Commit | Line | Data |
---|---|---|
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" | |
f34fb6ec | 25 | #include <linux/buffer_head.h> |
1da177e4 | 26 | #include <linux/pagemap.h> |
f34fb6ec | 27 | #include <linux/swap.h> |
1da177e4 LT |
28 | |
29 | typedef struct ext2_dir_entry_2 ext2_dirent; | |
30 | ||
31 | /* | |
32 | * ext2 uses block-sized chunks. Arguably, sector-sized ones would be | |
33 | * more robust, but we have what we have | |
34 | */ | |
35 | static inline unsigned ext2_chunk_size(struct inode *inode) | |
36 | { | |
37 | return inode->i_sb->s_blocksize; | |
38 | } | |
39 | ||
40 | static inline void ext2_put_page(struct page *page) | |
41 | { | |
42 | kunmap(page); | |
43 | page_cache_release(page); | |
44 | } | |
45 | ||
46 | static inline unsigned long dir_pages(struct inode *inode) | |
47 | { | |
48 | return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; | |
49 | } | |
50 | ||
51 | /* | |
52 | * Return the offset into page `page_nr' of the last valid | |
53 | * byte in that page, plus one. | |
54 | */ | |
55 | static unsigned | |
56 | ext2_last_byte(struct inode *inode, unsigned long page_nr) | |
57 | { | |
58 | unsigned last_byte = inode->i_size; | |
59 | ||
60 | last_byte -= page_nr << PAGE_CACHE_SHIFT; | |
61 | if (last_byte > PAGE_CACHE_SIZE) | |
62 | last_byte = PAGE_CACHE_SIZE; | |
63 | return last_byte; | |
64 | } | |
65 | ||
f34fb6ec | 66 | static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len) |
1da177e4 | 67 | { |
f34fb6ec NP |
68 | struct address_space *mapping = page->mapping; |
69 | struct inode *dir = mapping->host; | |
1da177e4 | 70 | int err = 0; |
f34fb6ec | 71 | |
1da177e4 | 72 | dir->i_version++; |
f34fb6ec NP |
73 | block_write_end(NULL, mapping, pos, len, len, page, NULL); |
74 | ||
75 | if (pos+len > dir->i_size) { | |
76 | i_size_write(dir, pos+len); | |
77 | mark_inode_dirty(dir); | |
78 | } | |
79 | ||
1da177e4 LT |
80 | if (IS_DIRSYNC(dir)) |
81 | err = write_one_page(page, 1); | |
82 | else | |
83 | unlock_page(page); | |
f34fb6ec | 84 | |
1da177e4 LT |
85 | return err; |
86 | } | |
87 | ||
88 | static void ext2_check_page(struct page *page) | |
89 | { | |
90 | struct inode *dir = page->mapping->host; | |
91 | struct super_block *sb = dir->i_sb; | |
92 | unsigned chunk_size = ext2_chunk_size(dir); | |
93 | char *kaddr = page_address(page); | |
94 | u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); | |
95 | unsigned offs, rec_len; | |
96 | unsigned limit = PAGE_CACHE_SIZE; | |
97 | ext2_dirent *p; | |
98 | char *error; | |
99 | ||
100 | if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { | |
101 | limit = dir->i_size & ~PAGE_CACHE_MASK; | |
102 | if (limit & (chunk_size - 1)) | |
103 | goto Ebadsize; | |
104 | if (!limit) | |
105 | goto out; | |
106 | } | |
107 | for (offs = 0; offs <= limit - EXT2_DIR_REC_LEN(1); offs += rec_len) { | |
108 | p = (ext2_dirent *)(kaddr + offs); | |
109 | rec_len = le16_to_cpu(p->rec_len); | |
110 | ||
111 | if (rec_len < EXT2_DIR_REC_LEN(1)) | |
112 | goto Eshort; | |
113 | if (rec_len & 3) | |
114 | goto Ealign; | |
115 | if (rec_len < EXT2_DIR_REC_LEN(p->name_len)) | |
116 | goto Enamelen; | |
117 | if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)) | |
118 | goto Espan; | |
119 | if (le32_to_cpu(p->inode) > max_inumber) | |
