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OMAP3 SRF: Generic shared resource f/w
[linux-ginger.git] / fs / exofs / dir.c
blob4cfab1cc75c03a0bb7654e5c8150c2009fe4aa11
1 /*
2 * Copyright (C) 2005, 2006
3 * Avishay Traeger (avishay@gmail.com)
4 * Copyright (C) 2008, 2009
5 * Boaz Harrosh <bharrosh@panasas.com>
6 *
7 * Copyrights for code taken from ext2:
8 * Copyright (C) 1992, 1993, 1994, 1995
9 * Remy Card (card@masi.ibp.fr)
10 * Laboratoire MASI - Institut Blaise Pascal
11 * Universite Pierre et Marie Curie (Paris VI)
12 * from
13 * linux/fs/minix/inode.c
14 * Copyright (C) 1991, 1992 Linus Torvalds
15 *
16 * This file is part of exofs.
17 *
18 * exofs is free software; you can redistribute it and/or modify
19 * it under the terms of the GNU General Public License as published by
20 * the Free Software Foundation. Since it is based on ext2, and the only
21 * valid version of GPL for the Linux kernel is version 2, the only valid
22 * version of GPL for exofs is version 2.
23 *
24 * exofs is distributed in the hope that it will be useful,
25 * but WITHOUT ANY WARRANTY; without even the implied warranty of
26 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
27 * GNU General Public License for more details.
28 *
29 * You should have received a copy of the GNU General Public License
30 * along with exofs; if not, write to the Free Software
31 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
32 */
33
34 #include "exofs.h"
35
36 static inline unsigned exofs_chunk_size(struct inode *inode)
37 {
38 return inode->i_sb->s_blocksize;
39 }
40
41 static inline void exofs_put_page(struct page *page)
42 {
43 kunmap(page);
44 page_cache_release(page);
45 }
46
47 /* Accesses dir's inode->i_size must be called under inode lock */
48 static inline unsigned long dir_pages(struct inode *inode)
49 {
50 return (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
51 }
52
53 static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
54 {
55 loff_t last_byte = inode->i_size;
56
57 last_byte -= page_nr << PAGE_CACHE_SHIFT;
58 if (last_byte > PAGE_CACHE_SIZE)
59 last_byte = PAGE_CACHE_SIZE;
60 return last_byte;
61 }
62
63 static int exofs_commit_chunk(struct page *page, loff_t pos, unsigned len)
64 {
65 struct address_space *mapping = page->mapping;
66 struct inode *dir = mapping->host;
67 int err = 0;
68
69 dir->i_version++;
70
71 if (!PageUptodate(page))
72 SetPageUptodate(page);
73
74 if (pos+len > dir->i_size) {
75 i_size_write(dir, pos+len);
76 mark_inode_dirty(dir);
77 }
78 set_page_dirty(page);
79
80 if (IS_DIRSYNC(dir))
81 err = write_one_page(page, 1);
82 else
83 unlock_page(page);
84
85 return err;
86 }
87
88 static void exofs_check_page(struct page *page)
89 {
90 struct inode *dir = page->mapping->host;
91 unsigned chunk_size = exofs_chunk_size(dir);
92 char *kaddr = page_address(page);
93 unsigned offs, rec_len;
94 unsigned limit = PAGE_CACHE_SIZE;
95 struct exofs_dir_entry *p;
96 char *error;
97
98 /* if the page is the last one in the directory */
99 if ((dir->i_size >> PAGE_CACHE_SHIFT) == page->index) {
100 limit = dir->i_size & ~PAGE_CACHE_MASK;
101 if (limit & (chunk_size - 1))
102 goto Ebadsize;
103 if (!limit)
104 goto out;
105 }
106 for (offs = 0; offs <= limit - EXOFS_DIR_REC_LEN(1); offs += rec_len) {
107 p = (struct exofs_dir_entry *)(kaddr + offs);
108 rec_len = le16_to_cpu(p->rec_len);
109
110 if (rec_len < EXOFS_DIR_REC_LEN(1))
111 goto Eshort;
112 if (rec_len & 3)
113 goto Ealign;
114 if (rec_len < EXOFS_DIR_REC_LEN(p->name_len))
115 goto Enamelen;
116 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
117 goto Espan;
118 }
119 if (offs != limit)
120 goto Eend;
121 out:
122 SetPageChecked(page);
123 return;
124
125 Ebadsize:
