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,
204 struct nameidata *nd)
206 struct super_block *sb = dir->i_sb;
207 struct fat_slot_info sinfo;
213 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
215 if (err == -ENOENT) {
222 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
225 err = PTR_ERR(inode);
230 return d_splice_alias(inode, dentry);
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;
247 memcpy(de.name, name, MSDOS_NAME);
248 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
250 de.attr |= ATTR_HIDDEN;
252 fat_time_unix2fat(sbi, ts, &time, &date, NULL);
253 de.cdate = de.adate = 0;
258 de.start = cpu_to_le16(cluster);
259 de.starthi = cpu_to_le16(cluster >> 16);
262 err = fat_add_entries(dir, &de, 1, sinfo);
266 dir->i_ctime = dir->i_mtime = *ts;
268 (void)fat_sync_inode(dir);
270 mark_inode_dirty(dir);
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;
283 unsigned char msdos_name[MSDOS_NAME];
288 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
289 msdos_name, &MSDOS_SB(sb)->options);
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)) {
300 ts = CURRENT_TIME_SEC;
301 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
304 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
307 err = PTR_ERR(inode);
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);
317 err = fat_flush_inodes(sb, dir, inode);
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;
329 dentry_unhash(dentry);
333 * Check whether the directory is not in use, then check
334 * whether it is empty.
336 err = fat_dir_empty(inode);
339 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
343 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
349 inode->i_ctime = CURRENT_TIME_SEC;
354 err = fat_flush_inodes(sb, dir, inode);
359 /***** Make a directory */
360 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
362 struct super_block *sb = dir->i_sb;
363 struct fat_slot_info sinfo;
365 unsigned char msdos_name[MSDOS_NAME];
367 int err, is_hid, cluster;
371 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
372 msdos_name, &MSDOS_SB(sb)->options);
375 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
376 /* foo vs .foo situation */
377 if (!fat_scan(dir, msdos_name, &sinfo)) {
383 ts = CURRENT_TIME_SEC;
384 cluster = fat_alloc_new_dir(dir, &ts);
389 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
394 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
397 err = PTR_ERR(inode);
398 /* the directory was completed, just return a error */
402 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
403 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
405 d_instantiate(dentry, inode);
408 fat_flush_inodes(sb, dir, inode);
412 fat_free_clusters(dir, cluster);
418 /***** Unlink a file */
419 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
421 struct inode *inode = dentry->d_inode;
422 struct super_block *sb= inode->i_sb;
423 struct fat_slot_info sinfo;
427 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
431 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
435 inode->i_ctime = CURRENT_TIME_SEC;
440 err = fat_flush_inodes(sb, dir, inode);
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)
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;
455 loff_t dotdot_i_pos, new_i_pos;
456 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
458 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
459 old_inode = old_dentry->d_inode;
460 new_inode = new_dentry->d_inode;
462 err = fat_scan(old_dir, old_name, &old_sinfo);
468 is_dir = S_ISDIR(old_inode->i_mode);
469 update_dotdot = (is_dir && old_dir != new_dir);
471 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
472 &dotdot_i_pos) < 0) {
478 old_attrs = MSDOS_I(old_inode)->i_attrs;
479 err = fat_scan(new_dir, new_name, &sinfo);
482 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
483 if (sinfo.de != old_sinfo.de) {
488 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
490 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
491 if (IS_DIRSYNC(old_dir)) {
492 err = fat_sync_inode(old_inode);
494 MSDOS_I(old_inode)->i_attrs = old_attrs;
