Commit | Line | Data |
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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> | |
1da177e4 LT |
26 | |
27 | typedef struct ext2_dir_entry_2 ext2_dirent; | |
28 | ||
29 | /* | |
30 | * ext2 uses block-sized chunks. Arguably, sector-sized ones would be | |
31 | * more robust, but we have what we have | |
32 | */ | |
33 | static inline unsigned ext2_chunk_size(struct inode *inode) | |
34 | { | |
35 | return inode->i_sb->s_blocksize; | |
36 | } | |
37 | ||
38 | static inline void ext2_put_page(struct page *page) | |
39 | { | |
40 | kunmap(page); | |
41 | page_cache_release(page); | |
42 | } | |
43 | ||
44 | static inline unsigned long dir_pages(struct inode *inode) | |
45 | { | |
46 | return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; | |
47 | } | |
48 | ||
49 | /* | |
50 | * Return the offset into page `page_nr' of the last valid | |
51 | * byte in that page, plus one. | |
52 | */ | |
53 | static unsigned | |
54 | ext2_last_byte(struct inode *inode, unsigned long page_nr) | |
55 | { | |
56 | unsigned last_byte = inode->i_size; | |
57 | ||
58 | last_byte -= page_nr << PAGE_CACHE_SHIFT; | |
59 | if (last_byte > PAGE_CACHE_SIZE) | |
60 | last_byte = PAGE_CACHE_SIZE; | |
61 | return last_byte; | |
62 | } | |
63 | ||
64 | static int ext2_commit_chunk(struct page *page, unsigned from, unsigned to) | |
65 | { | |
66 | struct inode *dir = page->mapping->host; | |
67 | int err = 0; | |
68 | dir->i_version++; | |
69 | page->mapping->a_ops->commit_write(NULL, page, from, to); | |
70 | if (IS_DIRSYNC(dir)) | |
71 | err = write_one_page(page, 1); | |
72 | else | |
73 | unlock_page(page); | |
74 | return err; | |
75 | } | |
76 | ||
77 | static void ext2_check_page(struct page *page) | |
78 | { | |
79 | struct inode *dir = page->mapping->host; | |
80 | struct super_block *sb = dir->i_sb; | |
81 | unsigned chunk_size = ext2_chunk_size(dir); | |
82 | char *kaddr = page_address(page); | |
83 | u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); | |
84 | unsigned offs, rec_len; | |
85 | unsigned limit = PAGE_CACHE_SIZE; | |
86 | ext2_dirent *p; | |
87 | char *error; | |
88 | ||
89 | if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { | |
90 | limit = dir->i_size & ~PAGE_CACHE_MASK; | |
91 | if (limit & (chunk_size - 1)) | |
92 | goto Ebadsize; | |
93 | if (!limit) | |
94 | goto out; | |
95 | } | |
96 | for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) { | |
97 | p = (ext2_dirent *)(kaddr + offs); | |
98 | rec_len = le16_to_cpu(p->rec_len); | |
99 | ||
100 | if (rec_len < EXT2_DIR_REC_LEN(1)) | |
101 | goto Eshort; | |
102 | if (rec_len & 3) | |
103 | goto Ealign; | |
104 | if (rec_len < EXT2_DIR_REC_LEN(p->name_len)) | |
105 | goto Enamelen; | |
106 | if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)) | |
107 | goto Espan; | |
108 | if (le32_to_cpu(p->inode) > max_inumber) | |
109 | goto Einumber; | |
110 | } | |
111 | if (offs != limit) | |
112 | goto Eend; | |
113 | out: | |
114 | SetPageChecked(page); | |
115 | return; | |
116 | ||
117 | /* Too bad, we had an error */ | |
118 | ||
119 | Ebadsize: | |
120 | ext2_error(sb, "ext2_check_page", | |
121 | "size of directory #%lu is not a multiple of chunk size", | |
122 | dir->i_ino | |
123 | ); | |
124 | goto fail; | |
125 | Eshort: | |
126 | error = "rec_len is smaller than minimal"; | |
127 | goto bad_entry; | |
128 | Ealign: | |
129 | error = "unaligned directory entry"; | |
130 | goto bad_entry; | |
131 | Enamelen: | |
132 | error = "rec_len is too small for name_len"; | |
133 | goto bad_entry; | |
134 | Espan: | |
135 | error = "directory entry across blocks"; | |
136 | goto bad_entry; | |
137 | Einumber: | |
138 | error = "inode out of bounds"; | |
