Add linux-next specific files for 20110716
[linux-2.6/next.git] / fs / fat / namei_msdos.c
blob3b222dafd15b7eb6fa8f8b425a407f8a70dc7a19
1 /*
2 * linux/fs/msdos/namei.c
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 */
9 #include <linux/module.h>
10 #include <linux/time.h>
11 #include <linux/buffer_head.h>
12 #include "fat.h"
14 /* Characters that are undesirable in an MS-DOS file name */
15 static unsigned char bad_chars[] = "*?<>|\"";
16 static unsigned char bad_if_strict[] = "+=,; ";
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)
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)
28 unsigned char *walk;
29 unsigned char c;
30 int space;
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;
41 * disallow names that _really_ start with a dot
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;
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.
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;
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;
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;
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;
107 if (space)
108 return -EINVAL;
109 if (opts->name_check == 's' && len)
110 return -EINVAL;
112 while (walk - res < MSDOS_NAME)
113 *walk++ = ' ';
115 return 0;
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)
122 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
123 unsigned char msdos_name[MSDOS_NAME];
124 int err;
126 err = msdos_format_name(name, len, msdos_name, &sbi->options);
127 if (err)
128 return -ENOENT;
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;
139 if (err)
140 brelse(sinfo->bh);
142 return err;
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.
151 static int msdos_hash(const struct dentry *dentry, const struct inode *inode,
152 struct qstr *qstr)
154 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
155 unsigned char msdos_name[MSDOS_NAME];
156 int error;
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;
165 * Compare two msdos names. If either of the names are invalid,
166 * we fall back to doing the standard name comparison.
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)
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;
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;
186 old_compare:
187 error = 1;
188 if (name->len == len)
189 error = memcmp(name->name, str, len);
190 goto out;
193 static const struct dentry_operations msdos_dentry_operations = {
194 .d_hash = msdos_hash,
195 .d_compare = msdos_cmp,
199 * AV. Wrappers for FAT sb operations. Is it wise?
202 /***** Get inode using directory and name */
203 static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
204 struct nameidata *nd)
206 struct super_block *sb = dir->i_sb;
207 struct fat_slot_info sinfo;
208 struct inode *inode;
209 int err;
211 lock_super(sb);
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;
219 goto error;
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;
228 out:
229 unlock_super(sb);
230 return d_splice_alias(inode, dentry);
232 error:
233 unlock_super(sb);
234 return ERR_PTR(err);
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)
242 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
243 struct msdos_dir_entry de;
244 __le16 time, date;
245 int err;
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;
262 err = fat_add_entries(dir, &de, 1, sinfo);
263 if (err)
264 return err;
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);
272 return 0;
275 /***** Create a file */
276 static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
277 struct nameidata *nd)
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;
286 lock_super(sb);
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;
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;
310 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
311 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
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;
321 /***** Remove a directory */
322 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
324 struct super_block *sb = dir->i_sb;
325 struct inode *inode = dentry->d_inode;
326 struct fat_slot_info sinfo;
327 int err;
329 lock_super(sb);
331 * Check whether the directory is not in use, then check
332 * whether it is empty.
