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11#include "minix.h"
12#include <linux/buffer_head.h>
13#include <linux/highmem.h>
14#include <linux/swap.h>
15
16typedef struct minix_dir_entry minix_dirent;
17typedef struct minix3_dir_entry minix3_dirent;
18
19static int minix_readdir(struct file *, struct dir_context *);
20
21const struct file_operations minix_dir_operations = {
22 .llseek = generic_file_llseek,
23 .read = generic_read_dir,
24 .iterate = minix_readdir,
25 .fsync = generic_file_fsync,
26};
27
28static inline void dir_put_page(struct page *page)
29{
30 kunmap(page);
31 page_cache_release(page);
32}
33
34
35
36
37
38static unsigned
39minix_last_byte(struct inode *inode, unsigned long page_nr)
40{
41 unsigned last_byte = PAGE_CACHE_SIZE;
42
43 if (page_nr == (inode->i_size >> PAGE_CACHE_SHIFT))
44 last_byte = inode->i_size & (PAGE_CACHE_SIZE - 1);
45 return last_byte;
46}
47
48static inline unsigned long dir_pages(struct inode *inode)
49{
50 return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT;
51}
52
53static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len)
54{
55 struct address_space *mapping = page->mapping;
56 struct inode *dir = mapping->host;
57 int err = 0;
58 block_write_end(NULL, mapping, pos, len, len, page, NULL);
59
60 if (pos+len > dir->i_size) {
61 i_size_write(dir, pos+len);
62 mark_inode_dirty(dir);
63 }
64 if (IS_DIRSYNC(dir))
65 err = write_one_page(page, 1);
66 else
67 unlock_page(page);
68 return err;
69}
70
71static struct page * dir_get_page(struct inode *dir, unsigned long n)
72{
73 struct address_space *mapping = dir->i_mapping;
74 struct page *page = read_mapping_page(mapping, n, NULL);
75 if (!IS_ERR(page))
76 kmap(page);
77 return page;
78}
79
80static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi)
81{
82 return (void*)((char*)de + sbi->s_dirsize);
83}
84
85static int minix_readdir(struct file *file, struct dir_context *ctx)
86{
87 struct inode *inode = file_inode(file);
88 struct super_block *sb = inode->i_sb;
89 struct minix_sb_info *sbi = minix_sb(sb);
90 unsigned chunk_size = sbi->s_dirsize;
91 unsigned long npages = dir_pages(inode);
92 unsigned long pos = ctx->pos;
93 unsigned offset;
94 unsigned long n;
95
96 ctx->pos = pos = ALIGN(pos, chunk_size);
97 if (pos >= inode->i_size)
98 return 0;
99
100 offset = pos & ~PAGE_CACHE_MASK;
101 n = pos >> PAGE_CACHE_SHIFT;
102
103 for ( ; n < npages; n++, offset = 0) {
104 char *p, *kaddr, *limit;
105 struct page *page = dir_get_page(inode, n);
106
107 if (IS_ERR(page))
108 continue;
109 kaddr = (char *)page_address(page);
110 p = kaddr+offset;
111 limit = kaddr + minix_last_byte(inode, n) - chunk_size;
112 for ( ; p <= limit; p = minix_next_entry(p, sbi)) {
113 const char *name;
114 __u32 inumber;
115 if (sbi->s_version == MINIX_V3) {
116 minix3_dirent *de3 = (minix3_dirent *)p;
117 name = de3->name;
118 inumber = de3->inode;
119 } else {
120 minix_dirent *de = (minix_dirent *)p;
121 name = de->name;
122 inumber = de->inode;
123 }
124 if (inumber) {
125 unsigned l = strnlen(name, sbi->s_namelen);
126 if (!dir_emit(ctx, name, l,
127 inumber, DT_UNKNOWN)) {
128 dir_put_page(page);
129 return 0;
130 }
131 }
132 ctx->pos += chunk_size;
133 }
134 dir_put_page(page);
135 }
136 return 0;
137}
138
139static inline int namecompare(int len, int maxlen,
140 const char * name, const char * buffer)
141{
142 if (len < maxlen && buffer[len])
143 return 0;
144 return !memcmp(name, buffer, len);
145}
146
147
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149
150
151
152
153
154
155minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page)
156{
157 const char * name = dentry->d_name.name;
158 int namelen = dentry->d_name.len;
159 struct inode * dir = dentry->d_parent->d_inode;
160 struct super_block * sb = dir->i_sb;
161 struct minix_sb_info * sbi = minix_sb(sb);
