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e6af00f1 BH |
1 | /* |
2 | * Copyright (C) 2005, 2006 | |
3 | * Avishay Traeger (avishay@gmail.com) (avishay@il.ibm.com) | |
4 | * Copyright (C) 2005, 2006 | |
5 | * International Business Machines | |
6 | * Copyright (C) 2008, 2009 | |
7 | * Boaz Harrosh <bharrosh@panasas.com> | |
8 | * | |
9 | * Copyrights for code taken from ext2: | |
10 | * Copyright (C) 1992, 1993, 1994, 1995 | |
11 | * Remy Card (card@masi.ibp.fr) | |
12 | * Laboratoire MASI - Institut Blaise Pascal | |
13 | * Universite Pierre et Marie Curie (Paris VI) | |
14 | * from | |
15 | * linux/fs/minix/inode.c | |
16 | * Copyright (C) 1991, 1992 Linus Torvalds | |
17 | * | |
18 | * This file is part of exofs. | |
19 | * | |
20 | * exofs is free software; you can redistribute it and/or modify | |
21 | * it under the terms of the GNU General Public License as published by | |
22 | * the Free Software Foundation. Since it is based on ext2, and the only | |
23 | * valid version of GPL for the Linux kernel is version 2, the only valid | |
24 | * version of GPL for exofs is version 2. | |
25 | * | |
26 | * exofs is distributed in the hope that it will be useful, | |
27 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
28 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
29 | * GNU General Public License for more details. | |
30 | * | |
31 | * You should have received a copy of the GNU General Public License | |
32 | * along with exofs; if not, write to the Free Software | |
33 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA | |
34 | */ | |
35 | ||
36 | #include "exofs.h" | |
37 | ||
38 | static inline unsigned exofs_chunk_size(struct inode *inode) | |
39 | { | |
40 | return inode->i_sb->s_blocksize; | |
41 | } | |
42 | ||
43 | static inline void exofs_put_page(struct page *page) | |
44 | { | |
45 | kunmap(page); | |
46 | page_cache_release(page); | |
47 | } | |
48 | ||
49 | /* Accesses dir's inode->i_size must be called under inode lock */ | |
50 | static inline unsigned long dir_pages(struct inode *inode) | |
51 | { | |
52 | return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
53 | } | |
54 | ||
55 | static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr) | |
56 | { | |
57 | loff_t 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 exofs_commit_chunk(struct page *page, loff_t pos, unsigned len) | |
66 | { | |
67 | struct address_space *mapping = page->mapping; | |
68 | struct inode *dir = mapping->host; | |
69 | int err = 0; | |
70 | ||
71 | dir->i_version++; | |
72 | ||
73 | if (!PageUptodate(page)) | |
74 | SetPageUptodate(page); | |
75 | ||
76 | if (pos+len > dir->i_size) { | |
77 | i_size_write(dir, pos+len); | |
78 | mark_inode_dirty(dir); | |
79 | } | |
80 | set_page_dirty(page); | |
81 | ||
82 | if (IS_DIRSYNC(dir)) | |
83 | err = write_one_page(page, 1); | |
84 | else | |
85 | unlock_page(page); | |
86 | ||
87 | return err; | |
88 | } | |
89 | ||
90 | static void exofs_check_page(struct page *page) | |
91 | { | |
92 | struct inode *dir = page->mapping->host; | |
93 | unsigned chunk_size = exofs_chunk_size(dir); | |
94 | char *kaddr = page_address(page); | |
95 | unsigned offs, rec_len; | |
96 | unsigned limit = PAGE_CACHE_SIZE; | |
97 | struct exofs_dir_entry *p; | |
98 | char *error; | |
99 | ||
100 | /* if the page is the last one in the directory */ | |
101 | if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) { | |
102 | limit = dir->i_size & ~PAGE_CACHE_MASK; | |
103 | if (limit & (chunk_size - 1)) | |
104 | goto Ebadsize; | |
105 | if (!limit) | |
106 | goto out; | |
107 | } | |
