1/*
2 *  linux/fs/adfs/dir.c
3 *
4 *  Copyright (C) 1999-2000 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10 *  Common directory handling for ADFS
11 */
12#include <linux/errno.h>
13#include <linux/fs.h>
14#include <linux/adfs_fs.h>
15#include <linux/time.h>
16#include <linux/stat.h>
17#include <linux/spinlock.h>
18#include <linux/smp_lock.h>
19#include <linux/buffer_head.h>		/* for file_fsync() */
20
21#include "adfs.h"
22
23/*
24 * For future.  This should probably be per-directory.
25 */
26static DEFINE_RWLOCK(adfs_dir_lock);
27
28static int
29adfs_readdir(struct file *filp, void *dirent, filldir_t filldir)
30{
31	struct inode *inode = filp->f_path.dentry->d_inode;
32	struct super_block *sb = inode->i_sb;
33	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
34	struct object_info obj;
35	struct adfs_dir dir;
36	int ret = 0;
37
38	lock_kernel();
39
40	if (filp->f_pos >> 32)
41		goto out;
42
43	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
44	if (ret)
45		goto out;
46
47	switch ((unsigned long)filp->f_pos) {
48	case 0:
49		if (filldir(dirent, ".", 1, 0, inode->i_ino, DT_DIR) < 0)
50			goto free_out;
51		filp->f_pos += 1;
52
53	case 1:
54		if (filldir(dirent, "..", 2, 1, dir.parent_id, DT_DIR) < 0)
55			goto free_out;
56		filp->f_pos += 1;
57
58	default:
59		break;
60	}
61
62	read_lock(&adfs_dir_lock);
63
64	ret = ops->setpos(&dir, filp->f_pos - 2);
65	if (ret)
66		goto unlock_out;
67	while (ops->getnext(&dir, &obj) == 0) {
68		if (filldir(dirent, obj.name, obj.name_len,
69			    filp->f_pos, obj.file_id, DT_UNKNOWN) < 0)
70			goto unlock_out;
71		filp->f_pos += 1;
72	}
73
74unlock_out:
75	read_unlock(&adfs_dir_lock);
76
77free_out:
78	ops->free(&dir);
79
80out:
81	unlock_kernel();
82	return ret;
83}
84
85int
86adfs_dir_update(struct super_block *sb, struct object_info *obj)
87{
88	int ret = -EINVAL;
89#ifdef CONFIG_ADFS_FS_RW
90	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
91	struct adfs_dir dir;
92
93	printk(KERN_INFO "adfs_dir_update: object %06X in dir %06X\n",
94		 obj->file_id, obj->parent_id);
95
96	if (!ops->update) {
97		ret = -EINVAL;
98		goto out;
99	}
100
101	ret = ops->read(sb, obj->parent_id, 0, &dir);
102	if (ret)
103		goto out;
104
105	write_lock(&adfs_dir_lock);
106	ret = ops->update(&dir, obj);
107	write_unlock(&adfs_dir_lock);
108
109	ops->free(&dir);
110out:
111#endif
112	return ret;
113}
114
115static int
116adfs_match(struct qstr *name, struct object_info *obj)
117{
118	int i;
119
120	if (name->len != obj->name_len)
121		return 0;
122
123	for (i = 0; i < name->len; i++) {
124		char c1, c2;
125
126		c1 = name->name[i];
127		c2 = obj->name[i];
128
129		if (c1 >= 'A' && c1 <= 'Z')
130			c1 += 'a' - 'A';
131		if (c2 >= 'A' && c2 <= 'Z')
132			c2 += 'a' - 'A';
133
134		if (c1 != c2)
135			return 0;
136	}
137	return 1;
138}
139
140static int
141adfs_dir_lookup_byname(struct inode *inode, struct qstr *name, struct object_info *obj)
142{
143	struct super_block *sb = inode->i_sb;
144	struct adfs_dir_ops *ops = ADFS_SB(sb)->s_dir;
145	struct adfs_dir dir;
146	int ret;
147
148	ret = ops->read(sb, inode->i_ino, inode->i_size, &dir);
149	if (ret)
150		goto out;
151
152	if (ADFS_I(inode)->parent_id != dir.parent_id) {
153		adfs_error(sb, "parent directory changed under me! (%lx but got %lx)\n",
154			   ADFS_I(inode)->parent_id, dir.parent_id);
155		ret = -EIO;
156		goto free_out;
157	}
158
159	obj->parent_id = inode->i_ino;
160
161	/*
162	 * '.' is handled by reserved_lookup() in fs/namei.c
163	 */
164	if (name->len == 2 && name->name[0] == '.' && name->name[1] == '.') {
165		/*
166		 * Currently unable to fill in the rest of 'obj',
167		 * but this is better than nothing.  We need to
168		 * ascend one level to find it's parent.