139 | bad_entry: | |
140 | ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - " | |
141 | "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", | |
142 | dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
143 | (unsigned long) le32_to_cpu(p->inode), | |
144 | rec_len, p->name_len); | |
145 | goto fail; | |
146 | Eend: | |
147 | p = (ext2_dirent *)(kaddr + offs); | |
148 | ext2_error (sb, "ext2_check_page", | |
149 | "entry in directory #%lu spans the page boundary" | |
150 | "offset=%lu, inode=%lu", | |
151 | dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
152 | (unsigned long) le32_to_cpu(p->inode)); | |
153 | fail: | |
154 | SetPageChecked(page); | |
155 | SetPageError(page); | |
156 | } | |
157 | ||
158 | static struct page * ext2_get_page(struct inode *dir, unsigned long n) | |
159 | { | |
160 | struct address_space *mapping = dir->i_mapping; | |
090d2b18 | 161 | struct page *page = read_mapping_page(mapping, n, NULL); |
1da177e4 | 162 | if (!IS_ERR(page)) { |
1da177e4 | 163 | kmap(page); |
1da177e4 LT |
164 | if (!PageChecked(page)) |
165 | ext2_check_page(page); | |
166 | if (PageError(page)) | |
167 | goto fail; | |
168 | } | |
169 | return page; | |
170 | ||
171 | fail: | |
172 | ext2_put_page(page); | |
173 | return ERR_PTR(-EIO); | |
174 | } | |
175 | ||
176 | /* | |
177 | * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure. | |
178 | * | |
179 | * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller. | |
180 | */ | |
181 | static inline int ext2_match (int len, const char * const name, | |
182 | struct ext2_dir_entry_2 * de) | |
183 | { | |
184 | if (len != de->name_len) | |
185 | return 0; | |
186 | if (!de->inode) | |
187 | return 0; | |
188 | return !memcmp(name, de->name, len); | |
189 | } | |
190 | ||
191 | /* | |
192 | * p is at least 6 bytes before the end of page | |
193 | */ | |
194 | static inline ext2_dirent *ext2_next_entry(ext2_dirent *p) | |
195 | { | |
196 | return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len)); | |
197 | } | |
198 | ||
199 | static inline unsigned | |
200 | ext2_validate_entry(char *base, unsigned offset, unsigned mask) | |
201 | { | |
202 | ext2_dirent *de = (ext2_dirent*)(base + offset); | |
203 | ext2_dirent *p = (ext2_dirent*)(base + (offset&mask)); | |
204 | while ((char*)p < (char*)de) { | |
205 | if (p->rec_len == 0) | |
206 | break; | |
207 | p = ext2_next_entry(p); | |
208 | } | |
209 | return (char *)p - base; | |
210 | } | |
211 | ||
212 | static unsigned char ext2_filetype_table[EXT2_FT_MAX] = { | |
213 | [EXT2_FT_UNKNOWN] = DT_UNKNOWN, | |
214 | [EXT2_FT_REG_FILE] = DT_REG, | |
215 | [EXT2_FT_DIR] = DT_DIR, | |
216 | [EXT2_FT_CHRDEV] = DT_CHR, | |
217 | [EXT2_FT_BLKDEV] = DT_BLK, | |
218 | [EXT2_FT_FIFO] = DT_FIFO, | |
219 | [EXT2_FT_SOCK] = DT_SOCK, | |
220 | [EXT2_FT_SYMLINK] = DT_LNK, | |
221 | }; | |
222 | ||
223 | #define S_SHIFT 12 | |
224 | static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = { | |
225 | [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE, | |
226 | [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR, | |
227 | [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV, | |
228 | [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV, | |
229 | [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO, | |
230 | [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK, | |
231 | [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK, | |
232 | }; | |
233 | ||
234 | static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode) | |
235 | { | |
236 | mode_t mode = inode->i_mode; | |
237 | if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) | |
238 | de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; | |