120 | goto Einumber; | |
121 | } | |
122 | if (offs != limit) | |
123 | goto Eend; | |
124 | out: | |
125 | SetPageChecked(page); | |
126 | return; | |
127 | ||
128 | /* Too bad, we had an error */ | |
129 | ||
130 | Ebadsize: | |
131 | ext2_error(sb, "ext2_check_page", | |
132 | "size of directory #%lu is not a multiple of chunk size", | |
133 | dir->i_ino | |
134 | ); | |
135 | goto fail; | |
136 | Eshort: | |
137 | error = "rec_len is smaller than minimal"; | |
138 | goto bad_entry; | |
139 | Ealign: | |
140 | error = "unaligned directory entry"; | |
141 | goto bad_entry; | |
142 | Enamelen: | |
143 | error = "rec_len is too small for name_len"; | |
144 | goto bad_entry; | |
145 | Espan: | |
146 | error = "directory entry across blocks"; | |
147 | goto bad_entry; | |
148 | Einumber: | |
149 | error = "inode out of bounds"; | |
150 | bad_entry: | |
151 | ext2_error (sb, "ext2_check_page", "bad entry in directory #%lu: %s - " | |
152 | "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", | |
153 | dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
154 | (unsigned long) le32_to_cpu(p->inode), | |
155 | rec_len, p->name_len); | |
156 | goto fail; | |
157 | Eend: | |
158 | p = (ext2_dirent *)(kaddr + offs); | |
159 | ext2_error (sb, "ext2_check_page", | |
160 | "entry in directory #%lu spans the page boundary" | |
161 | "offset=%lu, inode=%lu", | |
162 | dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
163 | (unsigned long) le32_to_cpu(p->inode)); | |
164 | fail: | |
165 | SetPageChecked(page); | |
166 | SetPageError(page); | |
167 | } | |
168 | ||
169 | static struct page * ext2_get_page(struct inode *dir, unsigned long n) | |
170 | { | |
171 | struct address_space *mapping = dir->i_mapping; | |
090d2b18 | 172 | struct page *page = read_mapping_page(mapping, n, NULL); |
1da177e4 | 173 | if (!IS_ERR(page)) { |
1da177e4 | 174 | kmap(page); |
1da177e4 LT |
175 | if (!PageChecked(page)) |
176 | ext2_check_page(page); | |
177 | if (PageError(page)) | |
178 | goto fail; | |
179 | } | |
180 | return page; | |
181 | ||
182 | fail: | |
183 | ext2_put_page(page); | |
184 | return ERR_PTR(-EIO); | |
185 | } | |
186 | ||
187 | /* | |
188 | * NOTE! unlike strncmp, ext2_match returns 1 for success, 0 for failure. | |
189 | * | |
190 | * len <= EXT2_NAME_LEN and de != NULL are guaranteed by caller. | |
191 | */ | |
192 | static inline int ext2_match (int len, const char * const name, | |
193 | struct ext2_dir_entry_2 * de) | |
194 | { | |
195 | if (len != de->name_len) | |
196 | return 0; | |
197 | if (!de->inode) | |
198 | return 0; | |
199 | return !memcmp(name, de->name, len); | |
200 | } | |
201 | ||
202 | /* | |
203 | * p is at least 6 bytes before the end of page | |
204 | */ | |
205 | static inline ext2_dirent *ext2_next_entry(ext2_dirent *p) | |
206 | { | |
207 | return (ext2_dirent *)((char*)p + le16_to_cpu(p->rec_len)); | |
208 | } | |
209 | ||
210 | static inline unsigned | |
211 | ext2_validate_entry(char *base, unsigned offset, unsigned mask) | |
212 | { | |
213 | ext2_dirent *de = (ext2_dirent*)(base + offset); | |
214 | ext2_dirent *p = (ext2_dirent*)(base + (offset&mask)); | |
215 | while ((char*)p < (char*)de) { | |
216 | if (p->rec_len == 0) | |
217 | break; | |
218 | p = ext2_next_entry(p); | |
219 | } | |
220 | return (char *)p - base; | |
