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Linux 3.16-rc2
[linux/fpc-iii.git] / fs / exofs / dir.c
blob49f51ab4caac7689d48049790eae2e0b22d4c082
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(0x%lx) is not a multiple of chunk size\n",
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(0x%lx): %s - "
146 "offset=%lu, inode=0x%llu, rec_len=%d, name_len=%d\n",
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(0x%lx) spans the page boundary"
155 "offset=%lu, inode=0x%llx\n",
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 umode_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 *file, struct dir_context *ctx)
243 {
244 loff_t pos = ctx->pos;
245 struct inode *inode = file_inode(file);
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 int need_revalidate = (file->f_version != inode->i_version);
251
252 if (pos > inode->i_size - EXOFS_DIR_REC_LEN(1))
253 return 0;
254
255 for ( ; n < npages; n++, offset = 0) {
256 char *kaddr, *limit;
257 struct exofs_dir_entry *de;
258 struct page *page = exofs_get_page(inode, n);
259
260 if (IS_ERR(page)) {
261 EXOFS_ERR("ERROR: bad page in directory(0x%lx)\n",
262 inode->i_ino);
263 ctx->pos += PAGE_CACHE_SIZE - offset;
264 return PTR_ERR(page);
265 }
266 kaddr = page_address(page);
267 if (unlikely(need_revalidate)) {
268 if (offset) {
269 offset = exofs_validate_entry(kaddr, offset,
270 chunk_mask);
271 ctx->pos = (n<<PAGE_CACHE_SHIFT) + offset;
272 }
273 file->f_version = inode->i_version;
274 need_revalidate = 0;
275 }
276 de = (struct exofs_dir_entry *)(kaddr + offset);
277 limit = kaddr + exofs_last_byte(inode, n) -
278 EXOFS_DIR_REC_LEN(1);
279 for (; (char *)de <= limit; de = exofs_next_entry(de)) {
280 if (de->rec_len == 0) {
281 EXOFS_ERR("ERROR: "
282 "zero-length entry in directory(0x%lx)\n",
283 inode->i_ino);
284 exofs_put_page(page);
285 return -EIO;
286 }
287 if (de->inode_no) {
288 unsigned char t;
289
290 if (de->file_type < EXOFS_FT_MAX)
291 t = exofs_filetype_table[de->file_type];
292 else
293 t = DT_UNKNOWN;
294
295 if (!dir_emit(ctx, de->name, de->name_len,
296 le64_to_cpu(de->inode_no),
297 t)) {
298 exofs_put_page(page);
299 return 0;
300 }
301 }
302 ctx->pos += le16_to_cpu(de->rec_len);
303 }
304 exofs_put_page(page);
305 }
306 return 0;
307 }
308
309 struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
310 struct dentry *dentry, struct page **res_page)
311 {
312 const unsigned char *name = dentry->d_name.name;
313 int namelen = dentry->d_name.len;
314 unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
315 unsigned long start, n;
316 unsigned long npages = dir_pages(dir);
317 struct page *page = NULL;
318 struct exofs_i_info *oi = exofs_i(dir);
319 struct exofs_dir_entry *de;
320
321 if (npages == 0)
322 goto out;
323
324 *res_page = NULL;
325
326 start = oi->i_dir_start_lookup;
327 if (start >= npages)
328 start = 0;
329 n = start;
330 do {
331 char *kaddr;
332 page = exofs_get_page(dir, n);
333 if (!IS_ERR(page)) {
334 kaddr = page_address(page);
335 de = (struct exofs_dir_entry *) kaddr;
336 kaddr += exofs_last_byte(dir, n) - reclen;
337 while ((char *) de <= kaddr) {
338 if (de->rec_len == 0) {
339 EXOFS_ERR("ERROR: zero-length entry in "
340 "directory(0x%lx)\n",
341 dir->i_ino);
342 exofs_put_page(page);
343 goto out;
344 }
345 if (exofs_match(namelen, name, de))
346 goto found;
347 de = exofs_next_entry(de);
348 }
349 exofs_put_page(page);
350 }
351 if (++n >= npages)
352 n = 0;
353 } while (n != start);
354 out:
355 return NULL;
356
357 found:
358 *res_page = page;
359 oi->i_dir_start_lookup = n;
360 return de;
361 }
362
363 struct exofs_dir_entry *exofs_dotdot(struct inode *dir, struct page **p)
364 {
365 struct page *page = exofs_get_page(dir, 0);
366 struct exofs_dir_entry *de = NULL;
367
368 if (!IS_ERR(page)) {
369 de = exofs_next_entry(
370 (struct exofs_dir_entry *)page_address(page));
371 *p = page;
372 }
373 return de;
374 }
375
376 ino_t exofs_parent_ino(struct dentry *child)
377 {
378 struct page *page;
