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1da177e4 LT |
1 | /* |
2 | * linux/fs/ext2/dir.c | |
3 | * | |
4 | * Copyright (C) 1992, 1993, 1994, 1995 | |
5 | * Remy Card (card@masi.ibp.fr) | |
6 | * Laboratoire MASI - Institut Blaise Pascal | |
7 | * Universite Pierre et Marie Curie (Paris VI) | |
8 | * | |
9 | * from | |
10 | * | |
11 | * linux/fs/minix/dir.c | |
12 | * | |
13 | * Copyright (C) 1991, 1992 Linus Torvalds | |
14 | * | |
15 | * ext2 directory handling functions | |
16 | * | |
17 | * Big-endian to little-endian byte-swapping/bitmaps by | |
18 | * David S. Miller (davem@caip.rutgers.edu), 1995 | |
19 | * | |
20 | * All code that works with directory layout had been switched to pagecache | |
21 | * and moved here. AV | |
22 | */ | |
23 | ||
24 | #include "ext2.h" | |
25 | #include <linux/pagemap.h> | |
26 | #include <linux/smp_lock.h> | |
27 | ||
28 | typedef struct ext2_dir_entry_2 ext2_dirent; | |
29 | ||
30 | /* | |
31 | * ext2 uses block-sized chunks. Arguably, sector-sized ones would be | |
32 | * more robust, but we have what we have | |
33 | */ | |
34 | static inline unsigned ext2_chunk_size(struct inode *inode) | |
35 | { | |
36 | return inode->i_sb->s_blocksize; | |
37 | } | |
38 | ||
39 | static inline void ext2_put_page(struct page *page) | |
40 | { | |
41 | kunmap(page); | |
42 | page_cache_release(page); | |
43 | } | |
44 | ||
45 | static inline unsigned long dir_pages(struct inode *inode) | |
46 | { | |
47 | return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; | |
48 | } | |
49 | ||
50 | /* | |
51 | * Return the offset into page `page_nr' of the last valid | |
52 | * byte in that page, plus one. | |
53 | */ | |
54 | static unsigned | |
55 | ext2_last_byte(struct inode *inode, unsigned long page_nr) | |
56 | { | |
57 | unsigned last_byte = inode->i_size; | |
58 | ||
59 | last_byte -= page_nr << PAGE_CACHE_SHIFT; | |
60 | if (last_byte > PAGE_CACHE_SIZE) | |
61 | last_byte = PAGE_CACHE_SIZE; | |
62 | return last_byte; | |
63 | } | |
64 | ||
65 | static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to) | |
66 | { | |
67 | struct inode *dir = page->mapping->host; | |
68 | int err = 0; | |
69 | dir->i_version++; | |
70 | page->mapping->a_ops->commit_write(NULL, page, from, to); | |
71 | if (IS_DIRSYNC(dir)) | |
72 | err = write_one_page(page, 1); | |
73 | else | |
74 | unlock_page(page); | |
75 | return err; | |
76 | } | |
77 | ||
78 | static void ext2_check_page(struct page *page) | |
79 | { | |
80 | struct inode *dir = page->mapping->host; | |
81 | struct super_block *sb = dir->i_sb; | |
82 | unsigned chunk_size = ext2_chunk_size(dir); | |
83 | char *kaddr = page_address(page); | |
84 | u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); | |
85 | unsigned offs, rec_len; | |
86 | unsigned limit = PAGE_CACHE_SIZE; | |
87 | ext2_dirent *p; | |
88 | char *error; | |
89 | ||
90 | if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { | |
91 | limit = dir->i_size & ~PAGE_CACHE_MASK; | |
92 | if (limit & (chunk_size - 1)) | |
93 | goto Ebadsize; | |
94 | if (!limit) | |
95 | goto out; | |
96 | } | |
97 | for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) { | |
98 | p = (ext2_dirent *)(kaddr + offs); | |
99 | rec_len = le16_to_cpu(p->rec_len); | |
100 | ||
101 | if (rec_len < EXT2_DIR_REC_LEN(1)) | |
102 | goto Eshort; | |
103 | if (rec_len & 3) | |
104 | goto Ealign; | |
105 | if (rec_len < EXT2_DIR_REC_LEN(p->name_len)) | |
106 | goto Enamelen; | |
107 | if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)) | |
108 | goto Espan; | |
109 | if (le32_to_cpu(p->inode) > max_inumber) | |
110 | goto Einumber; | |
111 | } | |
112 | if (offs != limit) | |
113 | goto Eend; | |
114 | out: | |
115 | SetPageChecked(page); | |
116 | return; | |
117 | ||
