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/time.h>
17 #include <linux/fs.h>
18 #include <linux/qnx4_fs.h>
19 #include <linux/kernel.h>
20 #include <linux/string.h>
21 #include <linux/stat.h>
22 #include <linux/fcntl.h>
23 #include <linux/errno.h>
24 #include <linux/smp_lock.h>
25 #include <linux/buffer_head.h>
26
27
28 /*
29 * check if the filename is correct. For some obscure reason, qnx writes a
30 * new file twice in the directory entry, first with all possible options at 0
31 * and for a second time the way it is, they want us not to access the qnx
32 * filesystem when whe are using linux.
33 */
34 static int qnx4_match(int len, const char *name,
35 struct buffer_head *bh, unsigned long *offset)
36 {
37 struct qnx4_inode_entry *de;
38 int namelen, thislen;
39
40 if (bh == NULL) {
41 printk("qnx4: matching unassigned buffer !\n");
42 return 0;
43 }
44 de = (struct qnx4_inode_entry *) (bh->b_data + *offset);
45 *offset += QNX4_DIR_ENTRY_SIZE;
46 if ((de->di_status & QNX4_FILE_LINK) != 0) {
47 namelen = QNX4_NAME_MAX;
48 } else {
49 namelen = QNX4_SHORT_NAME_MAX;
50 }
51 /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
52 if (!len && (de->di_fname[0] == '.') && (de->di_fname[1] == '\0')) {
53 return 1;
54 }
55 thislen = strlen( de->di_fname );
56 if ( thislen > namelen )
57 thislen = namelen;
58 if (len != thislen) {
59 return 0;
60 }
61 if (strncmp(name, de->di_fname, len) == 0) {
62 if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) {
63 return 1;
64 }
65 }
66 return 0;
67 }
68
69 static struct buffer_head *qnx4_find_entry(int len, struct inode *dir,
70 const char *name, struct qnx4_inode_entry **res_dir, int *ino)
71 {
72 unsigned long block, offset, blkofs;
73 struct buffer_head *bh;
74
75 *res_dir = NULL;
76 if (!dir->i_sb) {
77 printk("qnx4: no superblock on dir.\n");
78 return NULL;
79 }
80 bh = NULL;
81 block = offset = blkofs = 0;
82 while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) {
83 if (!bh) {
84 bh = qnx4_bread(dir, blkofs, 0);
85 if (!bh) {
86 blkofs++;
87 continue;
88 }
89 }
90 *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
91 if (qnx4_match(len, name, bh, &offset)) {
92 block = qnx4_block_map( dir, blkofs );
93 *ino = block * QNX4_INODES_PER_BLOCK +
94 (offset / QNX4_DIR_ENTRY_SIZE) - 1;
95 return bh;
96 }
97 if (offset < bh->b_size) {
98 continue;
99 }
100 brelse(bh);
101 bh = NULL;
102 offset = 0;
103 blkofs++;
104 }
105 brelse(bh);
106 *res_dir = NULL;
107 return NULL;
108 }
109
110 struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
111 {
112 int ino;
113 struct qnx4_inode_entry *de;
114 struct qnx4_link_info *lnk;
115 struct buffer_head *bh;
116 const char *name = dentry->d_name.name;
117 int len = dentry->d_name.len;
118 struct inode *foundinode = NULL;
119
120 lock_kernel();
121 if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
122 goto out;
123 /* The entry is linked, let's get the real info */
124 if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) {
125 lnk = (struct qnx4_link_info *) de;
126 ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) *
127 QNX4_INODES_PER_BLOCK +
128 lnk->dl_inode_ndx;
129 }
130 brelse(bh);
131
132 if ((foundinode = iget(dir->i_sb, ino)) == NULL) {
133 unlock_kernel();
134 QNX4DEBUG(("qnx4: lookup->iget -> NULL\n"));
135 return ERR_PTR(-EACCES);
136 }
137 out:
138 unlock_kernel();
139 d_add(dentry, foundinode);
140
141 return NULL;
142 }
143
144 #ifdef CONFIG_QNX4FS_RW
145 int qnx4_create(struct inode *dir, struct dentry *dentry, int mode,
146 struct nameidata *nd)
147 {
148 QNX4DEBUG(("qnx4: qnx4_create\n"));
149 if (dir == NULL) {
150 return -ENOENT;
151 }
152 return -ENOSPC;
153 }
154
155 int qnx4_rmdir(struct inode *dir, struct dentry *dentry)
156 {
157 struct buffer_head *bh;
158 struct qnx4_inode_entry *de;
159 struct inode *inode;
160 int retval;
161 int ino;
162
163 QNX4DEBUG(("qnx4: qnx4_rmdir [%s]\n", dentry->d_name.name));
164 lock_kernel();
165 bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
166 &de, &ino);
167 if (bh == NULL) {
168 unlock_kernel();
169 return -ENOENT;
170 }
171 inode = dentry->d_inode;
172 if (inode->i_ino != ino) {
173 retval = -EIO;
174 goto end_rmdir;
175 }
176 #if 0
177 if (!empty_dir(inode)) {
178 retval = -ENOTEMPTY;
179 goto end_rmdir;
180 }
181 #endif
182 if (inode->i_nlink != 2) {
183 QNX4DEBUG(("empty directory has nlink!=2 (%d)\n", inode->i_nlink));
184 }
185 QNX4DEBUG(("qnx4: deleting directory\n"));
186 de->di_status = 0;
187 memset(de->di_fname, 0, sizeof de->di_fname);
188 de->di_mode = 0;
189 mark_buffer_dirty(bh);
190 inode->i_nlink = 0;
191 mark_inode_dirty(inode);
192 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
193 dir->i_nlink--;
194 mark_inode_dirty(dir);
195 retval = 0;
196
197 end_rmdir:
198 brelse(bh);
199
200 unlock_kernel();
201 return retval;
202 }
203
204 int qnx4_unlink(struct inode *dir, struct dentry *dentry)
205 {
206 struct buffer_head *bh;
207 struct qnx4_inode_entry *de;
208 struct inode *inode;
209 int retval;
210 int ino;
211
212 QNX4DEBUG(("qnx4: qnx4_unlink [%s]\n", dentry->d_name.name));
213 lock_kernel();
214 bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
215 &de, &ino);
216 if (bh == NULL) {
217 unlock_kernel();
218 return -ENOENT;
219 }
220 inode = dentry->d_inode;
221 if (inode->i_ino != ino) {
222 retval = -EIO;
223 goto end_unlink;
224 }
225 retval = -EPERM;
226 if (!inode->i_nlink) {
227 QNX4DEBUG(("Deleting nonexistent file (%s:%lu), %d\n",
228 inode->i_sb->s_id,
229 inode->i_ino, inode->i_nlink));
230 inode->i_nlink = 1;
231 }
232 de->di_status = 0;
233 memset(de->di_fname, 0, sizeof de->di_fname);
234 de->di_mode = 0;
235 mark_buffer_dirty(bh);
236 dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
237 mark_inode_dirty(dir);
238 inode->i_nlink--;
239 inode->i_ctime = dir->i_ctime;
240 mark_inode_dirty(inode);
241 retval = 0;
242
243 end_unlink:
244 unlock_kernel();
245 brelse(bh);
246
247 return retval;
248 }
249 #endif
250
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