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
9 #include <linux/module.h>
10 #include <linux/time.h>
11 #include <linux/buffer_head.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)
32 if (name[0] == '.') { /* dotfile because . and .. already done */
34 /* Get rid of dot - test for it elsewhere */
41 * disallow names that _really_ start with a dot
45 for (walk = res; len && walk - res < 8; walk++) {
48 if (opts->name_check != 'r' && strchr(bad_chars, c))
50 if (opts->name_check == 's' && strchr(bad_if_strict, c))
52 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
54 if (c < ' ' || c == ':' || c == '\\')
57 * 0xE5 is legal as a first character, but we must substitute
58 * 0x05 because 0xE5 marks deleted files. Yes, DOS really
60 * It seems that Microsoft hacked DOS to support non-US
61 * characters after the 0xE5 character was already in use to
64 if ((res == walk) && (c == 0xE5))
69 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
73 if (opts->name_check == 's' && len && c != '.') {
79 while (c != '.' && len--)
82 while (walk - res < 8)
84 while (len > 0 && walk - res < MSDOS_NAME) {
87 if (opts->name_check != 'r' && strchr(bad_chars, c))
89 if (opts->name_check == 's' &&
90 strchr(bad_if_strict, c))
92 if (c < ' ' || c == ':' || c == '\\')
95 if (opts->name_check == 's')
99 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
102 if (!opts->nocase && c >= 'a' && c <= 'z')
109 if (opts->name_check == 's' && len)
112 while (walk - res < MSDOS_NAME)
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];
126 err = msdos_format_name(name, len, msdos_name, &sbi->options);
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))
136 if (sinfo->de->attr & ATTR_HIDDEN)
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,
154 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
155 unsigned char msdos_name[MSDOS_NAME];
158 error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
160 qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
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];
176 error = msdos_format_name(name->name, name->len, a_msdos_name, options);
179 error = msdos_format_name(str, len, b_msdos_name, options);
182 error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
188 if (name->len == len)
189 error = memcmp(name->name, str, len);
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,
206 struct super_block *sb = dir->i_sb;
207 struct fat_slot_info sinfo;
211 mutex_lock(&MSDOS_SB(sb)->s_lock);
212 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
218 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
222 inode = ERR_PTR(err);
224 mutex_unlock(&MSDOS_SB(sb)->s_lock);
225 return d_splice_alias(inode, dentry);
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)
233 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
234 struct msdos_dir_entry de;
238 memcpy(de.name, name, MSDOS_NAME);
239 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
241 de.attr |= ATTR_HIDDEN;
243 fat_time_unix2fat(sbi, ts, &time, &date, NULL);
244 de.cdate = de.adate = 0;
249 fat_set_start(&de, cluster);
252 err = fat_add_entries(dir, &de, 1, sinfo);
256 dir->i_ctime = dir->i_mtime = *ts;
258 (void)fat_sync_inode(dir);
260 mark_inode_dirty(dir);
265 /***** Create a file */
266 static int msdos_create(struct inode *dir, struct dentry *dentry, umode_t mode,
269 struct super_block *sb = dir->i_sb;
270 struct inode *inode = NULL;
271 struct fat_slot_info sinfo;
273 unsigned char msdos_name[MSDOS_NAME];
276 mutex_lock(&MSDOS_SB(sb)->s_lock);
278 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
279 msdos_name, &MSDOS_SB(sb)->options);
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)) {
290 ts = CURRENT_TIME_SEC;
291 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
294 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
297 err = PTR_ERR(inode);
300 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
301 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
303 d_instantiate(dentry, inode);
305 mutex_unlock(&MSDOS_SB(sb)->s_lock);
307 err = fat_flush_inodes(sb, dir, inode);
311 /***** Remove a directory */
312 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
314 struct super_block *sb = dir->i_sb;
315 struct inode *inode = dentry->d_inode;
316 struct fat_slot_info sinfo;
319 mutex_lock(&MSDOS_SB(sb)->s_lock);
321 * Check whether the directory is not in use, then check
322 * whether it is empty.
