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2ba466d7 YA |
1 | /* |
2 | * dir.c - NILFS directory entry operations | |
3 | * | |
4 | * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation; either version 2 of the License, or | |
9 | * (at your option) any later version. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | * | |
20 | * Modified for NILFS by Amagai Yoshiji <amagai@osrg.net> | |
21 | */ | |
22 | /* | |
23 | * linux/fs/ext2/dir.c | |
24 | * | |
25 | * Copyright (C) 1992, 1993, 1994, 1995 | |
26 | * Remy Card (card@masi.ibp.fr) | |
27 | * Laboratoire MASI - Institut Blaise Pascal | |
28 | * Universite Pierre et Marie Curie (Paris VI) | |
29 | * | |
30 | * from | |
31 | * | |
32 | * linux/fs/minix/dir.c | |
33 | * | |
34 | * Copyright (C) 1991, 1992 Linus Torvalds | |
35 | * | |
36 | * ext2 directory handling functions | |
37 | * | |
38 | * Big-endian to little-endian byte-swapping/bitmaps by | |
39 | * David S. Miller (davem@caip.rutgers.edu), 1995 | |
40 | * | |
41 | * All code that works with directory layout had been switched to pagecache | |
42 | * and moved here. AV | |
43 | */ | |
44 | ||
45 | #include <linux/pagemap.h> | |
2ba466d7 YA |
46 | #include "nilfs.h" |
47 | #include "page.h" | |
48 | ||
49 | /* | |
50 | * nilfs uses block-sized chunks. Arguably, sector-sized ones would be | |
51 | * more robust, but we have what we have | |
52 | */ | |
53 | static inline unsigned nilfs_chunk_size(struct inode *inode) | |
54 | { | |
55 | return inode->i_sb->s_blocksize; | |
56 | } | |
57 | ||
58 | static inline void nilfs_put_page(struct page *page) | |
59 | { | |
60 | kunmap(page); | |
61 | page_cache_release(page); | |
62 | } | |
63 | ||
64 | static inline unsigned long dir_pages(struct inode *inode) | |
65 | { | |
66 | return (inode->i_size+PAGE_CACHE_SIZE-1)>>PAGE_CACHE_SHIFT; | |
67 | } | |
68 | ||
69 | /* | |
70 | * Return the offset into page `page_nr' of the last valid | |
71 | * byte in that page, plus one. | |
72 | */ | |
73 | static unsigned nilfs_last_byte(struct inode *inode, unsigned long page_nr) | |
74 | { | |
75 | unsigned last_byte = inode->i_size; | |
76 | ||
77 | last_byte -= page_nr << PAGE_CACHE_SHIFT; | |
78 | if (last_byte > PAGE_CACHE_SIZE) | |
79 | last_byte = PAGE_CACHE_SIZE; | |
80 | return last_byte; | |
81 | } | |
82 | ||
83 | static int nilfs_prepare_chunk_uninterruptible(struct page *page, | |
84 | struct address_space *mapping, | |
85 | unsigned from, unsigned to) | |
86 | { | |
87 | loff_t pos = page_offset(page) + from; | |
88 | return block_write_begin(NULL, mapping, pos, to - from, | |
89 | AOP_FLAG_UNINTERRUPTIBLE, &page, | |
90 | NULL, nilfs_get_block); | |
91 | } | |
92 | ||
93 | static int nilfs_prepare_chunk(struct page *page, | |
94 | struct address_space *mapping, | |
95 | unsigned from, unsigned to) | |
96 | { | |
97 | loff_t pos = page_offset(page) + from; | |
98 | return block_write_begin(NULL, mapping, pos, to - from, 0, &page, | |