118 | /* Too bad, we had an error */ | |
119 | ||
120 | Ebadsize: | |
121 | ext2_error(sb, "ext2_check_page", | |
122 | "size of directory #%lu is not a multiple of chunk size", | |
123 | dir->i_ino | |
124 | ); | |
125 | goto fail; | |
126 | Eshort: | |
127 | error = "rec_len is smaller than minimal"; | |
128 | goto bad_entry; | |
129 | Ealign: | |
130 | error = "unaligned directory entry"; | |
131 | goto bad_entry; | |
132 | Enamelen: | |
133 | error = "rec_len is too small for name_len"; | |
134 | goto bad_entry; | |
135 | Espan: | |
136 | error = "directory entry across blocks"; | |
137 | goto bad_entry; | |
138 | Einumber: | |
139 | error = "inode out of bounds"; | |
140 | bad_entry: | |
141 | ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - " | |
142 | "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", | |
143 | dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
144 | (unsigned long) le32_to_cpu(p->inode), | |
145 | rec_len, p->name_len); | |
146 | goto fail; | |
147 | Eend: | |
148 | p = (ext2_dirent *)(kaddr + offs); | |
149 | ext2_error (sb, "ext2_check_page", | |
150 | "entry in directory #%lu spans the page boundary" | |
151 | "offset=%lu, inode=%lu", | |
152 | dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
153 | (unsigned long) le32_to_cpu(p->inode)); | |
154 | fail: | |
155 | SetPageChecked(page); | |
156 | SetPageError(page); | |
157 | } | |
158 | ||
159 | static struct page * ext2_get_page(struct inode *dir, unsigned long n) | |
160 | { | |
161 | struct address_space *mapping = dir->i_mapping; | |
162 | struct page *page = read_cache_page(mapping, n, | |
163 | (filler_t*)mapping->a_ops->readpage, NULL); | |
164 | if (!IS_ERR(page)) { | |
165 | wait_on_page_locked(page); | |
166 | kmap(page); | |
167 | if (!PageUptodate(page)) | |
168 | goto fail; | |
169 | if (!PageChecked(page)) | |
170 | ext2_check_page(page); | |
171 | if (PageError(page)) | |
172 | goto fail; | |
173 | } | |
174 | return page; | |
175 | ||
176 | fail: | |
177 | ext2_put_page(page); | |
178 | return ERR_PTR(-EIO); | |
179 | } | |
180 | ||
181 | /* | |
182 | * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure. | |
183 | * | |
184 | * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller. | |
185 | */ | |
186 | static inline int ext2_match (int len, const char * const name, | |
187 | struct ext2_dir_entry_2 * de) | |
188 | { | |
189 | if (len != de->name_len) | |
190 | return 0; | |
191 | if (!de->inode) | |
192 | return 0; | |
193 | return !memcmp(name, de->name, len); | |
194 | } | |
195 | ||
196 | /* | |
197 | * p is at least 6 bytes before the end of page | |
198 | */ | |
199 | static inline ext2_dirent *ext2_next_entry(ext2_dirent *p) | |
200 | { | |
201 | return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len)); | |
202 | } | |
203 | ||
204 | static inline unsigned | |
205 | ext2_validate_entry(char *base, unsigned offset, unsigned mask) | |
206 | { | |
207 | ext2_dirent *de = (ext2_dirent*)(base + offset); | |
208 | ext2_dirent *p = (ext2_dirent*)(base + (offset&mask)); | |
209 | while ((char*)p < (char*)de) { | |
210 | if (p->rec_len == 0) | |
211 | break; | |
212 | p = ext2_next_entry(p); | |
213 | } | |
214 | return (char *)p - base; | |
215 | } | |
216 | ||
217 | static unsigned char ext2_filetype_table[EXT2_FT_MAX] = { | |
218 | [EXT2_FT_UNKNOWN] = DT_UNKNOWN, | |
219 | [EXT2_FT_REG_FILE] = DT_REG, | |
220 | [EXT2_FT_DIR] = DT_DIR, | |
221 | [EXT2_FT_CHRDEV] = DT_CHR, | |
222 | [EXT2_FT_BLKDEV] = DT_BLK, | |
223 | [EXT2_FT_FIFO] = DT_FIFO, | |
224 | [EXT2_FT_SOCK] = DT_SOCK, | |
225 | [EXT2_FT_SYMLINK] = DT_LNK, | |
226 | }; | |
227 | ||
228 | #define S_SHIFT 12 | |
229 | static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = { | |
230 | [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE, | |
