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