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btrfs: no need to check for btrfs_fs_devices::seeding
[linux/fpc-iii.git] / fs / exofs / dir.c
blob98233a97b7b87fb43ccb2584f35e38309be978b7
1 /*
2 * Copyright (C) 2005, 2006
3 * Avishay Traeger (avishay@gmail.com)
4 * Copyright (C) 2008, 2009
5 * Boaz Harrosh <ooo@electrozaur.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 put_page(page);
45 }
46
47 static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
48 {
49 loff_t last_byte = inode->i_size;
50
51 last_byte -= page_nr << PAGE_SHIFT;
52 if (last_byte > PAGE_SIZE)
53 last_byte = PAGE_SIZE;
54 return last_byte;
55 }
56
57 static int exofs_commit_chunk(struct page *page, loff_t pos, unsigned len)
58 {
59 struct address_space *mapping = page->mapping;
60 struct inode *dir = mapping->host;
61 int err = 0;
62
63 dir->i_version++;
64
65 if (!PageUptodate(page))
66 SetPageUptodate(page);
67
68 if (pos+len > dir->i_size) {
69 i_size_write(dir, pos+len);
70 mark_inode_dirty(dir);
71 }
72 set_page_dirty(page);
73
74 if (IS_DIRSYNC(dir))
75 err = write_one_page(page);
76 else
77 unlock_page(page);
78
79 return err;
80 }
81
82 static bool exofs_check_page(struct page *page)
83 {
84 struct inode *dir = page->mapping->host;
85 unsigned chunk_size = exofs_chunk_size(dir);
86 char *kaddr = page_address(page);
87 unsigned offs, rec_len;
88 unsigned limit = PAGE_SIZE;
89 struct exofs_dir_entry *p;
90 char *error;
91
92 /* if the page is the last one in the directory */
93 if ((dir->i_size >> PAGE_SHIFT) == page->index) {
94 limit = dir->i_size & ~PAGE_MASK;
95 if (limit & (chunk_size - 1))
96 goto Ebadsize;
97 if (!limit)
98 goto out;
99 }
100 for (offs = 0; offs <= limit - EXOFS_DIR_REC_LEN(1); offs += rec_len) {
101 p = (struct exofs_dir_entry *)(kaddr + offs);
102 rec_len = le16_to_cpu(p->rec_len);
103
104 if (rec_len < EXOFS_DIR_REC_LEN(1))
105 goto Eshort;
106 if (rec_len & 3)
107 goto Ealign;
108 if (rec_len < EXOFS_DIR_REC_LEN(p->name_len))
109 goto Enamelen;
110 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
111 goto Espan;
112 }
113 if (offs != limit)
114 goto Eend;
115 out:
116 SetPageChecked(page);
117 return true;
118
119 Ebadsize:
120 EXOFS_ERR("ERROR [exofs_check_page]: "
121 "size of directory(0x%lx) is not a multiple of chunk size\n",
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 bad_entry:
138 EXOFS_ERR(
139 "ERROR [exofs_check_page]: bad entry in directory(0x%lx): %s - "
140 "offset=%lu, inode=0x%llx, rec_len=%d, name_len=%d\n",
141 dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
142 _LLU(le64_to_cpu(p->inode_no)),
143 rec_len, p->name_len);
144 goto fail;
145 Eend:
146 p = (struct exofs_dir_entry *)(kaddr + offs);
147 EXOFS_ERR("ERROR [exofs_check_page]: "
148 "entry in directory(0x%lx) spans the page boundary"
149 "offset=%lu, inode=0x%llx\n",
150 dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
151 _LLU(le64_to_cpu(p->inode_no)));
152 fail:
153 SetPageError(page);
154 return false;
155 }
156
157 static struct page *exofs_get_page(struct inode *dir, unsigned long n)
158 {
159 struct address_space *mapping = dir->i_mapping;
160 struct page *page = read_mapping_page(mapping, n, NULL);
161
162 if (!IS_ERR(page)) {
163 kmap(page);
164 if (unlikely(!PageChecked(page))) {
165 if (PageError(page) || !exofs_check_page(page))
166 goto fail;
167 }
168 }
169 return page;
170
171 fail:
172 exofs_put_page(page);
173 return ERR_PTR(-EIO);
174 }
175
176 static inline int exofs_match(int len, const unsigned char *name,
177 struct exofs_dir_entry *de)
178 {
179 if (len != de->name_len)
180 return 0;
181 if (!de->inode_no)
182 return 0;
183 return !memcmp(name, de->name, len);
184 }
185
186 static inline
187 struct exofs_dir_entry *exofs_next_entry(struct exofs_dir_entry *p)
188 {
189 return (struct exofs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
190 }
191