99 | NULL, nilfs_get_block); | |
100 | } | |
101 | ||
102 | static int nilfs_commit_chunk(struct page *page, | |
103 | struct address_space *mapping, | |
104 | unsigned from, unsigned to) | |
105 | { | |
106 | struct inode *dir = mapping->host; | |
107 | struct nilfs_sb_info *sbi = NILFS_SB(dir->i_sb); | |
108 | loff_t pos = page_offset(page) + from; | |
109 | unsigned len = to - from; | |
110 | unsigned nr_dirty, copied; | |
111 | int err; | |
112 | ||
113 | nr_dirty = nilfs_page_count_clean_buffers(page, from, to); | |
114 | copied = block_write_end(NULL, mapping, pos, len, len, page, NULL); | |
115 | if (pos + copied > dir->i_size) { | |
116 | i_size_write(dir, pos + copied); | |
117 | mark_inode_dirty(dir); | |
118 | } | |
119 | if (IS_DIRSYNC(dir)) | |
120 | nilfs_set_transaction_flag(NILFS_TI_SYNC); | |
121 | err = nilfs_set_file_dirty(sbi, dir, nr_dirty); | |
122 | unlock_page(page); | |
123 | return err; | |
124 | } | |
125 | ||
126 | static void nilfs_check_page(struct page *page) | |
127 | { | |
128 | struct inode *dir = page->mapping->host; | |
129 | struct super_block *sb = dir->i_sb; | |
130 | unsigned chunk_size = nilfs_chunk_size(dir); | |
131 | char *kaddr = page_address(page); | |
132 | unsigned offs, rec_len; | |
133 | unsigned limit = PAGE_CACHE_SIZE; | |
134 | struct nilfs_dir_entry *p; | |
135 | char *error; | |
136 | ||
137 | if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { | |
138 | limit = dir->i_size & ~PAGE_CACHE_MASK; | |
139 | if (limit & (chunk_size - 1)) | |
140 | goto Ebadsize; | |
141 | if (!limit) | |
142 | goto out; | |
143 | } | |
144 | for (offs = 0; offs <= limit - NILFS_DIR_REC_LEN(1); offs += rec_len) { | |
145 | p = (struct nilfs_dir_entry *)(kaddr + offs); | |
146 | rec_len = le16_to_cpu(p->rec_len); | |
147 | ||
148 | if (rec_len < NILFS_DIR_REC_LEN(1)) | |
149 | goto Eshort; | |
150 | if (rec_len & 3) | |
151 | goto Ealign; | |
152 | if (rec_len < NILFS_DIR_REC_LEN(p->name_len)) | |
153 | goto Enamelen; | |
154 | if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)) | |
155 | goto Espan; | |
156 | } | |
157 | if (offs != limit) | |
158 | goto Eend; | |
159 | out: | |
160 | SetPageChecked(page); | |
161 | return; | |
162 | ||
163 | /* Too bad, we had an error */ | |
164 | ||
165 | Ebadsize: | |
166 | nilfs_error(sb, "nilfs_check_page", | |
167 | "size of directory #%lu is not a multiple of chunk size", | |
168 | dir->i_ino | |
169 | ); | |
170 | goto fail; | |
171 | Eshort: | |
172 | error = "rec_len is smaller than minimal"; | |
173 | goto bad_entry; | |
174 | Ealign: | |
175 | error = "unaligned directory entry"; | |
176 | goto bad_entry; | |
177 | Enamelen: | |
178 | error = "rec_len is too small for name_len"; | |
179 | goto bad_entry; | |
180 | Espan: | |
181 | error = "directory entry across blocks"; | |
182 | bad_entry: | |
183 | nilfs_error(sb, "nilfs_check_page", "bad entry in directory #%lu: %s - " | |
184 | "offset=%lu, inode=%lu, rec_len=%d, name_len=%d", | |