126 EXOFS_ERR("ERROR [exofs_check_page]: "
127 "size of directory #%lu is not a multiple of chunk size",
128 dir->i_ino
129 );
130 goto fail;
131 Eshort:
132 error = "rec_len is smaller than minimal";
133 goto bad_entry;
134 Ealign:
135 error = "unaligned directory entry";
136 goto bad_entry;
137 Enamelen:
138 error = "rec_len is too small for name_len";
139 goto bad_entry;
140 Espan:
141 error = "directory entry across blocks";
142 goto bad_entry;
143 bad_entry:
144 EXOFS_ERR(
145 "ERROR [exofs_check_page]: bad entry in directory #%lu: %s - "
146 "offset=%lu, inode=%llu, rec_len=%d, name_len=%d",
147 dir->i_ino, error, (page->index<<PAGE_CACHE_SHIFT)+offs,
148 _LLU(le64_to_cpu(p->inode_no)),
149 rec_len, p->name_len);
150 goto fail;
151 Eend:
152 p = (struct exofs_dir_entry *)(kaddr + offs);
153 EXOFS_ERR("ERROR [exofs_check_page]: "
154 "entry in directory #%lu spans the page boundary"
155 "offset=%lu, inode=%llu",
156 dir->i_ino, (page->index<<PAGE_CACHE_SHIFT)+offs,
157 _LLU(le64_to_cpu(p->inode_no)));
158 fail:
159 SetPageChecked(page);
160 SetPageError(page);
161 }
162
163 static struct page *exofs_get_page(struct inode *dir, unsigned long n)
164 {
165 struct address_space *mapping = dir->i_mapping;
166 struct page *page = read_mapping_page(mapping, n, NULL);
167
168 if (!IS_ERR(page)) {
169 kmap(page);
170 if (!PageChecked(page))
171 exofs_check_page(page);
172 if (PageError(page))
173 goto fail;
174 }
175 return page;
176
177 fail:
178 exofs_put_page(page);
179 return ERR_PTR(-EIO);
180 }
181
182 static inline int exofs_match(int len, const unsigned char *name,
183 struct exofs_dir_entry *de)
184 {
185 if (len != de->name_len)
186 return 0;
187 if (!de->inode_no)
188 return 0;
189 return !memcmp(name, de->name, len);
190 }
191
192 static inline
193 struct exofs_dir_entry *exofs_next_entry(struct exofs_dir_entry *p)
194 {
195 return (struct exofs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
196 }
197
198 static inline unsigned
199 exofs_validate_entry(char *base, unsigned offset, unsigned mask)
200 {
201 struct exofs_dir_entry *de = (struct exofs_dir_entry *)(base + offset);
202 struct exofs_dir_entry *p =
203 (struct exofs_dir_entry *)(base + (offset&mask));
204 while ((char *)p < (char *)de) {
205 if (p->rec_len == 0)
206 break;
207 p = exofs_next_entry(p);
208 }
209 return (char *)p - base;
210 }
211
212 static unsigned char exofs_filetype_table[EXOFS_FT_MAX] = {
213 [EXOFS_FT_UNKNOWN] = DT_UNKNOWN,
214 [EXOFS_FT_REG_FILE] = DT_REG,
215 [EXOFS_FT_DIR] = DT_DIR,
216 [EXOFS_FT_CHRDEV] = DT_CHR,
217 [EXOFS_FT_BLKDEV] = DT_BLK,
218 [EXOFS_FT_FIFO] = DT_FIFO,
219 [EXOFS_FT_SOCK] = DT_SOCK,
220 [EXOFS_FT_SYMLINK] = DT_LNK,
221 };
222
223 #define S_SHIFT 12
224 static unsigned char exofs_type_by_mode[S_IFMT >> S_SHIFT] = {
225 [S_IFREG >> S_SHIFT] = EXOFS_FT_REG_FILE,
226 [S_IFDIR >> S_SHIFT] = EXOFS_FT_DIR,
227 [S_IFCHR >> S_SHIFT] = EXOFS_FT_CHRDEV,
228 [S_IFBLK >> S_SHIFT] = EXOFS_FT_BLKDEV,
229 [S_IFIFO >> S_SHIFT] = EXOFS_FT_FIFO,
230 [S_IFSOCK >> S_SHIFT] = EXOFS_FT_SOCK,
231 [S_IFLNK >> S_SHIFT] = EXOFS_FT_SYMLINK,
232 };
233
234 static inline
235 void exofs_set_de_type(struct exofs_dir_entry *de, struct inode *inode)
236 {
237 mode_t mode = inode->i_mode;
238 de->file_type = exofs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
239 }
240
241 static int
242 exofs_readdir(struct file *filp, void *dirent, filldir_t filldir)
243 {
244 loff_t pos = filp->f_pos;
245 struct inode *inode = filp->f_path.dentry->d_inode;
246 unsigned int offset = pos & ~PAGE_CACHE_MASK;
247 unsigned long n = pos >> PAGE_CACHE_SHIFT;
248 unsigned long npages = dir_pages(inode);
249 unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