379 struct exofs_dir_entry *de;
380 ino_t ino;
381
382 de = exofs_dotdot(child->d_inode, &page);
383 if (!de)
384 return 0;
385
386 ino = le64_to_cpu(de->inode_no);
387 exofs_put_page(page);
388 return ino;
389 }
390
391 ino_t exofs_inode_by_name(struct inode *dir, struct dentry *dentry)
392 {
393 ino_t res = 0;
394 struct exofs_dir_entry *de;
395 struct page *page;
396
397 de = exofs_find_entry(dir, dentry, &page);
398 if (de) {
399 res = le64_to_cpu(de->inode_no);
400 exofs_put_page(page);
401 }
402 return res;
403 }
404
405 int exofs_set_link(struct inode *dir, struct exofs_dir_entry *de,
406 struct page *page, struct inode *inode)
407 {
408 loff_t pos = page_offset(page) +
409 (char *) de - (char *) page_address(page);
410 unsigned len = le16_to_cpu(de->rec_len);
411 int err;
412
413 lock_page(page);
414 err = exofs_write_begin(NULL, page->mapping, pos, len,
415 AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
416 if (err)
417 EXOFS_ERR("exofs_set_link: exofs_write_begin FAILED => %d\n",
418 err);
419
420 de->inode_no = cpu_to_le64(inode->i_ino);
421 exofs_set_de_type(de, inode);
422 if (likely(!err))
423 err = exofs_commit_chunk(page, pos, len);
424 exofs_put_page(page);
425 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
426 mark_inode_dirty(dir);
427 return err;
428 }
429
430 int exofs_add_link(struct dentry *dentry, struct inode *inode)
431 {
432 struct inode *dir = dentry->d_parent->d_inode;
433 const unsigned char *name = dentry->d_name.name;
434 int namelen = dentry->d_name.len;
435 unsigned chunk_size = exofs_chunk_size(dir);
436 unsigned reclen = EXOFS_DIR_REC_LEN(namelen);
437 unsigned short rec_len, name_len;
438 struct page *page = NULL;
439 struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
440 struct exofs_dir_entry *de;
441 unsigned long npages = dir_pages(dir);
442 unsigned long n;
443 char *kaddr;
444 loff_t pos;
445 int err;
446
447 for (n = 0; n <= npages; n++) {
448 char *dir_end;
449
450 page = exofs_get_page(dir, n);
451 err = PTR_ERR(page);
452 if (IS_ERR(page))
453 goto out;
454 lock_page(page);
455 kaddr = page_address(page);
456 dir_end = kaddr + exofs_last_byte(dir, n);
457 de = (struct exofs_dir_entry *)kaddr;
458 kaddr += PAGE_CACHE_SIZE - reclen;
459 while ((char *)de <= kaddr) {
460 if ((char *)de == dir_end) {
461 name_len = 0;
462 rec_len = chunk_size;
463 de->rec_len = cpu_to_le16(chunk_size);
464 de->inode_no = 0;
465 goto got_it;
466 }
467 if (de->rec_len == 0) {
468 EXOFS_ERR("ERROR: exofs_add_link: "
469 "zero-length entry in directory(0x%lx)\n",
470 inode->i_ino);
471 err = -EIO;
472 goto out_unlock;
473 }
474 err = -EEXIST;
475 if (exofs_match(namelen, name, de))
476 goto out_unlock;
477 name_len = EXOFS_DIR_REC_LEN(de->name_len);
478 rec_len = le16_to_cpu(de->rec_len);
479 if (!de->inode_no && rec_len >= reclen)
480 goto got_it;
481 if (rec_len >= name_len + reclen)
482 goto got_it;
483 de = (struct exofs_dir_entry *) ((char *) de + rec_len);
484 }
485 unlock_page(page);
486 exofs_put_page(page);
487 }
488
489 EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=0x%lx\n",
490 dentry, inode->i_ino);
491 return -EINVAL;
492
493 got_it:
494 pos = page_offset(page) +
495 (char *)de - (char *)page_address(page);
496 err = exofs_write_begin(NULL, page->mapping, pos, rec_len, 0,
497 &page, NULL);
498 if (err)
499 goto out_unlock;
500 if (de->inode_no) {
501 struct exofs_dir_entry *de1 =
502 (struct exofs_dir_entry *)((char *)de + name_len);
503 de1->rec_len = cpu_to_le16(rec_len - name_len);
504 de->rec_len = cpu_to_le16(name_len);
505 de = de1;
506 }
507 de->name_len = namelen;
508 memcpy(de->name, name, namelen);
509 de->inode_no = cpu_to_le64(inode->i_ino);
510 exofs_set_de_type(de, inode);
511 err = exofs_commit_chunk(page, pos, rec_len);
512 dir->i_mtime = dir->i_ctime = CURRENT_TIME;
513 mark_inode_dirty(dir);
514 sbi->s_numfiles++;
515
516 out_put:
517 exofs_put_page(page);
518 out:
519 return err;
520 out_unlock:
521 unlock_page(page);
522 goto out_put;
523 }
524
