Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/minix/dir.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * minix directory handling functions | |
939b00df AB |
7 | * |
8 | * Updated to filesystem version 3 by Daniel Aragones | |
1da177e4 LT |
9 | */ |
10 | ||
11 | #include "minix.h" | |
4a66af9e | 12 | #include <linux/buffer_head.h> |
1da177e4 LT |
13 | #include <linux/highmem.h> |
14 | #include <linux/smp_lock.h> | |
4a66af9e | 15 | #include <linux/swap.h> |
1da177e4 LT |
16 | |
17 | typedef struct minix_dir_entry minix_dirent; | |
939b00df | 18 | typedef struct minix3_dir_entry minix3_dirent; |
1da177e4 LT |
19 | |
20 | static int minix_readdir(struct file *, void *, filldir_t); | |
21 | ||
4b6f5d20 | 22 | const struct file_operations minix_dir_operations = { |
1da177e4 LT |
23 | .read = generic_read_dir, |
24 | .readdir = minix_readdir, | |
25 | .fsync = minix_sync_file, | |
26 | }; | |
27 | ||
28 | static inline void dir_put_page(struct page *page) | |
29 | { | |
30 | kunmap(page); | |
31 | page_cache_release(page); | |
32 | } | |
33 | ||
34 | /* | |
35 | * Return the offset into page `page_nr' of the last valid | |
36 | * byte in that page, plus one. | |
37 | */ | |
38 | static unsigned | |
39 | minix_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 | ||
48 | static inline unsigned long dir_pages(struct inode *inode) | |
49 | { | |
50 | return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; | |
51 | } | |
52 | ||
4a66af9e | 53 | static int dir_commit_chunk(struct page *page, loff_t pos, unsigned len) |
1da177e4 | 54 | { |
4a66af9e NP |
55 | struct address_space *mapping = page->mapping; |
56 | struct inode *dir = mapping->host; | |
1da177e4 | 57 | int err = 0; |
4a66af9e NP |
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 | } | |
1da177e4 LT |
64 | if (IS_DIRSYNC(dir)) |
65 | err = write_one_page(page, 1); | |
66 | else | |
67 | unlock_page(page); | |
68 | return err; | |
69 | } | |
70 | ||
71 | static struct page * dir_get_page(struct inode *dir, unsigned long n) | |
72 | { | |
73 | struct address_space *mapping = dir->i_mapping; | |
090d2b18 | 74 | struct page *page = read_mapping_page(mapping, n, NULL); |
1da177e4 | 75 | if (!IS_ERR(page)) { |
1da177e4 LT |
76 | kmap(page); |
77 | if (!PageUptodate(page)) | |
78 | goto fail; | |
79 | } | |
80 | return page; | |
81 | ||
82 | fail: | |
83 | dir_put_page(page); | |
84 | return ERR_PTR(-EIO); | |
85 | } | |
86 | ||
87 | static inline void *minix_next_entry(void *de, struct minix_sb_info *sbi) | |
88 | { | |
89 | return (void*)((char*)de + sbi->s_dirsize); | |
90 | } | |
91 | ||
92 | static int minix_readdir(struct file * filp, void * dirent, filldir_t filldir) | |
93 | { | |
94 | unsigned long pos = filp->f_pos; | |
dcf258ae | 95 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
96 | struct super_block *sb = inode->i_sb; |
97 | unsigned offset = pos & ~PAGE_CACHE_MASK; | |
98 | unsigned long n = pos >> PAGE_CACHE_SHIFT; | |
99 | unsigned long npages = dir_pages(inode); | |
100 | struct minix_sb_info *sbi = minix_sb(sb); | |
101 | unsigned chunk_size = sbi->s_dirsize; | |
939b00df AB |
102 | char *name; |
103 | __u32 inumber; | |
1da177e4 LT |
104 | |
105 | lock_kernel(); | |
106 | ||