221 | } | |
222 | ||
223 | static unsigned char ext2_filetype_table[EXT2_FT_MAX] = { | |
224 | [EXT2_FT_UNKNOWN] = DT_UNKNOWN, | |
225 | [EXT2_FT_REG_FILE] = DT_REG, | |
226 | [EXT2_FT_DIR] = DT_DIR, | |
227 | [EXT2_FT_CHRDEV] = DT_CHR, | |
228 | [EXT2_FT_BLKDEV] = DT_BLK, | |
229 | [EXT2_FT_FIFO] = DT_FIFO, | |
230 | [EXT2_FT_SOCK] = DT_SOCK, | |
231 | [EXT2_FT_SYMLINK] = DT_LNK, | |
232 | }; | |
233 | ||
234 | #define S_SHIFT 12 | |
235 | static unsigned char ext2_type_by_mode[S_IFMT >> S_SHIFT] = { | |
236 | [S_IFREG >> S_SHIFT] = EXT2_FT_REG_FILE, | |
237 | [S_IFDIR >> S_SHIFT] = EXT2_FT_DIR, | |
238 | [S_IFCHR >> S_SHIFT] = EXT2_FT_CHRDEV, | |
239 | [S_IFBLK >> S_SHIFT] = EXT2_FT_BLKDEV, | |
240 | [S_IFIFO >> S_SHIFT] = EXT2_FT_FIFO, | |
241 | [S_IFSOCK >> S_SHIFT] = EXT2_FT_SOCK, | |
242 | [S_IFLNK >> S_SHIFT] = EXT2_FT_SYMLINK, | |
243 | }; | |
244 | ||
245 | static inline void ext2_set_de_type(ext2_dirent *de, struct inode *inode) | |
246 | { | |
247 | mode_t mode = inode->i_mode; | |
248 | if (EXT2_HAS_INCOMPAT_FEATURE(inode->i_sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) | |
249 | de->file_type = ext2_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; | |
250 | else | |
251 | de->file_type = 0; | |
252 | } | |
253 | ||
254 | static int | |
255 | ext2_readdir (struct file * filp, void * dirent, filldir_t filldir) | |
256 | { | |
257 | loff_t pos = filp->f_pos; | |
c29c6934 | 258 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
259 | struct super_block *sb = inode->i_sb; |
260 | unsigned int offset = pos & ~PAGE_CACHE_MASK; | |
261 | unsigned long n = pos >> PAGE_CACHE_SHIFT; | |
262 | unsigned long npages = dir_pages(inode); | |
263 | unsigned chunk_mask = ~(ext2_chunk_size(inode)-1); | |
264 | unsigned char *types = NULL; | |
2d7f2ea9 | 265 | int need_revalidate = filp->f_version != inode->i_version; |
1da177e4 LT |
266 | |
267 | if (pos > inode->i_size - EXT2_DIR_REC_LEN(1)) | |
2d7f2ea9 | 268 | return 0; |
1da177e4 LT |
269 | |
270 | if (EXT2_HAS_INCOMPAT_FEATURE(sb, EXT2_FEATURE_INCOMPAT_FILETYPE)) | |
271 | types = ext2_filetype_table; | |
272 | ||
273 | for ( ; n < npages; n++, offset = 0) { | |
274 | char *kaddr, *limit; | |
275 | ext2_dirent *de; | |
276 | struct page *page = ext2_get_page(inode, n); | |
277 | ||
278 | if (IS_ERR(page)) { | |
279 | ext2_error(sb, __FUNCTION__, | |
280 | "bad page in #%lu", | |
281 | inode->i_ino); | |
282 | filp->f_pos += PAGE_CACHE_SIZE - offset; | |
2d7f2ea9 | 283 | return -EIO; |
1da177e4 LT |
284 | } |
285 | kaddr = page_address(page); | |
2d7f2ea9 AV |
286 | if (unlikely(need_revalidate)) { |
287 | if (offset) { | |
288 | offset = ext2_validate_entry(kaddr, offset, chunk_mask); | |
289 | filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset; | |
290 | } | |
291 | filp->f_version = inode->i_version; | |
1da177e4 LT |
292 | need_revalidate = 0; |
293 | } | |
294 | de = (ext2_dirent *)(kaddr+offset); | |
295 | limit = kaddr + ext2_last_byte(inode, n) - EXT2_DIR_REC_LEN(1); | |
296 | for ( ;(char*)de <= limit; de = ext2_next_entry(de)) { | |
297 | if (de->rec_len == 0) { | |
298 | ext2_error(sb, __FUNCTION__, | |
299 | "zero-length directory entry"); | |
1da177e4 | 300 | ext2_put_page(page); |
2d7f2ea9 | 301 | return -EIO; |
1da177e4 LT |
302 | } |
303 | if (de->inode) { | |