250 unsigned char *types = NULL;
251 int need_revalidate = (filp->f_version != inode->i_version);
252
253 if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1))
254 return 0;
255
256 types = exofs_filetype_table;
257
258 for ( ; n < npages; n++, offset = 0) {
259 char *kaddr, *limit;
260 struct exofs_dir_entry *de;
261 struct page *page = exofs_get_page(inode, n);
262
263 if (IS_ERR(page)) {
264 EXOFS_ERR("ERROR: "
265 "bad page in #%lu",
266 inode->i_ino);
267 filp->f_pos += PAGE_CACHE_SIZE - offset;
268 return PTR_ERR(page);
269 }
270 kaddr = page_address(page);
271 if (unlikely(need_revalidate)) {
272 if (offset) {
273 offset = exofs_validate_entry(kaddr, offset,
274 chunk_mask);
275 filp->f_pos = (n<<PAGE_CACHE_SHIFT) + offset;
276 }
277 filp->f_version = inode->i_version;
278 need_revalidate = 0;
279 }
280 de = (struct exofs_dir_entry *)(kaddr + offset);
281 limit = kaddr + exofs_last_byte(inode, n) -
282 EXOFS_DIR_REC_LEN(1);
283 for (; (char *)de <= limit; de = exofs_next_entry(de)) {
284 if (de->rec_len == 0) {
285 EXOFS_ERR("ERROR: "
286 "zero-length directory entry");
287 exofs_put_page(page);
288 return -EIO;
289 }
290 if (de->inode_no) {
291 int over;
292 unsigned char d_type = DT_UNKNOWN;
293
294 if (types && de->file_type < EXOFS_FT_MAX)
295 d_type = types[de->file_type];
296
297 offset = (char *)de - kaddr;
298 over = filldir(dirent, de->name, de->name_len,
299 (n<<PAGE_CACHE_SHIFT) | offset,
300 le64_to_cpu(de->inode_no),
301 d_type);
302 if (over) {
303 exofs_put_page(page);
304 return 0;
305 }
306 }
307 filp->f_pos += le16_to_cpu(de->rec_len);
308 }
309 exofs_put_page(page);
310 }
311
312 return 0;
313 }
314
315 struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
316 struct dentry *dentry, struct page **res_page)
317 {
318 const unsigned char *name = dentry->d_name.name;
319 int namelen = dentry->d_name.len;
320 unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
321 unsigned long start, n;
322 unsigned long npages = dir_pages(dir);
323 struct page *page = NULL;
324 struct exofs_i_info *oi = exofs_i(dir);
325 struct exofs_dir_entry *de;
326
327 if (npages == 0)
328 goto out;
329
330 *res_page = NULL;
331
332 start = oi->i_dir_start_lookup;
333 if (start >= npages)
334 start = 0;
335 n = start;
336 do {
337 char *kaddr;
338 page = exofs_get_page(dir, n);
339 if (!IS_ERR(page)) {
340 kaddr = page_address(page);
341 de = (struct exofs_dir_entry *) kaddr;
342 kaddr += exofs_last_byte(dir, n) - reclen;
343 while ((char *) de <= kaddr) {
344 if (de->rec_len == 0) {
345 EXOFS_ERR(
346 "ERROR: exofs_find_entry: "
347 "zero-length directory entry");
348 exofs_put_page(page);
349 goto out;
350 }
351 if (exofs_match(namelen, name, de))
352 goto found;
353 de = exofs_next_entry(de);
354 }
355 exofs_put_page(page);
356 }
357 if (++n >= npages)
358 n = 0;
359 } while (n != start);
360 out:
361 return NULL;
362
363 found:
364 *res_page = page;
365 oi->i_dir_start_lookup = n;
366 return de;
367 }
368
369 struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p)
370 {
371 struct page *page = exofs_get_page(dir, 0);
372 struct exofs_dir_entry *de = NULL;
373
374 if (!IS_ERR(page)) {
375 de = exofs_next_entry(
376 (struct exofs_dir_entry *)page_address(page));
377 *p = page;
378 }
379 return de;
380 }
381
382 ino_t exofs_parent_ino(struct dentry *child)
383 {
384 struct page *page;
385 struct exofs_dir_entry *de;
386 ino_t ino;
387
388 de = exofs_dotdot(child->d_inode, &page);
389 if (!de)
390 return 0;
391
392 ino = le64_to_cpu(de->inode_no);
393 exofs_put_page(page);
394 return ino;
395 }
396
397 ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry)
398 {
399 ino_t res = 0;
400 struct exofs_dir_entry *de;
401 struct page *page;
402