231 | [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR, | |
232 | [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV, | |
233 | [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV, | |
234 | [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO, | |
235 | [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK, | |
236 | [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK, | |
237 | }; | |
238 | ||
239 | static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode) | |
240 | { | |
241 | mode_t mode = inode->i_mode; | |
242 | if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) | |
243 | de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; | |
244 | else | |
245 | de->file_type = 0; | |
246 | } | |
247 | ||
248 | static int | |
249 | ext2_readdir (struct file * filp, void * dirent, filldir_t filldir) | |
250 | { | |
251 | loff_t pos = filp->f_pos; | |
252 | struct inode *inode = filp->f_dentry->d_inode; | |
253 | struct super_block *sb = inode->i_sb; | |
254 | unsigned int offset = pos & ~PAGE_CACHE_MASK; | |
255 | unsigned long n = pos >> PAGE_CACHE_SHIFT; | |
256 | unsigned long npages = dir_pages(inode); | |
257 | unsigned chunk_mask = ~(ext2_chunk_size(inode)-1); | |
258 | unsigned char *types = NULL; | |
2d7f2ea9 | 259 | int need_revalidate = filp->f_version != inode->i_version; |
1da177e4 LT |
260 | |
261 | if (pos > inode->i_size - EXT2_DIR_REC_LEN(1)) | |
2d7f2ea9 | 262 | return 0; |
1da177e4 LT |
263 | |
264 | if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) | |
265 | types = ext2_filetype_table; | |
266 | ||
267 | for ( ; n < npages; n++, offset = 0) { | |
268 | char *kaddr, *limit; | |
269 | ext2_dirent *de; | |
270 | struct page *page = ext2_get_page(inode, n); | |
271 | ||
272 | if (IS_ERR(page)) { | |
273 | ext2_error(sb, __FUNCTION__, | |
274 | "bad page in #%lu", | |
275 | inode->i_ino); | |
276 | filp->f_pos += PAGE_CACHE_SIZE - offset; | |
2d7f2ea9 | 277 | return -EIO; |
1da177e4 LT |
278 | } |
279 | kaddr = page_address(page); | |
2d7f2ea9 AV |
280 | if (unlikely(need_revalidate)) { |
281 | if (offset) { | |
282 | offset = ext2_validate_entry(kaddr, offset, chunk_mask); | |
283 | filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset; | |
284 | } | |
285 | filp->f_version = inode->i_version; | |
1da177e4 LT |
286 | need_revalidate = 0; |
287 | } | |
288 | de = (ext2_dirent *)(kaddr+offset); | |
289 | limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1); | |
290 | for ( ;(char*)de <= limit; de = ext2_next_entry(de)) { | |
291 | if (de->rec_len == 0) { | |
292 | ext2_error(sb, __FUNCTION__, | |
293 | "zero-length directory entry"); | |
1da177e4 | 294 | ext2_put_page(page); |
2d7f2ea9 | 295 | return -EIO; |
1da177e4 LT |
296 | } |
297 | if (de->inode) { | |
298 | int over; | |
299 | unsigned char d_type = DT_UNKNOWN; | |
300 | ||
301 | if (types && de->file_type < EXT2_FT_MAX) | |
302 | d_type = types[de->file_type]; | |
303 | ||
304 | offset = (char *)de - kaddr; | |
305 | over = filldir(dirent, de->name, de->name_len, | |
306 | (n<<PAGE_CACHE_SHIFT) | offset, | |
307 | le32_to_cpu(de->inode), d_type); | |
308 | if (over) { | |
309 | ext2_put_page(page); | |
2d7f2ea9 | 310 | return 0; |
1da177e4 LT |
311 | } |
312 | } | |
313 | filp->f_pos += le16_to_cpu(de->rec_len); | |
314 | } | |
315 | ext2_put_page(page); | |
316 | } | |
2d7f2ea9 | 317 | return 0; |
1da177e4 LT |
318 | } |
319 | ||
320 | /* | |
321 | * ext2_find_entry() | |
322 | * | |
323 | * finds an entry in the specified directory with the wanted name. It | |
324 | * returns the page in which the entry was found, and the entry itself | |
325 | * (as a parameter - res_dir). Page is returned mapped and unlocked. | |
326 | * Entry is guaranteed to be valid. | |
