dblist.c revision a6ce1349539f866334ef3d5758bc2ee44a454acd 
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 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 <string.h>
17#include <time.h>
18
19#include "ext2_fs.h"
20#include "ext2fsP.h"
21
22static EXT2_QSORT_TYPE dir_block_cmp(const void *a, const void *b);
23
24/*
25 * Returns the number of directories in the filesystem as reported by
26 * the group descriptors.  Of course, the group descriptors could be
27 * wrong!
28 */
29errcode_t ext2fs_get_num_dirs(ext2_filsys fs, ext2_ino_t *ret_num_dirs)
30{
31	dgrp_t	i;
32	ext2_ino_t	num_dirs, max_dirs;
33
34	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
35
36	num_dirs = 0;
37	max_dirs = fs->super->s_inodes_per_group;
38	for (i = 0; i < fs->group_desc_count; i++) {
39		if (fs->group_desc[i].bg_used_dirs_count > max_dirs)
40			num_dirs += max_dirs / 8;
41		else
42			num_dirs += fs->group_desc[i].bg_used_dirs_count;
43	}
44	if (num_dirs > fs->super->s_inodes_count)
45		num_dirs = fs->super->s_inodes_count;
46
47	*ret_num_dirs = num_dirs;
48
49	return 0;
50}
51
52/*
53 * helper function for making a new directory block list (for
54 * initialize and copy).
55 */
56static errcode_t make_dblist(ext2_filsys fs, ext2_ino_t size, ext2_ino_t count,
57			     struct ext2_db_entry *list,
58			     ext2_dblist *ret_dblist)
59{
60	ext2_dblist	dblist;
61	errcode_t	retval;
62	size_t		len;
63
64	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
65
66	if ((ret_dblist == 0) && fs->dblist &&
67	    (fs->dblist->magic == EXT2_ET_MAGIC_DBLIST))
68		return 0;
69
70	retval = ext2fs_get_mem(sizeof(struct ext2_struct_dblist), &dblist);
71	if (retval)
72		return retval;
73	memset(dblist, 0, sizeof(struct ext2_struct_dblist));
74
75	dblist->magic = EXT2_ET_MAGIC_DBLIST;
76	dblist->fs = fs;
77	if (size)
78		dblist->size = size;
79	else {
80		retval = ext2fs_get_num_dirs(fs, &dblist->size);
81		if (retval)
82			goto cleanup;
83		dblist->size = (dblist->size * 2) + 12;
84	}
85	len = (size_t) sizeof(struct ext2_db_entry) * dblist->size;
86	dblist->count = count;
87	retval = ext2fs_get_array(dblist->size, sizeof(struct ext2_db_entry),
88		&dblist->list);
89	if (retval)
90		goto cleanup;
91
92	if (list)
93		memcpy(dblist->list, list, len);
94	else
95		memset(dblist->list, 0, len);
96	if (ret_dblist)
97		*ret_dblist = dblist;
98	else
99		fs->dblist = dblist;
100	return 0;
101cleanup:
102	if (dblist)
103		ext2fs_free_mem(&dblist);
104	return retval;
105}
106
107/*
108 * Initialize a directory block list
109 */
110errcode_t ext2fs_init_dblist(ext2_filsys fs, ext2_dblist *ret_dblist)
111{
112	ext2_dblist	dblist;
113	errcode_t	retval;
114
115	retval = make_dblist(fs, 0, 0, 0, &dblist);
116	if (retval)
117		return retval;
118
119	dblist->sorted = 1;
120	if (ret_dblist)
121		*ret_dblist = dblist;
122	else
123		fs->dblist = dblist;
124
125	return 0;
126}
127
128/*
129 * Copy a directory block list
130 */
131errcode_t ext2fs_copy_dblist(ext2_dblist src, ext2_dblist *dest)
132{
133	ext2_dblist	dblist;
134	errcode_t	retval;
135
136	retval = make_dblist(src->fs, src->size, src->count, src->list,
137			     &dblist);
138	if (retval)
139		return retval;
140	dblist->sorted = src->sorted;
141	*dest = dblist;
142	return 0;
143}
144
145/*
146 * Close a directory block list
147 *
148 * (moved to closefs.c)
149 */
150
151
152/*
153 * Add a directory block to the directory block list