304 | int over; | |
305 | unsigned char d_type = DT_UNKNOWN; | |
306 | ||
307 | if (types && de->file_type < EXT2_FT_MAX) | |
308 | d_type = types[de->file_type]; | |
309 | ||
310 | offset = (char *)de - kaddr; | |
311 | over = filldir(dirent, de->name, de->name_len, | |
312 | (n<<PAGE_CACHE_SHIFT) | offset, | |
313 | le32_to_cpu(de->inode), d_type); | |
314 | if (over) { | |
315 | ext2_put_page(page); | |
2d7f2ea9 | 316 | return 0; |
1da177e4 LT |
317 | } |
318 | } | |
319 | filp->f_pos += le16_to_cpu(de->rec_len); | |
320 | } | |
321 | ext2_put_page(page); | |
322 | } | |
2d7f2ea9 | 323 | return 0; |
1da177e4 LT |
324 | } |
325 | ||
326 | /* | |
327 | * ext2_find_entry() | |
328 | * | |
329 | * finds an entry in the specified directory with the wanted name. It | |
330 | * returns the page in which the entry was found, and the entry itself | |
331 | * (as a parameter - res_dir). Page is returned mapped and unlocked. | |
332 | * Entry is guaranteed to be valid. | |
333 | */ | |
334 | struct ext2_dir_entry_2 * ext2_find_entry (struct inode * dir, | |
335 | struct dentry *dentry, struct page ** res_page) | |
336 | { | |
337 | const char *name = dentry->d_name.name; | |
338 | int namelen = dentry->d_name.len; | |
339 | unsigned reclen = EXT2_DIR_REC_LEN(namelen); | |
340 | unsigned long start, n; | |
341 | unsigned long npages = dir_pages(dir); | |
342 | struct page *page = NULL; | |
343 | struct ext2_inode_info *ei = EXT2_I(dir); | |
344 | ext2_dirent * de; | |
345 | ||
346 | if (npages == 0) | |
347 | goto out; | |
348 | ||
349 | /* OFFSET_CACHE */ | |
350 | *res_page = NULL; | |
351 | ||
352 | start = ei->i_dir_start_lookup; | |
353 | if (start >= npages) | |
354 | start = 0; | |
355 | n = start; | |
356 | do { | |
357 | char *kaddr; | |
358 | page = ext2_get_page(dir, n); | |
359 | if (!IS_ERR(page)) { | |
360 | kaddr = page_address(page); | |
361 | de = (ext2_dirent *) kaddr; | |
362 | kaddr += ext2_last_byte(dir, n) - reclen; | |
363 | while ((char *) de <= kaddr) { | |
364 | if (de->rec_len == 0) { | |
365 | ext2_error(dir->i_sb, __FUNCTION__, | |
366 | "zero-length directory entry"); | |
367 | ext2_put_page(page); | |
368 | goto out; | |
369 | } | |
370 | if (ext2_match (namelen, name, de)) | |
371 | goto found; | |
372 | de = ext2_next_entry(de); | |
373 | } | |
374 | ext2_put_page(page); | |
375 | } | |
376 | if (++n >= npages) | |
377 | n = 0; | |
d8adb9ce ES |
378 | /* next page is past the blocks we've got */ |
379 | if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) { | |
380 | ext2_error(dir->i_sb, __FUNCTION__, | |
381 | "dir %lu size %lld exceeds block count %llu", | |
382 | dir->i_ino, dir->i_size, | |
383 | (unsigned long long)dir->i_blocks); | |
384 | goto out; | |
385 | } | |
1da177e4 LT |
386 | } while (n != start); |
387 | out: | |
388 | return NULL; | |
389 | ||
390 | found: | |
391 | *res_page = page; | |
392 | ei->i_dir_start_lookup = n; | |
393 | return de; | |
394 | } | |
395 | ||
396 | struct ext2_dir_entry_2 * ext2_dotdot (struct inode *dir, struct page **p) | |
397 | { | |
398 | struct page *page = ext2_get_page(dir, 0); | |
399 | ext2_dirent *de = NULL; | |
400 | ||
401 | if (!IS_ERR(page)) { | |
402 | de = ext2_next_entry((ext2_dirent *) page_address(page)); | |
403 | *p = page; | |
404 | } | |
405 | return de; | |