108 | for (offs = 0; offs <= limit - EXOFS_DIR_REC_LEN(1); offs += rec_len) { | |
109 | p = (struct exofs_dir_entry *)(kaddr + offs); | |
110 | rec_len = le16_to_cpu(p->rec_len); | |
111 | ||
112 | if (rec_len < EXOFS_DIR_REC_LEN(1)) | |
113 | goto Eshort; | |
114 | if (rec_len & 3) | |
115 | goto Ealign; | |
116 | if (rec_len < EXOFS_DIR_REC_LEN(p->name_len)) | |
117 | goto Enamelen; | |
118 | if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1)) | |
119 | goto Espan; | |
120 | } | |
121 | if (offs != limit) | |
122 | goto Eend; | |
123 | out: | |
124 | SetPageChecked(page); | |
125 | return; | |
126 | ||
127 | Ebadsize: | |
128 | EXOFS_ERR("ERROR [exofs_check_page]: " | |
129 | "size of directory #%lu is not a multiple of chunk size", | |
130 | dir->i_ino | |
131 | ); | |
132 | goto fail; | |
133 | Eshort: | |
134 | error = "rec_len is smaller than minimal"; | |
135 | goto bad_entry; | |
136 | Ealign: | |
137 | error = "unaligned directory entry"; | |
138 | goto bad_entry; | |
139 | Enamelen: | |
140 | error = "rec_len is too small for name_len"; | |
141 | goto bad_entry; | |
142 | Espan: | |
143 | error = "directory entry across blocks"; | |
144 | goto bad_entry; | |
145 | bad_entry: | |
146 | EXOFS_ERR( | |
147 | "ERROR [exofs_check_page]: bad entry in directory #%lu: %s - " | |
148 | "offset=%lu, inode=%llu, rec_len=%d, name_len=%d", | |
149 | dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
150 | _LLU(le64_to_cpu(p->inode_no)), | |
151 | rec_len, p->name_len); | |
152 | goto fail; | |
153 | Eend: | |
154 | p = (struct exofs_dir_entry *)(kaddr + offs); | |
155 | EXOFS_ERR("ERROR [exofs_check_page]: " | |
156 | "entry in directory #%lu spans the page boundary" | |
157 | "offset=%lu, inode=%llu", | |
158 | dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs, | |
159 | _LLU(le64_to_cpu(p->inode_no))); | |
160 | fail: | |
161 | SetPageChecked(page); | |
162 | SetPageError(page); | |
163 | } | |
164 | ||
165 | static struct page *exofs_get_page(struct inode *dir, unsigned long n) | |
166 | { | |
167 | struct address_space *mapping = dir->i_mapping; | |
168 | struct page *page = read_mapping_page(mapping, n, NULL); | |
169 | ||
170 | if (!IS_ERR(page)) { | |
171 | kmap(page); | |
172 | if (!PageChecked(page)) | |
173 | exofs_check_page(page); | |
174 | if (PageError(page)) | |
175 | goto fail; | |
176 | } | |
177 | return page; | |
178 | ||
179 | fail: | |
180 | exofs_put_page(page); | |
181 | return ERR_PTR(-EIO); | |
182 | } | |
183 | ||
184 | static inline int exofs_match(int len, const unsigned char *name, | |
185 | struct exofs_dir_entry *de) | |
186 | { | |
187 | if (len != de->name_len) | |
188 | return 0; | |
189 | if (!de->inode_no) | |
190 | return 0; | |
191 | return !memcmp(name, de->name, len); | |
192 | } | |
193 | ||
194 | static inline | |
195 | struct exofs_dir_entry *exofs_next_entry(struct exofs_dir_entry *p) | |
196 | { | |
197 | return (struct exofs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len)); | |
198 | } | |
199 | ||
200 | static inline unsigned | |
201 | exofs_validate_entry(char *base, unsigned offset, unsigned mask) | |
202 | { | |
203 | struct exofs_dir_entry *de = (struct exofs_dir_entry *)(base + offset); | |
204 | struct exofs_dir_entry *p = | |
205 | (struct exofs_dir_entry *)(base + (offset&mask)); | |
206 | while ((char *)p < (char *)de) { | |
207 | if (p->rec_len == 0) | |
208 | break; | |
209 | p = exofs_next_entry(p); | |
210 | } | |
211 | return (char *)p - base; | |
212 | } | |
213 | ||
214 | static unsigned char exofs_filetype_table[EXOFS_FT_MAX] = { | |
215 | [EXOFS_FT_UNKNOWN] = DT_UNKNOWN, | |
216 | [EXOFS_FT_REG_FILE] = DT_REG, | |
