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1/*
2 * QNX6 file system, Linux implementation.
3 *
4 * Version : 1.0.0
5 *
6 * History :
7 *
8 * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release.
9 * 16-02-2012 pagemap extension by Al Viro
10 *
11 */
12
13#include "qnx6.h"
14
15static unsigned qnx6_lfile_checksum(char *name, unsigned size)
16{
17 unsigned crc = 0;
18 char *end = name + size;
19 while (name < end) {
20 crc = ((crc >> 1) + *(name++)) ^
21 ((crc & 0x00000001) ? 0x80000000 : 0);
22 }
23 return crc;
24}
25
26static struct page *qnx6_get_page(struct inode *dir, unsigned long n)
27{
28 struct address_space *mapping = dir->i_mapping;
29 struct page *page = read_mapping_page(mapping, n, NULL);
30 if (!IS_ERR(page))
31 kmap(page);
32 return page;
33}
34
35static inline unsigned long dir_pages(struct inode *inode)
36{
37 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
38}
39
40static unsigned last_entry(struct inode *inode, unsigned long page_nr)
41{
42 unsigned long last_byte = inode->i_size;
43 last_byte -= page_nr << PAGE_CACHE_SHIFT;
44 if (last_byte > PAGE_CACHE_SIZE)
45 last_byte = PAGE_CACHE_SIZE;
46 return last_byte / QNX6_DIR_ENTRY_SIZE;
47}
48
49static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
50 struct qnx6_long_dir_entry *de,
51 struct page **p)
52{
53 struct qnx6_sb_info *sbi = QNX6_SB(sb);
54 u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
55 u32 n = s >> (PAGE_CACHE_SHIFT - sb->s_blocksize_bits); /* in pages */
56 /* within page */
57 u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_CACHE_MASK;
58 struct address_space *mapping = sbi->longfile->i_mapping;
59 struct page *page = read_mapping_page(mapping, n, NULL);
60 if (IS_ERR(page))
61 return ERR_CAST(page);
62 kmap(*p = page);
63 return (struct qnx6_long_filename *)(page_address(page) + offs);
64}
65
66static int qnx6_dir_longfilename(struct inode *inode,
67 struct qnx6_long_dir_entry *de,
68 void *dirent, loff_t pos,
69 unsigned de_inode, filldir_t filldir)
70{
71 struct qnx6_long_filename *lf;
72 struct super_block *s = inode->i_sb;
73 struct qnx6_sb_info *sbi = QNX6_SB(s);
74 struct page *page;
75 int lf_size;
76
77 if (de->de_size != 0xff) {
78 /* error - long filename entries always have size 0xff
79 in direntry */
80 printk(KERN_ERR "qnx6: invalid direntry size (%i).\n",
81 de->de_size);
82 return 0;
83 }
84 lf = qnx6_longname(s, de, &page);
85 if (IS_ERR(lf)) {
86 printk(KERN_ERR "qnx6:Error reading longname\n");
87 return 0;
88 }
89
90 lf_size = fs16_to_cpu(sbi, lf->lf_size);
91
92 if (lf_size > QNX6_LONG_NAME_MAX) {
93 QNX6DEBUG((KERN_INFO "file %s\n", lf->lf_fname));
94 printk(KERN_ERR "qnx6:Filename too long (%i)\n", lf_size);
95 qnx6_put_page(page);
96 return 0;
97 }
98
99 /* calc & validate longfilename checksum
100 mmi 3g filesystem does not have that checksum */
101 if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
102 qnx6_lfile_checksum(lf->lf_fname, lf_size))
103 printk(KERN_INFO "qnx6: long filename checksum error.\n");
104
105 QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s inode:%u\n",
106 lf_size, lf->lf_fname, de_inode));
107 if (filldir(dirent, lf->lf_fname, lf_size, pos, de_inode,
108 DT_UNKNOWN) < 0) {
109 qnx6_put_page(page);
110 return 0;
111 }
112
113 qnx6_put_page(page);
114 /* success */
115 return 1;
116}
117
118static int qnx6_readdir(struct file *filp, void *dirent, filldir_t filldir)
119{
120 struct inode *inode = filp->f_path.dentry->d_inode;
121 struct super_block *s = inode->i_sb;
122 struct qnx6_sb_info *sbi = QNX6_SB(s);
123 loff_t pos = filp->f_pos & (QNX6_DIR_ENTRY_SIZE - 1);
124 unsigned long npages = dir_pages(inode);
125 unsigned long n = pos >> PAGE_CACHE_SHIFT;
126 unsigned start = (pos & ~PAGE_CACHE_MASK) / QNX6_DIR_ENTRY_SIZE;
127 bool done = false;
128
129 if (filp->f_pos >= inode->i_size)
130 return 0;
131
132 for ( ; !done && n < npages; n++, start = 0) {
