xref: /openbmc/linux/fs/qnx4/namei.c (revision e868d61272caa648214046a096e5a6bfc068dc8c)
1 /*
2  * QNX4 file system, Linux implementation.
3  *
4  * Version : 0.2.1
5  *
6  * Using parts of the xiafs filesystem.
7  *
8  * History :
9  *
10  * 01-06-1998 by Richard Frowijn : first release.
11  * 21-06-1998 by Frank Denis : dcache support, fixed error codes.
12  * 04-07-1998 by Frank Denis : first step for rmdir/unlink.
13  */
14 
15 #include <linux/time.h>
16 #include <linux/fs.h>
17 #include <linux/qnx4_fs.h>
18 #include <linux/kernel.h>
19 #include <linux/string.h>
20 #include <linux/stat.h>
21 #include <linux/fcntl.h>
22 #include <linux/errno.h>
23 #include <linux/smp_lock.h>
24 #include <linux/buffer_head.h>
25 
26 
27 /*
28  * check if the filename is correct. For some obscure reason, qnx writes a
29  * new file twice in the directory entry, first with all possible options at 0
30  * and for a second time the way it is, they want us not to access the qnx
31  * filesystem when whe are using linux.
32  */
33 static int qnx4_match(int len, const char *name,
34 		      struct buffer_head *bh, unsigned long *offset)
35 {
36 	struct qnx4_inode_entry *de;
37 	int namelen, thislen;
38 
39 	if (bh == NULL) {
40 		printk("qnx4: matching unassigned buffer !\n");
41 		return 0;
42 	}
43 	de = (struct qnx4_inode_entry *) (bh->b_data + *offset);
44 	*offset += QNX4_DIR_ENTRY_SIZE;
45 	if ((de->di_status & QNX4_FILE_LINK) != 0) {
46 		namelen = QNX4_NAME_MAX;
47 	} else {
48 		namelen = QNX4_SHORT_NAME_MAX;
49 	}
50 	/* "" means "." ---> so paths like "/usr/lib//libc.a" work */
51 	if (!len && (de->di_fname[0] == '.') && (de->di_fname[1] == '\0')) {
52 		return 1;
53 	}
54 	thislen = strlen( de->di_fname );
55 	if ( thislen > namelen )
56 		thislen = namelen;
57 	if (len != thislen) {
58 		return 0;
59 	}
60 	if (strncmp(name, de->di_fname, len) == 0) {
61 		if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) {
62 			return 1;
63 		}
64 	}
65 	return 0;
66 }
67 
68 static struct buffer_head *qnx4_find_entry(int len, struct inode *dir,
69 	   const char *name, struct qnx4_inode_entry **res_dir, int *ino)
70 {
71 	unsigned long block, offset, blkofs;
72 	struct buffer_head *bh;
73 
74 	*res_dir = NULL;
75 	if (!dir->i_sb) {
76 		printk("qnx4: no superblock on dir.\n");
77 		return NULL;
78 	}
79 	bh = NULL;
80 	block = offset = blkofs = 0;
81 	while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) {
82 		if (!bh) {
83 			bh = qnx4_bread(dir, blkofs, 0);
84 			if (!bh) {
85 				blkofs++;
86 				continue;
87 			}
88 		}
89 		*res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
90 		if (qnx4_match(len, name, bh, &offset)) {
91 			block = qnx4_block_map( dir, blkofs );
92 			*ino = block * QNX4_INODES_PER_BLOCK +
93 			    (offset / QNX4_DIR_ENTRY_SIZE) - 1;
94 			return bh;
95 		}
96 		if (offset < bh->b_size) {
97 			continue;
98 		}
99 		brelse(bh);
100 		bh = NULL;
101 		offset = 0;
102 		blkofs++;
103 	}
104 	brelse(bh);
105 	*res_dir = NULL;
106 	return NULL;
107 }
108 
109 struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
110 {
111 	int ino;
112 	struct qnx4_inode_entry *de;
113 	struct qnx4_link_info *lnk;
114 	struct buffer_head *bh;
115 	const char *name = dentry->d_name.name;
116 	int len = dentry->d_name.len;
117 	struct inode *foundinode = NULL;
118 
