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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 "exofs.h"
35
36static inline unsigned exofs_chunk_size(struct inode *inode)
37{
38 return inode->i_sb->s_blocksize;
39}
40
41static inline void exofs_put_page(struct page *page)
42{
43 kunmap(page);
44 put_page(page);
45}
46
47static 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
57static 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, 1);
76 else
77 unlock_page(page);
78
79 return err;
80}
81
82static 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;
115out:
116 SetPageChecked(page);
117 return true;
118
119Ebadsize:
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;
125Eshort:
126 error = "rec_len is smaller than minimal";
127 goto bad_entry;
128Ealign:
129 error = "unaligned directory entry";
130 goto bad_entry;
131Enamelen:
132 error = "rec_len is too small for name_len";
133 goto bad_entry;
134Espan:
135 error = "directory entry across blocks";
136 goto bad_entry;
137bad_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;
145Eend:
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)));
152fail:
153 SetPageError(page);
154 return false;
155}
156
157static 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
171fail:
172 exofs_put_page(page);
173 return ERR_PTR(-EIO);
174}
175
176static 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
186static inline
187struct 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
192static inline unsigned
193exofs_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
206static 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
218static 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
228static inline
229void 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
235static int
236exofs_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
303struct 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);
348out:
349 return NULL;
350
351found:
352 *res_page = page;
353 oi->i_dir_start_lookup = n;
354 return de;
355}
356
357struct 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
370ino_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
385ino_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
399int 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,
409 AOP_FLAG_UNINTERRUPTIBLE, &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};