498 mark_inode_dirty(old_inode);
500 old_dir->i_version++;
501 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
502 if (IS_DIRSYNC(old_dir))
503 (void)fat_sync_inode(old_dir);
505 mark_inode_dirty(old_dir);
510 ts = CURRENT_TIME_SEC;
515 err = fat_dir_empty(new_inode);
519 new_i_pos = MSDOS_I(new_inode)->i_pos;
520 fat_detach(new_inode);
522 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
526 new_i_pos = sinfo.i_pos;
528 new_dir->i_version++;
530 fat_detach(old_inode);
531 fat_attach(old_inode, new_i_pos);
533 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
535 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
536 if (IS_DIRSYNC(new_dir)) {
537 err = fat_sync_inode(old_inode);
541 mark_inode_dirty(old_inode);
544 int start = MSDOS_I(new_dir)->i_logstart;
545 dotdot_de->start = cpu_to_le16(start);
546 dotdot_de->starthi = cpu_to_le16(start >> 16);
547 mark_buffer_dirty_inode(dotdot_bh, old_inode);
548 if (IS_DIRSYNC(new_dir)) {
549 err = sync_dirty_buffer(dotdot_bh);
558 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
562 old_dir->i_version++;
563 old_dir->i_ctime = old_dir->i_mtime = ts;
564 if (IS_DIRSYNC(old_dir))
565 (void)fat_sync_inode(old_dir);
567 mark_inode_dirty(old_dir);
570 drop_nlink(new_inode);
572 drop_nlink(new_inode);
573 new_inode->i_ctime = ts;
578 brelse(old_sinfo.bh);
582 /* data cluster is shared, serious corruption */
586 int start = MSDOS_I(old_dir)->i_logstart;
587 dotdot_de->start = cpu_to_le16(start);
588 dotdot_de->starthi = cpu_to_le16(start >> 16);
589 mark_buffer_dirty_inode(dotdot_bh, old_inode);
590 corrupt |= sync_dirty_buffer(dotdot_bh);
593 fat_detach(old_inode);
594 fat_attach(old_inode, old_sinfo.i_pos);
595 MSDOS_I(old_inode)->i_attrs = old_attrs;
597 fat_attach(new_inode, new_i_pos);
599 corrupt |= fat_sync_inode(new_inode);
602 * If new entry was not sharing the data cluster, it
603 * shouldn't be serious corruption.
605 int err2 = fat_remove_entries(new_dir, &sinfo);
611 fat_fs_error(new_dir->i_sb,
612 "%s: Filesystem corrupted (i_pos %lld)",
613 __func__, sinfo.i_pos);
618 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
619 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
620 struct inode *new_dir, struct dentry *new_dentry)
622 struct super_block *sb = old_dir->i_sb;
623 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
628 err = msdos_format_name(old_dentry->d_name.name,
629 old_dentry->d_name.len, old_msdos_name,
630 &MSDOS_SB(old_dir->i_sb)->options);
633 err = msdos_format_name(new_dentry->d_name.name,
634 new_dentry->d_name.len, new_msdos_name,
635 &MSDOS_SB(new_dir->i_sb)->options);
640 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
642 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
643 new_dir, new_msdos_name, new_dentry, is_hid);
647 err = fat_flush_inodes(sb, old_dir, new_dir);
651 static const struct inode_operations msdos_dir_inode_operations = {
652 .create = msdos_create,
653 .lookup = msdos_lookup,
654 .unlink = msdos_unlink,
655 .mkdir = msdos_mkdir,
656 .rmdir = msdos_rmdir,
657 .rename = msdos_rename,
658 .setattr = fat_setattr,
659 .getattr = fat_getattr,
662 static void setup(struct super_block *sb)
664 sb->s_d_op = &msdos_dentry_operations;
665 sb->s_flags |= MS_NOATIME;
668 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
670 return fat_fill_super(sb, data, silent, &msdos_dir_inode_operations,
674 static struct dentry *msdos_mount(struct file_system_type *fs_type,
675 int flags, const char *dev_name,
678 return mount_bdev(fs_type, flags, dev_name, data, msdos_fill_super);
681 static struct file_system_type msdos_fs_type = {
682 .owner = THIS_MODULE,
684 .mount = msdos_mount,
685 .kill_sb = kill_block_super,
686 .fs_flags = FS_REQUIRES_DEV,
689 static int __init init_msdos_fs(void)
691 return register_filesystem(&msdos_fs_type);
694 static void __exit exit_msdos_fs(void)
696 unregister_filesystem(&msdos_fs_type);
699 MODULE_LICENSE("GPL");
700 MODULE_AUTHOR("Werner Almesberger");
701 MODULE_DESCRIPTION("MS-DOS filesystem support");
703 module_init(init_msdos_fs)
704 module_exit(exit_msdos_fs)