403 de = exofs_find_entry(dir, dentry, &page);
404 if (de) {
405 res = le64_to_cpu(de->inode_no);
406 exofs_put_page(page);
407 }
408 return res;
409 }
410
411 int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de,
412 struct page *page, struct inode *inode)
413 {
414 loff_t pos = page_offset(page) +
415 (char *) de - (char *) page_address(page);
416 unsigned len = le16_to_cpu(de->rec_len);
417 int err;
418
419 lock_page(page);
420 err = exofs_write_begin(NULL, page->mapping, pos, len,
421 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
422 if (err)
423 EXOFS_ERR("exofs_set_link: exofs_write_begin FAILD => %d\n",
424 err);
425
426 de->inode_no = cpu_to_le64(inode->i_ino);
427 exofs_set_de_type(de, inode);
428 if (likely(!err))
429 err = exofs_commit_chunk(page, pos, len);
430 exofs_put_page(page);
431 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
432 mark_inode_dirty(dir);
433 return err;
434 }
435
436 int exofs_add_link(struct dentry *dentry, struct inode *inode)
437 {
438 struct inode *dir = dentry->d_parent->d_inode;
439 const unsigned char *name = dentry->d_name.name;
440 int namelen = dentry->d_name.len;
441 unsigned chunk_size = exofs_chunk_size(dir);
442 unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
443 unsigned short rec_len, name_len;
444 struct page *page = NULL;
445 struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
446 struct exofs_dir_entry *de;
447 unsigned long npages = dir_pages(dir);
448 unsigned long n;
449 char *kaddr;
450 loff_t pos;
451 int err;
452
453 for (n = 0; n <= npages; n++) {
454 char *dir_end;
455
456 page = exofs_get_page(dir, n);
457 err = PTR_ERR(page);
458 if (IS_ERR(page))
459 goto out;
460 lock_page(page);
461 kaddr = page_address(page);
462 dir_end = kaddr + exofs_last_byte(dir, n);
463 de = (struct exofs_dir_entry *)kaddr;
464 kaddr += PAGE_CACHE_SIZE - reclen;
465 while ((char *)de <= kaddr) {
466 if ((char *)de == dir_end) {
467 name_len = 0;
468 rec_len = chunk_size;
469 de->rec_len = cpu_to_le16(chunk_size);
470 de->inode_no = 0;
471 goto got_it;
472 }
473 if (de->rec_len == 0) {
474 EXOFS_ERR("ERROR: exofs_add_link: "
475 "zero-length directory entry");
476 err = -EIO;
477 goto out_unlock;
478 }
479 err = -EEXIST;
480 if (exofs_match(namelen, name, de))
481 goto out_unlock;
482 name_len = EXOFS_DIR_REC_LEN(de->name_len);
483 rec_len = le16_to_cpu(de->rec_len);
484 if (!de->inode_no && rec_len >= reclen)
485 goto got_it;
486 if (rec_len >= name_len + reclen)
487 goto got_it;
488 de = (struct exofs_dir_entry *) ((char *) de + rec_len);
489 }
490 unlock_page(page);
491 exofs_put_page(page);
492 }
493
494 EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=%p", dentry, inode);
495 return -EINVAL;
496
497 got_it:
498 pos = page_offset(page) +
499 (char *)de - (char *)page_address(page);
500 err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0,
501 &page, NULL);
502 if (err)
503 goto out_unlock;
504 if (de->inode_no) {
505 struct exofs_dir_entry *de1 =
506 (struct exofs_dir_entry *)((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_no = cpu_to_le64(inode->i_ino);
514 exofs_set_de_type(de, inode);
515 err = exofs_commit_chunk(page, pos, rec_len);
516 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
517 mark_inode_dirty(dir);
518 sbi->s_numfiles++;
519
520 out_put:
521 exofs_put_page(page);
522 out:
523 return err;
524 out_unlock:
525 unlock_page(page);
526 goto out_put;
527 }
528
529 int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page)
530 {
531 struct address_space *mapping = page->mapping;
532 struct inode *inode = mapping->host;
533 struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
534 char *kaddr = page_address(page);