217 | [EXOFS_FT_DIR] = DT_DIR, | |
218 | [EXOFS_FT_CHRDEV] = DT_CHR, | |
219 | [EXOFS_FT_BLKDEV] = DT_BLK, | |
220 | [EXOFS_FT_FIFO] = DT_FIFO, | |
221 | [EXOFS_FT_SOCK] = DT_SOCK, | |
222 | [EXOFS_FT_SYMLINK] = DT_LNK, | |
223 | }; | |
224 | ||
225 | #define S_SHIFT 12 | |
226 | static unsigned char exofs_type_by_mode[S_IFMT >> S_SHIFT] = { | |
227 | [S_IFREG >> S_SHIFT] = EXOFS_FT_REG_FILE, | |
228 | [S_IFDIR >> S_SHIFT] = EXOFS_FT_DIR, | |
229 | [S_IFCHR >> S_SHIFT] = EXOFS_FT_CHRDEV, | |
230 | [S_IFBLK >> S_SHIFT] = EXOFS_FT_BLKDEV, | |
231 | [S_IFIFO >> S_SHIFT] = EXOFS_FT_FIFO, | |
232 | [S_IFSOCK >> S_SHIFT] = EXOFS_FT_SOCK, | |
233 | [S_IFLNK >> S_SHIFT] = EXOFS_FT_SYMLINK, | |
234 | }; | |
235 | ||
236 | static inline | |
237 | void exofs_set_de_type(struct exofs_dir_entry *de, struct inode *inode) | |
238 | { | |
239 | mode_t mode = inode->i_mode; | |
240 | de->file_type = exofs_type_by_mode[(mode & S_IFMT) >> S_SHIFT]; | |
241 | } | |
242 | ||
243 | static int | |
244 | exofs_readdir(struct file *filp, void *dirent, filldir_t filldir) | |
245 | { | |
246 | loff_t pos = filp->f_pos; | |
247 | struct inode *inode = filp->f_path.dentry->d_inode; | |
248 | unsigned int offset = pos & ~PAGE_CACHE_MASK; | |
249 | unsigned long n = pos >> PAGE_CACHE_SHIFT; | |
250 | unsigned long npages = dir_pages(inode); | |
251 | unsigned chunk_mask = ~(exofs_chunk_size(inode)-1); | |
252 | unsigned char *types = NULL; | |
253 | int need_revalidate = (filp->f_version != inode->i_version); | |
254 | ||
255 | if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1)) | |
256 | return 0; | |
257 | ||
258 | types = exofs_filetype_table; | |
259 | ||
260 | for ( ; n < npages; n++, offset = 0) { | |
261 | char *kaddr, *limit; | |
262 | struct exofs_dir_entry *de; | |
263 | struct page *page = exofs_get_page(inode, n); | |
264 | ||
265 | if (IS_ERR(page)) { | |
266 | EXOFS_ERR("ERROR: " | |
267 | "bad page in #%lu", | |
268 | inode->i_ino); | |
269 | filp->f_pos += PAGE_CACHE_SIZE - offset; | |
270 | return PTR_ERR(page); | |
271 | } | |
272 | kaddr = page_address(page); | |
273 | if (unlikely(need_revalidate)) { | |
274 | if (offset) { | |
275 | offset = exofs_validate_entry(kaddr, offset, | |
276 | chunk_mask); | |
277 | filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset; | |
278 | } | |
279 | filp->f_version = inode->i_version; | |
280 | need_revalidate = 0; | |
281 | } | |
282 | de = (struct exofs_dir_entry *)(kaddr + offset); | |
283 | limit = kaddr + exofs_last_byte(inode, n) - | |
284 | EXOFS_DIR_REC_LEN(1); | |
285 | for (; (char *)de <= limit; de = exofs_next_entry(de)) { | |
286 | if (de->rec_len == 0) { | |
287 | EXOFS_ERR("ERROR: " | |
288 | "zero-length directory entry"); | |
289 | exofs_put_page(page); | |
290 | return -EIO; | |
291 | } | |
292 | if (de->inode_no) { | |
293 | int over; | |
294 | unsigned char d_type = DT_UNKNOWN; | |
295 | ||
296 | if (types && de->file_type < EXOFS_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 | le64_to_cpu(de->inode_no), | |
303 | d_type); | |
304 | if (over) { | |
305 | exofs_put_page(page); | |
306 | return 0; | |
307 | } | |
308 | } | |
309 | filp->f_pos += le16_to_cpu(de->rec_len); | |
310 | } | |
311 | exofs_put_page(page); | |
312 | } | |
313 | ||
314 | return 0; | |
315 | } | |
316 | ||
317 | struct exofs_dir_entry *exofs_find_entry(struct inode *dir, | |
318 | struct dentry *dentry, struct page **res_page) | |
319 | { | |
320 | const unsigned char *name = dentry->d_name.name; | |
321 | int namelen = dentry->d_name.len; | |
322 | unsigned reclen = EXOFS_DIR_REC_LEN(namelen); | |
323 | unsigned long start, n; | |