119 	lock_kernel();
120 	if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
121 		goto out;
122 	/* The entry is linked, let's get the real info */
123 	if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) {
124 		lnk = (struct qnx4_link_info *) de;
125 		ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) *
126                     QNX4_INODES_PER_BLOCK +
127 		    lnk->dl_inode_ndx;
128 	}
129 	brelse(bh);
130 
131 	if ((foundinode = iget(dir->i_sb, ino)) == NULL) {
132 		unlock_kernel();
133 		QNX4DEBUG(("qnx4: lookup->iget -> NULL\n"));
134 		return ERR_PTR(-EACCES);
135 	}
136 out:
137 	unlock_kernel();
138 	d_add(dentry, foundinode);
139 
140 	return NULL;
141 }
142 
143 #ifdef CONFIG_QNX4FS_RW
144 int qnx4_create(struct inode *dir, struct dentry *dentry, int mode,
145 		struct nameidata *nd)
146 {
147 	QNX4DEBUG(("qnx4: qnx4_create\n"));
148 	if (dir == NULL) {
149 		return -ENOENT;
150 	}
151 	return -ENOSPC;
152 }
153 
154 int qnx4_rmdir(struct inode *dir, struct dentry *dentry)
155 {
156 	struct buffer_head *bh;
157 	struct qnx4_inode_entry *de;
158 	struct inode *inode;
159 	int retval;
160 	int ino;
161 
162 	QNX4DEBUG(("qnx4: qnx4_rmdir [%s]\n", dentry->d_name.name));
163 	lock_kernel();
164 	bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
165 			     &de, &ino);
166 	if (bh == NULL) {
167 		unlock_kernel();
168 		return -ENOENT;
169 	}
170 	inode = dentry->d_inode;
171 	if (inode->i_ino != ino) {
172 		retval = -EIO;
173 		goto end_rmdir;
174 	}
175 #if 0
176 	if (!empty_dir(inode)) {
177 		retval = -ENOTEMPTY;
178 		goto end_rmdir;
179 	}
180 #endif
181 	if (inode->i_nlink != 2) {
182 		QNX4DEBUG(("empty directory has nlink!=2 (%d)\n", inode->i_nlink));
183 	}
184 	QNX4DEBUG(("qnx4: deleting directory\n"));
185 	de->di_status = 0;
186 	memset(de->di_fname, 0, sizeof de->di_fname);
187 	de->di_mode = 0;
188 	mark_buffer_dirty(bh);
189 	clear_nlink(inode);
190 	mark_inode_dirty(inode);
191 	inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
192 	inode_dec_link_count(dir);
193 	retval = 0;
194 
195       end_rmdir:
196 	brelse(bh);
197 
198 	unlock_kernel();
199 	return retval;
200 }
201 
202 int qnx4_unlink(struct inode *dir, struct dentry *dentry)
203 {
204 	struct buffer_head *bh;
205 	struct qnx4_inode_entry *de;
206 	struct inode *inode;
207 	int retval;
208 	int ino;
209 
210 	QNX4DEBUG(("qnx4: qnx4_unlink [%s]\n", dentry->d_name.name));
211 	lock_kernel();
212 	bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
213 			     &de, &ino);
214 	if (bh == NULL) {
215 		unlock_kernel();
216 		return -ENOENT;
217 	}
218 	inode = dentry->d_inode;
219 	if (inode->i_ino != ino) {
220 		retval = -EIO;
221 		goto end_unlink;
222 	}
223 	retval = -EPERM;
224 	if (!inode->i_nlink) {
225 		QNX4DEBUG(("Deleting nonexistent file (%s:%lu), %d\n",
226 			   inode->i_sb->s_id,
227 			   inode->i_ino, inode->i_nlink));
228 		inode->i_nlink = 1;
229 	}
230 	de->di_status = 0;
231 	memset(de->di_fname, 0, sizeof de->di_fname);
232 	de->di_mode = 0;
233 	mark_buffer_dirty(bh);
234 	dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
235 	mark_inode_dirty(dir);
236 	inode->i_ctime = dir->i_ctime;
237 	inode_dec_link_count(inode);
238 	retval = 0;
239 
240 end_unlink:
241 	unlock_kernel();
242 	brelse(bh);
243 
244 	return retval;
245 }
246 #endif
247