239 | else | |
240 | de->file_type = 0; | |
241 | } | |
242 | ||
243 | static int | |
244 | ext2_readdir (struct file * filp, void * dirent, filldir_t filldir) | |
245 | { | |
246 | loff_t pos = filp->f_pos; | |
c29c6934 | 247 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
248 | struct super_block *sb = inode->i_sb; |
249 | unsigned int offset = pos & ~PAGE_CACHE_MASK; | |
250 | unsigned long n = pos >> PAGE_CACHE_SHIFT; | |
251 | unsigned long npages = dir_pages(inode); | |
252 | unsigned chunk_mask = ~(ext2_chunk_size(inode)-1); | |
253 | unsigned char *types = NULL; | |
2d7f2ea9 | 254 | int need_revalidate = filp->f_version != inode->i_version; |
1da177e4 LT |
255 | |
256 | if (pos > inode->i_size - EXT2_DIR_REC_LEN(1)) | |
2d7f2ea9 | 257 | return 0; |
1da177e4 LT |
258 | |
259 | if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) | |
260 | types = ext2_filetype_table; | |
261 | ||
262 | for ( ; n < npages; n++, offset = 0) { | |
263 | char *kaddr, *limit; | |
264 | ext2_dirent *de; | |
265 | struct page *page = ext2_get_page(inode, n); | |
266 | ||
267 | if (IS_ERR(page)) { | |
268 | ext2_error(sb, __FUNCTION__, | |
269 | "bad page in #%lu", | |
270 | inode->i_ino); | |
271 | filp->f_pos += PAGE_CACHE_SIZE - offset; | |
2d7f2ea9 | 272 | return -EIO; |
1da177e4 LT |
273 | } |
274 | kaddr = page_address(page); | |
2d7f2ea9 AV |
275 | if (unlikely(need_revalidate)) { |
276 | if (offset) { | |
277 | offset = ext2_validate_entry(kaddr, offset, chunk_mask); | |
278 | filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset; | |
279 | } | |
280 | filp->f_version = inode->i_version; | |
1da177e4 LT |
281 | need_revalidate = 0; |
282 | } | |
283 | de = (ext2_dirent *)(kaddr+offset); | |
284 | limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1); | |
285 | for ( ;(char*)de <= limit; de = ext2_next_entry(de)) { | |
286 | if (de->rec_len == 0) { | |
287 | ext2_error(sb, __FUNCTION__, | |
288 | "zero-length directory entry"); | |
1da177e4 | 289 | ext2_put_page(page); |
2d7f2ea9 | 290 | return -EIO; |
1da177e4 LT |
291 | } |
292 | if (de->inode) { | |
293 | int over; | |
294 | unsigned char d_type = DT_UNKNOWN; | |
295 | ||
296 | if (types && de->file_type < EXT2_FT_MAX) | |
297 | d_type = types[de->file_type]; | |
298 | ||
299 | offset = (char *)de - kaddr; | |
300 | over = filldir(dirent, de->name, de->name_len, | |
301 | (n<<PAGE_CACHE_SHIFT) | offset, | |
302 | le32_to_cpu(de->inode), d_type); | |
303 | if (over) { | |
304 | ext2_put_page(page); | |
2d7f2ea9 | 305 | return 0; |
1da177e4 LT |
306 | } |
307 | } | |
308 | filp->f_pos += le16_to_cpu(de->rec_len); | |
309 | } | |
310 | ext2_put_page(page); | |
311 | } | |
2d7f2ea9 | 312 | return 0; |
1da177e4 LT |
313 | } |
314 | ||
315 | /* | |
316 | * ext2_find_entry() | |
317 | * | |
318 | * finds an entry in the specified directory with the wanted name. It | |
319 | * returns the page in which the entry was found, and the entry itself | |
320 | * (as a parameter - res_dir). Page is returned mapped and unlocked. | |
321 | * Entry is guaranteed to be valid. | |
322 | */ | |
323 | struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir, | |
324 | struct dentry *dentry, struct page ** res_page) | |
325 | { | |
326 | const char *name = dentry->d_name.name; | |
327 | int namelen = dentry->d_name.len; | |
328 | unsigned reclen = EXT2_DIR_REC_LEN(namelen); | |
329 | unsigned long start, n; | |
330 | unsigned long npages = dir_pages(dir); | |
331 | struct page *page = NULL; | |
332 | struct ext2_inode_info *ei = EXT2_I(dir); | |
333 | ext2_dirent * de; | |
334 | ||
335 | if (npages == 0) | |
336 | goto out; | |
337 | ||
338 | /* OFFSET_CACHE */ | |
339 | *res_page = NULL; | |
340 | ||
