This source file includes following definitions.
- dir_put_page
- minix_last_byte
- dir_commit_chunk
- dir_get_page
- minix_next_entry
- minix_readdir
- namecompare
- minix_find_entry
- minix_add_link
- minix_delete_entry
- minix_make_empty
- minix_empty_dir
- minix_set_link
- minix_dotdot
- minix_inode_by_name
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12 #include "minix.h"
13 #include <linux/buffer_head.h>
14 #include <linux/highmem.h>
15 #include <linux/swap.h>
16
17 typedef struct minix_dir_entry minix_dirent;
18 typedef struct minix3_dir_entry minix3_dirent;
19
20 static int minix_readdir(struct file *, struct dir_context *);
21
22 const struct file_operations minix_dir_operations = {
23 .llseek = generic_file_llseek,
24 .read = generic_read_dir,
25 .iterate_shared = minix_readdir,
26 .fsync = generic_file_fsync,
27 };
28
29 static inline void dir_put_page(struct page *page)
30 {
31 kunmap(page);
32 put_page(page);
33 }
34
35
36
37
38
39 static unsigned
40 minix_last_byte(struct inode *inode, unsigned long page_nr)
41 {
42 unsigned last_byte = PAGE_SIZE;
43
44 if (page_nr == (inode->i_size >> PAGE_SHIFT))
45 last_byte = inode->i_size & (PAGE_SIZE - 1);
46 return last_byte;
47 }
48
49 static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
50 {
51 struct address_space *mapping = page->mapping;
52 struct inode *dir = mapping->host;
53 int err = 0;
54 block_write_end(NULL, mapping, pos, len, len, page, NULL);
55
56 if (pos+len > dir->i_size) {
57 i_size_write(dir, pos+len);
58 mark_inode_dirty(dir);
59 }
60 if (IS_DIRSYNC(dir))
61 err = write_one_page(page);
62 else
63 unlock_page(page);
64 return err;
65 }
66
67 static struct page * dir_get_page(struct inode *dir, unsigned long n)
68 {
69 struct address_space *mapping = dir->i_mapping;
70 struct page *page = read_mapping_page(mapping, n, NULL);
71 if (!IS_ERR(page))
72 kmap(page);
73 return page;
74 }
75
76 static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
77 {
78 return (void*)((char*)de + sbi->s_dirsize);
79 }
80
81 static int minix_readdir(struct file *file, struct dir_context *ctx)
82 {
83 struct inode *inode = file_inode(file);
84 struct super_block *sb = inode->i_sb;
85 struct minix_sb_info *sbi = minix_sb(sb);
86 unsigned chunk_size = sbi->s_dirsize;
87 unsigned long npages = dir_pages(inode);
88 unsigned long pos = ctx->pos;
89 unsigned offset;
90 unsigned long n;
91
92 ctx->pos = pos = ALIGN(pos, chunk_size);
93 if (pos >= inode->i_size)
94 return 0;
95
96 offset = pos & ~PAGE_MASK;
97 n = pos >> PAGE_SHIFT;
98
99 for ( ; n < npages; n++, offset = 0) {
100 char *p, *kaddr, *limit;
101 struct page *page = dir_get_page(inode, n);
102
103 if (IS_ERR(page))
104 continue;
105 kaddr = (char *)page_address(page);
106 p = kaddr+offset;
107 limit = kaddr + minix_last_byte(inode, n) - chunk_size;
108 for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
109 const char *name;
110 __u32 inumber;
111 if (sbi->s_version == MINIX_V3) {
112 minix3_dirent *de3 = (minix3_dirent *)p;
113 name = de3->name;
114 inumber = de3->inode;
115 } else {
116 minix_dirent *de = (minix_dirent *)p;
117 name = de->name;
118 inumber = de->inode;
119 }
120 if (inumber) {
121 unsigned l = strnlen(name, sbi->s_namelen);
122 if (!dir_emit(ctx, name, l,
123 inumber, DT_UNKNOWN)) {
124 dir_put_page(page);
125 return 0;
126 }
127 }
128 ctx->pos += chunk_size;
129 }
130 dir_put_page(page);
131 }
132 return 0;
133 }
134
135 static inline int namecompare(int len, int maxlen,
136 const char * name, const char * buffer)
137 {
138 if (len < maxlen && buffer[len])
139 return 0;
140 return !memcmp(name, buffer, len);
141 }
142
143
144
145
146
147
148
149
150
151 minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
152 {
153 const char * name = dentry->d_name.name;
154 int namelen = dentry->d_name.len;
155 struct inode * dir = d_inode(dentry->d_parent);