406 | } | |
407 | ||
408 | ino_t ext2_inode_by_name(struct inode * dir, struct dentry *dentry) | |
409 | { | |
410 | ino_t res = 0; | |
411 | struct ext2_dir_entry_2 * de; | |
412 | struct page *page; | |
413 | ||
414 | de = ext2_find_entry (dir, dentry, &page); | |
415 | if (de) { | |
416 | res = le32_to_cpu(de->inode); | |
7d93a1a5 | 417 | ext2_put_page(page); |
1da177e4 LT |
418 | } |
419 | return res; | |
420 | } | |
421 | ||
422 | /* Releases the page */ | |
423 | void ext2_set_link(struct inode *dir, struct ext2_dir_entry_2 *de, | |
424 | struct page *page, struct inode *inode) | |
425 | { | |
f34fb6ec NP |
426 | loff_t pos = page_offset(page) + |
427 | (char *) de - (char *) page_address(page); | |
428 | unsigned len = le16_to_cpu(de->rec_len); | |
1da177e4 LT |
429 | int err; |
430 | ||
431 | lock_page(page); | |
f34fb6ec NP |
432 | err = __ext2_write_begin(NULL, page->mapping, pos, len, |
433 | AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); | |
309be53d | 434 | BUG_ON(err); |
1da177e4 | 435 | de->inode = cpu_to_le32(inode->i_ino); |
f34fb6ec NP |
436 | ext2_set_de_type(de, inode); |
437 | err = ext2_commit_chunk(page, pos, len); | |
1da177e4 LT |
438 | ext2_put_page(page); |
439 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; | |
440 | EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; | |
441 | mark_inode_dirty(dir); | |
442 | } | |
443 | ||
444 | /* | |
445 | * Parent is locked. | |
446 | */ | |
447 | int ext2_add_link (struct dentry *dentry, struct inode *inode) | |
448 | { | |
449 | struct inode *dir = dentry->d_parent->d_inode; | |
450 | const char *name = dentry->d_name.name; | |
451 | int namelen = dentry->d_name.len; | |
452 | unsigned chunk_size = ext2_chunk_size(dir); | |
453 | unsigned reclen = EXT2_DIR_REC_LEN(namelen); | |
454 | unsigned short rec_len, name_len; | |
455 | struct page *page = NULL; | |
456 | ext2_dirent * de; | |
457 | unsigned long npages = dir_pages(dir); | |
458 | unsigned long n; | |
459 | char *kaddr; | |
f34fb6ec | 460 | loff_t pos; |
1da177e4 LT |
461 | int err; |
462 | ||
463 | /* | |
464 | * We take care of directory expansion in the same loop. | |
465 | * This code plays outside i_size, so it locks the page | |
466 | * to protect that region. | |
467 | */ | |
468 | for (n = 0; n <= npages; n++) { | |
469 | char *dir_end; | |
470 | ||
471 | page = ext2_get_page(dir, n); | |
472 | err = PTR_ERR(page); | |
473 | if (IS_ERR(page)) | |
474 | goto out; | |
475 | lock_page(page); | |
476 | kaddr = page_address(page); | |
477 | dir_end = kaddr + ext2_last_byte(dir, n); | |
478 | de = (ext2_dirent *)kaddr; | |
479 | kaddr += PAGE_CACHE_SIZE - reclen; | |
480 | while ((char *)de <= kaddr) { | |
481 | if ((char *)de == dir_end) { | |
482 | /* We hit i_size */ | |
483 | name_len = 0; | |
484 | rec_len = chunk_size; | |
485 | de->rec_len = cpu_to_le16(chunk_size); | |
486 | de->inode = 0; | |
487 | goto got_it; | |
488 | } | |
489 | if (de->rec_len == 0) { | |
490 | ext2_error(dir->i_sb, __FUNCTION__, | |
491 | "zero-length directory entry"); | |
492 | err = -EIO; | |
493 | goto out_unlock; | |
494 | } | |
495 | err = -EEXIST; | |
496 | if (ext2_match (namelen, name, de)) | |
497 | goto out_unlock; | |
498 | name_len = EXT2_DIR_REC_LEN(de->name_len); | |
499 | rec_len = le16_to_cpu(de->rec_len); | |