185 | dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
186 | (unsigned long) le64_to_cpu(p->inode), | |
187 | rec_len, p->name_len); | |
188 | goto fail; | |
189 | Eend: | |
190 | p = (struct nilfs_dir_entry *)(kaddr + offs); | |
191 | nilfs_error(sb, "nilfs_check_page", | |
192 | "entry in directory #%lu spans the page boundary" | |
193 | "offset=%lu, inode=%lu", | |
194 | dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
195 | (unsigned long) le64_to_cpu(p->inode)); | |
196 | fail: | |
197 | SetPageChecked(page); | |
198 | SetPageError(page); | |
199 | } | |
200 | ||
201 | static struct page *nilfs_get_page(struct inode *dir, unsigned long n) | |
202 | { | |
203 | struct address_space *mapping = dir->i_mapping; | |
204 | struct page *page = read_cache_page(mapping, n, | |
205 | (filler_t *)mapping->a_ops->readpage, NULL); | |
206 | if (!IS_ERR(page)) { | |
207 | wait_on_page_locked(page); | |
208 | kmap(page); | |
209 | if (!PageUptodate(page)) | |
210 | goto fail; | |
211 | if (!PageChecked(page)) | |
212 | nilfs_check_page(page); | |
213 | if (PageError(page)) | |
214 | goto fail; | |
215 | } | |
216 | return page; | |
217 | ||
218 | fail: | |
219 | nilfs_put_page(page); | |
220 | return ERR_PTR(-EIO); | |
221 | } | |
222 | ||
223 | /* | |
224 | * NOTE! unlike strncmp, nilfs_match returns 1 for success, 0 for failure. | |
225 | * | |
226 | * len <= NILFS_NAME_LEN and de != NULL are guaranteed by caller. | |
227 | */ | |
228 | static int | |
229 | nilfs_match(int len, const char * const name, struct nilfs_dir_entry *de) | |
230 | { | |
231 | if (len != de->name_len) | |
232 | return 0; | |
233 | if (!de->inode) | |
234 | return 0; | |
235 | return !memcmp(name, de->name, len); | |
236 | } | |
237 | ||
238 | /* | |
239 | * p is at least 6 bytes before the end of page | |
240 | */ | |
241 | static struct nilfs_dir_entry *nilfs_next_entry(struct nilfs_dir_entry *p) | |
242 | { | |
243 | return (struct nilfs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len)); | |
244 | } | |
245 | ||
246 | static unsigned char | |
247 | nilfs_filetype_table[NILFS_FT_MAX] = { | |
248 | [NILFS_FT_UNKNOWN] = DT_UNKNOWN, | |
249 | [NILFS_FT_REG_FILE] = DT_REG, | |
250 | [NILFS_FT_DIR] = DT_DIR, | |
251 | [NILFS_FT_CHRDEV] = DT_CHR, | |
252 | [NILFS_FT_BLKDEV] = DT_BLK, | |
253 | [NILFS_FT_FIFO] = DT_FIFO, | |
254 | [NILFS_FT_SOCK] = DT_SOCK, | |
255 | [NILFS_FT_SYMLINK] = DT_LNK, | |
256 | }; | |
257 | ||
258 | #define S_SHIFT 12 | |
259 | static unsigned char | |
260 | nilfs_type_by_mode[S_IFMT >> S_SHIFT] = { | |
261 | [S_IFREG >> S_SHIFT] = NILFS_FT_REG_FILE, | |
262 | [S_IFDIR >> S_SHIFT] = NILFS_FT_DIR, | |
263 | [S_IFCHR >> S_SHIFT] = NILFS_FT_CHRDEV, | |
264 | [S_IFBLK >> S_SHIFT] = NILFS_FT_BLKDEV, | |
265 | [S_IFIFO >> S_SHIFT] = NILFS_FT_FIFO, | |
266 | [S_IFSOCK >> S_SHIFT] = NILFS_FT_SOCK, | |
267 | [S_IFLNK >> S_SHIFT] = NILFS_FT_SYMLINK, | |
268 | }; | |
269 | ||