192 static inline unsigned
193 exofs_validate_entry(char *base, unsigned offset, unsigned mask)
194 {
195 struct exofs_dir_entry *de = (struct exofs_dir_entry *)(base + offset);
196 struct exofs_dir_entry *p =
197 (struct exofs_dir_entry *)(base + (offset&mask));
198 while ((char *)p < (char *)de) {
199 if (p->rec_len == 0)
200 break;
201 p = exofs_next_entry(p);
202 }
203 return (char *)p - base;
204 }
205
206 static unsigned char exofs_filetype_table[EXOFS_FT_MAX] = {
207 [EXOFS_FT_UNKNOWN] = DT_UNKNOWN,
208 [EXOFS_FT_REG_FILE] = DT_REG,
209 [EXOFS_FT_DIR] = DT_DIR,
210 [EXOFS_FT_CHRDEV] = DT_CHR,
211 [EXOFS_FT_BLKDEV] = DT_BLK,
212 [EXOFS_FT_FIFO] = DT_FIFO,
213 [EXOFS_FT_SOCK] = DT_SOCK,
214 [EXOFS_FT_SYMLINK] = DT_LNK,
215 };
216
217 #define S_SHIFT 12
218 static unsigned char exofs_type_by_mode[S_IFMT >> S_SHIFT] = {
219 [S_IFREG >> S_SHIFT] = EXOFS_FT_REG_FILE,
220 [S_IFDIR >> S_SHIFT] = EXOFS_FT_DIR,
221 [S_IFCHR >> S_SHIFT] = EXOFS_FT_CHRDEV,
222 [S_IFBLK >> S_SHIFT] = EXOFS_FT_BLKDEV,
223 [S_IFIFO >> S_SHIFT] = EXOFS_FT_FIFO,
224 [S_IFSOCK >> S_SHIFT] = EXOFS_FT_SOCK,
225 [S_IFLNK >> S_SHIFT] = EXOFS_FT_SYMLINK,
226 };
227
228 static inline
229 void exofs_set_de_type(struct exofs_dir_entry *de, struct inode *inode)
230 {
231 umode_t mode = inode->i_mode;
232 de->file_type = exofs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
233 }
234
235 static int
236 exofs_readdir(struct file *file, struct dir_context *ctx)
237 {
238 loff_t pos = ctx->pos;
239 struct inode *inode = file_inode(file);
240 unsigned int offset = pos & ~PAGE_MASK;
241 unsigned long n = pos >> PAGE_SHIFT;
242 unsigned long npages = dir_pages(inode);
243 unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
244 int need_revalidate = (file->f_version != inode->i_version);
245
246 if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1))
247 return 0;
248
249 for ( ; n < npages; n++, offset = 0) {
250 char *kaddr, *limit;
251 struct exofs_dir_entry *de;
252 struct page *page = exofs_get_page(inode, n);
253
254 if (IS_ERR(page)) {
255 EXOFS_ERR("ERROR: bad page in directory(0x%lx)\n",
256 inode->i_ino);
257 ctx->pos += PAGE_SIZE - offset;
258 return PTR_ERR(page);
259 }
260 kaddr = page_address(page);
261 if (unlikely(need_revalidate)) {
262 if (offset) {
263 offset = exofs_validate_entry(kaddr, offset,
264 chunk_mask);
265 ctx->pos = (n<<PAGE_SHIFT) + offset;
266 }
267 file->f_version = inode->i_version;
268 need_revalidate = 0;
269 }
270 de = (struct exofs_dir_entry *)(kaddr + offset);
271 limit = kaddr + exofs_last_byte(inode, n) -
272 EXOFS_DIR_REC_LEN(1);
273 for (; (char *)de <= limit; de = exofs_next_entry(de)) {
274 if (de->rec_len == 0) {
275 EXOFS_ERR("ERROR: "
276 "zero-length entry in directory(0x%lx)\n",
277 inode->i_ino);
278 exofs_put_page(page);
279 return -EIO;
280 }
281 if (de->inode_no) {
282 unsigned char t;
283
284 if (de->file_type < EXOFS_FT_MAX)
285 t = exofs_filetype_table[de->file_type];
286 else
287 t = DT_UNKNOWN;
288
289 if (!dir_emit(ctx, de->name, de->name_len,
290 le64_to_cpu(de->inode_no),
291 t)) {
292 exofs_put_page(page);
293 return 0;
294 }
295 }
296 ctx->pos += le16_to_cpu(de->rec_len);
297 }
298 exofs_put_page(page);
299 }
300 return 0;
301 }
302
303 struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
304 struct dentry *dentry, struct page **res_page)
305 {
306 const unsigned char *name = dentry->d_name.name;
307 int namelen = dentry->d_name.len;
308 unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
309 unsigned long start, n;
310 unsigned long npages = dir_pages(dir);
311 struct page *page = NULL;
312 struct exofs_i_info *oi = exofs_i(dir);
313 struct exofs_dir_entry *de;
314
315 if (npages == 0)
316 goto out;
317
318 *res_page = NULL;
319
320 start = oi->i_dir_start_lookup;
321 if (start >= npages)
322 start = 0;
323 n = start;
324 do {
325 char *kaddr;