334 err = fat_dir_empty(inode);
335 if (err)
336 goto out;
337 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
338 if (err)
339 goto out;
341 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
342 if (err)
343 goto out;
344 drop_nlink(dir);
346 clear_nlink(inode);
347 inode->i_ctime = CURRENT_TIME_SEC;
348 fat_detach(inode);
349 out:
350 unlock_super(sb);
351 if (!err)
352 err = fat_flush_inodes(sb, dir, inode);
354 return err;
357 /***** Make a directory */
358 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
360 struct super_block *sb = dir->i_sb;
361 struct fat_slot_info sinfo;
362 struct inode *inode;
363 unsigned char msdos_name[MSDOS_NAME];
364 struct timespec ts;
365 int err, is_hid, cluster;
367 lock_super(sb);
369 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
370 msdos_name, &MSDOS_SB(sb)->options);
371 if (err)
372 goto out;
373 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
374 /* foo vs .foo situation */
375 if (!fat_scan(dir, msdos_name, &sinfo)) {
376 brelse(sinfo.bh);
377 err = -EINVAL;
378 goto out;
381 ts = CURRENT_TIME_SEC;
382 cluster = fat_alloc_new_dir(dir, &ts);
383 if (cluster < 0) {
384 err = cluster;
385 goto out;
387 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
388 if (err)
389 goto out_free;
390 inc_nlink(dir);
392 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
393 brelse(sinfo.bh);
394 if (IS_ERR(inode)) {
395 err = PTR_ERR(inode);
396 /* the directory was completed, just return a error */
397 goto out;
399 inode->i_nlink = 2;
400 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
401 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
403 d_instantiate(dentry, inode);
405 unlock_super(sb);
406 fat_flush_inodes(sb, dir, inode);
407 return 0;
409 out_free:
410 fat_free_clusters(dir, cluster);
411 out:
412 unlock_super(sb);
413 return err;
416 /***** Unlink a file */
417 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
419 struct inode *inode = dentry->d_inode;
420 struct super_block *sb= inode->i_sb;
421 struct fat_slot_info sinfo;
422 int err;
424 lock_super(sb);
425 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
426 if (err)
427 goto out;
429 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
430 if (err)
431 goto out;
432 clear_nlink(inode);
433 inode->i_ctime = CURRENT_TIME_SEC;
434 fat_detach(inode);
435 out:
436 unlock_super(sb);
437 if (!err)
438 err = fat_flush_inodes(sb, dir, inode);
440 return err;
443 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
444 struct dentry *old_dentry,
445 struct inode *new_dir, unsigned char *new_name,
446 struct dentry *new_dentry, int is_hid)
448 struct buffer_head *dotdot_bh;
449 struct msdos_dir_entry *dotdot_de;
450 struct inode *old_inode, *new_inode;
451 struct fat_slot_info old_sinfo, sinfo;
452 struct timespec ts;
453 loff_t dotdot_i_pos, new_i_pos;
454 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
456 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
457 old_inode = old_dentry->d_inode;
458 new_inode = new_dentry->d_inode;
460 err = fat_scan(old_dir, old_name, &old_sinfo);
461 if (err) {
462 err = -EIO;
463 goto out;
466 is_dir = S_ISDIR(old_inode->i_mode);
467 update_dotdot = (is_dir && old_dir != new_dir);
468 if (update_dotdot) {
469 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
470 &dotdot_i_pos) < 0) {
471 err = -EIO;
472 goto out;
476 old_attrs = MSDOS_I(old_inode)->i_attrs;
477 err = fat_scan(new_dir, new_name, &sinfo);
478 if (!err) {
479 if (!new_inode) {
480 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
481 if (sinfo.de != old_sinfo.de) {
482 err = -EINVAL;
483 goto out;
485 if (is_hid)
486 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
487 else
488 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
489 if (IS_DIRSYNC(old_dir)) {
490 err = fat_sync_inode(old_inode);
491 if (err) {
492 MSDOS_I(old_inode)->i_attrs = old_attrs;
493 goto out;
495 } else
496 mark_inode_dirty(old_inode);
498 old_dir->i_version++;
499 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
500 if (IS_DIRSYNC(old_dir))
501 (void)fat_sync_inode(old_dir);
502 else
503 mark_inode_dirty(old_dir);
504 goto out;
508 ts = CURRENT_TIME_SEC;
509 if (new_inode) {
510 if (err)
511 goto out;
512 if (is_dir) {
513 err = fat_dir_empty(new_inode);
514 if (err)
515 goto out;
517 new_i_pos = MSDOS_I(new_inode)->i_pos;
518 fat_detach(new_inode);
519 } else {
520 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
521 &ts, &sinfo);
522 if (err)
523 goto out;
524 new_i_pos = sinfo.i_pos;