169		 */
170		obj->name_len = 0;
171		obj->file_id  = obj->parent_id;
172		goto free_out;
173	}
174
175	read_lock(&adfs_dir_lock);
176
177	ret = ops->setpos(&dir, 0);
178	if (ret)
179		goto unlock_out;
180
181	ret = -ENOENT;
182	while (ops->getnext(&dir, obj) == 0) {
183		if (adfs_match(name, obj)) {
184			ret = 0;
185			break;
186		}
187	}
188
189unlock_out:
190	read_unlock(&adfs_dir_lock);
191
192free_out:
193	ops->free(&dir);
194out:
195	return ret;
196}
197
198const struct file_operations adfs_dir_operations = {
199	.read		= generic_read_dir,
200	.readdir	= adfs_readdir,
201	.fsync		= file_fsync,
202};
203
204static int
205adfs_hash(struct dentry *parent, struct qstr *qstr)
206{
207	const unsigned int name_len = ADFS_SB(parent->d_sb)->s_namelen;
208	const unsigned char *name;
209	unsigned long hash;
210	int i;
211
212	if (qstr->len < name_len)
213		return 0;
214
215	/*
216	 * Truncate the name in place, avoids
217	 * having to define a compare function.
218	 */
219	qstr->len = i = name_len;
220	name = qstr->name;
221	hash = init_name_hash();
222	while (i--) {
223		char c;
224
225		c = *name++;
226		if (c >= 'A' && c <= 'Z')
227			c += 'a' - 'A';
228
229		hash = partial_name_hash(c, hash);
230	}
231	qstr->hash = end_name_hash(hash);
232
233	return 0;
234}
235
236/*
237 * Compare two names, taking note of the name length
238 * requirements of the underlying filesystem.
239 */
240static int
241adfs_compare(struct dentry *parent, struct qstr *entry, struct qstr *name)
242{
243	int i;
244
245	if (entry->len != name->len)
246		return 1;
247
248	for (i = 0; i < name->len; i++) {
249		char a, b;
250
251		a = entry->name[i];
252		b = name->name[i];
253
254		if (a >= 'A' && a <= 'Z')
255			a += 'a' - 'A';
256		if (b >= 'A' && b <= 'Z')
257			b += 'a' - 'A';
258
259		if (a != b)
260			return 1;
261	}
262	return 0;
263}
264
265struct dentry_operations adfs_dentry_operations = {
266	.d_hash		= adfs_hash,
267	.d_compare	= adfs_compare,
268};
269
270static struct dentry *
271adfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
272{
273	struct inode *inode = NULL;
274	struct object_info obj;
275	int error;
276
277	dentry->d_op = &adfs_dentry_operations;
278	lock_kernel();
279	error = adfs_dir_lookup_byname(dir, &dentry->d_name, &obj);
280	if (error == 0) {
281		error = -EACCES;
282		/*
283		 * This only returns NULL if get_empty_inode
284		 * fails.
285		 */
286		inode = adfs_iget(dir->i_sb, &obj);
287		if (inode)
288			error = 0;
289	}
290	unlock_kernel();
291	d_add(dentry, inode);
292	return ERR_PTR(error);
293}
294
295/*
296 * directories can handle most operations...
297 */
298const struct inode_operations adfs_dir_inode_operations = {
299	.lookup		= adfs_lookup,
300	.setattr	= adfs_notify_change,
301};
302