270 | static void nilfs_set_de_type(struct nilfs_dir_entry *de, struct inode *inode) | |
271 | { | |
272 | mode_t mode = inode->i_mode; | |
273 | ||
274 | de->file_type = nilfs_type_by_mode[(mode & S_IFMT)>>S_SHIFT]; | |
275 | } | |
276 | ||
277 | static int nilfs_readdir(struct file *filp, void *dirent, filldir_t filldir) | |
278 | { | |
279 | loff_t pos = filp->f_pos; | |
280 | struct inode *inode = filp->f_dentry->d_inode; | |
281 | struct super_block *sb = inode->i_sb; | |
282 | unsigned int offset = pos & ~PAGE_CACHE_MASK; | |
283 | unsigned long n = pos >> PAGE_CACHE_SHIFT; | |
284 | unsigned long npages = dir_pages(inode); | |
285 | /* unsigned chunk_mask = ~(nilfs_chunk_size(inode)-1); */ | |
286 | unsigned char *types = NULL; | |
287 | int ret; | |
288 | ||
289 | if (pos > inode->i_size - NILFS_DIR_REC_LEN(1)) | |
290 | goto success; | |
291 | ||
292 | types = nilfs_filetype_table; | |
293 | ||
294 | for ( ; n < npages; n++, offset = 0) { | |
295 | char *kaddr, *limit; | |
296 | struct nilfs_dir_entry *de; | |
297 | struct page *page = nilfs_get_page(inode, n); | |
298 | ||
299 | if (IS_ERR(page)) { | |
300 | nilfs_error(sb, __func__, "bad page in #%lu", | |
301 | inode->i_ino); | |
302 | filp->f_pos += PAGE_CACHE_SIZE - offset; | |
303 | ret = -EIO; | |
304 | goto done; | |
305 | } | |
306 | kaddr = page_address(page); | |
307 | de = (struct nilfs_dir_entry *)(kaddr + offset); | |
308 | limit = kaddr + nilfs_last_byte(inode, n) - | |
309 | NILFS_DIR_REC_LEN(1); | |
310 | for ( ; (char *)de <= limit; de = nilfs_next_entry(de)) { | |
311 | if (de->rec_len == 0) { | |
312 | nilfs_error(sb, __func__, | |
313 | "zero-length directory entry"); | |
314 | ret = -EIO; | |
315 | nilfs_put_page(page); | |
316 | goto done; | |
317 | } | |
318 | if (de->inode) { | |
319 | int over; | |
320 | unsigned char d_type = DT_UNKNOWN; | |
321 | ||
322 | if (types && de->file_type < NILFS_FT_MAX) | |
323 | d_type = types[de->file_type]; | |
324 | ||
325 | offset = (char *)de - kaddr; | |
326 | over = filldir(dirent, de->name, de->name_len, | |
327 | (n<<PAGE_CACHE_SHIFT) | offset, | |
328 | le64_to_cpu(de->inode), d_type); | |
329 | if (over) { | |
330 | nilfs_put_page(page); | |
331 | goto success; | |
332 | } | |
333 | } | |
334 | filp->f_pos += le16_to_cpu(de->rec_len); | |
335 | } | |
336 | nilfs_put_page(page); | |
337 | } | |
338 | ||
339 | success: | |
340 | ret = 0; | |
341 | done: | |
342 | return ret; | |
343 | } | |
344 | ||
345 | /* | |
346 | * nilfs_find_entry() | |
347 | * | |
348 | * finds an entry in the specified directory with the wanted name. It | |
349 | * returns the page in which the entry was found, and the entry itself | |
350 | * (as a parameter - res_dir). Page is returned mapped and unlocked. | |
351 | * Entry is guaranteed to be valid. | |
352 | */ | |
353 | struct nilfs_dir_entry * | |
354 | nilfs_find_entry(struct inode *dir, struct dentry *dentry, | |
355 | struct page **res_page) | |
356 | { | |