156 struct super_block * sb = dir->i_sb;
157 struct minix_sb_info * sbi = minix_sb(sb);
158 unsigned long n;
159 unsigned long npages = dir_pages(dir);
160 struct page *page = NULL;
161 char *p;
162
163 char *namx;
164 __u32 inumber;
165 *res_page = NULL;
166
167 for (n = 0; n < npages; n++) {
168 char *kaddr, *limit;
169
170 page = dir_get_page(dir, n);
171 if (IS_ERR(page))
172 continue;
173
174 kaddr = (char*)page_address(page);
175 limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
176 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
177 if (sbi->s_version == MINIX_V3) {
178 minix3_dirent *de3 = (minix3_dirent *)p;
179 namx = de3->name;
180 inumber = de3->inode;
181 } else {
182 minix_dirent *de = (minix_dirent *)p;
183 namx = de->name;
184 inumber = de->inode;
185 }
186 if (!inumber)
187 continue;
188 if (namecompare(namelen, sbi->s_namelen, name, namx))
189 goto found;
190 }
191 dir_put_page(page);
192 }
193 return NULL;
194
195 found:
196 *res_page = page;
197 return (minix_dirent *)p;
198 }
199
200 int minix_add_link(struct dentry *dentry, struct inode *inode)
201 {
202 struct inode *dir = d_inode(dentry->d_parent);
203 const char * name = dentry->d_name.name;
204 int namelen = dentry->d_name.len;
205 struct super_block * sb = dir->i_sb;
206 struct minix_sb_info * sbi = minix_sb(sb);
207 struct page *page = NULL;
208 unsigned long npages = dir_pages(dir);
209 unsigned long n;
210 char *kaddr, *p;
211 minix_dirent *de;
212 minix3_dirent *de3;
213 loff_t pos;
214 int err;
215 char *namx = NULL;
216 __u32 inumber;
217
218
219
220
221
222
223 for (n = 0; n <= npages; n++) {
224 char *limit, *dir_end;
225
226 page = dir_get_page(dir, n);
227 err = PTR_ERR(page);
228 if (IS_ERR(page))
229 goto out;
230 lock_page(page);
231 kaddr = (char*)page_address(page);
232 dir_end = kaddr + minix_last_byte(dir, n);
233 limit = kaddr + PAGE_SIZE - sbi->s_dirsize;
234 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
235 de = (minix_dirent *)p;
236 de3 = (minix3_dirent *)p;
237 if (sbi->s_version == MINIX_V3) {
238 namx = de3->name;
239 inumber = de3->inode;
240 } else {
241 namx = de->name;
242 inumber = de->inode;
243 }
244 if (p == dir_end) {
245
246 if (sbi->s_version == MINIX_V3)
247 de3->inode = 0;
248 else
249 de->inode = 0;
250 goto got_it;
251 }
252 if (!inumber)
253 goto got_it;
254 err = -EEXIST;
255 if (namecompare(namelen, sbi->s_namelen, name, namx))
256 goto out_unlock;
257 }
258 unlock_page(page);
259 dir_put_page(page);
260 }
261 BUG();
262 return -EINVAL;
263
264 got_it:
265 pos = page_offset(page) + p - (char *)page_address(page);
266 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
267 if (err)
268 goto out_unlock;
269 memcpy (namx, name, namelen);
270 if (sbi->s_version == MINIX_V3) {
271 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
272 de3->inode = inode->i_ino;
273 } else {
274 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
275 de->inode = inode->i_ino;
276 }
277 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
278 dir->i_mtime = dir->i_ctime = current_time(dir);
279 mark_inode_dirty(dir);
280 out_put:
281 dir_put_page(page);
282 out:
283 return err;
284 out_unlock:
285 unlock_page(page);
286 goto out_put;
287 }
288
289 int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
290 {
291 struct inode *inode = page->mapping->host;
292 char *kaddr = page_address(page);
293 loff_t pos = page_offset(page) + (char*)de - kaddr;
294 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
295 unsigned len = sbi->s_dirsize;
296 int err;
297
298 lock_page(page);
299 err = minix_prepare_chunk(page, pos, len);
300 if (err == 0) {
301 if (sbi->s_version == MINIX_V3)
302 ((minix3_dirent *) de)->inode = 0;
303 else
304 de->inode = 0;
305 err = dir_commit_chunk(page, pos, len);
306 } else {
307 unlock_page(page);
308 }
309 dir_put_page(page);
310 inode->i_ctime = inode->i_mtime = current_time(inode);