107 | pos = (pos + chunk_size-1) & ~(chunk_size-1); | |
108 | if (pos >= inode->i_size) | |
109 | goto done; | |
110 | ||
111 | for ( ; n < npages; n++, offset = 0) { | |
112 | char *p, *kaddr, *limit; | |
113 | struct page *page = dir_get_page(inode, n); | |
114 | ||
115 | if (IS_ERR(page)) | |
116 | continue; | |
117 | kaddr = (char *)page_address(page); | |
118 | p = kaddr+offset; | |
119 | limit = kaddr + minix_last_byte(inode, n) - chunk_size; | |
939b00df AB |
120 | for ( ; p <= limit; p = minix_next_entry(p, sbi)) { |
121 | if (sbi->s_version == MINIX_V3) { | |
122 | minix3_dirent *de3 = (minix3_dirent *)p; | |
123 | name = de3->name; | |
124 | inumber = de3->inode; | |
125 | } else { | |
126 | minix_dirent *de = (minix_dirent *)p; | |
127 | name = de->name; | |
128 | inumber = de->inode; | |
129 | } | |
130 | if (inumber) { | |
1da177e4 | 131 | int over; |
1da177e4 | 132 | |
939b00df | 133 | unsigned l = strnlen(name, sbi->s_namelen); |
1da177e4 | 134 | offset = p - kaddr; |
939b00df AB |
135 | over = filldir(dirent, name, l, |
136 | (n << PAGE_CACHE_SHIFT) | offset, | |
137 | inumber, DT_UNKNOWN); | |
1da177e4 LT |
138 | if (over) { |
139 | dir_put_page(page); | |
140 | goto done; | |
141 | } | |
142 | } | |
143 | } | |
144 | dir_put_page(page); | |
145 | } | |
146 | ||
147 | done: | |
148 | filp->f_pos = (n << PAGE_CACHE_SHIFT) | offset; | |
149 | unlock_kernel(); | |
150 | return 0; | |
151 | } | |
152 | ||
153 | static inline int namecompare(int len, int maxlen, | |
154 | const char * name, const char * buffer) | |
155 | { | |
156 | if (len < maxlen && buffer[len]) | |
157 | return 0; | |
158 | return !memcmp(name, buffer, len); | |
159 | } | |
160 | ||
161 | /* | |
162 | * minix_find_entry() | |
163 | * | |
164 | * finds an entry in the specified directory with the wanted name. It | |
165 | * returns the cache buffer in which the entry was found, and the entry | |
166 | * itself (as a parameter - res_dir). It does NOT read the inode of the | |
167 | * entry - you'll have to do that yourself if you want to. | |
168 | */ | |
169 | minix_dirent *minix_find_entry(struct dentry *dentry, struct page **res_page) | |
170 | { | |
171 | const char * name = dentry->d_name.name; | |
172 | int namelen = dentry->d_name.len; | |
173 | struct inode * dir = dentry->d_parent->d_inode; | |
174 | struct super_block * sb = dir->i_sb; | |
175 | struct minix_sb_info * sbi = minix_sb(sb); | |
176 | unsigned long n; | |
177 | unsigned long npages = dir_pages(dir); | |
178 | struct page *page = NULL; | |
939b00df | 179 | char *p; |
1da177e4 | 180 | |
939b00df AB |
181 | char *namx; |
182 | __u32 inumber; | |
1da177e4 LT |
183 | *res_page = NULL; |
184 | ||
185 | for (n = 0; n < npages; n++) { | |
939b00df AB |
186 | char *kaddr, *limit; |
187 | ||
1da177e4 LT |
188 | page = dir_get_page(dir, n); |
189 | if (IS_ERR(page)) | |
190 | continue; | |
191 | ||
192 | kaddr = (char*)page_address(page); | |
939b00df AB |
193 | limit = kaddr + minix_last_byte(dir, n) - sbi->s_dirsize; |
194 | for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) { | |
195 | if (sbi->s_version == MINIX_V3) { | |
196 | minix3_dirent *de3 = (minix3_dirent *)p; | |
197 | namx = de3->name; | |
198 | inumber = de3->inode; | |
199 | } else { | |
