Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6
[deliverable/linux.git] / fs / fat / namei_msdos.c
1 /*
2 * linux/fs/msdos/namei.c
3 *
4 * Written 1992,1993 by Werner Almesberger
5 * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
6 * Rewritten for constant inumbers 1999 by Al Viro
7 */
8
9 #include <linux/module.h>
10 #include <linux/time.h>
11 #include <linux/buffer_head.h>
12 #include "fat.h"
13
14 /* Characters that are undesirable in an MS-DOS file name */
15 static unsigned char bad_chars[] = "*?<>|\"";
16 static unsigned char bad_if_strict[] = "+=,; ";
17
18 /***** Formats an MS-DOS file name. Rejects invalid names. */
19 static int msdos_format_name(const unsigned char *name, int len,
20 unsigned char *res, struct fat_mount_options *opts)
21 /*
22 * name is the proposed name, len is its length, res is
23 * the resulting name, opts->name_check is either (r)elaxed,
24 * (n)ormal or (s)trict, opts->dotsOK allows dots at the
25 * beginning of name (for hidden files)
26 */
27 {
28 unsigned char *walk;
29 unsigned char c;
30 int space;
31
32 if (name[0] == '.') { /* dotfile because . and .. already done */
33 if (opts->dotsOK) {
34 /* Get rid of dot - test for it elsewhere */
35 name++;
36 len--;
37 } else
38 return -EINVAL;
39 }
40 /*
41 * disallow names that _really_ start with a dot
42 */
43 space = 1;
44 c = 0;
45 for (walk = res; len && walk - res < 8; walk++) {
46 c = *name++;
47 len--;
48 if (opts->name_check != 'r' && strchr(bad_chars, c))
49 return -EINVAL;
50 if (opts->name_check == 's' && strchr(bad_if_strict, c))
51 return -EINVAL;
52 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
53 return -EINVAL;
54 if (c < ' ' || c == ':' || c == '\\')
55 return -EINVAL;
56 /*
57 * 0xE5 is legal as a first character, but we must substitute
58 * 0x05 because 0xE5 marks deleted files. Yes, DOS really
59 * does this.
60 * It seems that Microsoft hacked DOS to support non-US
61 * characters after the 0xE5 character was already in use to
62 * mark deleted files.
63 */
64 if ((res == walk) && (c == 0xE5))
65 c = 0x05;
66 if (c == '.')
67 break;
68 space = (c == ' ');
69 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
70 }
71 if (space)
72 return -EINVAL;
73 if (opts->name_check == 's' && len && c != '.') {
74 c = *name++;
75 len--;
76 if (c != '.')
77 return -EINVAL;
78 }
79 while (c != '.' && len--)
80 c = *name++;
81 if (c == '.') {
82 while (walk - res < 8)
83 *walk++ = ' ';
84 while (len > 0 && walk - res < MSDOS_NAME) {
85 c = *name++;
86 len--;
87 if (opts->name_check != 'r' && strchr(bad_chars, c))
88 return -EINVAL;
89 if (opts->name_check == 's' &&
90 strchr(bad_if_strict, c))
91 return -EINVAL;
92 if (c < ' ' || c == ':' || c == '\\')
93 return -EINVAL;
94 if (c == '.') {
95 if (opts->name_check == 's')
96 return -EINVAL;
97 break;
98 }
99 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
100 return -EINVAL;
101 space = c == ' ';
102 if (!opts->nocase && c >= 'a' && c <= 'z')
103 *walk++ = c - 32;
104 else
105 *walk++ = c;
106 }
107 if (space)
108 return -EINVAL;
109 if (opts->name_check == 's' && len)
110 return -EINVAL;
111 }
112 while (walk - res < MSDOS_NAME)
113 *walk++ = ' ';
114
115 return 0;
116 }
117
118 /***** Locates a directory entry. Uses unformatted name. */
119 static int msdos_find(struct inode *dir, const unsigned char *name, int len,
120 struct fat_slot_info *sinfo)
121 {
122 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
123 unsigned char msdos_name[MSDOS_NAME];
124 int err;
125
126 err = msdos_format_name(name, len, msdos_name, &sbi->options);
127 if (err)
128 return -ENOENT;
129
130 err = fat_scan(dir, msdos_name, sinfo);
131 if (!err && sbi->options.dotsOK) {
132 if (name[0] == '.') {
133 if (!(sinfo->de->attr & ATTR_HIDDEN))
134 err = -ENOENT;
135 } else {
136 if (sinfo->de->attr & ATTR_HIDDEN)
137 err = -ENOENT;
138 }
139 if (err)
140 brelse(sinfo->bh);
141 }
142 return err;
143 }
144
145 /*
146 * Compute the hash for the msdos name corresponding to the dentry.