324 | unsigned long npages = dir_pages(dir); | |
325 | struct page *page = NULL; | |
326 | struct exofs_i_info *oi = exofs_i(dir); | |
327 | struct exofs_dir_entry *de; | |
328 | ||
329 | if (npages == 0) | |
330 | goto out; | |
331 | ||
332 | *res_page = NULL; | |
333 | ||
334 | start = oi->i_dir_start_lookup; | |
335 | if (start >= npages) | |
336 | start = 0; | |
337 | n = start; | |
338 | do { | |
339 | char *kaddr; | |
340 | page = exofs_get_page(dir, n); | |
341 | if (!IS_ERR(page)) { | |
342 | kaddr = page_address(page); | |
343 | de = (struct exofs_dir_entry *) kaddr; | |
344 | kaddr += exofs_last_byte(dir, n) - reclen; | |
345 | while ((char *) de <= kaddr) { | |
346 | if (de->rec_len == 0) { | |
347 | EXOFS_ERR( | |
348 | "ERROR: exofs_find_entry: " | |
349 | "zero-length directory entry"); | |
350 | exofs_put_page(page); | |
351 | goto out; | |
352 | } | |
353 | if (exofs_match(namelen, name, de)) | |
354 | goto found; | |
355 | de = exofs_next_entry(de); | |
356 | } | |
357 | exofs_put_page(page); | |
358 | } | |
359 | if (++n >= npages) | |
360 | n = 0; | |
361 | } while (n != start); | |
362 | out: | |
363 | return NULL; | |
364 | ||
365 | found: | |
366 | *res_page = page; | |
367 | oi->i_dir_start_lookup = n; | |
368 | return de; | |
369 | } | |
370 | ||
371 | struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p) | |
372 | { | |
373 | struct page *page = exofs_get_page(dir, 0); | |
374 | struct exofs_dir_entry *de = NULL; | |
375 | ||
376 | if (!IS_ERR(page)) { | |
377 | de = exofs_next_entry( | |
378 | (struct exofs_dir_entry *)page_address(page)); | |
379 | *p = page; | |
380 | } | |
381 | return de; | |
382 | } | |
383 | ||
384 | ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry) | |
385 | { | |
386 | ino_t res = 0; | |
387 | struct exofs_dir_entry *de; | |
388 | struct page *page; | |
389 | ||
390 | de = exofs_find_entry(dir, dentry, &page); | |
391 | if (de) { | |
392 | res = le64_to_cpu(de->inode_no); | |
393 | exofs_put_page(page); | |
394 | } | |
395 | return res; | |
396 | } | |
397 | ||
398 | int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de, | |
399 | struct page *page, struct inode *inode) | |
400 | { | |
401 | loff_t pos = page_offset(page) + | |
402 | (char *) de - (char *) page_address(page); | |
403 | unsigned len = le16_to_cpu(de->rec_len); | |
404 | int err; | |
405 | ||
406 | lock_page(page); | |
407 | err = exofs_write_begin(NULL, page->mapping, pos, len, | |
408 | AOP_FLAG_UNINTERRUPTIBLE, &page, NULL); | |
409 | if (err) | |
410 | EXOFS_ERR("exofs_set_link: exofs_write_begin FAILD => %d\n", | |
411 | err); | |
412 | ||
413 | de->inode_no = cpu_to_le64(inode->i_ino); | |
414 | exofs_set_de_type(de, inode); | |
415 | if (likely(!err)) | |
416 | err = exofs_commit_chunk(page, pos, len); | |
417 | exofs_put_page(page); | |
418 | dir->i_mtime = dir->i_ctime = CURRENT_TIME; | |
419 | mark_inode_dirty(dir); | |
420 | return err; | |
421 | } | |
422 | ||
423 | int exofs_add_link(struct dentry *dentry, struct inode *inode) | |
424 | { | |
425 | struct inode *dir = dentry->d_parent->d_inode; | |
426 | const unsigned char *name = dentry->d_name.name; | |
427 | int namelen = dentry->d_name.len; | |
428 | unsigned chunk_size = exofs_chunk_size(dir); | |
429 | unsigned reclen = EXOFS_DIR_REC_LEN(namelen); | |
430 | unsigned short rec_len, name_len; | |
431 | struct page *page = NULL; | |
432 | struct exofs_sb_info *sbi = inode->i_sb->s_fs_info; | |
433 | struct exofs_dir_entry *de; | |
434 | unsigned long npages = dir_pages(dir); | |
435 | unsigned long n; | |
436 | char *kaddr; | |
437 | loff_t pos; | |
438 | int err; | |
439 | ||