357 | const char *name = dentry->d_name.name; | |
358 | int namelen = dentry->d_name.len; | |
359 | unsigned reclen = NILFS_DIR_REC_LEN(namelen); | |
360 | unsigned long start, n; | |
361 | unsigned long npages = dir_pages(dir); | |
362 | struct page *page = NULL; | |
363 | struct nilfs_inode_info *ei = NILFS_I(dir); | |
364 | struct nilfs_dir_entry *de; | |
365 | ||
366 | if (npages == 0) | |
367 | goto out; | |
368 | ||
369 | /* OFFSET_CACHE */ | |
370 | *res_page = NULL; | |
371 | ||
372 | start = ei->i_dir_start_lookup; | |
373 | if (start >= npages) | |
374 | start = 0; | |
375 | n = start; | |
376 | do { | |
377 | char *kaddr; | |
378 | page = nilfs_get_page(dir, n); | |
379 | if (!IS_ERR(page)) { | |
380 | kaddr = page_address(page); | |
381 | de = (struct nilfs_dir_entry *)kaddr; | |
382 | kaddr += nilfs_last_byte(dir, n) - reclen; | |
383 | while ((char *) de <= kaddr) { | |
384 | if (de->rec_len == 0) { | |
385 | nilfs_error(dir->i_sb, __func__, | |
386 | "zero-length directory entry"); | |
387 | nilfs_put_page(page); | |
388 | goto out; | |
389 | } | |
390 | if (nilfs_match(namelen, name, de)) | |
391 | goto found; | |
392 | de = nilfs_next_entry(de); | |
393 | } | |
394 | nilfs_put_page(page); | |
395 | } | |
396 | if (++n >= npages) | |
397 | n = 0; | |
398 | /* next page is past the blocks we've got */ | |
399 | if (unlikely(n > (dir->i_blocks >> (PAGE_CACHE_SHIFT - 9)))) { | |
400 | nilfs_error(dir->i_sb, __func__, | |
401 | "dir %lu size %lld exceeds block cout %llu", | |
402 | dir->i_ino, dir->i_size, | |
403 | (unsigned long long)dir->i_blocks); | |
404 | goto out; | |
405 | } | |
406 | } while (n != start); | |
407 | out: | |
408 | return NULL; | |
409 | ||
410 | found: | |
411 | *res_page = page; | |
412 | ei->i_dir_start_lookup = n; | |
413 | return de; | |
414 | } | |
415 | ||
416 | struct nilfs_dir_entry *nilfs_dotdot(struct inode *dir, struct page **p) | |
417 | { | |
418 | struct page *page = nilfs_get_page(dir, 0); | |
419 | struct nilfs_dir_entry *de = NULL; | |
420 | ||
421 | if (!IS_ERR(page)) { | |
422 | de = nilfs_next_entry( | |
423 | (struct nilfs_dir_entry *)page_address(page)); | |
424 | *p = page; | |
425 | } | |
426 | return de; | |
427 | } | |
428 | ||
429 | ino_t nilfs_inode_by_name(struct inode *dir, struct dentry *dentry) | |
430 | { | |
431 | ino_t res = 0; | |
432 | struct nilfs_dir_entry *de; | |
433 | struct page *page; | |
434 | ||
435 | de = nilfs_find_entry(dir, dentry, &page); | |
436 | if (de) { | |
437 | res = le64_to_cpu(de->inode); | |
438 | kunmap(page); | |
439 | page_cache_release(page); | |
440 | } | |
441 | return res; | |
442 | } | |
443 | ||
444 | /* Releases the page */ | |
445 | void nilfs_set_link(struct inode *dir, struct nilfs_dir_entry *de, | |
446 | struct page *page, struct inode *inode) | |
447 | { | |
448 | unsigned from = (char *) de - (char *) page_address(page); | |
449 | unsigned to = from + le16_to_cpu(de->rec_len); | |
450 | struct address_space *mapping = page->mapping; | |