341 | start = ei->i_dir_start_lookup; | |
342 | if (start >= npages) | |
343 | start = 0; | |
344 | n = start; | |
345 | do { | |
346 | char *kaddr; | |
347 | page = ext2_get_page(dir, n); | |
348 | if (!IS_ERR(page)) { | |
349 | kaddr = page_address(page); | |
350 | de = (ext2_dirent *) kaddr; | |
351 | kaddr += ext2_last_byte(dir, n) - reclen; | |
352 | while ((char *) de <= kaddr) { | |
353 | if (de->rec_len == 0) { | |
354 | ext2_error(dir->i_sb, __FUNCTION__, | |
355 | "zero-length directory entry"); | |
356 | ext2_put_page(page); | |
357 | goto out; | |
358 | } | |
359 | if (ext2_match (namelen, name, de)) | |
360 | goto found; | |
361 | de = ext2_next_entry(de); | |
362 | } | |
363 | ext2_put_page(page); | |
364 | } | |
365 | if (++n >= npages) | |
366 | n = 0; | |
d8adb9ce ES |
367 | /* next page is past the blocks we've got */ |
368 | if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) { | |
369 | ext2_error(dir->i_sb, __FUNCTION__, | |
370 | "dir %lu size %lld exceeds block count %llu", | |
371 | dir->i_ino, dir->i_size, | |
372 | (unsigned long long)dir->i_blocks); | |
373 | goto out; | |
374 | } | |
1da177e4 LT |
375 | } while (n != start); |
376 | out: | |
377 | return NULL; | |
378 | ||
379 | found: | |
380 | *res_page = page; | |
381 | ei->i_dir_start_lookup = n; | |
382 | return de; | |
383 | } | |
384 | ||
385 | struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p) | |
386 | { | |
387 | struct page *page = ext2_get_page(dir, 0); | |
388 | ext2_dirent *de = NULL; | |
389 | ||
390 | if (!IS_ERR(page)) { | |
391 | de = ext2_next_entry((ext2_dirent *) page_address(page)); | |
392 | *p = page; | |
393 | } | |
394 | return de; | |
395 | } | |
396 | ||
397 | ino_t ext2_inode_by_name(struct inode * dir, struct dentry *dentry) | |
398 | { | |
399 | ino_t res = 0; | |
400 | struct ext2_dir_entry_2 * de; | |
401 | struct page *page; | |
402 | ||
403 | de = ext2_find_entry (dir, dentry, &page); | |
404 | if (de) { | |
405 | res = le32_to_cpu(de->inode); | |
7d93a1a5 | 406 | ext2_put_page(page); |
1da177e4 LT |
407 | } |
408 | return res; | |
409 | } | |
410 | ||
411 | /* Releases the page */ | |
412 | void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de, | |
413 | struct page *page, struct inode *inode) | |
414 | { | |
415 | unsigned from = (char *) de - (char *) page_address(page); | |
416 | unsigned to = from + le16_to_cpu(de->rec_len); | |
417 | int err; | |
418 | ||
419 | lock_page(page); | |
420 | err = page->mapping->a_ops->prepare_write(NULL, page, from, to); | |
309be53d | 421 | BUG_ON(err); |
1da177e4 LT |
422 | de->inode = cpu_to_le32(inode->i_ino); |
423 | ext2_set_de_type (de, inode); | |
424 | err = ext2_commit_chunk(page, from, to); | |
425 | ext2_put_page(page); | |
426 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; | |
427 | EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; | |
428 | mark_inode_dirty(dir); | |
429 | } | |
430 | ||
431 | /* | |
432 | * Parent is locked. | |
433 | */ | |
434 | int ext2_add_link (struct dentry *dentry, struct inode *inode) | |
435 | { | |
436 | struct inode *dir = dentry->d_parent->d_inode; | |
437 | const char *name = dentry->d_name.name; | |
438 | int namelen = dentry->d_name.len; | |
439 | unsigned chunk_size = ext2_chunk_size(dir); | |
440 | unsigned reclen = EXT2_DIR_REC_LEN(namelen); | |
441 | unsigned short rec_len, name_len; | |
442 | struct page *page = NULL; | |
443 | ext2_dirent * de; | |
444 | unsigned long npages = dir_pages(dir); | |
445 | unsigned long n; | |
446 | char *kaddr; | |
447 | unsigned from, to; | |
448 | int err; | |
449 | ||
450 | /* | |
451 | * We take care of directory expansion in the same loop. | |
452 | * This code plays outside i_size, so it locks the page | |