200 | minix_dirent *de = (minix_dirent *)p; | |
201 | namx = de->name; | |
202 | inumber = de->inode; | |
203 | } | |
204 | if (!inumber) | |
1da177e4 | 205 | continue; |
939b00df | 206 | if (namecompare(namelen, sbi->s_namelen, name, namx)) |
1da177e4 LT |
207 | goto found; |
208 | } | |
209 | dir_put_page(page); | |
210 | } | |
211 | return NULL; | |
212 | ||
213 | found: | |
214 | *res_page = page; | |
939b00df | 215 | return (minix_dirent *)p; |
1da177e4 LT |
216 | } |
217 | ||
218 | int minix_add_link(struct dentry *dentry, struct inode *inode) | |
219 | { | |
220 | struct inode *dir = dentry->d_parent->d_inode; | |
221 | const char * name = dentry->d_name.name; | |
222 | int namelen = dentry->d_name.len; | |
223 | struct super_block * sb = dir->i_sb; | |
224 | struct minix_sb_info * sbi = minix_sb(sb); | |
225 | struct page *page = NULL; | |
1da177e4 LT |
226 | unsigned long npages = dir_pages(dir); |
227 | unsigned long n; | |
939b00df AB |
228 | char *kaddr, *p; |
229 | minix_dirent *de; | |
230 | minix3_dirent *de3; | |
4a66af9e | 231 | loff_t pos; |
1da177e4 | 232 | int err; |
939b00df AB |
233 | char *namx = NULL; |
234 | __u32 inumber; | |
1da177e4 LT |
235 | |
236 | /* | |
237 | * We take care of directory expansion in the same loop | |
238 | * This code plays outside i_size, so it locks the page | |
239 | * to protect that region. | |
240 | */ | |
241 | for (n = 0; n <= npages; n++) { | |
939b00df | 242 | char *limit, *dir_end; |
1da177e4 LT |
243 | |
244 | page = dir_get_page(dir, n); | |
245 | err = PTR_ERR(page); | |
246 | if (IS_ERR(page)) | |
247 | goto out; | |
248 | lock_page(page); | |
249 | kaddr = (char*)page_address(page); | |
250 | dir_end = kaddr + minix_last_byte(dir, n); | |
939b00df AB |
251 | limit = kaddr + PAGE_CACHE_SIZE - sbi->s_dirsize; |
252 | for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) { | |
253 | de = (minix_dirent *)p; | |
254 | de3 = (minix3_dirent *)p; | |
255 | if (sbi->s_version == MINIX_V3) { | |
256 | namx = de3->name; | |
257 | inumber = de3->inode; | |
258 | } else { | |
259 | namx = de->name; | |
260 | inumber = de->inode; | |
261 | } | |
262 | if (p == dir_end) { | |
1da177e4 | 263 | /* We hit i_size */ |
939b00df AB |
264 | if (sbi->s_version == MINIX_V3) |
265 | de3->inode = 0; | |
266 | else | |
267 | de->inode = 0; | |
1da177e4 LT |
268 | goto got_it; |
269 | } | |
939b00df | 270 | if (!inumber) |
1da177e4 LT |
271 | goto got_it; |
272 | err = -EEXIST; | |
939b00df | 273 | if (namecompare(namelen, sbi->s_namelen, name, namx)) |
1da177e4 | 274 | goto out_unlock; |
1da177e4 LT |
275 | } |
276 | unlock_page(page); | |
277 | dir_put_page(page); | |
278 | } | |
279 | BUG(); | |
280 | return -EINVAL; | |
281 | ||
282 | got_it: | |
d6b54841 | 283 | pos = page_offset(page) + p - (char *)page_address(page); |
4a66af9e NP |
284 | err = __minix_write_begin(NULL, page->mapping, pos, sbi->s_dirsize, |
285 | AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); | |
1da177e4 LT |
286 | if (err) |
287 | goto out_unlock; | |
939b00df AB |
288 | memcpy (namx, name, namelen); |
289 | if (sbi->s_version == MINIX_V3) { | |
290 | memset (namx + namelen, 0, sbi->s_dirsize - namelen - 4); | |
291 | de3->inode = inode->i_ino; | |
292 | } else { | |