440 | for (n = 0; n <= npages; n++) { | |
441 | char *dir_end; | |
442 | ||
443 | page = exofs_get_page(dir, n); | |
444 | err = PTR_ERR(page); | |
445 | if (IS_ERR(page)) | |
446 | goto out; | |
447 | lock_page(page); | |
448 | kaddr = page_address(page); | |
449 | dir_end = kaddr + exofs_last_byte(dir, n); | |
450 | de = (struct exofs_dir_entry *)kaddr; | |
451 | kaddr += PAGE_CACHE_SIZE - reclen; | |
452 | while ((char *)de <= kaddr) { | |
453 | if ((char *)de == dir_end) { | |
454 | name_len = 0; | |
455 | rec_len = chunk_size; | |
456 | de->rec_len = cpu_to_le16(chunk_size); | |
457 | de->inode_no = 0; | |
458 | goto got_it; | |
459 | } | |
460 | if (de->rec_len == 0) { | |
461 | EXOFS_ERR("ERROR: exofs_add_link: " | |
462 | "zero-length directory entry"); | |
463 | err = -EIO; | |
464 | goto out_unlock; | |
465 | } | |
466 | err = -EEXIST; | |
467 | if (exofs_match(namelen, name, de)) | |
468 | goto out_unlock; | |
469 | name_len = EXOFS_DIR_REC_LEN(de->name_len); | |
470 | rec_len = le16_to_cpu(de->rec_len); | |
471 | if (!de->inode_no && rec_len >= reclen) | |
472 | goto got_it; | |
473 | if (rec_len >= name_len + reclen) | |
474 | goto got_it; | |
475 | de = (struct exofs_dir_entry *) ((char *) de + rec_len); | |
476 | } | |
477 | unlock_page(page); | |
478 | exofs_put_page(page); | |
479 | } | |
480 | ||
481 | EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=%p", dentry, inode); | |
482 | return -EINVAL; | |
483 | ||
484 | got_it: | |
485 | pos = page_offset(page) + | |
486 | (char *)de - (char *)page_address(page); | |
487 | err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0, | |
488 | &page, NULL); | |
489 | if (err) | |
490 | goto out_unlock; | |
491 | if (de->inode_no) { | |
492 | struct exofs_dir_entry *de1 = | |
493 | (struct exofs_dir_entry *)((char *)de + name_len); | |
494 | de1->rec_len = cpu_to_le16(rec_len - name_len); | |
495 | de->rec_len = cpu_to_le16(name_len); | |
496 | de = de1; | |
497 | } | |
498 | de->name_len = namelen; | |
499 | memcpy(de->name, name, namelen); | |
500 | de->inode_no = cpu_to_le64(inode->i_ino); | |
501 | exofs_set_de_type(de, inode); | |
502 | err = exofs_commit_chunk(page, pos, rec_len); | |
503 | dir->i_mtime = dir->i_ctime = CURRENT_TIME; | |
504 | mark_inode_dirty(dir); | |
505 | sbi->s_numfiles++; | |
506 | ||
507 | out_put: | |
508 | exofs_put_page(page); | |
509 | out: | |
510 | return err; | |
511 | out_unlock: | |
512 | unlock_page(page); | |
513 | goto out_put; | |
514 | } | |
515 | ||
516 | int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page) | |
517 | { | |
518 | struct address_space *mapping = page->mapping; | |
519 | struct inode *inode = mapping->host; | |
520 | struct exofs_sb_info *sbi = inode->i_sb->s_fs_info; | |
521 | char *kaddr = page_address(page); | |
522 | unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1); | |
523 | unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len); | |
524 | loff_t pos; | |
525 | struct exofs_dir_entry *pde = NULL; | |
526 | struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from); | |
527 | int err; | |
528 | ||
529 | while (de < dir) { | |
530 | if (de->rec_len == 0) { | |
531 | EXOFS_ERR("ERROR: exofs_delete_entry:" | |
532 | "zero-length directory entry"); | |
533 | err = -EIO; | |
534 | goto out; | |
535 | } | |
536 | pde = de; | |
537 | de = exofs_next_entry(de); | |
538 | } | |
539 | if (pde) | |
540 | from = (char *)pde - (char *)page_address(page); | |
541 | pos = page_offset(page) + from; | |
542 | lock_page(page); | |
543 | err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0, | |
544 | &page, NULL); | |
545 | if (err) | |
