Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty...
[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 unsigned int flags)
205 {
206 struct super_block *sb = dir->i_sb;
207 struct fat_slot_info sinfo;
208 struct inode *inode;
209 int err;
210
211 mutex_lock(&MSDOS_SB(sb)->s_lock);
212 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
213 switch (err) {
214 case -ENOENT:
215 inode = NULL;
216 break;
217 case 0:
218 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
219 brelse(sinfo.bh);
220 break;
221 default:
222 inode = ERR_PTR(err);
223 }
224 mutex_unlock(&MSDOS_SB(sb)->s_lock);
225 return d_splice_alias(inode, dentry);
226 }
227
228 /***** Creates a directory entry (name is already formatted). */
229 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
230 int is_dir, int is_hid, int cluster,
231 struct timespec *ts, struct fat_slot_info *sinfo)
232 {
233 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
234 struct msdos_dir_entry de;
235 __le16 time, date;
236 int err;
237
238 memcpy(de.name, name, MSDOS_NAME);
239 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
240 if (is_hid)
241 de.attr |= ATTR_HIDDEN;
242 de.lcase = 0;
243 fat_time_unix2fat(sbi, ts, &time, &date, NULL);
244 de.cdate = de.adate = 0;
245 de.ctime = 0;
246 de.ctime_cs = 0;
247 de.time = time;
248 de.date = date;
249 fat_set_start(&de, cluster);
250 de.size = 0;
251
252 err = fat_add_entries(dir, &de, 1, sinfo);
253 if (err)
254 return err;
255
256 dir->i_ctime = dir->i_mtime = *ts;
257 if (IS_DIRSYNC(dir))
258 (void)fat_sync_inode(dir);
259 else
260 mark_inode_dirty(dir);
261
262 return 0;
263 }
264
265 /***** Create a file */
266 static int msdos_create(struct inode *dir, struct dentry *dentry, umode_t mode,
267 bool excl)
268 {
269 struct super_block *sb = dir->i_sb;
270 struct inode *inode = NULL;
271 struct fat_slot_info sinfo;
272 struct timespec ts;
273 unsigned char msdos_name[MSDOS_NAME];
274 int err, is_hid;
275
276 mutex_lock(&MSDOS_SB(sb)->s_lock);
277
278 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
279 msdos_name, &MSDOS_SB(sb)->options);
280 if (err)
281 goto out;
282 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
283 /* Have to do it due to foo vs. .foo conflicts */
284 if (!fat_scan(dir, msdos_name, &sinfo)) {
285 brelse(sinfo.bh);
286 err = -EINVAL;
287 goto out;
288 }
289
290 ts = CURRENT_TIME_SEC;
291 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
292 if (err)
293 goto out;
294 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
295 brelse(sinfo.bh);
296 if (IS_ERR(inode)) {
297 err = PTR_ERR(inode);
298 goto out;
299 }
300 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
301 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
302
303 d_instantiate(dentry, inode);
304 out:
305 mutex_unlock(&MSDOS_SB(sb)->s_lock);
306 if (!err)
307 err = fat_flush_inodes(sb, dir, inode);
308 return err;
309 }
310
311 /***** Remove a directory */
312 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
313 {
314 struct super_block *sb = dir->i_sb;
315 struct inode *inode = dentry->d_inode;
316 struct fat_slot_info sinfo;
317 int err;
318
319 mutex_lock(&MSDOS_SB(sb)->s_lock);
320 /*
321 * Check whether the directory is not in use, then check
322 * whether it is empty.