451 | int err; | |
452 | ||
453 | lock_page(page); | |
454 | err = nilfs_prepare_chunk_uninterruptible(page, mapping, from, to); | |
455 | BUG_ON(err); | |
456 | de->inode = cpu_to_le64(inode->i_ino); | |
457 | nilfs_set_de_type(de, inode); | |
458 | err = nilfs_commit_chunk(page, mapping, from, to); | |
459 | nilfs_put_page(page); | |
460 | dir->i_mtime = dir->i_ctime = CURRENT_TIME; | |
461 | /* NILFS_I(dir)->i_flags &= ~NILFS_BTREE_FL; */ | |
462 | mark_inode_dirty(dir); | |
463 | } | |
464 | ||
465 | /* | |
466 | * Parent is locked. | |
467 | */ | |
468 | int nilfs_add_link(struct dentry *dentry, struct inode *inode) | |
469 | { | |
470 | struct inode *dir = dentry->d_parent->d_inode; | |
471 | const char *name = dentry->d_name.name; | |
472 | int namelen = dentry->d_name.len; | |
473 | unsigned chunk_size = nilfs_chunk_size(dir); | |
474 | unsigned reclen = NILFS_DIR_REC_LEN(namelen); | |
475 | unsigned short rec_len, name_len; | |
476 | struct page *page = NULL; | |
477 | struct nilfs_dir_entry *de; | |
478 | unsigned long npages = dir_pages(dir); | |
479 | unsigned long n; | |
480 | char *kaddr; | |
481 | unsigned from, to; | |
482 | int err; | |
483 | ||
484 | /* | |
485 | * We take care of directory expansion in the same loop. | |
486 | * This code plays outside i_size, so it locks the page | |
487 | * to protect that region. | |
488 | */ | |
489 | for (n = 0; n <= npages; n++) { | |
490 | char *dir_end; | |
491 | ||
492 | page = nilfs_get_page(dir, n); | |
493 | err = PTR_ERR(page); | |
494 | if (IS_ERR(page)) | |
495 | goto out; | |
496 | lock_page(page); | |
497 | kaddr = page_address(page); | |
498 | dir_end = kaddr + nilfs_last_byte(dir, n); | |
499 | de = (struct nilfs_dir_entry *)kaddr; | |
500 | kaddr += PAGE_CACHE_SIZE - reclen; | |
501 | while ((char *)de <= kaddr) { | |
502 | if ((char *)de == dir_end) { | |
503 | /* We hit i_size */ | |
504 | name_len = 0; | |
505 | rec_len = chunk_size; | |
506 | de->rec_len = cpu_to_le16(chunk_size); | |
507 | de->inode = 0; | |
508 | goto got_it; | |
509 | } | |
510 | if (de->rec_len == 0) { | |
511 | nilfs_error(dir->i_sb, __func__, | |
512 | "zero-length directory entry"); | |
513 | err = -EIO; | |
514 | goto out_unlock; | |
515 | } | |
516 | err = -EEXIST; | |
517 | if (nilfs_match(namelen, name, de)) | |
518 | goto out_unlock; | |
519 | name_len = NILFS_DIR_REC_LEN(de->name_len); | |
520 | rec_len = le16_to_cpu(de->rec_len); | |
521 | if (!de->inode && rec_len >= reclen) | |
522 | goto got_it; | |
523 | if (rec_len >= name_len + reclen) | |
524 | goto got_it; | |
525 | de = (struct nilfs_dir_entry *)((char *)de + rec_len); | |
526 | } | |
527 | unlock_page(page); | |
528 | nilfs_put_page(page); | |
529 | } | |
530 | BUG(); | |
531 | return -EINVAL; | |
532 | ||
533 | got_it: | |
534 | from = (char *)de - (char *)page_address(page); | |
535 | to = from + rec_len; | |
536 | err = nilfs_prepare_chunk(page, page->mapping, from, to); | |