293 | memset (namx + namelen, 0, sbi->s_dirsize - namelen - 2); | |
294 | de->inode = inode->i_ino; | |
295 | } | |
4a66af9e | 296 | err = dir_commit_chunk(page, pos, sbi->s_dirsize); |
1da177e4 LT |
297 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; |
298 | mark_inode_dirty(dir); | |
299 | out_put: | |
300 | dir_put_page(page); | |
301 | out: | |
302 | return err; | |
303 | out_unlock: | |
304 | unlock_page(page); | |
305 | goto out_put; | |
306 | } | |
307 | ||
308 | int minix_delete_entry(struct minix_dir_entry *de, struct page *page) | |
309 | { | |
310 | struct address_space *mapping = page->mapping; | |
311 | struct inode *inode = (struct inode*)mapping->host; | |
312 | char *kaddr = page_address(page); | |
4a66af9e NP |
313 | loff_t pos = page_offset(page) + (char*)de - kaddr; |
314 | unsigned len = minix_sb(inode->i_sb)->s_dirsize; | |
1da177e4 LT |
315 | int err; |
316 | ||
317 | lock_page(page); | |
4a66af9e NP |
318 | err = __minix_write_begin(NULL, mapping, pos, len, |
319 | AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); | |
1da177e4 LT |
320 | if (err == 0) { |
321 | de->inode = 0; | |
4a66af9e | 322 | err = dir_commit_chunk(page, pos, len); |
1da177e4 LT |
323 | } else { |
324 | unlock_page(page); | |
325 | } | |
326 | dir_put_page(page); | |
327 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; | |
328 | mark_inode_dirty(inode); | |
329 | return err; | |
330 | } | |
331 | ||
332 | int minix_make_empty(struct inode *inode, struct inode *dir) | |
333 | { | |
334 | struct address_space *mapping = inode->i_mapping; | |
335 | struct page *page = grab_cache_page(mapping, 0); | |
939b00df | 336 | struct minix_sb_info *sbi = minix_sb(inode->i_sb); |
1da177e4 LT |
337 | char *kaddr; |
338 | int err; | |
339 | ||
340 | if (!page) | |
341 | return -ENOMEM; | |
4a66af9e NP |
342 | err = __minix_write_begin(NULL, mapping, 0, 2 * sbi->s_dirsize, |
343 | AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); | |
1da177e4 LT |
344 | if (err) { |
345 | unlock_page(page); | |
346 | goto fail; | |
347 | } | |
348 | ||
349 | kaddr = kmap_atomic(page, KM_USER0); | |
350 | memset(kaddr, 0, PAGE_CACHE_SIZE); | |
351 | ||
939b00df AB |
352 | if (sbi->s_version == MINIX_V3) { |
353 | minix3_dirent *de3 = (minix3_dirent *)kaddr; | |
354 | ||
355 | de3->inode = inode->i_ino; | |
356 | strcpy(de3->name, "."); | |
357 | de3 = minix_next_entry(de3, sbi); | |
358 | de3->inode = dir->i_ino; | |
359 | strcpy(de3->name, ".."); | |
360 | } else { | |
361 | minix_dirent *de = (minix_dirent *)kaddr; | |
362 | ||
363 | de->inode = inode->i_ino; | |
364 | strcpy(de->name, "."); | |
365 | de = minix_next_entry(de, sbi); | |
366 | de->inode = dir->i_ino; | |
367 | strcpy(de->name, ".."); | |
368 | } | |
1da177e4 LT |
369 | kunmap_atomic(kaddr, KM_USER0); |
370 | ||
371 | err = dir_commit_chunk(page, 0, 2 * sbi->s_dirsize); | |
372 | fail: | |
373 | page_cache_release(page); | |
374 | return err; | |
375 | } | |
376 | ||
377 | /* | |
378 | * routine to check that the specified directory is empty (for rmdir) | |
379 | */ | |
380 | int minix_empty_dir(struct inode * inode) | |
381 | { | |
382 | struct page *page = NULL; | |
383 | unsigned long i, npages = dir_pages(inode); | |