147 * Note: if the name is invalid, we leave the hash code unchanged so
148 * that the existing dentry can be used. The msdos fs routines will
149 * return ENOENT or EINVAL as appropriate.
150 */
151 static int msdos_hash(const struct dentry *dentry, const struct inode *inode,
152 struct qstr *qstr)
153 {
154 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
155 unsigned char msdos_name[MSDOS_NAME];
156 int error;
157
158 error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
159 if (!error)
160 qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
161 return 0;
162 }
163
164 /*
165 * Compare two msdos names. If either of the names are invalid,
166 * we fall back to doing the standard name comparison.
167 */
168 static int msdos_cmp(const struct dentry *parent, const struct inode *pinode,
169 const struct dentry *dentry, const struct inode *inode,
170 unsigned int len, const char *str, const struct qstr *name)
171 {
172 struct fat_mount_options *options = &MSDOS_SB(parent->d_sb)->options;
173 unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
174 int error;
175
176 error = msdos_format_name(name->name, name->len, a_msdos_name, options);
177 if (error)
178 goto old_compare;
179 error = msdos_format_name(str, len, b_msdos_name, options);
180 if (error)
181 goto old_compare;
182 error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
183 out:
184 return error;
185
186 old_compare:
187 error = 1;
188 if (name->len == len)
189 error = memcmp(name->name, str, len);
190 goto out;
191 }
192
193 static const struct dentry_operations msdos_dentry_operations = {
194 .d_hash = msdos_hash,
195 .d_compare = msdos_cmp,
196 };
197
198 /*
199 * AV. Wrappers for FAT sb operations. Is it wise?
200 */
201
202 /***** Get inode using directory and name */
203 static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
204 struct nameidata *nd)
205 {
206 struct super_block *sb = dir->i_sb;
207 struct fat_slot_info sinfo;
208 struct inode *inode;
209 int err;
210
211 lock_super(sb);
212
213 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
214 if (err) {
215 if (err == -ENOENT) {
216 inode = NULL;
217 goto out;
218 }
219 goto error;
220 }
221
222 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
223 brelse(sinfo.bh);
224 if (IS_ERR(inode)) {
225 err = PTR_ERR(inode);
226 goto error;
227 }
228 out:
229 unlock_super(sb);
230 return d_splice_alias(inode, dentry);
231
232 error:
233 unlock_super(sb);
234 return ERR_PTR(err);
235 }
236
237 /***** Creates a directory entry (name is already formatted). */
238 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
239 int is_dir, int is_hid, int cluster,
240 struct timespec *ts, struct fat_slot_info *sinfo)
241 {
242 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
243 struct msdos_dir_entry de;
244 __le16 time, date;
245 int err;
246
247 memcpy(de.name, name, MSDOS_NAME);
248 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
249 if (is_hid)
250 de.attr |= ATTR_HIDDEN;
251 de.lcase = 0;
252 fat_time_unix2fat(sbi, ts, &time, &date, NULL);
253 de.cdate = de.adate = 0;
254 de.ctime = 0;
255 de.ctime_cs = 0;
256 de.time = time;
257 de.date = date;
258 de.start = cpu_to_le16(cluster);
259 de.starthi = cpu_to_le16(cluster >> 16);
260 de.size = 0;
261
262 err = fat_add_entries(dir, &de, 1, sinfo);
263 if (err)
264 return err;
265
266 dir->i_ctime = dir->i_mtime = *ts;
267 if (IS_DIRSYNC(dir))
268 (void)fat_sync_inode(dir);
269 else
270 mark_inode_dirty(dir);
271
272 return 0;
273 }
274
275 /***** Create a file */
276 static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
277 struct nameidata *nd)
278 {
279 struct super_block *sb = dir->i_sb;
280 struct inode *inode = NULL;
281 struct fat_slot_info sinfo;
282 struct timespec ts;
283 unsigned char msdos_name[MSDOS_NAME];
284 int err, is_hid;
285
286 lock_super(sb);
287
288 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
289 msdos_name, &MSDOS_SB(sb)->options);
290 if (err)
291 goto out;