326 page = exofs_get_page(dir, n);
327 if (!IS_ERR(page)) {
328 kaddr = page_address(page);
329 de = (struct exofs_dir_entry *) kaddr;
330 kaddr += exofs_last_byte(dir, n) - reclen;
331 while ((char *) de <= kaddr) {
332 if (de->rec_len == 0) {
333 EXOFS_ERR("ERROR: zero-length entry in "
334 "directory(0x%lx)\n",
335 dir->i_ino);
336 exofs_put_page(page);
337 goto out;
338 }
339 if (exofs_match(namelen, name, de))
340 goto found;
341 de = exofs_next_entry(de);
342 }
343 exofs_put_page(page);
344 }
345 if (++n >= npages)
346 n = 0;
347 } while (n != start);
348 out:
349 return NULL;
350
351 found:
352 *res_page = page;
353 oi->i_dir_start_lookup = n;
354 return de;
355 }
356
357 struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p)
358 {
359 struct page *page = exofs_get_page(dir, 0);
360 struct exofs_dir_entry *de = NULL;
361
362 if (!IS_ERR(page)) {
363 de = exofs_next_entry(
364 (struct exofs_dir_entry *)page_address(page));
365 *p = page;
366 }
367 return de;
368 }
369
370 ino_t exofs_parent_ino(struct dentry *child)
371 {
372 struct page *page;
373 struct exofs_dir_entry *de;
374 ino_t ino;
375
376 de = exofs_dotdot(d_inode(child), &page);
377 if (!de)
378 return 0;
379
380 ino = le64_to_cpu(de->inode_no);
381 exofs_put_page(page);
382 return ino;
383 }
384
385 ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry)
386 {
387 ino_t res = 0;
388 struct exofs_dir_entry *de;
389 struct page *page;
390
391 de = exofs_find_entry(dir, dentry, &page);
392 if (de) {
393 res = le64_to_cpu(de->inode_no);
394 exofs_put_page(page);
395 }
396 return res;
397 }
398
399 int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de,
400 struct page *page, struct inode *inode)
401 {
402 loff_t pos = page_offset(page) +
403 (char *) de - (char *) page_address(page);
404 unsigned len = le16_to_cpu(de->rec_len);
405 int err;
406
407 lock_page(page);
408 err = exofs_write_begin(NULL, page->mapping, pos, len, 0, &page, NULL);
409 if (err)
410 EXOFS_ERR("exofs_set_link: exofs_write_begin FAILED => %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(dir);
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 = d_inode(dentry->d_parent);
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_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 entry in directory(0x%lx)\n",
463 inode->i_ino);
464 err = -EIO;
465 goto out_unlock;
466 }
467 err = -EEXIST;
468 if (exofs_match(namelen, name, de))
469 goto out_unlock;
470 name_len = EXOFS_DIR_REC_LEN(de->name_len);
471 rec_len = le16_to_cpu(de->rec_len);
472 if (!de->inode_no && rec_len >= reclen)
473 goto got_it;
474 if (rec_len >= name_len + reclen)
475 goto got_it;
476 de = (struct exofs_dir_entry *) ((char *) de + rec_len);
477 }
478 unlock_page(page);
479 exofs_put_page(page);
480 }
481
482 EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=0x%lx\n",
483 dentry, inode->i_ino);
484 return -EINVAL;
485
486 got_it:
487 pos = page_offset(page) +
488 (char *)de - (char *)page_address(page);
489 err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0,
490 &page, NULL);
491 if (err)
492 goto out_unlock;
493 if (de->inode_no) {
494 struct exofs_dir_entry *de1 =
495 (struct exofs_dir_entry *)((char *)de + name_len);
496 de1->rec_len = cpu_to_le16(rec_len - name_len);
497 de->rec_len = cpu_to_le16(name_len);
498 de = de1;
499 }
500 de->name_len = namelen;
501 memcpy(de->name, name, namelen);
502 de->inode_no = cpu_to_le64(inode->i_ino);
503 exofs_set_de_type(de, inode);
504 err = exofs_commit_chunk(page, pos, rec_len);
505 dir->i_mtime = dir->i_ctime = current_time(dir);
506 mark_inode_dirty(dir);
507 sbi->s_numfiles++;
508
509 out_put:
510 exofs_put_page(page);
511 out:
512 return err;
513 out_unlock:
514 unlock_page(page);
515 goto out_put;
516 }
517
518 int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page)
519 {
520 struct address_space *mapping = page->mapping;