535 unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1);
536 unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
537 loff_t pos;
538 struct exofs_dir_entry *pde = NULL;
539 struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from);
540 int err;
541
542 while (de < dir) {
543 if (de->rec_len == 0) {
544 EXOFS_ERR("ERROR: exofs_delete_entry:"
545 "zero-length directory entry");
546 err = -EIO;
547 goto out;
548 }
549 pde = de;
550 de = exofs_next_entry(de);
551 }
552 if (pde)
553 from = (char *)pde - (char *)page_address(page);
554 pos = page_offset(page) + from;
555 lock_page(page);
556 err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0,
557 &page, NULL);
558 if (err)
559 EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILD => %d\n",
560 err);
561 if (pde)
562 pde->rec_len = cpu_to_le16(to - from);
563 dir->inode_no = 0;
564 if (likely(!err))
565 err = exofs_commit_chunk(page, pos, to - from);
566 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
567 mark_inode_dirty(inode);
568 sbi->s_numfiles--;
569 out:
570 exofs_put_page(page);
571 return err;
572 }
573
574 /* kept aligned on 4 bytes */
575 #define THIS_DIR ".\0\0"
576 #define PARENT_DIR "..\0"
577
578 int exofs_make_empty(struct inode *inode, struct inode *parent)
579 {
580 struct address_space *mapping = inode->i_mapping;
581 struct page *page = grab_cache_page(mapping, 0);
582 unsigned chunk_size = exofs_chunk_size(inode);
583 struct exofs_dir_entry *de;
584 int err;
585 void *kaddr;
586
587 if (!page)
588 return -ENOMEM;
589
590 err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0,
591 &page, NULL);
592 if (err) {
593 unlock_page(page);
594 goto fail;
595 }
596
597 kaddr = kmap_atomic(page, KM_USER0);
598 de = (struct exofs_dir_entry *)kaddr;
599 de->name_len = 1;
600 de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1));
601 memcpy(de->name, THIS_DIR, sizeof(THIS_DIR));
602 de->inode_no = cpu_to_le64(inode->i_ino);
603 exofs_set_de_type(de, inode);
604
605 de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1));
606 de->name_len = 2;
607 de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1));
608 de->inode_no = cpu_to_le64(parent->i_ino);
609 memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
610 exofs_set_de_type(de, inode);
611 kunmap_atomic(page, KM_USER0);
612 err = exofs_commit_chunk(page, 0, chunk_size);
613 fail:
614 page_cache_release(page);
615 return err;
616 }
617
618 int exofs_empty_dir(struct inode *inode)
619 {
620 struct page *page = NULL;
621 unsigned long i, npages = dir_pages(inode);
622
623 for (i = 0; i < npages; i++) {
624 char *kaddr;
625 struct exofs_dir_entry *de;
626 page = exofs_get_page(inode, i);
627
628 if (IS_ERR(page))
629 continue;
630
631 kaddr = page_address(page);
632 de = (struct exofs_dir_entry *)kaddr;
633 kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1);
634
635 while ((char *)de <= kaddr) {
636 if (de->rec_len == 0) {
637 EXOFS_ERR("ERROR: exofs_empty_dir: "
638 "zero-length directory entry"
639 "kaddr=%p, de=%p\n", kaddr, de);
640 goto not_empty;
641 }
642 if (de->inode_no != 0) {
643 /* check for . and .. */
644 if (de->name[0] != '.')
645 goto not_empty;
646 if (de->name_len > 2)
647 goto not_empty;
648 if (de->name_len < 2) {
649 if (le64_to_cpu(de->inode_no) !=
650 inode->i_ino)
651 goto not_empty;
652 } else if (de->name[1] != '.')
653 goto not_empty;
654 }
655 de = exofs_next_entry(de);
656 }
657 exofs_put_page(page);
658 }
659 return 1;
660
661 not_empty:
662 exofs_put_page(page);
663 return 0;
664 }
665
666 const struct file_operations exofs_dir_operations = {
667 .llseek = generic_file_llseek,
668 .read = generic_read_dir,
669 .readdir = exofs_readdir,
670 };
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