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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 <linux/iversion.h>
35#include "exofs.h"
36
37static inline unsigned exofs_chunk_size(struct inode *inode)
38{
39 return inode->i_sb->s_blocksize;
40}
41
42static inline void exofs_put_page(struct page *page)
43{
44 kunmap(page);
45 put_page(page);
46}
47
48static unsigned exofs_last_byte(struct inode *inode, unsigned long page_nr)
49{
50 loff_t last_byte = inode->i_size;
51
52 last_byte -= page_nr << PAGE_SHIFT;
53 if (last_byte > PAGE_SIZE)
54 last_byte = PAGE_SIZE;
55 return last_byte;
56}
57
58static int exofs_commit_chunk(struct page *page, loff_t pos, unsigned len)
59{
60 struct address_space *mapping = page->mapping;
61 struct inode *dir = mapping->host;
62 int err = 0;
63
64 inode_inc_iversion(dir);
65
66 if (!PageUptodate(page))
67 SetPageUptodate(page);
68
69 if (pos+len > dir->i_size) {
70 i_size_write(dir, pos+len);
71 mark_inode_dirty(dir);
72 }
73 set_page_dirty(page);
74
75 if (IS_DIRSYNC(dir))
76 err = write_one_page(page);
77 else
78 unlock_page(page);
79
80 return err;
81}
82
83static bool exofs_check_page(struct page *page)
84{
85 struct inode *dir = page->mapping->host;
86 unsigned chunk_size = exofs_chunk_size(dir);
87 char *kaddr = page_address(page);
88 unsigned offs, rec_len;
89 unsigned limit = PAGE_SIZE;
90 struct exofs_dir_entry *p;
91 char *error;
92
93 /* if the page is the last one in the directory */
94 if ((dir->i_size >> PAGE_SHIFT) == page->index) {
95 limit = dir->i_size & ~PAGE_MASK;
96 if (limit & (chunk_size - 1))
97 goto Ebadsize;
98 if (!limit)
99 goto out;
100 }
101 for (offs = 0; offs <= limit - EXOFS_DIR_REC_LEN(1); offs += rec_len) {
102 p = (struct exofs_dir_entry *)(kaddr + offs);
103 rec_len = le16_to_cpu(p->rec_len);
104
105 if (rec_len < EXOFS_DIR_REC_LEN(1))
106 goto Eshort;
107 if (rec_len & 3)
108 goto Ealign;
109 if (rec_len < EXOFS_DIR_REC_LEN(p->name_len))
110 goto Enamelen;
111 if (((offs + rec_len - 1) ^ offs) & ~(chunk_size-1))
112 goto Espan;
113 }
114 if (offs != limit)
115 goto Eend;
116out:
117 SetPageChecked(page);
118 return true;
119
120Ebadsize:
121 EXOFS_ERR("ERROR [exofs_check_page]: "
122 "size of directory(0x%lx) is not a multiple of chunk size\n",
123 dir->i_ino
124 );
125 goto fail;
126Eshort:
127 error = "rec_len is smaller than minimal";
128 goto bad_entry;
129Ealign:
130 error = "unaligned directory entry";
131 goto bad_entry;
132Enamelen:
133 error = "rec_len is too small for name_len";
134 goto bad_entry;
135Espan:
136 error = "directory entry across blocks";
137 goto bad_entry;
138bad_entry:
139 EXOFS_ERR(
140 "ERROR [exofs_check_page]: bad entry in directory(0x%lx): %s - "
141 "offset=%lu, inode=0x%llx, rec_len=%d, name_len=%d\n",
142 dir->i_ino, error, (page->index<<PAGE_SHIFT)+offs,
143 _LLU(le64_to_cpu(p->inode_no)),
144 rec_len, p->name_len);
145 goto fail;
146Eend:
147 p = (struct exofs_dir_entry *)(kaddr + offs);
148 EXOFS_ERR("ERROR [exofs_check_page]: "
149 "entry in directory(0x%lx) spans the page boundary"
150 "offset=%lu, inode=0x%llx\n",
151 dir->i_ino, (page->index<<PAGE_SHIFT)+offs,
152 _LLU(le64_to_cpu(p->inode_no)));
153fail:
154 SetPageError(page);
155 return false;
156}
157
158static struct page *exofs_get_page(struct inode *dir, unsigned long n)
159{
160 struct address_space *mapping = dir->i_mapping;