453 | * to protect that region. | |
454 | */ | |
455 | for (n = 0; n <= npages; n++) { | |
456 | char *dir_end; | |
457 | ||
458 | page = ext2_get_page(dir, n); | |
459 | err = PTR_ERR(page); | |
460 | if (IS_ERR(page)) | |
461 | goto out; | |
462 | lock_page(page); | |
463 | kaddr = page_address(page); | |
464 | dir_end = kaddr + ext2_last_byte(dir, n); | |
465 | de = (ext2_dirent *)kaddr; | |
466 | kaddr += PAGE_CACHE_SIZE - reclen; | |
467 | while ((char *)de <= kaddr) { | |
468 | if ((char *)de == dir_end) { | |
469 | /* We hit i_size */ | |
470 | name_len = 0; | |
471 | rec_len = chunk_size; | |
472 | de->rec_len = cpu_to_le16(chunk_size); | |
473 | de->inode = 0; | |
474 | goto got_it; | |
475 | } | |
476 | if (de->rec_len == 0) { | |
477 | ext2_error(dir->i_sb, __FUNCTION__, | |
478 | "zero-length directory entry"); | |
479 | err = -EIO; | |
480 | goto out_unlock; | |
481 | } | |
482 | err = -EEXIST; | |
483 | if (ext2_match (namelen, name, de)) | |
484 | goto out_unlock; | |
485 | name_len = EXT2_DIR_REC_LEN(de->name_len); | |
486 | rec_len = le16_to_cpu(de->rec_len); | |
487 | if (!de->inode && rec_len >= reclen) | |
488 | goto got_it; | |
489 | if (rec_len >= name_len + reclen) | |
490 | goto got_it; | |
491 | de = (ext2_dirent *) ((char *) de + rec_len); | |
492 | } | |
493 | unlock_page(page); | |
494 | ext2_put_page(page); | |
495 | } | |
496 | BUG(); | |
497 | return -EINVAL; | |
498 | ||
499 | got_it: | |
500 | from = (char*)de - (char*)page_address(page); | |
501 | to = from + rec_len; | |
502 | err = page->mapping->a_ops->prepare_write(NULL, page, from, to); | |
503 | if (err) | |
504 | goto out_unlock; | |
505 | if (de->inode) { | |
506 | ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); | |
507 | de1->rec_len = cpu_to_le16(rec_len - name_len); | |
508 | de->rec_len = cpu_to_le16(name_len); | |
509 | de = de1; | |
510 | } | |
511 | de->name_len = namelen; | |
512 | memcpy (de->name, name, namelen); | |
513 | de->inode = cpu_to_le32(inode->i_ino); | |
514 | ext2_set_de_type (de, inode); | |
515 | err = ext2_commit_chunk(page, from, to); | |
516 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; | |
517 | EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; | |
518 | mark_inode_dirty(dir); | |
519 | /* OFFSET_CACHE */ | |
520 | out_put: | |
521 | ext2_put_page(page); | |
522 | out: | |
523 | return err; | |
524 | out_unlock: | |
525 | unlock_page(page); | |
526 | goto out_put; | |
527 | } | |
528 | ||
529 | /* | |
530 | * ext2_delete_entry deletes a directory entry by merging it with the | |
531 | * previous entry. Page is up-to-date. Releases the page. | |
532 | */ | |
533 | int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) | |
534 | { | |
535 | struct address_space *mapping = page->mapping; | |
536 | struct inode *inode = mapping->host; | |
537 | char *kaddr = page_address(page); | |
538 | unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); | |
539 | unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len); | |
540 | ext2_dirent * pde = NULL; | |
541 | ext2_dirent * de = (ext2_dirent *) (kaddr + from); | |
542 | int err; | |
543 | ||
544 | while ((char*)de < (char*)dir) { | |
545 | if (de->rec_len == 0) { | |
546 | ext2_error(inode->i_sb, __FUNCTION__, | |
547 | "zero-length directory entry"); | |
548 | err = -EIO; | |
549 | goto out; | |
550 | } | |
551 | pde = de; | |
552 | de = ext2_next_entry(de); | |
553 | } | |
554 | if (pde) | |
555 | from = (char*)pde - (char*)page_address(page); | |
556 | lock_page(page); | |
557 | err = mapping->a_ops->prepare_write(NULL, page, from, to); | |
309be53d | 558 | BUG_ON(err); |
1da177e4 LT |
559 | if (pde) |
560 | pde->rec_len = cpu_to_le16(to-from); | |