311 mark_inode_dirty(inode);
312 return err;
313 }
314
315 int minix_make_empty(struct inode *inode, struct inode *dir)
316 {
317 struct page *page = grab_cache_page(inode->i_mapping, 0);
318 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
319 char *kaddr;
320 int err;
321
322 if (!page)
323 return -ENOMEM;
324 err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
325 if (err) {
326 unlock_page(page);
327 goto fail;
328 }
329
330 kaddr = kmap_atomic(page);
331 memset(kaddr, 0, PAGE_SIZE);
332
333 if (sbi->s_version == MINIX_V3) {
334 minix3_dirent *de3 = (minix3_dirent *)kaddr;
335
336 de3->inode = inode->i_ino;
337 strcpy(de3->name, ".");
338 de3 = minix_next_entry(de3, sbi);
339 de3->inode = dir->i_ino;
340 strcpy(de3->name, "..");
341 } else {
342 minix_dirent *de = (minix_dirent *)kaddr;
343
344 de->inode = inode->i_ino;
345 strcpy(de->name, ".");
346 de = minix_next_entry(de, sbi);
347 de->inode = dir->i_ino;
348 strcpy(de->name, "..");
349 }
350 kunmap_atomic(kaddr);
351
352 err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
353 fail:
354 put_page(page);
355 return err;
356 }
357
358
359
360
361 int minix_empty_dir(struct inode * inode)
362 {
363 struct page *page = NULL;
364 unsigned long i, npages = dir_pages(inode);
365 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
366 char *name;
367 __u32 inumber;
368
369 for (i = 0; i < npages; i++) {
370 char *p, *kaddr, *limit;
371
372 page = dir_get_page(inode, i);
373 if (IS_ERR(page))
374 continue;
375
376 kaddr = (char *)page_address(page);
377 limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
378 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
379 if (sbi->s_version == MINIX_V3) {
380 minix3_dirent *de3 = (minix3_dirent *)p;
381 name = de3->name;
382 inumber = de3->inode;
383 } else {
384 minix_dirent *de = (minix_dirent *)p;
385 name = de->name;
386 inumber = de->inode;
387 }
388
389 if (inumber != 0) {
390
391 if (name[0] != '.')
392 goto not_empty;
393 if (!name[1]) {
394 if (inumber != inode->i_ino)
395 goto not_empty;
396 } else if (name[1] != '.')
397 goto not_empty;
398 else if (name[2])
399 goto not_empty;
400 }
401 }
402 dir_put_page(page);
403 }
404 return 1;
405
406 not_empty:
407 dir_put_page(page);
408 return 0;
409 }
410
411
412 void minix_set_link(struct minix_dir_entry *de, struct page *page,
413 struct inode *inode)
414 {
415 struct inode *dir = page->mapping->host;
416 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
417 loff_t pos = page_offset(page) +
418 (char *)de-(char*)page_address(page);
419 int err;
420
421 lock_page(page);
422
423 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
424 if (err == 0) {
425 if (sbi->s_version == MINIX_V3)
426 ((minix3_dirent *) de)->inode = inode->i_ino;
427 else
428 de->inode = inode->i_ino;
429 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
430 } else {
431 unlock_page(page);
432 }
433 dir_put_page(page);
434 dir->i_mtime = dir->i_ctime = current_time(dir);
435 mark_inode_dirty(dir);
436 }
437
438 struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
439 {
440 struct page *page = dir_get_page(dir, 0);
441 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
442 struct minix_dir_entry *de = NULL;
443
444 if (!IS_ERR(page)) {
445 de = minix_next_entry(page_address(page), sbi);
446 *p = page;
447 }
448 return de;
449 }
450
451 ino_t minix_inode_by_name(struct dentry *dentry)
452 {
453 struct page *page;
454 struct minix_dir_entry *de = minix_find_entry(dentry, &page);
455 ino_t res = 0;
456
457 if (de) {
458 struct address_space *mapping = page->mapping;
459 struct inode *inode = mapping->host;
460 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
461
462 if (sbi->s_version == MINIX_V3)
463 res = ((minix3_dirent *) de)->inode;
464 else
465 res = de->inode;
466 dir_put_page(page);
467 }
468 return res;
469 }