161 struct page *page = read_mapping_page(mapping, n, NULL);
162
163 if (!IS_ERR(page)) {
164 kmap(page);
165 if (unlikely(!PageChecked(page))) {
166 if (PageError(page) || !exofs_check_page(page))
167 goto fail;
168 }
169 }
170 return page;
171
172fail:
173 exofs_put_page(page);
174 return ERR_PTR(-EIO);
175}
176
177static inline int exofs_match(int len, const unsigned char *name,
178 struct exofs_dir_entry *de)
179{
180 if (len != de->name_len)
181 return 0;
182 if (!de->inode_no)
183 return 0;
184 return !memcmp(name, de->name, len);
185}
186
187static inline
188struct exofs_dir_entry *exofs_next_entry(struct exofs_dir_entry *p)
189{
190 return (struct exofs_dir_entry *)((char *)p + le16_to_cpu(p->rec_len));
191}
192
193static inline unsigned
194exofs_validate_entry(char *base, unsigned offset, unsigned mask)
195{
196 struct exofs_dir_entry *de = (struct exofs_dir_entry *)(base + offset);
197 struct exofs_dir_entry *p =
198 (struct exofs_dir_entry *)(base + (offset&mask));
199 while ((char *)p < (char *)de) {
200 if (p->rec_len == 0)
201 break;
202 p = exofs_next_entry(p);
203 }
204 return (char *)p - base;
205}
206
207static unsigned char exofs_filetype_table[EXOFS_FT_MAX] = {
208 [EXOFS_FT_UNKNOWN] = DT_UNKNOWN,
209 [EXOFS_FT_REG_FILE] = DT_REG,
210 [EXOFS_FT_DIR] = DT_DIR,
211 [EXOFS_FT_CHRDEV] = DT_CHR,
212 [EXOFS_FT_BLKDEV] = DT_BLK,
213 [EXOFS_FT_FIFO] = DT_FIFO,
214 [EXOFS_FT_SOCK] = DT_SOCK,
215 [EXOFS_FT_SYMLINK] = DT_LNK,
216};
217
218#define S_SHIFT 12
219static unsigned char exofs_type_by_mode[S_IFMT >> S_SHIFT] = {
220 [S_IFREG >> S_SHIFT] = EXOFS_FT_REG_FILE,
221 [S_IFDIR >> S_SHIFT] = EXOFS_FT_DIR,
222 [S_IFCHR >> S_SHIFT] = EXOFS_FT_CHRDEV,
223 [S_IFBLK >> S_SHIFT] = EXOFS_FT_BLKDEV,
224 [S_IFIFO >> S_SHIFT] = EXOFS_FT_FIFO,
225 [S_IFSOCK >> S_SHIFT] = EXOFS_FT_SOCK,
226 [S_IFLNK >> S_SHIFT] = EXOFS_FT_SYMLINK,
227};
228
229static inline
230void exofs_set_de_type(struct exofs_dir_entry *de, struct inode *inode)
231{
232 umode_t mode = inode->i_mode;
233 de->file_type = exofs_type_by_mode[(mode & S_IFMT) >> S_SHIFT];
234}
235
236static int
237exofs_readdir(struct file *file, struct dir_context *ctx)
238{
239 loff_t pos = ctx->pos;
240 struct inode *inode = file_inode(file);
241 unsigned int offset = pos & ~PAGE_MASK;
242 unsigned long n = pos >> PAGE_SHIFT;
243 unsigned long npages = dir_pages(inode);
244 unsigned chunk_mask = ~(exofs_chunk_size(inode)-1);
245 bool need_revalidate = !inode_eq_iversion(inode, file->f_version);
246
247 if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1))
248 return 0;
249
250 for ( ; n < npages; n++, offset = 0) {
251 char *kaddr, *limit;
252 struct exofs_dir_entry *de;
253 struct page *page = exofs_get_page(inode, n);
254
255 if (IS_ERR(page)) {
256 EXOFS_ERR("ERROR: bad page in directory(0x%lx)\n",
257 inode->i_ino);
258 ctx->pos += PAGE_SIZE - offset;
259 return PTR_ERR(page);
260 }
261 kaddr = page_address(page);
262 if (unlikely(need_revalidate)) {
263 if (offset) {
264 offset = exofs_validate_entry(kaddr, offset,
265 chunk_mask);
266 ctx->pos = (n<<PAGE_SHIFT) + offset;
267 }
268 file->f_version = inode_query_iversion(inode);
269 need_revalidate = false;
270 }
271 de = (struct exofs_dir_entry *)(kaddr + offset);
272 limit = kaddr + exofs_last_byte(inode, n) -
273 EXOFS_DIR_REC_LEN(1);
274 for (; (char *)de <= limit; de = exofs_next_entry(de)) {
275 if (de->rec_len == 0) {