292 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
293 /* Have to do it due to foo vs. .foo conflicts */
294 if (!fat_scan(dir, msdos_name, &sinfo)) {
295 brelse(sinfo.bh);
296 err = -EINVAL;
297 goto out;
298 }
299
300 ts = CURRENT_TIME_SEC;
301 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
302 if (err)
303 goto out;
304 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
305 brelse(sinfo.bh);
306 if (IS_ERR(inode)) {
307 err = PTR_ERR(inode);
308 goto out;
309 }
310 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
311 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
312
313 d_instantiate(dentry, inode);
314 out:
315 unlock_super(sb);
316 if (!err)
317 err = fat_flush_inodes(sb, dir, inode);
318 return err;
319 }
320
321 /***** Remove a directory */
322 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
323 {
324 struct super_block *sb = dir->i_sb;
325 struct inode *inode = dentry->d_inode;
326 struct fat_slot_info sinfo;
327 int err;
328
329 dentry_unhash(dentry);
330
331 lock_super(sb);
332 /*
333 * Check whether the directory is not in use, then check
334 * whether it is empty.
335 */
336 err = fat_dir_empty(inode);
337 if (err)
338 goto out;
339 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
340 if (err)
341 goto out;
342
343 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
344 if (err)
345 goto out;
346 drop_nlink(dir);
347
348 clear_nlink(inode);
349 inode->i_ctime = CURRENT_TIME_SEC;
350 fat_detach(inode);
351 out:
352 unlock_super(sb);
353 if (!err)
354 err = fat_flush_inodes(sb, dir, inode);
355
356 return err;
357 }
358
359 /***** Make a directory */
360 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
361 {
362 struct super_block *sb = dir->i_sb;
363 struct fat_slot_info sinfo;
364 struct inode *inode;
365 unsigned char msdos_name[MSDOS_NAME];
366 struct timespec ts;
367 int err, is_hid, cluster;
368
369 lock_super(sb);
370
371 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
372 msdos_name, &MSDOS_SB(sb)->options);
373 if (err)
374 goto out;
375 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
376 /* foo vs .foo situation */
377 if (!fat_scan(dir, msdos_name, &sinfo)) {
378 brelse(sinfo.bh);
379 err = -EINVAL;
380 goto out;
381 }
382
383 ts = CURRENT_TIME_SEC;
384 cluster = fat_alloc_new_dir(dir, &ts);
385 if (cluster < 0) {
386 err = cluster;
387 goto out;
388 }
389 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
390 if (err)
391 goto out_free;
392 inc_nlink(dir);
393
394 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
395 brelse(sinfo.bh);
396 if (IS_ERR(inode)) {
397 err = PTR_ERR(inode);
398 /* the directory was completed, just return a error */
399 goto out;
400 }
401 inode->i_nlink = 2;
402 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
403 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
404
405 d_instantiate(dentry, inode);
406
407 unlock_super(sb);
408 fat_flush_inodes(sb, dir, inode);
409 return 0;
410
411 out_free:
412 fat_free_clusters(dir, cluster);
413 out:
414 unlock_super(sb);
415 return err;
416 }
417
418 /***** Unlink a file */
419 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
420 {
421 struct inode *inode = dentry->d_inode;
422 struct super_block *sb= inode->i_sb;
423 struct fat_slot_info sinfo;
424 int err;
425
426 lock_super(sb);
427 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
428 if (err)
429 goto out;
430
431 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
432 if (err)
433 goto out;
434 clear_nlink(inode);
435 inode->i_ctime = CURRENT_TIME_SEC;
436 fat_detach(inode);
437 out:
438 unlock_super(sb);
439 if (!err)
440 err = fat_flush_inodes(sb, dir, inode);
441
442 return err;
443 }
444
445 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
446 struct dentry *old_dentry,
447 struct inode *new_dir, unsigned char *new_name,
448 struct dentry *new_dentry, int is_hid)
449 {
450 struct buffer_head *dotdot_bh;
451 struct msdos_dir_entry *dotdot_de;
452 struct inode *old_inode, *new_inode;