162 unsigned long n;
163 unsigned long npages = dir_pages(dir);
164 struct page *page = NULL;
165 char *p;
166
167 char *namx;
168 __u32 inumber;
169 *res_page = NULL;
170
171 for (n = 0; n < npages; n++) {
172 char *kaddr, *limit;
173
174 page = dir_get_page(dir, n);
175 if (IS_ERR(page))
176 continue;
177
178 kaddr = (char*)page_address(page);
179 limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize;
180 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
181 if (sbi->s_version == MINIX_V3) {
182 minix3_dirent *de3 = (minix3_dirent *)p;
183 namx = de3->name;
184 inumber = de3->inode;
185 } else {
186 minix_dirent *de = (minix_dirent *)p;
187 namx = de->name;
188 inumber = de->inode;
189 }
190 if (!inumber)
191 continue;
192 if (namecompare(namelen, sbi->s_namelen, name, namx))
193 goto found;
194 }
195 dir_put_page(page);
196 }
197 return NULL;
198
199found:
200 *res_page = page;
201 return (minix_dirent *)p;
202}
203
204int minix_add_link(struct dentry *dentry, struct inode *inode)
205{
206 struct inode *dir = dentry->d_parent->d_inode;
207 const char * name = dentry->d_name.name;
208 int namelen = dentry->d_name.len;
209 struct super_block * sb = dir->i_sb;
210 struct minix_sb_info * sbi = minix_sb(sb);
211 struct page *page = NULL;
212 unsigned long npages = dir_pages(dir);
213 unsigned long n;
214 char *kaddr, *p;
215 minix_dirent *de;
216 minix3_dirent *de3;
217 loff_t pos;
218 int err;
219 char *namx = NULL;
220 __u32 inumber;
221
222
223
224
225
226
227 for (n = 0; n <= npages; n++) {
228 char *limit, *dir_end;
229
230 page = dir_get_page(dir, n);
231 err = PTR_ERR(page);
232 if (IS_ERR(page))
233 goto out;
234 lock_page(page);
235 kaddr = (char*)page_address(page);
236 dir_end = kaddr + minix_last_byte(dir, n);
237 limit = kaddr + PAGE_CACHE_SIZE - sbi->s_dirsize;
238 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
239 de = (minix_dirent *)p;
240 de3 = (minix3_dirent *)p;
241 if (sbi->s_version == MINIX_V3) {
242 namx = de3->name;
243 inumber = de3->inode;
244 } else {
245 namx = de->name;
246 inumber = de->inode;
247 }
248 if (p == dir_end) {
249
250 if (sbi->s_version == MINIX_V3)
251 de3->inode = 0;
252 else
253 de->inode = 0;
254 goto got_it;
255 }
256 if (!inumber)
257 goto got_it;
258 err = -EEXIST;
259 if (namecompare(namelen, sbi->s_namelen, name, namx))
260 goto out_unlock;
261 }
262 unlock_page(page);
263 dir_put_page(page);
264 }
265 BUG();
266 return -EINVAL;
267
268got_it:
269 pos = page_offset(page) + p - (char *)page_address(page);
270 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
271 if (err)
272 goto out_unlock;
273 memcpy (namx, name, namelen);
274 if (sbi->s_version == MINIX_V3) {
275 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4);
276 de3->inode = inode->i_ino;
277 } else {
278 memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2);
279 de->inode = inode->i_ino;
280 }
281 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
282 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
283 mark_inode_dirty(dir);
284out_put:
285 dir_put_page(page);
286out:
287 return err;
288out_unlock:
289 unlock_page(page);
290 goto out_put;
291}
292
293int minix_delete_entry(struct minix_dir_entry *de, struct page *page)
294{
295 struct inode *inode = page->mapping->host;
296 char *kaddr = page_address(page);
297 loff_t pos = page_offset(page) + (char*)de - kaddr;
298 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
299 unsigned len = sbi->s_dirsize;
300 int err;
301
302 lock_page(page);
303 err = minix_prepare_chunk(page, pos, len);
304 if (err == 0) {
305 if (sbi->s_version == MINIX_V3)
306 ((minix3_dirent *) de)->inode = 0;
307 else
308 de->inode = 0;
309 err = dir_commit_chunk(page, pos, len);
310 } else {
311 unlock_page(page);
312 }
313 dir_put_page(page);
314 inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