276 EXOFS_ERR("ERROR: "
277 "zero-length entry in directory(0x%lx)\n",
278 inode->i_ino);
279 exofs_put_page(page);
280 return -EIO;
281 }
282 if (de->inode_no) {
283 unsigned char t;
284
285 if (de->file_type < EXOFS_FT_MAX)
286 t = exofs_filetype_table[de->file_type];
287 else
288 t = DT_UNKNOWN;
289
290 if (!dir_emit(ctx, de->name, de->name_len,
291 le64_to_cpu(de->inode_no),
292 t)) {
293 exofs_put_page(page);
294 return 0;
295 }
296 }
297 ctx->pos += le16_to_cpu(de->rec_len);
298 }
299 exofs_put_page(page);
300 }
301 return 0;
302}
303
304struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
305 struct dentry *dentry, struct page **res_page)
306{
307 const unsigned char *name = dentry->d_name.name;
308 int namelen = dentry->d_name.len;
309 unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
310 unsigned long start, n;
311 unsigned long npages = dir_pages(dir);
312 struct page *page = NULL;
313 struct exofs_i_info *oi = exofs_i(dir);
314 struct exofs_dir_entry *de;
315
316 if (npages == 0)
317 goto out;
318
319 *res_page = NULL;
320
321 start = oi->i_dir_start_lookup;
322 if (start >= npages)
323 start = 0;
324 n = start;
325 do {
326 char *kaddr;
327 page = exofs_get_page(dir, n);
328 if (!IS_ERR(page)) {
329 kaddr = page_address(page);
330 de = (struct exofs_dir_entry *) kaddr;
331 kaddr += exofs_last_byte(dir, n) - reclen;
332 while ((char *) de <= kaddr) {
333 if (de->rec_len == 0) {
334 EXOFS_ERR("ERROR: zero-length entry in "
335 "directory(0x%lx)\n",
336 dir->i_ino);
337 exofs_put_page(page);
338 goto out;
339 }
340 if (exofs_match(namelen, name, de))
341 goto found;
342 de = exofs_next_entry(de);
343 }
344 exofs_put_page(page);
345 }
346 if (++n >= npages)
347 n = 0;
348 } while (n != start);
349out:
350 return NULL;
351
352found:
353 *res_page = page;
354 oi->i_dir_start_lookup = n;
355 return de;
356}
357
358struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p)
359{
360 struct page *page = exofs_get_page(dir, 0);
361 struct exofs_dir_entry *de = NULL;
362
363 if (!IS_ERR(page)) {
364 de = exofs_next_entry(
365 (struct exofs_dir_entry *)page_address(page));
366 *p = page;
367 }
368 return de;
369}
370
371ino_t exofs_parent_ino(struct dentry *child)
372{
373 struct page *page;
374 struct exofs_dir_entry *de;
375 ino_t ino;
376
377 de = exofs_dotdot(d_inode(child), &page);
378 if (!de)
379 return 0;
380
381 ino = le64_to_cpu(de->inode_no);
382 exofs_put_page(page);
383 return ino;
384}
385
386ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry)
387{
388 ino_t res = 0;
389 struct exofs_dir_entry *de;
390 struct page *page;
391
392 de = exofs_find_entry(dir, dentry, &page);
393 if (de) {
394 res = le64_to_cpu(de->inode_no);
395 exofs_put_page(page);
396 }
397 return res;
398}
399
400int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de,
401 struct page *page, struct inode *inode)
402{
403 loff_t pos = page_offset(page) +
404 (char *) de - (char *) page_address(page);
405 unsigned len = le16_to_cpu(de->rec_len);
406 int err;
407
408 lock_page(page);
409 err = exofs_write_begin(NULL, page->mapping, pos, len, 0, &page, NULL);
410 if (err)
411 EXOFS_ERR("exofs_set_link: exofs_write_begin FAILED => %d\n",
412 err);
413
414 de->inode_no = cpu_to_le64(inode->i_ino);
415 exofs_set_de_type(de, inode);
416 if (likely(!err))
417 err = exofs_commit_chunk(page, pos, len);
418 exofs_put_page(page);
