		      sizeof(struct ext2_db_entry), dir_block_cmp);
226		dblist->sorted = 1;
227	}
228	for (i=0; i < dblist->count; i++) {
229		ret = (*func)(dblist->fs, &dblist->list[(int)i], priv_data);
230		if (ret & DBLIST_ABORT)
231			return 0;
232	}
233	return 0;
234}
235
236
237static EXT2_QSORT_TYPE dir_block_cmp(const void *a, const void *b)
238{
239	const struct ext2_db_entry *db_a =
240		(const struct ext2_db_entry *) a;
241	const struct ext2_db_entry *db_b =
242		(const struct ext2_db_entry *) b;
243
244	if (db_a->blk != db_b->blk)
245		return (int) (db_a->blk - db_b->blk);
246
247	if (db_a->ino != db_b->ino)
248		return (int) (db_a->ino - db_b->ino);
249
250	return (int) (db_a->blockcnt - db_b->blockcnt);
251}
252
253int ext2fs_dblist_count(ext2_dblist dblist)
254{
255	return (int) dblist->count;
256}
257