521 struct inode *inode = mapping->host;
522 struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
523 char *kaddr = page_address(page);
524 unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1);
525 unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
526 loff_t pos;
527 struct exofs_dir_entry *pde = NULL;
528 struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from);
529 int err;
530
531 while (de < dir) {
532 if (de->rec_len == 0) {
533 EXOFS_ERR("ERROR: exofs_delete_entry:"
534 "zero-length entry in directory(0x%lx)\n",
535 inode->i_ino);
536 err = -EIO;
537 goto out;
538 }
539 pde = de;
540 de = exofs_next_entry(de);
541 }
542 if (pde)
543 from = (char *)pde - (char *)page_address(page);
544 pos = page_offset(page) + from;
545 lock_page(page);
546 err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0,
547 &page, NULL);
548 if (err)
549 EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILED => %d\n",
550 err);
551 if (pde)
552 pde->rec_len = cpu_to_le16(to - from);
553 dir->inode_no = 0;
554 if (likely(!err))
555 err = exofs_commit_chunk(page, pos, to - from);
556 inode->i_ctime = inode->i_mtime = current_time(inode);
557 mark_inode_dirty(inode);
558 sbi->s_numfiles--;
559 out:
560 exofs_put_page(page);
561 return err;
562 }
563
564 /* kept aligned on 4 bytes */
565 #define THIS_DIR ".\0\0"
566 #define PARENT_DIR "..\0"
567
568 int exofs_make_empty(struct inode *inode, struct inode *parent)
569 {
570 struct address_space *mapping = inode->i_mapping;
571 struct page *page = grab_cache_page(mapping, 0);
572 unsigned chunk_size = exofs_chunk_size(inode);
573 struct exofs_dir_entry *de;
574 int err;
575 void *kaddr;
576
577 if (!page)
578 return -ENOMEM;
579
580 err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0,
581 &page, NULL);
582 if (err) {
583 unlock_page(page);
584 goto fail;
585 }
586
587 kaddr = kmap_atomic(page);
588 de = (struct exofs_dir_entry *)kaddr;
589 de->name_len = 1;
590 de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1));
591 memcpy(de->name, THIS_DIR, sizeof(THIS_DIR));
592 de->inode_no = cpu_to_le64(inode->i_ino);
593 exofs_set_de_type(de, inode);
594
595 de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1));
596 de->name_len = 2;
597 de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1));
598 de->inode_no = cpu_to_le64(parent->i_ino);
599 memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
600 exofs_set_de_type(de, inode);
601 kunmap_atomic(kaddr);
602 err = exofs_commit_chunk(page, 0, chunk_size);
603 fail:
604 put_page(page);
605 return err;
606 }
607
608 int exofs_empty_dir(struct inode *inode)
609 {
610 struct page *page = NULL;
611 unsigned long i, npages = dir_pages(inode);
612
613 for (i = 0; i < npages; i++) {
614 char *kaddr;
615 struct exofs_dir_entry *de;
616 page = exofs_get_page(inode, i);
617
618 if (IS_ERR(page))
619 continue;
620
621 kaddr = page_address(page);
622 de = (struct exofs_dir_entry *)kaddr;
623 kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1);
624
625 while ((char *)de <= kaddr) {
626 if (de->rec_len == 0) {
627 EXOFS_ERR("ERROR: exofs_empty_dir: "
628 "zero-length directory entry"
629 "kaddr=%p, de=%p\n", kaddr, de);
630 goto not_empty;
631 }
632 if (de->inode_no != 0) {
633 /* check for . and .. */
634 if (de->name[0] != '.')
635 goto not_empty;
636 if (de->name_len > 2)
637 goto not_empty;
638 if (de->name_len < 2) {
639 if (le64_to_cpu(de->inode_no) !=
640 inode->i_ino)
641 goto not_empty;
642 } else if (de->name[1] != '.')
643 goto not_empty;
644 }
645 de = exofs_next_entry(de);
646 }
647 exofs_put_page(page);
648 }
649 return 1;
650
651 not_empty:
652 exofs_put_page(page);
653 return 0;
654 }
655
656 const struct file_operations exofs_dir_operations = {
657 .llseek = generic_file_llseek,
658 .read = generic_read_dir,
659 .iterate_shared = exofs_readdir,
660 };
Linux with added FPC-III support