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/smp_lock.h>
16 #include <linux/buffer_head.h>
17 #include "qnx4.h"
18
19
20 /*
21 * check if the filename is correct. For some obscure reason, qnx writes a
22 * new file twice in the directory entry, first with all possible options at 0
23 * and for a second time the way it is, they want us not to access the qnx
24 * filesystem when whe are using linux.
25 */
26 static int qnx4_match(int len, const char *name,
27 struct buffer_head *bh, unsigned long *offset)
28 {
29 struct qnx4_inode_entry *de;
30 int namelen, thislen;
31
32 if (bh == NULL) {
33 printk("qnx4: matching unassigned buffer !\n");
34 return 0;
35 }
36 de = (struct qnx4_inode_entry *) (bh->b_data + *offset);
37 *offset += QNX4_DIR_ENTRY_SIZE;
38 if ((de->di_status & QNX4_FILE_LINK) != 0) {
39 namelen = QNX4_NAME_MAX;
40 } else {
41 namelen = QNX4_SHORT_NAME_MAX;
42 }
43 /* "" means "." ---> so paths like "/usr/lib//libc.a" work */
44 if (!len && (de->di_fname[0] == '.') && (de->di_fname[1] == '\0')) {
45 return 1;
46 }
47 thislen = strlen( de->di_fname );
48 if ( thislen > namelen )
49 thislen = namelen;
50 if (len != thislen) {
51 return 0;
52 }
53 if (strncmp(name, de->di_fname, len) == 0) {
54 if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) {
55 return 1;
56 }
57 }
58 return 0;
59 }
60
61 static struct buffer_head *qnx4_find_entry(int len, struct inode *dir,
62 const char *name, struct qnx4_inode_entry **res_dir, int *ino)
63 {
64 unsigned long block, offset, blkofs;
65 struct buffer_head *bh;
66
67 *res_dir = NULL;
68 if (!dir->i_sb) {
69 printk("qnx4: no superblock on dir.\n");
70 return NULL;
71 }
72 bh = NULL;
73 block = offset = blkofs = 0;
74 while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) {
75 if (!bh) {
76 bh = qnx4_bread(dir, blkofs, 0);
77 if (!bh) {
78 blkofs++;
79 continue;
80 }
81 }
82 *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset);
83 if (qnx4_match(len, name, bh, &offset)) {
84 block = qnx4_block_map( dir, blkofs );
85 *ino = block * QNX4_INODES_PER_BLOCK +
86 (offset / QNX4_DIR_ENTRY_SIZE) - 1;
87 return bh;
88 }
89 if (offset < bh->b_size) {
90 continue;
91 }
92 brelse(bh);
93 bh = NULL;
94 offset = 0;
95 blkofs++;
96 }
97 brelse(bh);
98 *res_dir = NULL;
99 return NULL;
100 }
101
102 struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
103 {
104 int ino;
105 struct qnx4_inode_entry *de;
106 struct qnx4_link_info *lnk;
107 struct buffer_head *bh;
108 const char *name = dentry->d_name.name;
109 int len = dentry->d_name.len;
110 struct inode *foundinode = NULL;
111
112 lock_kernel();
113 if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino)))
114 goto out;
115 /* The entry is linked, let's get the real info */
116 if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) {
117 lnk = (struct qnx4_link_info *) de;
118 ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) *
119 QNX4_INODES_PER_BLOCK +
120 lnk->dl_inode_ndx;
121 }
122 brelse(bh);
123
124 foundinode = qnx4_iget(dir->i_sb, ino);
125 if (IS_ERR(foundinode)) {
126 unlock_kernel();
127 QNX4DEBUG(("qnx4: lookup->iget -> error %ld\n",
128 PTR_ERR(foundinode)));
129 return ERR_CAST(foundinode);
130 }
131 out:
132 unlock_kernel();
133 d_add(dentry, foundinode);
134
135 return NULL;
136 }
137
138 #ifdef CONFIG_QNX4FS_RW
139 int qnx4_create(struct inode *dir, struct dentry *dentry, int mode,
140 struct nameidata *nd)
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 lock_kernel();
159 bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
160 &de, &ino);
161 if (bh == NULL) {
162 unlock_kernel();
163 return -ENOENT;
164 }
165 inode = dentry->d_inode;
166 if (inode->i_ino != ino) {
167 retval = -EIO;
168 goto end_rmdir;
169 }
170 #if 0
171 if (!empty_dir(inode)) {
172 retval = -ENOTEMPTY;
173 goto end_rmdir;
174 }
175 #endif
176 if (inode->i_nlink != 2) {
177 QNX4DEBUG(("empty directory has nlink!=2 (%d)\n", inode->i_nlink));
178 }
179 QNX4DEBUG(("qnx4: deleting directory\n"));
180 de->di_status = 0;
181 memset(de->di_fname, 0, sizeof de->di_fname);
182 de->di_mode = 0;
183 mark_buffer_dirty_inode(bh, dir);
184 clear_nlink(inode);
185 mark_inode_dirty(inode);
186 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
187 inode_dec_link_count(dir);
188 retval = 0;
189
190 end_rmdir:
191 brelse(bh);
192
193 unlock_kernel();
194 return retval;
195 }
196
197 int qnx4_unlink(struct inode *dir, struct dentry *dentry)
198 {
199 struct buffer_head *bh;
200 struct qnx4_inode_entry *de;
201 struct inode *inode;
202 int retval;
203 int ino;
204
205 QNX4DEBUG(("qnx4: qnx4_unlink [%s]\n", dentry->d_name.name));
206 lock_kernel();
207 bh = qnx4_find_entry(dentry->d_name.len, dir, dentry->d_name.name,
208 &de, &ino);
209 if (bh == NULL) {
210 unlock_kernel();
211 return -ENOENT;
212 }
213 inode = dentry->d_inode;
214 if (inode->i_ino != ino) {
215 retval = -EIO;
216 goto end_unlink;
217 }
218 retval = -EPERM;
219 if (!inode->i_nlink) {
220 QNX4DEBUG(("Deleting nonexistent file (%s:%lu), %d\n",
221 inode->i_sb->s_id,
222 inode->i_ino, inode->i_nlink));
223 inode->i_nlink = 1;
224 }
225 de->di_status = 0;
226 memset(de->di_fname, 0, sizeof de->di_fname);
227 de->di_mode = 0;
228 mark_buffer_dirty_inode(bh, dir);
229 dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
230 mark_inode_dirty(dir);
231 inode->i_ctime = dir->i_ctime;
232 inode_dec_link_count(inode);
233 retval = 0;
234
235 end_unlink:
236 unlock_kernel();
237 brelse(bh);
238
239 return retval;
240 }
241 #endif
242
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