327 | */ | |
328 | struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir, | |
329 | struct dentry *dentry, struct page ** res_page) | |
330 | { | |
331 | const char *name = dentry->d_name.name; | |
332 | int namelen = dentry->d_name.len; | |
333 | unsigned reclen = EXT2_DIR_REC_LEN(namelen); | |
334 | unsigned long start, n; | |
335 | unsigned long npages = dir_pages(dir); | |
336 | struct page *page = NULL; | |
337 | struct ext2_inode_info *ei = EXT2_I(dir); | |
338 | ext2_dirent * de; | |
339 | ||
340 | if (npages == 0) | |
341 | goto out; | |
342 | ||
343 | /* OFFSET_CACHE */ | |
344 | *res_page = NULL; | |
345 | ||
346 | start = ei->i_dir_start_lookup; | |
347 | if (start >= npages) | |
348 | start = 0; | |
349 | n = start; | |
350 | do { | |
351 | char *kaddr; | |
352 | page = ext2_get_page(dir, n); | |
353 | if (!IS_ERR(page)) { | |
354 | kaddr = page_address(page); | |
355 | de = (ext2_dirent *) kaddr; | |
356 | kaddr += ext2_last_byte(dir, n) - reclen; | |
357 | while ((char *) de <= kaddr) { | |
358 | if (de->rec_len == 0) { | |
359 | ext2_error(dir->i_sb, __FUNCTION__, | |
360 | "zero-length directory entry"); | |
361 | ext2_put_page(page); | |
362 | goto out; | |
363 | } | |
364 | if (ext2_match (namelen, name, de)) | |
365 | goto found; | |
366 | de = ext2_next_entry(de); | |
367 | } | |
368 | ext2_put_page(page); | |
369 | } | |
370 | if (++n >= npages) | |
371 | n = 0; | |
372 | } while (n != start); | |
373 | out: | |
374 | return NULL; | |
375 | ||
376 | found: | |
377 | *res_page = page; | |
378 | ei->i_dir_start_lookup = n; | |
379 | return de; | |
380 | } | |
381 | ||
382 | struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p) | |
383 | { | |
384 | struct page *page = ext2_get_page(dir, 0); | |
385 | ext2_dirent *de = NULL; | |
386 | ||
387 | if (!IS_ERR(page)) { | |
388 | de = ext2_next_entry((ext2_dirent *) page_address(page)); | |
389 | *p = page; | |
390 | } | |
391 | return de; | |
392 | } | |
393 | ||
394 | ino_t ext2_inode_by_name(struct inode * dir, struct dentry *dentry) | |
395 | { | |
396 | ino_t res = 0; | |
397 | struct ext2_dir_entry_2 * de; | |
398 | struct page *page; | |
399 | ||
400 | de = ext2_find_entry (dir, dentry, &page); | |
401 | if (de) { | |
402 | res = le32_to_cpu(de->inode); | |
403 | kunmap(page); | |
404 | page_cache_release(page); | |
405 | } | |
406 | return res; | |
407 | } | |
408 | ||
409 | /* Releases the page */ | |
410 | void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de, | |
411 | struct page *page, struct inode *inode) | |
412 | { | |
413 | unsigned from = (char *) de - (char *) page_address(page); | |
414 | unsigned to = from + le16_to_cpu(de->rec_len); | |
415 | int err; | |
416 | ||
417 | lock_page(page); | |
418 | err = page->mapping->a_ops->prepare_write(NULL, page, from, to); | |
309be53d | 419 | BUG_ON(err); |
1da177e4 LT |
420 | de->inode = cpu_to_le32(inode->i_ino); |
421 | ext2_set_de_type (de, inode); | |
422 | err = ext2_commit_chunk(page, from, to); | |
423 | ext2_put_page(page); | |
424 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; | |
425 | EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; | |
426 | mark_inode_dirty(dir); | |
427 | } | |
428 | ||
429 | /* | |
430 | * Parent is locked. | |
431 | */ | |
432 | int ext2_add_link (struct dentry *dentry, struct inode *inode) | |
433 | { | |
434 | struct inode *dir = dentry->d_parent->d_inode; | |
435 | const char *name = dentry->d_name.name; | |
436 | int namelen = dentry->d_name.len; | |
437 | unsigned chunk_size = ext2_chunk_size(dir); | |
438 | unsigned reclen = EXT2_DIR_REC_LEN(namelen); | |
439 | unsigned short rec_len, name_len; | |
440 | struct page *page = NULL; | |
441 | ext2_dirent * de; | |
442 | unsigned long npages = dir_pages(dir); | |