419 dir->i_mtime = dir->i_ctime = current_time(dir);
420 mark_inode_dirty(dir);
421 return err;
422}
423
424int exofs_add_link(struct dentry *dentry, struct inode *inode)
425{
426 struct inode *dir = d_inode(dentry->d_parent);
427 const unsigned char *name = dentry->d_name.name;
428 int namelen = dentry->d_name.len;
429 unsigned chunk_size = exofs_chunk_size(dir);
430 unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
431 unsigned short rec_len, name_len;
432 struct page *page = NULL;
433 struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
434 struct exofs_dir_entry *de;
435 unsigned long npages = dir_pages(dir);
436 unsigned long n;
437 char *kaddr;
438 loff_t pos;
439 int err;
440
441 for (n = 0; n <= npages; n++) {
442 char *dir_end;
443
444 page = exofs_get_page(dir, n);
445 err = PTR_ERR(page);
446 if (IS_ERR(page))
447 goto out;
448 lock_page(page);
449 kaddr = page_address(page);
450 dir_end = kaddr + exofs_last_byte(dir, n);
451 de = (struct exofs_dir_entry *)kaddr;
452 kaddr += PAGE_SIZE - reclen;
453 while ((char *)de <= kaddr) {
454 if ((char *)de == dir_end) {
455 name_len = 0;
456 rec_len = chunk_size;
457 de->rec_len = cpu_to_le16(chunk_size);
458 de->inode_no = 0;
459 goto got_it;
460 }
461 if (de->rec_len == 0) {
462 EXOFS_ERR("ERROR: exofs_add_link: "
463 "zero-length entry in directory(0x%lx)\n",
464 inode->i_ino);
465 err = -EIO;
466 goto out_unlock;
467 }
468 err = -EEXIST;
469 if (exofs_match(namelen, name, de))
470 goto out_unlock;
471 name_len = EXOFS_DIR_REC_LEN(de->name_len);
472 rec_len = le16_to_cpu(de->rec_len);
473 if (!de->inode_no && rec_len >= reclen)
474 goto got_it;
475 if (rec_len >= name_len + reclen)
476 goto got_it;
477 de = (struct exofs_dir_entry *) ((char *) de + rec_len);
478 }
479 unlock_page(page);
480 exofs_put_page(page);
481 }
482
483 EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=0x%lx\n",
484 dentry, inode->i_ino);
485 return -EINVAL;
486
487got_it:
488 pos = page_offset(page) +
489 (char *)de - (char *)page_address(page);
490 err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0,
491 &page, NULL);
492 if (err)
493 goto out_unlock;
494 if (de->inode_no) {
495 struct exofs_dir_entry *de1 =
496 (struct exofs_dir_entry *)((char *)de + name_len);
497 de1->rec_len = cpu_to_le16(rec_len - name_len);
498 de->rec_len = cpu_to_le16(name_len);
499 de = de1;
500 }
501 de->name_len = namelen;
502 memcpy(de->name, name, namelen);
503 de->inode_no = cpu_to_le64(inode->i_ino);
504 exofs_set_de_type(de, inode);
505 err = exofs_commit_chunk(page, pos, rec_len);
506 dir->i_mtime = dir->i_ctime = current_time(dir);
507 mark_inode_dirty(dir);
508 sbi->s_numfiles++;
509
510out_put:
511 exofs_put_page(page);
512out:
513 return err;
514out_unlock:
515 unlock_page(page);
516 goto out_put;
517}
518
519int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page)
520{
521 struct address_space *mapping = page->mapping;
522 struct inode *inode = mapping->host;
523 struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
524 char *kaddr = page_address(page);
525 unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1);
526 unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
527 loff_t pos;
528 struct exofs_dir_entry *pde = NULL;
529 struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from);
530 int err;
531
532 while (de < dir) {
533 if (de->rec_len == 0) {