315 mark_inode_dirty(inode);
316 return err;
317}
318
319int minix_make_empty(struct inode *inode, struct inode *dir)
320{
321 struct page *page = grab_cache_page(inode->i_mapping, 0);
322 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
323 char *kaddr;
324 int err;
325
326 if (!page)
327 return -ENOMEM;
328 err = minix_prepare_chunk(page, 0, 2 * sbi->s_dirsize);
329 if (err) {
330 unlock_page(page);
331 goto fail;
332 }
333
334 kaddr = kmap_atomic(page);
335 memset(kaddr, 0, PAGE_CACHE_SIZE);
336
337 if (sbi->s_version == MINIX_V3) {
338 minix3_dirent *de3 = (minix3_dirent *)kaddr;
339
340 de3->inode = inode->i_ino;
341 strcpy(de3->name, ".");
342 de3 = minix_next_entry(de3, sbi);
343 de3->inode = dir->i_ino;
344 strcpy(de3->name, "..");
345 } else {
346 minix_dirent *de = (minix_dirent *)kaddr;
347
348 de->inode = inode->i_ino;
349 strcpy(de->name, ".");
350 de = minix_next_entry(de, sbi);
351 de->inode = dir->i_ino;
352 strcpy(de->name, "..");
353 }
354 kunmap_atomic(kaddr);
355
356 err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize);
357fail:
358 page_cache_release(page);
359 return err;
360}
361
362
363
364
365int minix_empty_dir(struct inode * inode)
366{
367 struct page *page = NULL;
368 unsigned long i, npages = dir_pages(inode);
369 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
370 char *name;
371 __u32 inumber;
372
373 for (i = 0; i < npages; i++) {
374 char *p, *kaddr, *limit;
375
376 page = dir_get_page(inode, i);
377 if (IS_ERR(page))
378 continue;
379
380 kaddr = (char *)page_address(page);
381 limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize;
382 for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) {
383 if (sbi->s_version == MINIX_V3) {
384 minix3_dirent *de3 = (minix3_dirent *)p;
385 name = de3->name;
386 inumber = de3->inode;
387 } else {
388 minix_dirent *de = (minix_dirent *)p;
389 name = de->name;
390 inumber = de->inode;
391 }
392
393 if (inumber != 0) {
394
395 if (name[0] != '.')
396 goto not_empty;
397 if (!name[1]) {
398 if (inumber != inode->i_ino)
399 goto not_empty;
400 } else if (name[1] != '.')
401 goto not_empty;
402 else if (name[2])
403 goto not_empty;
404 }
405 }
406 dir_put_page(page);
407 }
408 return 1;
409
410not_empty:
411 dir_put_page(page);
412 return 0;
413}
414
415
416void minix_set_link(struct minix_dir_entry *de, struct page *page,
417 struct inode *inode)
418{
419 struct inode *dir = page->mapping->host;
420 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
421 loff_t pos = page_offset(page) +
422 (char *)de-(char*)page_address(page);
423 int err;
424
425 lock_page(page);
426
427 err = minix_prepare_chunk(page, pos, sbi->s_dirsize);
428 if (err == 0) {
429 if (sbi->s_version == MINIX_V3)
430 ((minix3_dirent *) de)->inode = inode->i_ino;
431 else
432 de->inode = inode->i_ino;
433 err = dir_commit_chunk(page, pos, sbi->s_dirsize);
434 } else {
435 unlock_page(page);
436 }
437 dir_put_page(page);
438 dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC;
439 mark_inode_dirty(dir);
440}
441
442struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p)
443{
444 struct page *page = dir_get_page(dir, 0);
445 struct minix_sb_info *sbi = minix_sb(dir->i_sb);
446 struct minix_dir_entry *de = NULL;
447
448 if (!IS_ERR(page)) {
449 de = minix_next_entry(page_address(page), sbi);
450 *p = page;
451 }
452 return de;
453}
454
455ino_t minix_inode_by_name(struct dentry *dentry)
456{
457 struct page *page;
458 struct minix_dir_entry *de = minix_find_entry(dentry, &page);
459 ino_t res = 0;
460
461 if (de) {
462 struct address_space *mapping = page->mapping;
463 struct inode *inode = mapping->host;
464 struct minix_sb_info *sbi = minix_sb(inode->i_sb);
465
466 if (sbi->s_version == MINIX_V3)
467 res = ((minix3_dirent *) de)->inode;
468 else
469 res = de->inode;
470 dir_put_page(page);
471 }
472 return res;
473}
474