537 | if (err) | |
538 | goto out_unlock; | |
539 | if (de->inode) { | |
540 | struct nilfs_dir_entry *de1; | |
541 | ||
542 | de1 = (struct nilfs_dir_entry *)((char *)de + name_len); | |
543 | de1->rec_len = cpu_to_le16(rec_len - name_len); | |
544 | de->rec_len = cpu_to_le16(name_len); | |
545 | de = de1; | |
546 | } | |
547 | de->name_len = namelen; | |
548 | memcpy(de->name, name, namelen); | |
549 | de->inode = cpu_to_le64(inode->i_ino); | |
550 | nilfs_set_de_type(de, inode); | |
551 | err = nilfs_commit_chunk(page, page->mapping, from, to); | |
552 | dir->i_mtime = dir->i_ctime = CURRENT_TIME; | |
553 | /* NILFS_I(dir)->i_flags &= ~NILFS_BTREE_FL; */ | |
554 | mark_inode_dirty(dir); | |
555 | /* OFFSET_CACHE */ | |
556 | out_put: | |
557 | nilfs_put_page(page); | |
558 | out: | |
559 | return err; | |
560 | out_unlock: | |
561 | unlock_page(page); | |
562 | goto out_put; | |
563 | } | |
564 | ||
565 | /* | |
566 | * nilfs_delete_entry deletes a directory entry by merging it with the | |
567 | * previous entry. Page is up-to-date. Releases the page. | |
568 | */ | |
569 | int nilfs_delete_entry(struct nilfs_dir_entry *dir, struct page *page) | |
570 | { | |
571 | struct address_space *mapping = page->mapping; | |
572 | struct inode *inode = mapping->host; | |
573 | char *kaddr = page_address(page); | |
574 | unsigned from = ((char *)dir - kaddr) & ~(nilfs_chunk_size(inode) - 1); | |
575 | unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len); | |
576 | struct nilfs_dir_entry *pde = NULL; | |
577 | struct nilfs_dir_entry *de = (struct nilfs_dir_entry *)(kaddr + from); | |
578 | int err; | |
579 | ||
580 | while ((char *)de < (char *)dir) { | |
581 | if (de->rec_len == 0) { | |
582 | nilfs_error(inode->i_sb, __func__, | |
583 | "zero-length directory entry"); | |
584 | err = -EIO; | |
585 | goto out; | |
586 | } | |
587 | pde = de; | |
588 | de = nilfs_next_entry(de); | |
589 | } | |
590 | if (pde) | |
591 | from = (char *)pde - (char *)page_address(page); | |
592 | lock_page(page); | |
593 | err = nilfs_prepare_chunk(page, mapping, from, to); | |
594 | BUG_ON(err); | |
595 | if (pde) | |
596 | pde->rec_len = cpu_to_le16(to - from); | |
597 | dir->inode = 0; | |
598 | err = nilfs_commit_chunk(page, mapping, from, to); | |
599 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
600 | /* NILFS_I(inode)->i_flags &= ~NILFS_BTREE_FL; */ | |
601 | mark_inode_dirty(inode); | |
602 | out: | |
603 | nilfs_put_page(page); | |
604 | return err; | |
605 | } | |
606 | ||
607 | /* | |
608 | * Set the first fragment of directory. | |
609 | */ | |
610 | int nilfs_make_empty(struct inode *inode, struct inode *parent) | |
611 | { | |
612 | struct address_space *mapping = inode->i_mapping; | |
613 | struct page *page = grab_cache_page(mapping, 0); | |
614 | unsigned chunk_size = nilfs_chunk_size(inode); | |
615 | struct nilfs_dir_entry *de; | |
616 | int err; | |
617 | void *kaddr; | |
618 | ||
619 | if (!page) | |