546 | EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILD => %d\n", | |
547 | err); | |
548 | if (pde) | |
549 | pde->rec_len = cpu_to_le16(to - from); | |
550 | dir->inode_no = 0; | |
551 | if (likely(!err)) | |
552 | err = exofs_commit_chunk(page, pos, to - from); | |
553 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
554 | mark_inode_dirty(inode); | |
555 | sbi->s_numfiles--; | |
556 | out: | |
557 | exofs_put_page(page); | |
558 | return err; | |
559 | } | |
560 | ||
561 | /* kept aligned on 4 bytes */ | |
562 | #define THIS_DIR ".\0\0" | |
563 | #define PARENT_DIR "..\0" | |
564 | ||
565 | int exofs_make_empty(struct inode *inode, struct inode *parent) | |
566 | { | |
567 | struct address_space *mapping = inode->i_mapping; | |
568 | struct page *page = grab_cache_page(mapping, 0); | |
569 | unsigned chunk_size = exofs_chunk_size(inode); | |
570 | struct exofs_dir_entry *de; | |
571 | int err; | |
572 | void *kaddr; | |
573 | ||
574 | if (!page) | |
575 | return -ENOMEM; | |
576 | ||
577 | err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0, | |
578 | &page, NULL); | |
579 | if (err) { | |
580 | unlock_page(page); | |
581 | goto fail; | |
582 | } | |
583 | ||
584 | kaddr = kmap_atomic(page, KM_USER0); | |
585 | de = (struct exofs_dir_entry *)kaddr; | |
586 | de->name_len = 1; | |
587 | de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1)); | |
588 | memcpy(de->name, THIS_DIR, sizeof(THIS_DIR)); | |
589 | de->inode_no = cpu_to_le64(inode->i_ino); | |
590 | exofs_set_de_type(de, inode); | |
591 | ||
592 | de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1)); | |
593 | de->name_len = 2; | |
594 | de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1)); | |
595 | de->inode_no = cpu_to_le64(parent->i_ino); | |
596 | memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR)); | |
597 | exofs_set_de_type(de, inode); | |
598 | kunmap_atomic(page, KM_USER0); | |
599 | err = exofs_commit_chunk(page, 0, chunk_size); | |
600 | fail: | |
601 | page_cache_release(page); | |
602 | return err; | |
603 | } | |
604 | ||
605 | int exofs_empty_dir(struct inode *inode) | |
606 | { | |
607 | struct page *page = NULL; | |
608 | unsigned long i, npages = dir_pages(inode); | |
609 | ||
610 | for (i = 0; i < npages; i++) { | |
611 | char *kaddr; | |
612 | struct exofs_dir_entry *de; | |
613 | page = exofs_get_page(inode, i); | |
614 | ||
615 | if (IS_ERR(page)) | |
616 | continue; | |
617 | ||
618 | kaddr = page_address(page); | |
619 | de = (struct exofs_dir_entry *)kaddr; | |
620 | kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1); | |
621 | ||
622 | while ((char *)de <= kaddr) { | |
623 | if (de->rec_len == 0) { | |
624 | EXOFS_ERR("ERROR: exofs_empty_dir: " | |
625 | "zero-length directory entry" | |
626 | "kaddr=%p, de=%p\n", kaddr, de); | |
627 | goto not_empty; | |
628 | } | |
629 | if (de->inode_no != 0) { | |
630 | /* check for . and .. */ | |
631 | if (de->name[0] != '.') | |
632 | goto not_empty; | |
633 | if (de->name_len > 2) | |
634 | goto not_empty; | |
635 | if (de->name_len < 2) { | |
636 | if (le64_to_cpu(de->inode_no) != | |
637 | inode->i_ino) | |
638 | goto not_empty; | |
639 | } else if (de->name[1] != '.') | |
640 | goto not_empty; | |
641 | } | |
642 | de = exofs_next_entry(de); | |
643 | } | |
644 | exofs_put_page(page); | |
645 | } | |
646 | return 1; | |
647 | ||
648 | not_empty: | |
649 | exofs_put_page(page); | |
650 | return 0; | |
651 | } | |
652 | ||
653 | const struct file_operations exofs_dir_operations = { | |
654 | .llseek = generic_file_llseek, | |
655 | .read = generic_read_dir, | |
656 | .readdir = exofs_readdir, | |
657 | }; |