526 new_dir->i_version++;
528 fat_detach(old_inode);
529 fat_attach(old_inode, new_i_pos);
530 if (is_hid)
531 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
532 else
533 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
534 if (IS_DIRSYNC(new_dir)) {
535 err = fat_sync_inode(old_inode);
536 if (err)
537 goto error_inode;
538 } else
539 mark_inode_dirty(old_inode);
541 if (update_dotdot) {
542 int start = MSDOS_I(new_dir)->i_logstart;
543 dotdot_de->start = cpu_to_le16(start);
544 dotdot_de->starthi = cpu_to_le16(start >> 16);
545 mark_buffer_dirty_inode(dotdot_bh, old_inode);
546 if (IS_DIRSYNC(new_dir)) {
547 err = sync_dirty_buffer(dotdot_bh);
548 if (err)
549 goto error_dotdot;
551 drop_nlink(old_dir);
552 if (!new_inode)
553 inc_nlink(new_dir);
556 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
557 old_sinfo.bh = NULL;
558 if (err)
559 goto error_dotdot;
560 old_dir->i_version++;
561 old_dir->i_ctime = old_dir->i_mtime = ts;
562 if (IS_DIRSYNC(old_dir))
563 (void)fat_sync_inode(old_dir);
564 else
565 mark_inode_dirty(old_dir);
567 if (new_inode) {
568 drop_nlink(new_inode);
569 if (is_dir)
570 drop_nlink(new_inode);
571 new_inode->i_ctime = ts;
573 out:
574 brelse(sinfo.bh);
575 brelse(dotdot_bh);
576 brelse(old_sinfo.bh);
577 return err;
579 error_dotdot:
580 /* data cluster is shared, serious corruption */
581 corrupt = 1;
583 if (update_dotdot) {
584 int start = MSDOS_I(old_dir)->i_logstart;
585 dotdot_de->start = cpu_to_le16(start);
586 dotdot_de->starthi = cpu_to_le16(start >> 16);
587 mark_buffer_dirty_inode(dotdot_bh, old_inode);
588 corrupt |= sync_dirty_buffer(dotdot_bh);
590 error_inode:
591 fat_detach(old_inode);
592 fat_attach(old_inode, old_sinfo.i_pos);
593 MSDOS_I(old_inode)->i_attrs = old_attrs;
594 if (new_inode) {
595 fat_attach(new_inode, new_i_pos);
596 if (corrupt)
597 corrupt |= fat_sync_inode(new_inode);
598 } else {
600 * If new entry was not sharing the data cluster, it
601 * shouldn't be serious corruption.
603 int err2 = fat_remove_entries(new_dir, &sinfo);
604 if (corrupt)
605 corrupt |= err2;
606 sinfo.bh = NULL;
608 if (corrupt < 0) {
609 fat_fs_error(new_dir->i_sb,
610 "%s: Filesystem corrupted (i_pos %lld)",
611 __func__, sinfo.i_pos);
613 goto out;
616 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
617 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
618 struct inode *new_dir, struct dentry *new_dentry)
620 struct super_block *sb = old_dir->i_sb;
621 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
622 int err, is_hid;
624 lock_super(sb);
626 err = msdos_format_name(old_dentry->d_name.name,
627 old_dentry->d_name.len, old_msdos_name,
628 &MSDOS_SB(old_dir->i_sb)->options);
629 if (err)
630 goto out;
631 err = msdos_format_name(new_dentry->d_name.name,
632 new_dentry->d_name.len, new_msdos_name,
633 &MSDOS_SB(new_dir->i_sb)->options);
634 if (err)
635 goto out;
637 is_hid =
638 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
640 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
641 new_dir, new_msdos_name, new_dentry, is_hid);
642 out:
643 unlock_super(sb);
644 if (!err)
645 err = fat_flush_inodes(sb, old_dir, new_dir);
646 return err;
649 static const struct inode_operations msdos_dir_inode_operations = {
650 .create = msdos_create,
651 .lookup = msdos_lookup,
652 .unlink = msdos_unlink,
653 .mkdir = msdos_mkdir,
654 .rmdir = msdos_rmdir,
655 .rename = msdos_rename,
656 .setattr = fat_setattr,
657 .getattr = fat_getattr,
660 static void setup(struct super_block *sb)
662 MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
663 sb->s_d_op = &msdos_dentry_operations;
664 sb->s_flags |= MS_NOATIME;
667 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
669 return fat_fill_super(sb, data, silent, 0, setup);
672 static struct dentry *msdos_mount(struct file_system_type *fs_type,
673 int flags, const char *dev_name,
674 void *data)
676 return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
679 static struct file_system_type msdos_fs_type = {
680 .owner = THIS_MODULE,
681 .name = "msdos",
682 .mount = msdos_mount,
683 .kill_sb = kill_block_super,
684 .fs_flags = FS_REQUIRES_DEV,
687 static int __init init_msdos_fs(void)
689 return register_filesystem(&msdos_fs_type);
692 static void __exit exit_msdos_fs(void)
694 unregister_filesystem(&msdos_fs_type);
697 MODULE_LICENSE("GPL");
698 MODULE_AUTHOR("Werner Almesberger");
699 MODULE_DESCRIPTION("MS-DOS filesystem support");
701 module_init(init_msdos_fs)
702 module_exit(exit_msdos_fs)