323 */
324 err = fat_dir_empty(inode);
325 if (err)
326 goto out;
327 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
328 if (err)
329 goto out;
330
331 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
332 if (err)
333 goto out;
334 drop_nlink(dir);
335
336 clear_nlink(inode);
337 inode->i_ctime = CURRENT_TIME_SEC;
338 fat_detach(inode);
339 out:
340 mutex_unlock(&MSDOS_SB(sb)->s_lock);
341 if (!err)
342 err = fat_flush_inodes(sb, dir, inode);
343
344 return err;
345 }
346
347 /***** Make a directory */
348 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
349 {
350 struct super_block *sb = dir->i_sb;
351 struct fat_slot_info sinfo;
352 struct inode *inode;
353 unsigned char msdos_name[MSDOS_NAME];
354 struct timespec ts;
355 int err, is_hid, cluster;
356
357 mutex_lock(&MSDOS_SB(sb)->s_lock);
358
359 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
360 msdos_name, &MSDOS_SB(sb)->options);
361 if (err)
362 goto out;
363 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
364 /* foo vs .foo situation */
365 if (!fat_scan(dir, msdos_name, &sinfo)) {
366 brelse(sinfo.bh);
367 err = -EINVAL;
368 goto out;
369 }
370
371 ts = CURRENT_TIME_SEC;
372 cluster = fat_alloc_new_dir(dir, &ts);
373 if (cluster < 0) {
374 err = cluster;
375 goto out;
376 }
377 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
378 if (err)
379 goto out_free;
380 inc_nlink(dir);
381
382 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
383 brelse(sinfo.bh);
384 if (IS_ERR(inode)) {
385 err = PTR_ERR(inode);
386 /* the directory was completed, just return a error */
387 goto out;
388 }
389 set_nlink(inode, 2);
390 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
391 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
392
393 d_instantiate(dentry, inode);
394
395 mutex_unlock(&MSDOS_SB(sb)->s_lock);
396 fat_flush_inodes(sb, dir, inode);
397 return 0;
398
399 out_free:
400 fat_free_clusters(dir, cluster);
401 out:
402 mutex_unlock(&MSDOS_SB(sb)->s_lock);
403 return err;
404 }
405
406 /***** Unlink a file */
407 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
408 {
409 struct inode *inode = dentry->d_inode;
410 struct super_block *sb = inode->i_sb;
411 struct fat_slot_info sinfo;
412 int err;
413
414 mutex_lock(&MSDOS_SB(sb)->s_lock);
415 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
416 if (err)
417 goto out;
418
419 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
420 if (err)
421 goto out;
422 clear_nlink(inode);
423 inode->i_ctime = CURRENT_TIME_SEC;
424 fat_detach(inode);
425 out:
426 mutex_unlock(&MSDOS_SB(sb)->s_lock);
427 if (!err)
428 err = fat_flush_inodes(sb, dir, inode);
429
430 return err;
431 }
432
433 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
434 struct dentry *old_dentry,
435 struct inode *new_dir, unsigned char *new_name,
436 struct dentry *new_dentry, int is_hid)
437 {
438 struct buffer_head *dotdot_bh;
439 struct msdos_dir_entry *dotdot_de;
440 struct inode *old_inode, *new_inode;
441 struct fat_slot_info old_sinfo, sinfo;
442 struct timespec ts;
443 loff_t new_i_pos;
444 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
445
446 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
447 old_inode = old_dentry->d_inode;
448 new_inode = new_dentry->d_inode;
449
450 err = fat_scan(old_dir, old_name, &old_sinfo);
451 if (err) {
452 err = -EIO;
453 goto out;
454 }
455
456 is_dir = S_ISDIR(old_inode->i_mode);
457 update_dotdot = (is_dir && old_dir != new_dir);
458 if (update_dotdot) {
459 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
460 err = -EIO;
461 goto out;
462 }
463 }
464
465 old_attrs = MSDOS_I(old_inode)->i_attrs;
466 err = fat_scan(new_dir, new_name, &sinfo);
467 if (!err) {
468 if (!new_inode) {
469 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
470 if (sinfo.de != old_sinfo.de) {
471 err = -EINVAL;
472 goto out;
473 }
474 if (is_hid)
475 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
476 else
477 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
478 if (IS_DIRSYNC(old_dir)) {
479 err = fat_sync_inode(old_inode);
480 if (err) {
481 MSDOS_I(old_inode)->i_attrs = old_attrs;
482 goto out;
483 }
484 } else
485 mark_inode_dirty(old_inode);
486
487 old_dir->i_version++;
488 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
489 if (IS_DIRSYNC(old_dir))
490 (void)fat_sync_inode(old_dir);
491 else
492 mark_inode_dirty(old_dir);
493 goto out;
494 }
495 }
496
497 ts = CURRENT_TIME_SEC;
498 if (new_inode) {
499 if (err)
500 goto out;
501 if (is_dir) {
502 err = fat_dir_empty(new_inode);
503 if (err)
504 goto out;
505 }
506 new_i_pos = MSDOS_I(new_inode)->i_pos;
507 fat_detach(new_inode);
508 } else {
509 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
510 &ts, &sinfo);
511 if (err)