384 | struct minix_sb_info *sbi = minix_sb(inode->i_sb); | |
939b00df AB |
385 | char *name; |
386 | __u32 inumber; | |
1da177e4 LT |
387 | |
388 | for (i = 0; i < npages; i++) { | |
939b00df | 389 | char *p, *kaddr, *limit; |
1da177e4 | 390 | |
939b00df | 391 | page = dir_get_page(inode, i); |
1da177e4 LT |
392 | if (IS_ERR(page)) |
393 | continue; | |
394 | ||
395 | kaddr = (char *)page_address(page); | |
939b00df AB |
396 | limit = kaddr + minix_last_byte(inode, i) - sbi->s_dirsize; |
397 | for (p = kaddr; p <= limit; p = minix_next_entry(p, sbi)) { | |
398 | if (sbi->s_version == MINIX_V3) { | |
399 | minix3_dirent *de3 = (minix3_dirent *)p; | |
400 | name = de3->name; | |
401 | inumber = de3->inode; | |
402 | } else { | |
403 | minix_dirent *de = (minix_dirent *)p; | |
404 | name = de->name; | |
405 | inumber = de->inode; | |
406 | } | |
1da177e4 | 407 | |
939b00df | 408 | if (inumber != 0) { |
1da177e4 | 409 | /* check for . and .. */ |
939b00df | 410 | if (name[0] != '.') |
1da177e4 | 411 | goto not_empty; |
939b00df AB |
412 | if (!name[1]) { |
413 | if (inumber != inode->i_ino) | |
1da177e4 | 414 | goto not_empty; |
939b00df | 415 | } else if (name[1] != '.') |
1da177e4 | 416 | goto not_empty; |
939b00df | 417 | else if (name[2]) |
1da177e4 LT |
418 | goto not_empty; |
419 | } | |
1da177e4 LT |
420 | } |
421 | dir_put_page(page); | |
422 | } | |
423 | return 1; | |
424 | ||
425 | not_empty: | |
426 | dir_put_page(page); | |
427 | return 0; | |
428 | } | |
429 | ||
430 | /* Releases the page */ | |
431 | void minix_set_link(struct minix_dir_entry *de, struct page *page, | |
432 | struct inode *inode) | |
433 | { | |
4a66af9e NP |
434 | struct address_space *mapping = page->mapping; |
435 | struct inode *dir = mapping->host; | |
1da177e4 | 436 | struct minix_sb_info *sbi = minix_sb(dir->i_sb); |
4a66af9e NP |
437 | loff_t pos = page_offset(page) + |
438 | (char *)de-(char*)page_address(page); | |
1da177e4 LT |
439 | int err; |
440 | ||
441 | lock_page(page); | |
4a66af9e NP |
442 | |
443 | err = __minix_write_begin(NULL, mapping, pos, sbi->s_dirsize, | |
444 | AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); | |
1da177e4 LT |
445 | if (err == 0) { |
446 | de->inode = inode->i_ino; | |
4a66af9e | 447 | err = dir_commit_chunk(page, pos, sbi->s_dirsize); |
1da177e4 LT |
448 | } else { |
449 | unlock_page(page); | |
450 | } | |
451 | dir_put_page(page); | |
452 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; | |
453 | mark_inode_dirty(dir); | |
454 | } | |
455 | ||
456 | struct minix_dir_entry * minix_dotdot (struct inode *dir, struct page **p) | |
457 | { | |
458 | struct page *page = dir_get_page(dir, 0); | |
459 | struct minix_sb_info *sbi = minix_sb(dir->i_sb); | |
460 | struct minix_dir_entry *de = NULL; | |
461 | ||
462 | if (!IS_ERR(page)) { | |
463 | de = minix_next_entry(page_address(page), sbi); | |
464 | *p = page; | |
465 | } | |
466 | return de; | |
467 | } | |
468 | ||
469 | ino_t minix_inode_by_name(struct dentry *dentry) | |
470 | { | |
471 | struct page *page; | |
472 | struct minix_dir_entry *de = minix_find_entry(dentry, &page); | |
473 | ino_t res = 0; | |
474 | ||
475 | if (de) { | |
476 | res = de->inode; | |
477 | dir_put_page(page); | |
478 | } | |
479 | return res; | |
480 | } |