133 struct page *page = qnx6_get_page(inode, n);
134 int limit = last_entry(inode, n);
135 struct qnx6_dir_entry *de;
136 int i = start;
137
138 if (IS_ERR(page)) {
139 printk(KERN_ERR "qnx6_readdir: read failed\n");
140 filp->f_pos = (n + 1) << PAGE_CACHE_SHIFT;
141 return PTR_ERR(page);
142 }
143 de = ((struct qnx6_dir_entry *)page_address(page)) + start;
144 for (; i < limit; i++, de++, pos += QNX6_DIR_ENTRY_SIZE) {
145 int size = de->de_size;
146 u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
147
148 if (!no_inode || !size)
149 continue;
150
151 if (size > QNX6_SHORT_NAME_MAX) {
152 /* long filename detected
153 get the filename from long filename
154 structure / block */
155 if (!qnx6_dir_longfilename(inode,
156 (struct qnx6_long_dir_entry *)de,
157 dirent, pos, no_inode,
158 filldir)) {
159 done = true;
160 break;
161 }
162 } else {
163 QNX6DEBUG((KERN_INFO "qnx6_readdir:%.*s"
164 " inode:%u\n", size, de->de_fname,
165 no_inode));
166 if (filldir(dirent, de->de_fname, size,
167 pos, no_inode, DT_UNKNOWN)
168 < 0) {
169 done = true;
170 break;
171 }
172 }
173 }
174 qnx6_put_page(page);
175 }
176 filp->f_pos = pos;
177 return 0;
178}
179
180/*
181 * check if the long filename is correct.
182 */
183static unsigned qnx6_long_match(int len, const char *name,
184 struct qnx6_long_dir_entry *de, struct inode *dir)
185{
186 struct super_block *s = dir->i_sb;
187 struct qnx6_sb_info *sbi = QNX6_SB(s);
188 struct page *page;
189 int thislen;
190 struct qnx6_long_filename *lf = qnx6_longname(s, de, &page);
191
192 if (IS_ERR(lf))
193 return 0;
194
195 thislen = fs16_to_cpu(sbi, lf->lf_size);
196 if (len != thislen) {
197 qnx6_put_page(page);
198 return 0;
199 }
200 if (memcmp(name, lf->lf_fname, len) == 0) {
201 qnx6_put_page(page);
202 return fs32_to_cpu(sbi, de->de_inode);
203 }
204 qnx6_put_page(page);
205 return 0;
206}
207
208/*
209 * check if the filename is correct.
210 */
211static unsigned qnx6_match(struct super_block *s, int len, const char *name,
212 struct qnx6_dir_entry *de)
213{
214 struct qnx6_sb_info *sbi = QNX6_SB(s);
215 if (memcmp(name, de->de_fname, len) == 0)
216 return fs32_to_cpu(sbi, de->de_inode);
217 return 0;
218}
219
220
221unsigned qnx6_find_entry(int len, struct inode *dir, const char *name,
222 struct page **res_page)
223{
224 struct super_block *s = dir->i_sb;
225 struct qnx6_inode_info *ei = QNX6_I(dir);
226 struct page *page = NULL;
227 unsigned long start, n;
228 unsigned long npages = dir_pages(dir);
229 unsigned ino;
230 struct qnx6_dir_entry *de;
231 struct qnx6_long_dir_entry *lde;
232
233 *res_page = NULL;
234
235 if (npages == 0)
236 return 0;
237 start = ei->i_dir_start_lookup;
238 if (start >= npages)
239 start = 0;
240 n = start;
241
242 do {
243 page = qnx6_get_page(dir, n);
244 if (!IS_ERR(page)) {
245 int limit = last_entry(dir, n);
246 int i;
247
248 de = (struct qnx6_dir_entry *)page_address(page);
249 for (i = 0; i < limit; i++, de++) {
250 if (len <= QNX6_SHORT_NAME_MAX) {
251 /* short filename */
252 if (len != de->de_size)
253 continue;
254 ino = qnx6_match(s, len, name, de);
255 if (ino)
256 goto found;
257 } else if (de->de_size == 0xff) {
258 /* deal with long filename */
259 lde = (struct qnx6_long_dir_entry *)de;
260 ino = qnx6_long_match(len,
261 name, lde, dir);
262 if (ino)
263 goto found;
264 } else
265 printk(KERN_ERR "qnx6: undefined "
266 "filename size in inode.\n");
267 }
268 qnx6_put_page(page);
269 }
270
271 if (++n >= npages)
272 n = 0;
273 } while (n != start);
274 return 0;
275
276found:
277 *res_page = page;
278 ei->i_dir_start_lookup = n;
279 return ino;
280}
281
282const struct file_operations qnx6_dir_operations = {
283 .llseek = generic_file_llseek,
284 .read = generic_read_dir,
285 .readdir = qnx6_readdir,
286 .fsync = generic_file_fsync,
287};
288
289const struct inode_operations qnx6_dir_inode_operations = {
290 .lookup = qnx6_lookup,
291};