561 | dir->inode = 0; | |
562 | err = ext2_commit_chunk(page, from, to); | |
563 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; | |
564 | EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL; | |
565 | mark_inode_dirty(inode); | |
566 | out: | |
567 | ext2_put_page(page); | |
568 | return err; | |
569 | } | |
570 | ||
571 | /* | |
572 | * Set the first fragment of directory. | |
573 | */ | |
574 | int ext2_make_empty(struct inode *inode, struct inode *parent) | |
575 | { | |
576 | struct address_space *mapping = inode->i_mapping; | |
577 | struct page *page = grab_cache_page(mapping, 0); | |
578 | unsigned chunk_size = ext2_chunk_size(inode); | |
579 | struct ext2_dir_entry_2 * de; | |
580 | int err; | |
581 | void *kaddr; | |
582 | ||
583 | if (!page) | |
584 | return -ENOMEM; | |
585 | err = mapping->a_ops->prepare_write(NULL, page, 0, chunk_size); | |
586 | if (err) { | |
587 | unlock_page(page); | |
588 | goto fail; | |
589 | } | |
590 | kaddr = kmap_atomic(page, KM_USER0); | |
7823c7c1 | 591 | memset(kaddr, 0, chunk_size); |
1da177e4 LT |
592 | de = (struct ext2_dir_entry_2 *)kaddr; |
593 | de->name_len = 1; | |
594 | de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1)); | |
595 | memcpy (de->name, ".\0\0", 4); | |
596 | de->inode = cpu_to_le32(inode->i_ino); | |
597 | ext2_set_de_type (de, inode); | |
598 | ||
599 | de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1)); | |
600 | de->name_len = 2; | |
601 | de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1)); | |
602 | de->inode = cpu_to_le32(parent->i_ino); | |
603 | memcpy (de->name, "..\0", 4); | |
604 | ext2_set_de_type (de, inode); | |
605 | kunmap_atomic(kaddr, KM_USER0); | |
606 | err = ext2_commit_chunk(page, 0, chunk_size); | |
607 | fail: | |
608 | page_cache_release(page); | |
609 | return err; | |
610 | } | |
611 | ||
612 | /* | |
613 | * routine to check that the specified directory is empty (for rmdir) | |
614 | */ | |
615 | int ext2_empty_dir (struct inode * inode) | |
616 | { | |
617 | struct page *page = NULL; | |
618 | unsigned long i, npages = dir_pages(inode); | |
619 | ||
620 | for (i = 0; i < npages; i++) { | |
621 | char *kaddr; | |
622 | ext2_dirent * de; | |
623 | page = ext2_get_page(inode, i); | |
624 | ||
625 | if (IS_ERR(page)) | |
626 | continue; | |
627 | ||
628 | kaddr = page_address(page); | |
629 | de = (ext2_dirent *)kaddr; | |
630 | kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1); | |
631 | ||
632 | while ((char *)de <= kaddr) { | |
633 | if (de->rec_len == 0) { | |
634 | ext2_error(inode->i_sb, __FUNCTION__, | |
635 | "zero-length directory entry"); | |
636 | printk("kaddr=%p, de=%p\n", kaddr, de); | |
637 | goto not_empty; | |
638 | } | |
639 | if (de->inode != 0) { | |
640 | /* check for . and .. */ | |
641 | if (de->name[0] != '.') | |
642 | goto not_empty; | |
643 | if (de->name_len > 2) | |
644 | goto not_empty; | |
645 | if (de->name_len < 2) { | |
646 | if (de->inode != | |
647 | cpu_to_le32(inode->i_ino)) | |
648 | goto not_empty; | |
649 | } else if (de->name[1] != '.') | |
650 | goto not_empty; | |
651 | } | |
652 | de = ext2_next_entry(de); | |
653 | } | |
654 | ext2_put_page(page); | |
655 | } | |
656 | return 1; | |
657 | ||
658 | not_empty: | |
659 | ext2_put_page(page); | |
660 | return 0; | |
661 | } | |
662 | ||
4b6f5d20 | 663 | const struct file_operations ext2_dir_operations = { |
1da177e4 LT |
664 | .llseek = generic_file_llseek, |
665 | .read = generic_read_dir, | |
666 | .readdir = ext2_readdir, | |
667 | .ioctl = ext2_ioctl, | |
e322ff07 DH |
668 | #ifdef CONFIG_COMPAT |
669 | .compat_ioctl = ext2_compat_ioctl, | |
670 | #endif | |
1da177e4 LT |
671 | .fsync = ext2_sync_file, |
672 | }; |