512 goto out;
513 new_i_pos = sinfo.i_pos;
514 }
515 new_dir->i_version++;
516
517 fat_detach(old_inode);
518 fat_attach(old_inode, new_i_pos);
519 if (is_hid)
520 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
521 else
522 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
523 if (IS_DIRSYNC(new_dir)) {
524 err = fat_sync_inode(old_inode);
525 if (err)
526 goto error_inode;
527 } else
528 mark_inode_dirty(old_inode);
529
530 if (update_dotdot) {
531 fat_set_start(dotdot_de, MSDOS_I(new_dir)->i_logstart);
532 mark_buffer_dirty_inode(dotdot_bh, old_inode);
533 if (IS_DIRSYNC(new_dir)) {
534 err = sync_dirty_buffer(dotdot_bh);
535 if (err)
536 goto error_dotdot;
537 }
538 drop_nlink(old_dir);
539 if (!new_inode)
540 inc_nlink(new_dir);
541 }
542
543 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
544 old_sinfo.bh = NULL;
545 if (err)
546 goto error_dotdot;
547 old_dir->i_version++;
548 old_dir->i_ctime = old_dir->i_mtime = ts;
549 if (IS_DIRSYNC(old_dir))
550 (void)fat_sync_inode(old_dir);
551 else
552 mark_inode_dirty(old_dir);
553
554 if (new_inode) {
555 drop_nlink(new_inode);
556 if (is_dir)
557 drop_nlink(new_inode);
558 new_inode->i_ctime = ts;
559 }
560 out:
561 brelse(sinfo.bh);
562 brelse(dotdot_bh);
563 brelse(old_sinfo.bh);
564 return err;
565
566 error_dotdot:
567 /* data cluster is shared, serious corruption */
568 corrupt = 1;
569
570 if (update_dotdot) {
571 fat_set_start(dotdot_de, MSDOS_I(old_dir)->i_logstart);
572 mark_buffer_dirty_inode(dotdot_bh, old_inode);
573 corrupt |= sync_dirty_buffer(dotdot_bh);
574 }
575 error_inode:
576 fat_detach(old_inode);
577 fat_attach(old_inode, old_sinfo.i_pos);
578 MSDOS_I(old_inode)->i_attrs = old_attrs;
579 if (new_inode) {
580 fat_attach(new_inode, new_i_pos);
581 if (corrupt)
582 corrupt |= fat_sync_inode(new_inode);
583 } else {
584 /*
585 * If new entry was not sharing the data cluster, it
586 * shouldn't be serious corruption.
587 */
588 int err2 = fat_remove_entries(new_dir, &sinfo);
589 if (corrupt)
590 corrupt |= err2;
591 sinfo.bh = NULL;
592 }
593 if (corrupt < 0) {
594 fat_fs_error(new_dir->i_sb,
595 "%s: Filesystem corrupted (i_pos %lld)",
596 __func__, sinfo.i_pos);
597 }
598 goto out;
599 }
600
601 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
602 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
603 struct inode *new_dir, struct dentry *new_dentry)
604 {
605 struct super_block *sb = old_dir->i_sb;
606 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
607 int err, is_hid;
608
609 mutex_lock(&MSDOS_SB(sb)->s_lock);
610
611 err = msdos_format_name(old_dentry->d_name.name,
612 old_dentry->d_name.len, old_msdos_name,
613 &MSDOS_SB(old_dir->i_sb)->options);
614 if (err)
615 goto out;
616 err = msdos_format_name(new_dentry->d_name.name,
617 new_dentry->d_name.len, new_msdos_name,
618 &MSDOS_SB(new_dir->i_sb)->options);
619 if (err)
620 goto out;
621
622 is_hid =
623 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
624
625 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
626 new_dir, new_msdos_name, new_dentry, is_hid);
627 out:
628 mutex_unlock(&MSDOS_SB(sb)->s_lock);
629 if (!err)
630 err = fat_flush_inodes(sb, old_dir, new_dir);
631 return err;
632 }
633
634 static const struct inode_operations msdos_dir_inode_operations = {
635 .create = msdos_create,
636 .lookup = msdos_lookup,
637 .unlink = msdos_unlink,
638 .mkdir = msdos_mkdir,
639 .rmdir = msdos_rmdir,
640 .rename = msdos_rename,
641 .setattr = fat_setattr,
642 .getattr = fat_getattr,
643 };
644
645 static void setup(struct super_block *sb)
646 {
647 MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
648 sb->s_d_op = &msdos_dentry_operations;
649 sb->s_flags |= MS_NOATIME;
650 }
651
652 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
653 {
654 return fat_fill_super(sb, data, silent, 0, setup);
655 }
656
657 static struct dentry *msdos_mount(struct file_system_type *fs_type,
658 int flags, const char *dev_name,
659 void *data)
660 {
661 return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
662 }
663
664 static struct file_system_type msdos_fs_type = {
665 .owner = THIS_MODULE,
666 .name = "msdos",
667 .mount = msdos_mount,
668 .kill_sb = kill_block_super,
669 .fs_flags = FS_REQUIRES_DEV,
670 };
671 MODULE_ALIAS_FS("msdos");
672
673 static int __init init_msdos_fs(void)
674 {
675 return register_filesystem(&msdos_fs_type);
676 }
677
678 static void __exit exit_msdos_fs(void)
679 {
680 unregister_filesystem(&msdos_fs_type);
681 }
682
683 MODULE_LICENSE("GPL");
684 MODULE_AUTHOR("Werner Almesberger");
685 MODULE_DESCRIPTION("MS-DOS filesystem support");
686
687 module_init(init_msdos_fs)
688 module_exit(exit_msdos_fs)
This page took 0.044967 seconds and 5 git commands to generate.