620 | return -ENOMEM; | |
621 | ||
622 | err = nilfs_prepare_chunk(page, mapping, 0, chunk_size); | |
623 | if (unlikely(err)) { | |
624 | unlock_page(page); | |
625 | goto fail; | |
626 | } | |
627 | kaddr = kmap_atomic(page, KM_USER0); | |
628 | memset(kaddr, 0, chunk_size); | |
629 | de = (struct nilfs_dir_entry *)kaddr; | |
630 | de->name_len = 1; | |
631 | de->rec_len = cpu_to_le16(NILFS_DIR_REC_LEN(1)); | |
632 | memcpy(de->name, ".\0\0", 4); | |
633 | de->inode = cpu_to_le64(inode->i_ino); | |
634 | nilfs_set_de_type(de, inode); | |
635 | ||
636 | de = (struct nilfs_dir_entry *)(kaddr + NILFS_DIR_REC_LEN(1)); | |
637 | de->name_len = 2; | |
638 | de->rec_len = cpu_to_le16(chunk_size - NILFS_DIR_REC_LEN(1)); | |
639 | de->inode = cpu_to_le64(parent->i_ino); | |
640 | memcpy(de->name, "..\0", 4); | |
641 | nilfs_set_de_type(de, inode); | |
642 | kunmap_atomic(kaddr, KM_USER0); | |
643 | err = nilfs_commit_chunk(page, mapping, 0, chunk_size); | |
644 | fail: | |
645 | page_cache_release(page); | |
646 | return err; | |
647 | } | |
648 | ||
649 | /* | |
650 | * routine to check that the specified directory is empty (for rmdir) | |
651 | */ | |
652 | int nilfs_empty_dir(struct inode *inode) | |
653 | { | |
654 | struct page *page = NULL; | |
655 | unsigned long i, npages = dir_pages(inode); | |
656 | ||
657 | for (i = 0; i < npages; i++) { | |
658 | char *kaddr; | |
659 | struct nilfs_dir_entry *de; | |
660 | ||
661 | page = nilfs_get_page(inode, i); | |
662 | if (IS_ERR(page)) | |
663 | continue; | |
664 | ||
665 | kaddr = page_address(page); | |
666 | de = (struct nilfs_dir_entry *)kaddr; | |
667 | kaddr += nilfs_last_byte(inode, i) - NILFS_DIR_REC_LEN(1); | |
668 | ||
669 | while ((char *)de <= kaddr) { | |
670 | if (de->rec_len == 0) { | |
671 | nilfs_error(inode->i_sb, __func__, | |
672 | "zero-length directory entry " | |
673 | "(kaddr=%p, de=%p)\n", kaddr, de); | |
674 | goto not_empty; | |
675 | } | |
676 | if (de->inode != 0) { | |
677 | /* check for . and .. */ | |
678 | if (de->name[0] != '.') | |
679 | goto not_empty; | |
680 | if (de->name_len > 2) | |
681 | goto not_empty; | |
682 | if (de->name_len < 2) { | |
683 | if (de->inode != | |
684 | cpu_to_le64(inode->i_ino)) | |
685 | goto not_empty; | |
686 | } else if (de->name[1] != '.') | |
687 | goto not_empty; | |
688 | } | |
689 | de = nilfs_next_entry(de); | |
690 | } | |
691 | nilfs_put_page(page); | |
692 | } | |
693 | return 1; | |
694 | ||
695 | not_empty: | |
696 | nilfs_put_page(page); | |
697 | return 0; | |
698 | } | |
699 | ||
700 | struct file_operations nilfs_dir_operations = { | |
701 | .llseek = generic_file_llseek, | |
702 | .read = generic_read_dir, | |
703 | .readdir = nilfs_readdir, | |
7a946193 | 704 | .unlocked_ioctl = nilfs_ioctl, |
2ba466d7 | 705 | #ifdef CONFIG_COMPAT |
8082d36a | 706 | .compat_ioctl = nilfs_ioctl, |
2ba466d7 YA |
707 | #endif /* CONFIG_COMPAT */ |
708 | .fsync = nilfs_sync_file, | |
709 | ||
710 | }; |