154 */
155errcode_t ext2fs_add_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
156			       int blockcnt)
157{
158	struct ext2_db_entry 	*new_entry;
159	errcode_t		retval;
160	unsigned long		old_size;
161
162	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
163
164	if (dblist->count >= dblist->size) {
165		old_size = dblist->size * sizeof(struct ext2_db_entry);
166		dblist->size += dblist->size > 200 ? dblist->size / 2 : 100;
167		retval = ext2fs_resize_mem(old_size, (size_t) dblist->size *
168					   sizeof(struct ext2_db_entry),
169					   &dblist->list);
170		if (retval) {
171			dblist->size -= 100;
172			return retval;
173		}
174	}
175	new_entry = dblist->list + ( (int) dblist->count++);
176	new_entry->blk = blk;
177	new_entry->ino = ino;
178	new_entry->blockcnt = blockcnt;
179
180	dblist->sorted = 0;
181
182	return 0;
183}
184
185/*
186 * Change the directory block to the directory block list
187 */
188errcode_t ext2fs_set_dir_block(ext2_dblist dblist, ext2_ino_t ino, blk_t blk,
189			       int blockcnt)
190{
191	dgrp_t			i;
192
193	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
194
195	for (i=0; i < dblist->count; i++) {
196		if ((dblist->list[i].ino != ino) ||
197		    (dblist->list[i].blockcnt != blockcnt))
198			continue;
199		dblist->list[i].blk = blk;
200		dblist->sorted = 0;
201		return 0;
202	}
203	return EXT2_ET_DB_NOT_FOUND;
204}
205
206void ext2fs_dblist_sort(ext2_dblist dblist,
207			EXT2_QSORT_TYPE (*sortfunc)(const void *,
208						    const void *))
209{
210	if (!sortfunc)
211		sortfunc = dir_block_cmp;
212	qsort(dblist->list, (size_t) dblist->count,
213	      sizeof(struct ext2_db_entry), sortfunc);
214	dblist->sorted = 1;
215}
216
217/*
218 * This function iterates over the directory block list
219 */
220errcode_t ext2fs_dblist_iterate(ext2_dblist dblist,
221				int (*func)(ext2_filsys fs,
222					    struct ext2_db_entry *db_info,
223					    void	*priv_data),
224				void *priv_data)
225{
226	ext2_ino_t	i;
227	int		ret;
228
229	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
230
231	if (!dblist->sorted)
232		ext2fs_dblist_sort(dblist, 0);
233	for (i=0; i < dblist->count; i++) {
234		ret = (*func)(dblist->fs, &dblist->list[(int)i], priv_data);
235		if (ret & DBLIST_ABORT)
236			return 0;
237	}
238	return 0;
239}
240
241static EXT2_QSORT_TYPE dir_block_cmp(const void *a, const void *b)
242{
243	const struct ext2_db_entry *db_a =
244		(const struct ext2_db_entry *) a;
245	const struct ext2_db_entry *db_b =
246		(const struct ext2_db_entry *) b;
247
248	if (db_a->blk != db_b->blk)
249		return (int) (db_a->blk - db_b->blk);
250
251	if (db_a->ino != db_b->ino)
252		return (int) (db_a->ino - db_b->ino);
253
254	return (int) (db_a->blockcnt - db_b->blockcnt);
255}
256
257int ext2fs_dblist_count(ext2_dblist dblist)
258{
259	return (int) dblist->count;
260}
261
262errcode_t ext2fs_dblist_get_last(ext2_dblist dblist,
263				 struct ext2_db_entry **entry)
264{
265	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
266
267	if (dblist->count == 0)
268		return EXT2_ET_DBLIST_EMPTY;
269
270	if (entry)
271		*entry = dblist->list + ( (int) dblist->count-1);
272	return 0;
273}
274
275errcode_t ext2fs_dblist_drop_last(ext2_dblist dblist)
276{
277	EXT2_CHECK_MAGIC(dblist, EXT2_ET_MAGIC_DBLIST);
278
279	if (dblist->count == 0)
280		return EXT2_ET_DBLIST_EMPTY;
281
282	dblist->count--;
283	return 0;
284}
285