534 EXOFS_ERR("ERROR: exofs_delete_entry:"
535 "zero-length entry in directory(0x%lx)\n",
536 inode->i_ino);
537 err = -EIO;
538 goto out;
539 }
540 pde = de;
541 de = exofs_next_entry(de);
542 }
543 if (pde)
544 from = (char *)pde - (char *)page_address(page);
545 pos = page_offset(page) + from;
546 lock_page(page);
547 err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0,
548 &page, NULL);
549 if (err)
550 EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILED => %d\n",
551 err);
552 if (pde)
553 pde->rec_len = cpu_to_le16(to - from);
554 dir->inode_no = 0;
555 if (likely(!err))
556 err = exofs_commit_chunk(page, pos, to - from);
557 inode->i_ctime = inode->i_mtime = current_time(inode);
558 mark_inode_dirty(inode);
559 sbi->s_numfiles--;
560out:
561 exofs_put_page(page);
562 return err;
563}
564
565/* kept aligned on 4 bytes */
566#define THIS_DIR ".\0\0"
567#define PARENT_DIR "..\0"
568
569int exofs_make_empty(struct inode *inode, struct inode *parent)
570{
571 struct address_space *mapping = inode->i_mapping;
572 struct page *page = grab_cache_page(mapping, 0);
573 unsigned chunk_size = exofs_chunk_size(inode);
574 struct exofs_dir_entry *de;
575 int err;
576 void *kaddr;
577
578 if (!page)
579 return -ENOMEM;
580
581 err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0,
582 &page, NULL);
583 if (err) {
584 unlock_page(page);
585 goto fail;
586 }
587
588 kaddr = kmap_atomic(page);
589 de = (struct exofs_dir_entry *)kaddr;
590 de->name_len = 1;
591 de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1));
592 memcpy(de->name, THIS_DIR, sizeof(THIS_DIR));
593 de->inode_no = cpu_to_le64(inode->i_ino);
594 exofs_set_de_type(de, inode);
595
596 de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1));
597 de->name_len = 2;
598 de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1));
599 de->inode_no = cpu_to_le64(parent->i_ino);
600 memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
601 exofs_set_de_type(de, inode);
602 kunmap_atomic(kaddr);
603 err = exofs_commit_chunk(page, 0, chunk_size);
604fail:
605 put_page(page);
606 return err;
607}
608
609int exofs_empty_dir(struct inode *inode)
610{
611 struct page *page = NULL;
612 unsigned long i, npages = dir_pages(inode);
613
614 for (i = 0; i < npages; i++) {
615 char *kaddr;
616 struct exofs_dir_entry *de;
617 page = exofs_get_page(inode, i);
618
619 if (IS_ERR(page))
620 continue;
621
622 kaddr = page_address(page);
623 de = (struct exofs_dir_entry *)kaddr;
624 kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1);
625
626 while ((char *)de <= kaddr) {
627 if (de->rec_len == 0) {
628 EXOFS_ERR("ERROR: exofs_empty_dir: "
629 "zero-length directory entry"
630 "kaddr=%p, de=%p\n", kaddr, de);
631 goto not_empty;
632 }
633 if (de->inode_no != 0) {
634 /* check for . and .. */
635 if (de->name[0] != '.')
636 goto not_empty;
637 if (de->name_len > 2)
638 goto not_empty;
639 if (de->name_len < 2) {
640 if (le64_to_cpu(de->inode_no) !=
641 inode->i_ino)
642 goto not_empty;
643 } else if (de->name[1] != '.')
644 goto not_empty;
645 }
646 de = exofs_next_entry(de);
647 }
648 exofs_put_page(page);
649 }
650 return 1;
651
652not_empty:
653 exofs_put_page(page);
654 return 0;
655}
656
657const struct file_operations exofs_dir_operations = {
658 .llseek = generic_file_llseek,
659 .read = generic_read_dir,
660 .iterate_shared = exofs_readdir,
661};