453 struct fat_slot_info old_sinfo, sinfo;
454 struct timespec ts;
455 loff_t dotdot_i_pos, new_i_pos;
456 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
457
458 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
459 old_inode = old_dentry->d_inode;
460 new_inode = new_dentry->d_inode;
461
462 if (new_inode && S_ISDIR(new_inode->i_mode))
463 dentry_unhash(new_dentry);
464
465 err = fat_scan(old_dir, old_name, &old_sinfo);
466 if (err) {
467 err = -EIO;
468 goto out;
469 }
470
471 is_dir = S_ISDIR(old_inode->i_mode);
472 update_dotdot = (is_dir && old_dir != new_dir);
473 if (update_dotdot) {
474 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
475 &dotdot_i_pos) < 0) {
476 err = -EIO;
477 goto out;
478 }
479 }
480
481 old_attrs = MSDOS_I(old_inode)->i_attrs;
482 err = fat_scan(new_dir, new_name, &sinfo);
483 if (!err) {
484 if (!new_inode) {
485 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
486 if (sinfo.de != old_sinfo.de) {
487 err = -EINVAL;
488 goto out;
489 }
490 if (is_hid)
491 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
492 else
493 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
494 if (IS_DIRSYNC(old_dir)) {
495 err = fat_sync_inode(old_inode);
496 if (err) {
497 MSDOS_I(old_inode)->i_attrs = old_attrs;
498 goto out;
499 }
500 } else
501 mark_inode_dirty(old_inode);
502
503 old_dir->i_version++;
504 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
505 if (IS_DIRSYNC(old_dir))
506 (void)fat_sync_inode(old_dir);
507 else
508 mark_inode_dirty(old_dir);
509 goto out;
510 }
511 }
512
513 ts = CURRENT_TIME_SEC;
514 if (new_inode) {
515 if (err)
516 goto out;
517 if (is_dir) {
518 err = fat_dir_empty(new_inode);
519 if (err)
520 goto out;
521 }
522 new_i_pos = MSDOS_I(new_inode)->i_pos;
523 fat_detach(new_inode);
524 } else {
525 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
526 &ts, &sinfo);
527 if (err)
528 goto out;
529 new_i_pos = sinfo.i_pos;
530 }
531 new_dir->i_version++;
532
533 fat_detach(old_inode);
534 fat_attach(old_inode, new_i_pos);
535 if (is_hid)
536 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
537 else
538 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
539 if (IS_DIRSYNC(new_dir)) {
540 err = fat_sync_inode(old_inode);
541 if (err)
542 goto error_inode;
543 } else
544 mark_inode_dirty(old_inode);
545
546 if (update_dotdot) {
547 int start = MSDOS_I(new_dir)->i_logstart;
548 dotdot_de->start = cpu_to_le16(start);
549 dotdot_de->starthi = cpu_to_le16(start >> 16);
550 mark_buffer_dirty_inode(dotdot_bh, old_inode);
551 if (IS_DIRSYNC(new_dir)) {
552 err = sync_dirty_buffer(dotdot_bh);
553 if (err)
554 goto error_dotdot;
555 }
556 drop_nlink(old_dir);
557 if (!new_inode)
558 inc_nlink(new_dir);
559 }
560
561 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
562 old_sinfo.bh = NULL;
563 if (err)
564 goto error_dotdot;
565 old_dir->i_version++;
566 old_dir->i_ctime = old_dir->i_mtime = ts;
567 if (IS_DIRSYNC(old_dir))
568 (void)fat_sync_inode(old_dir);
569 else
570 mark_inode_dirty(old_dir);
571
572 if (new_inode) {
573 drop_nlink(new_inode);
574 if (is_dir)
575 drop_nlink(new_inode);
576 new_inode->i_ctime = ts;
577 }
578 out:
579 brelse(sinfo.bh);
580 brelse(dotdot_bh);
581 brelse(old_sinfo.bh);
582 return err;
583
584 error_dotdot:
585 /* data cluster is shared, serious corruption */
586 corrupt = 1;
587
588 if (update_dotdot) {
589 int start = MSDOS_I(old_dir)->i_logstart;
590 dotdot_de->start = cpu_to_le16(start);
591 dotdot_de->starthi = cpu_to_le16(start >> 16);
592 mark_buffer_dirty_inode(dotdot_bh, old_inode);
593 corrupt |= sync_dirty_buffer(dotdot_bh);
594 }
595 error_inode:
596 fat_detach(old_inode);
597 fat_attach(old_inode, old_sinfo.i_pos);
598 MSDOS_I(old_inode)->i_attrs = old_attrs;
599 if (new_inode) {
600 fat_attach(new_inode, new_i_pos);
601 if (corrupt)
602 corrupt |= fat_sync_inode(new_inode);
603 } else {
604 /*
605 * If new entry was not sharing the data cluster, it
606 * shouldn't be serious corruption.