500 | if (!de->inode && rec_len >= reclen) | |
501 | goto got_it; | |
502 | if (rec_len >= name_len + reclen) | |
503 | goto got_it; | |
504 | de = (ext2_dirent *) ((char *) de + rec_len); | |
505 | } | |
506 | unlock_page(page); | |
507 | ext2_put_page(page); | |
508 | } | |
509 | BUG(); | |
510 | return -EINVAL; | |
511 | ||
512 | got_it: | |
f34fb6ec NP |
513 | pos = page_offset(page) + |
514 | (char*)de - (char*)page_address(page); | |
515 | err = __ext2_write_begin(NULL, page->mapping, pos, rec_len, 0, | |
516 | &page, NULL); | |
1da177e4 LT |
517 | if (err) |
518 | goto out_unlock; | |
519 | if (de->inode) { | |
520 | ext2_dirent *de1 = (ext2_dirent *) ((char *) de + name_len); | |
521 | de1->rec_len = cpu_to_le16(rec_len - name_len); | |
522 | de->rec_len = cpu_to_le16(name_len); | |
523 | de = de1; | |
524 | } | |
525 | de->name_len = namelen; | |
f34fb6ec | 526 | memcpy(de->name, name, namelen); |
1da177e4 LT |
527 | de->inode = cpu_to_le32(inode->i_ino); |
528 | ext2_set_de_type (de, inode); | |
f34fb6ec | 529 | err = ext2_commit_chunk(page, pos, rec_len); |
1da177e4 LT |
530 | dir->i_mtime = dir->i_ctime = CURRENT_TIME_SEC; |
531 | EXT2_I(dir)->i_flags &= ~EXT2_BTREE_FL; | |
532 | mark_inode_dirty(dir); | |
533 | /* OFFSET_CACHE */ | |
534 | out_put: | |
535 | ext2_put_page(page); | |
536 | out: | |
537 | return err; | |
538 | out_unlock: | |
539 | unlock_page(page); | |
540 | goto out_put; | |
541 | } | |
542 | ||
543 | /* | |
544 | * ext2_delete_entry deletes a directory entry by merging it with the | |
545 | * previous entry. Page is up-to-date. Releases the page. | |
546 | */ | |
547 | int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) | |
548 | { | |
549 | struct address_space *mapping = page->mapping; | |
550 | struct inode *inode = mapping->host; | |
551 | char *kaddr = page_address(page); | |
552 | unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); | |
553 | unsigned to = ((char*)dir - kaddr) + le16_to_cpu(dir->rec_len); | |
f34fb6ec | 554 | loff_t pos; |
1da177e4 LT |
555 | ext2_dirent * pde = NULL; |
556 | ext2_dirent * de = (ext2_dirent *) (kaddr + from); | |
557 | int err; | |
558 | ||
559 | while ((char*)de < (char*)dir) { | |
560 | if (de->rec_len == 0) { | |
561 | ext2_error(inode->i_sb, __FUNCTION__, | |
562 | "zero-length directory entry"); | |
563 | err = -EIO; | |
564 | goto out; | |
565 | } | |
566 | pde = de; | |
567 | de = ext2_next_entry(de); | |
568 | } | |
569 | if (pde) | |
570 | from = (char*)pde - (char*)page_address(page); | |
f34fb6ec | 571 | pos = page_offset(page) + from; |
1da177e4 | 572 | lock_page(page); |
f34fb6ec NP |
573 | err = __ext2_write_begin(NULL, page->mapping, pos, to - from, 0, |
574 | &page, NULL); | |
309be53d | 575 | BUG_ON(err); |
1da177e4 | 576 | if (pde) |
f34fb6ec | 577 | pde->rec_len = cpu_to_le16(to - from); |
1da177e4 | 578 | dir->inode = 0; |
f34fb6ec | 579 | err = ext2_commit_chunk(page, pos, to - from); |
1da177e4 LT |
580 | inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC; |
581 | EXT2_I(inode)->i_flags &= ~EXT2_BTREE_FL; | |
582 | mark_inode_dirty(inode); | |
583 | out: | |
584 | ext2_put_page(page); | |
585 | return err; | |
586 | } | |
587 | ||
588 | /* | |
589 | * Set the first fragment of directory. | |
590 | */ | |
591 | int ext2_make_empty(struct inode *inode, struct inode *parent) | |
