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;
331 * Check whether the directory is not in use, then check
332 * whether it is empty.
334 err = fat_dir_empty(inode);
337 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
341 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
347 inode->i_ctime = CURRENT_TIME_SEC;
352 err = fat_flush_inodes(sb, dir, inode);
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;
363 unsigned char msdos_name[MSDOS_NAME];
365 int err, is_hid, cluster;
369 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
370 msdos_name, &MSDOS_SB(sb)->options);
373 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
374 /* foo vs .foo situation */
375 if (!fat_scan(dir, msdos_name, &sinfo)) {
381 ts = CURRENT_TIME_SEC;
382 cluster = fat_alloc_new_dir(dir, &ts);
387 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
392 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
395 err = PTR_ERR(inode);
396 /* the directory was completed, just return a error */
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);
406 fat_flush_inodes(sb, dir, inode);
410 fat_free_clusters(dir, cluster);
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;
425 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
429 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
433 inode->i_ctime = CURRENT_TIME_SEC;
438 err = fat_flush_inodes(sb, dir, inode);
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;
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);
466 is_dir = S_ISDIR(old_inode->i_mode);
467 update_dotdot = (is_dir && old_dir != new_dir);
469 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
470 &dotdot_i_pos) < 0) {
476 old_attrs = MSDOS_I(old_inode)->i_attrs;
477 err = fat_scan(new_dir, new_name, &sinfo);
480 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
481 if (sinfo.de != old_sinfo.de) {
486 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
488 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
489 if (IS_DIRSYNC(old_dir)) {
490 err = fat_sync_inode(old_inode);
492 MSDOS_I(old_inode)->i_attrs = old_attrs;
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);
503 mark_inode_dirty(old_dir);
508 ts = CURRENT_TIME_SEC;
513 err = fat_dir_empty(new_inode);
517 new_i_pos = MSDOS_I(new_inode)->i_pos;
518 fat_detach(new_inode);
520 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
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);
531 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
533 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
534 if (IS_DIRSYNC(new_dir)) {
535 err = fat_sync_inode(old_inode);
539 mark_inode_dirty(old_inode);
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);
556 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
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);
565 mark_inode_dirty(old_dir);
568 drop_nlink(new_inode);
570 drop_nlink(new_inode);
571 new_inode->i_ctime = ts;
576 brelse(old_sinfo.bh);
580 /* data cluster is shared, serious corruption */
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);
591 fat_detach(old_inode);
592 fat_attach(old_inode, old_sinfo.i_pos);
593 MSDOS_I(old_inode)->i_attrs = old_attrs;
595 fat_attach(new_inode, new_i_pos);
597 corrupt |= fat_sync_inode(new_inode);
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);
609 fat_fs_error(new_dir->i_sb,
610 "%s: Filesystem corrupted (i_pos %lld)",
611 __func__, sinfo.i_pos);
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];
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);
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);
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);
645 err = fat_flush_inodes(sb, old_dir, new_dir);
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,
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,
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)