443 | unsigned long n; | |
444 | char *kaddr; | |
445 | unsigned from, to; | |
446 | int err; | |
447 | ||
448 | /* | |
449 | * We take care of directory expansion in the same loop. | |
450 | * This code plays outside i_size, so it locks the page | |
451 | * to protect that region. | |
452 | */ | |
453 | for (n = 0; n <= npages; n++) { | |
454 | char *dir_end; | |
455 | ||
456 | page = ext2_get_page(dir, n); | |
457 | err = PTR_ERR(page); | |
458 | if (IS_ERR(page)) | |
459 | goto out; | |
460 | lock_page(page); | |
461 | kaddr = page_address(page); | |
462 | dir_end = kaddr + ext2_last_byte(dir, n); | |
463 | de = (ext2_dirent *)kaddr; | |
464 | kaddr += PAGE_CACHE_SIZE - reclen; | |
465 | while ((char *)de <= kaddr) { | |
466 | if ((char *)de == dir_end) { | |
467 | /* We hit i_size */ | |
468 | name_len = 0; | |
469 | rec_len = chunk_size; | |
470 | de->rec_len = cpu_to_le16(chunk_size); | |
471 | de->inode = 0; | |
472 | goto got_it; | |
473 | } | |
474 | if (de->rec_len == 0) { | |
475 | ext2_error(dir->i_sb, __FUNCTION__, | |
476 | "zero-length directory entry"); | |
477 | err = -EIO; | |
478 | goto out_unlock; | |
479 | } | |
480 | err = -EEXIST; | |
481 | if (ext2_match (namelen, name, de)) | |
482 | goto out_unlock; | |
483 | name_len = EXT2_DIR_REC_LEN(de->name_len); | |
484 | rec_len = le16_to_cpu(de->rec_len); | |
485 | if (!de->inode && rec_len >= reclen) | |
486 | goto got_it; | |
487 | if (rec_len >= name_len + reclen) | |
488 | goto got_it; | |
489 | de = (ext2_dirent *) ((char *) de + rec_len); | |
490 | } | |
491 | unlock_page(page); | |
492 | ext2_put_page(page); | |
493 | } | |
494 | BUG(); | |
495 | return -EINVAL; | |
496 | ||
497 | got_it: | |
498 | from = (char*)de - (char*)page_address(page); | |
499 | to = from + rec_len; | |
500 | err = page->mapping->a_ops->prepare_write(NULL, page, from, to); | |
501 | if (err) | |
502 | goto out_unlock; | |
503 | if (de->inode) { | |
504 | ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); | |
505 | de1->rec_len = cpu_to_le16(rec_len - name_len); | |
506 | de->rec_len = cpu_to_le16(name_len); | |
507 | de = de1; | |
508 | } | |
509 | de->name_len = namelen; | |
510 | memcpy (de->name, name, namelen); | |
511 | de->inode = cpu_to_le32(inode->i_ino); | |
512 | ext2_set_de_type (de, inode); | |
513 | err = ext2_commit_chunk(page, from, to); | |
514 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; | |
515 | EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; | |
516 | mark_inode_dirty(dir); | |
517 | /* OFFSET_CACHE */ | |
518 | out_put: | |
519 | ext2_put_page(page); | |
520 | out: | |
521 | return err; | |
522 | out_unlock: | |
523 | unlock_page(page); | |
524 | goto out_put; | |
525 | } | |
526 | ||
527 | /* | |
528 | * ext2_delete_entry deletes a directory entry by merging it with the | |
529 | * previous entry. Page is up-to-date. Releases the page. | |
530 | */ | |
531 | int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) | |
532 | { | |
533 | struct address_space *mapping = page->mapping; | |
534 | struct inode *inode = mapping->host; | |
535 | char *kaddr = page_address(page); | |
536 | unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); | |
537 | unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len); | |
538 | ext2_dirent * pde = NULL; | |
539 | ext2_dirent * de = (ext2_dirent *) (kaddr + from); | |
540 | int err; | |
541 | ||
542 | while ((char*)de < (char*)dir) { | |
543 | if (de->rec_len == 0) { | |
544 | ext2_error(inode->i_sb, __FUNCTION__, | |
545 | "zero-length directory entry"); | |
546 | err = -EIO; | |
547 | goto out; | |
548 | } | |
549 | pde = de; | |
550 | de = ext2_next_entry(de); | |
551 | } | |
552 | if (pde) | |
553 | from = (char*)pde - (char*)page_address(page); | |
554 | lock_page(page); | |