592 | { | |
593 | struct address_space *mapping = inode->i_mapping; | |
594 | struct page *page = grab_cache_page(mapping, 0); | |
595 | unsigned chunk_size = ext2_chunk_size(inode); | |
596 | struct ext2_dir_entry_2 * de; | |
597 | int err; | |
598 | void *kaddr; | |
599 | ||
600 | if (!page) | |
601 | return -ENOMEM; | |
f34fb6ec NP |
602 | |
603 | err = __ext2_write_begin(NULL, page->mapping, 0, chunk_size, 0, | |
604 | &page, NULL); | |
1da177e4 LT |
605 | if (err) { |
606 | unlock_page(page); | |
607 | goto fail; | |
608 | } | |
609 | kaddr = kmap_atomic(page, KM_USER0); | |
7823c7c1 | 610 | memset(kaddr, 0, chunk_size); |
1da177e4 LT |
611 | de = (struct ext2_dir_entry_2 *)kaddr; |
612 | de->name_len = 1; | |
613 | de->rec_len = cpu_to_le16(EXT2_DIR_REC_LEN(1)); | |
614 | memcpy (de->name, ".\0\0", 4); | |
615 | de->inode = cpu_to_le32(inode->i_ino); | |
616 | ext2_set_de_type (de, inode); | |
617 | ||
618 | de = (struct ext2_dir_entry_2 *)(kaddr + EXT2_DIR_REC_LEN(1)); | |
619 | de->name_len = 2; | |
620 | de->rec_len = cpu_to_le16(chunk_size - EXT2_DIR_REC_LEN(1)); | |
621 | de->inode = cpu_to_le32(parent->i_ino); | |
622 | memcpy (de->name, "..\0", 4); | |
623 | ext2_set_de_type (de, inode); | |
624 | kunmap_atomic(kaddr, KM_USER0); | |
625 | err = ext2_commit_chunk(page, 0, chunk_size); | |
626 | fail: | |
627 | page_cache_release(page); | |
628 | return err; | |
629 | } | |
630 | ||
631 | /* | |
632 | * routine to check that the specified directory is empty (for rmdir) | |
633 | */ | |
634 | int ext2_empty_dir (struct inode * inode) | |
635 | { | |
636 | struct page *page = NULL; | |
637 | unsigned long i, npages = dir_pages(inode); | |
638 | ||
639 | for (i = 0; i < npages; i++) { | |
640 | char *kaddr; | |
641 | ext2_dirent * de; | |
642 | page = ext2_get_page(inode, i); | |
643 | ||
644 | if (IS_ERR(page)) | |
645 | continue; | |
646 | ||
647 | kaddr = page_address(page); | |
648 | de = (ext2_dirent *)kaddr; | |
649 | kaddr += ext2_last_byte(inode, i) - EXT2_DIR_REC_LEN(1); | |
650 | ||
651 | while ((char *)de <= kaddr) { | |
652 | if (de->rec_len == 0) { | |
653 | ext2_error(inode->i_sb, __FUNCTION__, | |
654 | "zero-length directory entry"); | |
655 | printk("kaddr=%p, de=%p\n", kaddr, de); | |
656 | goto not_empty; | |
657 | } | |
658 | if (de->inode != 0) { | |
659 | /* check for . and .. */ | |
660 | if (de->name[0] != '.') | |
661 | goto not_empty; | |
662 | if (de->name_len > 2) | |
663 | goto not_empty; | |
664 | if (de->name_len < 2) { | |
665 | if (de->inode != | |
666 | cpu_to_le32(inode->i_ino)) | |
667 | goto not_empty; | |
668 | } else if (de->name[1] != '.') | |
669 | goto not_empty; | |
670 | } | |
671 | de = ext2_next_entry(de); | |
672 | } | |
673 | ext2_put_page(page); | |
674 | } | |
675 | return 1; | |
676 | ||
677 | not_empty: | |
678 | ext2_put_page(page); | |
679 | return 0; | |
680 | } | |
681 | ||
4b6f5d20 | 682 | const struct file_operations ext2_dir_operations = { |
1da177e4 LT |
683 | .llseek = generic_file_llseek, |
684 | .read = generic_read_dir, | |
685 | .readdir = ext2_readdir, | |
686 | .ioctl = ext2_ioctl, | |
e322ff07 DH |
687 | #ifdef CONFIG_COMPAT |
688 | .compat_ioctl = ext2_compat_ioctl, | |
689 | #endif | |
1da177e4 LT |
690 | .fsync = ext2_sync_file, |
691 | }; |