324 err = fat_dir_empty(inode);
327 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
331 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
337 inode->i_ctime = CURRENT_TIME_SEC;
340 mutex_unlock(&MSDOS_SB(sb)->s_lock);
342 err = fat_flush_inodes(sb, dir, inode);
347 /***** Make a directory */
348 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
350 struct super_block *sb = dir->i_sb;
351 struct fat_slot_info sinfo;
353 unsigned char msdos_name[MSDOS_NAME];
355 int err, is_hid, cluster;
357 mutex_lock(&MSDOS_SB(sb)->s_lock);
359 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
360 msdos_name, &MSDOS_SB(sb)->options);
363 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
364 /* foo vs .foo situation */
365 if (!fat_scan(dir, msdos_name, &sinfo)) {
371 ts = CURRENT_TIME_SEC;
372 cluster = fat_alloc_new_dir(dir, &ts);
377 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
382 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
385 err = PTR_ERR(inode);
386 /* the directory was completed, just return a error */
390 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
391 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
393 d_instantiate(dentry, inode);
395 mutex_unlock(&MSDOS_SB(sb)->s_lock);
396 fat_flush_inodes(sb, dir, inode);
400 fat_free_clusters(dir, cluster);
402 mutex_unlock(&MSDOS_SB(sb)->s_lock);
406 /***** Unlink a file */
407 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
409 struct inode *inode = dentry->d_inode;
410 struct super_block *sb = inode->i_sb;
411 struct fat_slot_info sinfo;
414 mutex_lock(&MSDOS_SB(sb)->s_lock);
415 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
419 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
423 inode->i_ctime = CURRENT_TIME_SEC;
426 mutex_unlock(&MSDOS_SB(sb)->s_lock);
428 err = fat_flush_inodes(sb, dir, inode);
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)
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;
444 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
446 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
447 old_inode = old_dentry->d_inode;
448 new_inode = new_dentry->d_inode;
450 err = fat_scan(old_dir, old_name, &old_sinfo);
456 is_dir = S_ISDIR(old_inode->i_mode);
457 update_dotdot = (is_dir && old_dir != new_dir);
459 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de)) {
465 old_attrs = MSDOS_I(old_inode)->i_attrs;
466 err = fat_scan(new_dir, new_name, &sinfo);
469 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
470 if (sinfo.de != old_sinfo.de) {
475 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
477 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
478 if (IS_DIRSYNC(old_dir)) {
479 err = fat_sync_inode(old_inode);
481 MSDOS_I(old_inode)->i_attrs = old_attrs;
485 mark_inode_dirty(old_inode);
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);
492 mark_inode_dirty(old_dir);
497 ts = CURRENT_TIME_SEC;
502 err = fat_dir_empty(new_inode);
506 new_i_pos = MSDOS_I(new_inode)->i_pos;
507 fat_detach(new_inode);
509 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
513 new_i_pos = sinfo.i_pos;
515 new_dir->i_version++;
517 fat_detach(old_inode);
518 fat_attach(old_inode, new_i_pos);
520 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
522 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
523 if (IS_DIRSYNC(new_dir)) {
524 err = fat_sync_inode(old_inode);
528 mark_inode_dirty(old_inode);
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);
543 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
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);
552 mark_inode_dirty(old_dir);
555 drop_nlink(new_inode);
557 drop_nlink(new_inode);
558 new_inode->i_ctime = ts;
563 brelse(old_sinfo.bh);
567 /* data cluster is shared, serious corruption */
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);
576 fat_detach(old_inode);
577 fat_attach(old_inode, old_sinfo.i_pos);
578 MSDOS_I(old_inode)->i_attrs = old_attrs;
580 fat_attach(new_inode, new_i_pos);
582 corrupt |= fat_sync_inode(new_inode);
585 * If new entry was not sharing the data cluster, it
586 * shouldn't be serious corruption.
588 int err2 = fat_remove_entries(new_dir, &sinfo);
594 fat_fs_error(new_dir->i_sb,
595 "%s: Filesystem corrupted (i_pos %lld)",
596 __func__, sinfo.i_pos);
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)
605 struct super_block *sb = old_dir->i_sb;
606 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
609 mutex_lock(&MSDOS_SB(sb)->s_lock);
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);
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);
623 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
625 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
626 new_dir, new_msdos_name, new_dentry, is_hid);
628 mutex_unlock(&MSDOS_SB(sb)->s_lock);
630 err = fat_flush_inodes(sb, old_dir, new_dir);
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,
645 static void setup(struct super_block *sb)
647 MSDOS_SB(sb)->dir_ops = &msdos_dir_inode_operations;
648 sb->s_d_op = &msdos_dentry_operations;
649 sb->s_flags |= MS_NOATIME;
652 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
654 return fat_fill_super(sb, data, silent, 0, setup);
657 static struct dentry *msdos_mount(struct file_system_type *fs_type,
658 int flags, const char *dev_name,
661 return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
664 static struct file_system_type msdos_fs_type = {
665 .owner = THIS_MODULE,
667 .mount = msdos_mount,
668 .kill_sb = kill_block_super,
669 .fs_flags = FS_REQUIRES_DEV,
672 static int __init init_msdos_fs(void)
674 return register_filesystem(&msdos_fs_type);
677 static void __exit exit_msdos_fs(void)
679 unregister_filesystem(&msdos_fs_type);
682 MODULE_LICENSE("GPL");
683 MODULE_AUTHOR("Werner Almesberger");
684 MODULE_DESCRIPTION("MS-DOS filesystem support");
686 module_init(init_msdos_fs)
687 module_exit(exit_msdos_fs)