525 int exofs_delete_entry(struct exofs_dir_entry *dir, struct page *page)
526 {
527 struct address_space *mapping = page->mapping;
528 struct inode *inode = mapping->host;
529 struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;
530 char *kaddr = page_address(page);
531 unsigned from = ((char *)dir - kaddr) & ~(exofs_chunk_size(inode)-1);
532 unsigned to = ((char *)dir - kaddr) + le16_to_cpu(dir->rec_len);
533 loff_t pos;
534 struct exofs_dir_entry *pde = NULL;
535 struct exofs_dir_entry *de = (struct exofs_dir_entry *) (kaddr + from);
536 int err;
537
538 while (de < dir) {
539 if (de->rec_len == 0) {
540 EXOFS_ERR("ERROR: exofs_delete_entry:"
541 "zero-length entry in directory(0x%lx)\n",
542 inode->i_ino);
543 err = -EIO;
544 goto out;
545 }
546 pde = de;
547 de = exofs_next_entry(de);
548 }
549 if (pde)
550 from = (char *)pde - (char *)page_address(page);
551 pos = page_offset(page) + from;
552 lock_page(page);
553 err = exofs_write_begin(NULL, page->mapping, pos, to - from, 0,
554 &page, NULL);
555 if (err)
556 EXOFS_ERR("exofs_delete_entry: exofs_write_begin FAILED => %d\n",
557 err);
558 if (pde)
559 pde->rec_len = cpu_to_le16(to - from);
560 dir->inode_no = 0;
561 if (likely(!err))
562 err = exofs_commit_chunk(page, pos, to - from);
563 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
564 mark_inode_dirty(inode);
565 sbi->s_numfiles--;
566 out:
567 exofs_put_page(page);
568 return err;
569 }
570
571 /* kept aligned on 4 bytes */
572 #define THIS_DIR ".\0\0"
573 #define PARENT_DIR "..\0"
574
575 int exofs_make_empty(struct inode *inode, struct inode *parent)
576 {
577 struct address_space *mapping = inode->i_mapping;
578 struct page *page = grab_cache_page(mapping, 0);
579 unsigned chunk_size = exofs_chunk_size(inode);
580 struct exofs_dir_entry *de;
581 int err;
582 void *kaddr;
583
584 if (!page)
585 return -ENOMEM;
586
587 err = exofs_write_begin(NULL, page->mapping, 0, chunk_size, 0,
588 &page, NULL);
589 if (err) {
590 unlock_page(page);
591 goto fail;
592 }
593
594 kaddr = kmap_atomic(page);
595 de = (struct exofs_dir_entry *)kaddr;
596 de->name_len = 1;
597 de->rec_len = cpu_to_le16(EXOFS_DIR_REC_LEN(1));
598 memcpy(de->name, THIS_DIR, sizeof(THIS_DIR));
599 de->inode_no = cpu_to_le64(inode->i_ino);
600 exofs_set_de_type(de, inode);
601
602 de = (struct exofs_dir_entry *)(kaddr + EXOFS_DIR_REC_LEN(1));
603 de->name_len = 2;
604 de->rec_len = cpu_to_le16(chunk_size - EXOFS_DIR_REC_LEN(1));
605 de->inode_no = cpu_to_le64(parent->i_ino);
606 memcpy(de->name, PARENT_DIR, sizeof(PARENT_DIR));
607 exofs_set_de_type(de, inode);
608 kunmap_atomic(kaddr);
609 err = exofs_commit_chunk(page, 0, chunk_size);
610 fail:
611 page_cache_release(page);
612 return err;
613 }
614
615 int exofs_empty_dir(struct inode *inode)
616 {
617 struct page *page = NULL;
618 unsigned long i, npages = dir_pages(inode);
619
620 for (i = 0; i < npages; i++) {
621 char *kaddr;
622 struct exofs_dir_entry *de;
623 page = exofs_get_page(inode, i);
624
625 if (IS_ERR(page))
626 continue;
627
628 kaddr = page_address(page);
629 de = (struct exofs_dir_entry *)kaddr;
630 kaddr += exofs_last_byte(inode, i) - EXOFS_DIR_REC_LEN(1);
631
632 while ((char *)de <= kaddr) {
633 if (de->rec_len == 0) {
634 EXOFS_ERR("ERROR: exofs_empty_dir: "
635 "zero-length directory entry"
636 "kaddr=%p, de=%p\n", kaddr, de);
637 goto not_empty;
638 }
639 if (de->inode_no != 0) {
640 /* check for . and .. */
641 if (de->name[0] != '.')
642 goto not_empty;
643 if (de->name_len > 2)
644 goto not_empty;
645 if (de->name_len < 2) {
646 if (le64_to_cpu(de->inode_no) !=
647 inode->i_ino)
648 goto not_empty;
649 } else if (de->name[1] != '.')
650 goto not_empty;
651 }
652 de = exofs_next_entry(de);
653 }
654 exofs_put_page(page);
655 }
656 return 1;
657
658 not_empty:
659 exofs_put_page(page);
660 return 0;
661 }
662
663 const struct file_operations exofs_dir_operations = {
664 .llseek = generic_file_llseek,
665 .read = generic_read_dir,
666 .iterate = exofs_readdir,
667 };
Linux with added FPC-III support