607 */
608 int err2 = fat_remove_entries(new_dir, &sinfo);
609 if (corrupt)
610 corrupt |= err2;
611 sinfo.bh = NULL;
612 }
613 if (corrupt < 0) {
614 fat_fs_error(new_dir->i_sb,
615 "%s: Filesystem corrupted (i_pos %lld)",
616 __func__, sinfo.i_pos);
617 }
618 goto out;
619 }
620
621 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
622 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
623 struct inode *new_dir, struct dentry *new_dentry)
624 {
625 struct super_block *sb = old_dir->i_sb;
626 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
627 int err, is_hid;
628
629 lock_super(sb);
630
631 err = msdos_format_name(old_dentry->d_name.name,
632 old_dentry->d_name.len, old_msdos_name,
633 &MSDOS_SB(old_dir->i_sb)->options);
634 if (err)
635 goto out;
636 err = msdos_format_name(new_dentry->d_name.name,
637 new_dentry->d_name.len, new_msdos_name,
638 &MSDOS_SB(new_dir->i_sb)->options);
639 if (err)
640 goto out;
641
642 is_hid =
643 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
644
645 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
646 new_dir, new_msdos_name, new_dentry, is_hid);
647 out:
648 unlock_super(sb);
649 if (!err)
650 err = fat_flush_inodes(sb, old_dir, new_dir);
651 return err;
652 }
653
654 static const struct inode_operations msdos_dir_inode_operations = {
655 .create = msdos_create,
656 .lookup = msdos_lookup,
657 .unlink = msdos_unlink,
658 .mkdir = msdos_mkdir,
659 .rmdir = msdos_rmdir,
660 .rename = msdos_rename,
661 .setattr = fat_setattr,
662 .getattr = fat_getattr,
663 };
664
665 static void setup(struct super_block *sb)
666 {
667 MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
668 sb->s_d_op = &msdos_dentry_operations;
669 sb->s_flags |= MS_NOATIME;
670 }
671
672 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
673 {
674 return fat_fill_super(sb, data, silent, 0, setup);
675 }
676
677 static struct dentry *msdos_mount(struct file_system_type *fs_type,
678 int flags, const char *dev_name,
679 void *data)
680 {
681 return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
682 }
683
684 static struct file_system_type msdos_fs_type = {
685 .owner = THIS_MODULE,
686 .name = "msdos",
687 .mount = msdos_mount,
688 .kill_sb = kill_block_super,
689 .fs_flags = FS_REQUIRES_DEV,
690 };
691
692 static int __init init_msdos_fs(void)
693 {
694 return register_filesystem(&msdos_fs_type);
695 }
696
697 static void __exit exit_msdos_fs(void)
698 {
699 unregister_filesystem(&msdos_fs_type);
700 }
701
702 MODULE_LICENSE("GPL");
703 MODULE_AUTHOR("Werner Almesberger");
704 MODULE_DESCRIPTION("MS-DOS filesystem support");
705
706 module_init(init_msdos_fs)
707 module_exit(exit_msdos_fs)
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