555 | err = mapping->a_ops->prepare_write(NULL, page, from, to); | |
309be53d | 556 | BUG_ON(err); |
1da177e4 LT |
557 | if (pde) |
558 | pde->rec_len = cpu_to_le16(to-from); | |
559 | dir->inode = 0; | |
560 | err = ext2_commit_chunk(page, from, to); | |
561 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; | |
562 | EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL; | |
563 | mark_inode_dirty(inode); | |
564 | out: | |
565 | ext2_put_page(page); | |
566 | return err; | |
567 | } | |
568 | ||
569 | /* | |
570 | * Set the first fragment of directory. | |
571 | */ | |
572 | int ext2_make_empty(struct inode *inode, struct inode *parent) | |
573 | { | |
574 | struct address_space *mapping = inode->i_mapping; | |
575 | struct page *page = grab_cache_page(mapping, 0); | |
576 | unsigned chunk_size = ext2_chunk_size(inode); | |
577 | struct ext2_dir_entry_2 * de; | |
578 | int err; | |
579 | void *kaddr; | |
580 | ||
581 | if (!page) | |
582 | return -ENOMEM; | |
583 | err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size); | |
584 | if (err) { | |
585 | unlock_page(page); | |
586 | goto fail; | |
587 | } | |
588 | kaddr = kmap_atomic(page, KM_USER0); | |
7823c7c1 | 589 | memset(kaddr, 0, chunk_size); |
1da177e4 LT |
590 | de = (struct ext2_dir_entry_2 *)kaddr; |
591 | de->name_len = 1; | |
592 | de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1)); | |
593 | memcpy (de->name, ".\0\0", 4); | |
594 | de->inode = cpu_to_le32(inode->i_ino); | |
595 | ext2_set_de_type (de, inode); | |
596 | ||
597 | de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1)); | |
598 | de->name_len = 2; | |
599 | de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1)); | |
600 | de->inode = cpu_to_le32(parent->i_ino); | |
601 | memcpy (de->name, "..\0", 4); | |
602 | ext2_set_de_type (de, inode); | |
603 | kunmap_atomic(kaddr, KM_USER0); | |
604 | err = ext2_commit_chunk(page, 0, chunk_size); | |
605 | fail: | |
606 | page_cache_release(page); | |
607 | return err; | |
608 | } | |
609 | ||
610 | /* | |
611 | * routine to check that the specified directory is empty (for rmdir) | |
612 | */ | |
613 | int ext2_empty_dir (struct inode * inode) | |
614 | { | |
615 | struct page *page = NULL; | |
616 | unsigned long i, npages = dir_pages(inode); | |
617 | ||
618 | for (i = 0; i < npages; i++) { | |
619 | char *kaddr; | |
620 | ext2_dirent * de; | |
621 | page = ext2_get_page(inode, i); | |
622 | ||
623 | if (IS_ERR(page)) | |
624 | continue; | |
625 | ||
626 | kaddr = page_address(page); | |
627 | de = (ext2_dirent *)kaddr; | |
628 | kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1); | |
629 | ||
630 | while ((char *)de <= kaddr) { | |
631 | if (de->rec_len == 0) { | |
632 | ext2_error(inode->i_sb, __FUNCTION__, | |
633 | "zero-length directory entry"); | |
634 | printk("kaddr=%p, de=%p\n", kaddr, de); | |
635 | goto not_empty; | |
636 | } | |
637 | if (de->inode != 0) { | |
638 | /* check for . and .. */ | |
639 | if (de->name[0] != '.') | |
640 | goto not_empty; | |
641 | if (de->name_len > 2) | |
642 | goto not_empty; | |
643 | if (de->name_len < 2) { | |
644 | if (de->inode != | |
645 | cpu_to_le32(inode->i_ino)) | |
646 | goto not_empty; | |
647 | } else if (de->name[1] != '.') | |
648 | goto not_empty; | |
649 | } | |
650 | de = ext2_next_entry(de); | |
651 | } | |
652 | ext2_put_page(page); | |
653 | } | |
654 | return 1; | |
655 | ||
656 | not_empty: | |
657 | ext2_put_page(page); | |
658 | return 0; | |
659 | } | |
660 | ||
4b6f5d20 | 661 | const struct file_operations ext2_dir_operations = { |
1da177e4 LT |
662 | .llseek = generic_file_llseek, |
663 | .read = generic_read_dir, | |
664 | .readdir = ext2_readdir, | |
665 | .ioctl = ext2_ioctl, | |
666 | .fsync = ext2_sync_file, | |
667 | }; |