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>
12 #include <linux/msdos_fs.h>
13 #include <linux/smp_lock.h>
15 /* Characters that are undesirable in an MS-DOS file name */
16 static unsigned char bad_chars[] = "*?<>|\"";
17 static unsigned char bad_if_strict[] = "+=,; ";
19 /***** Formats an MS-DOS file name. Rejects invalid names. */
20 static int msdos_format_name(const unsigned char *name, int len,
21 unsigned char *res, struct fat_mount_options *opts)
23 * name is the proposed name, len is its length, res is
24 * the resulting name, opts->name_check is either (r)elaxed,
25 * (n)ormal or (s)trict, opts->dotsOK allows dots at the
26 * beginning of name (for hidden files)
33 if (name[0] == '.') { /* dotfile because . and .. already done */
35 /* Get rid of dot - test for it elsewhere */
42 * disallow names that _really_ start with a dot
46 for (walk = res; len && walk - res < 8; walk++) {
49 if (opts->name_check != 'r' && strchr(bad_chars, c))
51 if (opts->name_check == 's' && strchr(bad_if_strict, c))
53 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
55 if (c < ' ' || c == ':' || c == '\\')
58 * 0xE5 is legal as a first character, but we must substitute
59 * 0x05 because 0xE5 marks deleted files. Yes, DOS really
61 * It seems that Microsoft hacked DOS to support non-US
62 * characters after the 0xE5 character was already in use to
65 if ((res == walk) && (c == 0xE5))
70 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
74 if (opts->name_check == 's' && len && c != '.') {
80 while (c != '.' && len--)
83 while (walk - res < 8)
85 while (len > 0 && walk - res < MSDOS_NAME) {
88 if (opts->name_check != 'r' && strchr(bad_chars, c))
90 if (opts->name_check == 's' &&
91 strchr(bad_if_strict, c))
93 if (c < ' ' || c == ':' || c == '\\')
96 if (opts->name_check == 's')
100 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
103 if (!opts->nocase && c >= 'a' && c <= 'z')
110 if (opts->name_check == 's' && len)
113 while (walk - res < MSDOS_NAME)
119 /***** Locates a directory entry. Uses unformatted name. */
120 static int msdos_find(struct inode *dir, const unsigned char *name, int len,
121 struct fat_slot_info *sinfo)
123 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
124 unsigned char msdos_name[MSDOS_NAME];
127 err = msdos_format_name(name, len, msdos_name, &sbi->options);
131 err = fat_scan(dir, msdos_name, sinfo);
132 if (!err && sbi->options.dotsOK) {
133 if (name[0] == '.') {
134 if (!(sinfo->de->attr & ATTR_HIDDEN))
137 if (sinfo->de->attr & ATTR_HIDDEN)
147 * Compute the hash for the msdos name corresponding to the dentry.
148 * Note: if the name is invalid, we leave the hash code unchanged so
149 * that the existing dentry can be used. The msdos fs routines will
150 * return ENOENT or EINVAL as appropriate.
152 static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
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(struct dentry *dentry, struct qstr *a, struct qstr *b)
170 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
171 unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
174 error = msdos_format_name(a->name, a->len, a_msdos_name, options);
177 error = msdos_format_name(b->name, b->len, b_msdos_name, options);
180 error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
186 if (a->len == b->len)
187 error = memcmp(a->name, b->name, a->len);
191 static struct dentry_operations msdos_dentry_operations = {
192 .d_hash = msdos_hash,
193 .d_compare = msdos_cmp,
197 * AV. Wrappers for FAT sb operations. Is it wise?
200 /***** Get inode using directory and name */
201 static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
202 struct nameidata *nd)
204 struct super_block *sb = dir->i_sb;
205 struct fat_slot_info sinfo;
206 struct inode *inode = NULL;
209 dentry->d_op = &msdos_dentry_operations;
212 res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
217 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
220 res = PTR_ERR(inode);
225 dentry = d_splice_alias(inode, dentry);
227 dentry->d_op = &msdos_dentry_operations;
235 /***** Creates a directory entry (name is already formatted). */
236 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
237 int is_dir, int is_hid, int cluster,
238 struct timespec *ts, struct fat_slot_info *sinfo)
240 struct msdos_dir_entry de;
244 memcpy(de.name, name, MSDOS_NAME);
245 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
247 de.attr |= ATTR_HIDDEN;
249 fat_date_unix2dos(ts->tv_sec, &time, &date);
250 de.cdate = de.adate = 0;
255 de.start = cpu_to_le16(cluster);
256 de.starthi = cpu_to_le16(cluster >> 16);
259 err = fat_add_entries(dir, &de, 1, sinfo);
263 dir->i_ctime = dir->i_mtime = *ts;
265 (void)fat_sync_inode(dir);
267 mark_inode_dirty(dir);
272 /***** Create a file */
273 static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
274 struct nameidata *nd)
276 struct super_block *sb = dir->i_sb;
277 struct inode *inode = NULL;
278 struct fat_slot_info sinfo;
280 unsigned char msdos_name[MSDOS_NAME];
285 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
286 msdos_name, &MSDOS_SB(sb)->options);
289 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
290 /* Have to do it due to foo vs. .foo conflicts */
291 if (!fat_scan(dir, msdos_name, &sinfo)) {
297 ts = CURRENT_TIME_SEC;
298 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
301 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
304 err = PTR_ERR(inode);
307 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
308 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
310 d_instantiate(dentry, inode);
314 err = fat_flush_inodes(sb, dir, inode);
318 /***** Remove a directory */
319 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
321 struct super_block *sb = dir->i_sb;
322 struct inode *inode = dentry->d_inode;
323 struct fat_slot_info sinfo;
328 * Check whether the directory is not in use, then check
329 * whether it is empty.
331 err = fat_dir_empty(inode);
334 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
338 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
344 inode->i_ctime = CURRENT_TIME_SEC;
349 err = fat_flush_inodes(sb, dir, inode);
354 /***** Make a directory */
355 static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
357 struct super_block *sb = dir->i_sb;
358 struct fat_slot_info sinfo;
360 unsigned char msdos_name[MSDOS_NAME];
362 int err, is_hid, cluster;
366 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
367 msdos_name, &MSDOS_SB(sb)->options);
370 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
371 /* foo vs .foo situation */
372 if (!fat_scan(dir, msdos_name, &sinfo)) {
378 ts = CURRENT_TIME_SEC;
379 cluster = fat_alloc_new_dir(dir, &ts);
384 err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
389 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
392 err = PTR_ERR(inode);
393 /* the directory was completed, just return a error */
397 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
398 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
400 d_instantiate(dentry, inode);
403 fat_flush_inodes(sb, dir, inode);
407 fat_free_clusters(dir, cluster);
413 /***** Unlink a file */
414 static int msdos_unlink(struct inode *dir, struct dentry *dentry)
416 struct inode *inode = dentry->d_inode;
417 struct super_block *sb= inode->i_sb;
418 struct fat_slot_info sinfo;
422 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
426 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
430 inode->i_ctime = CURRENT_TIME_SEC;
435 err = fat_flush_inodes(sb, dir, inode);
440 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
441 struct dentry *old_dentry,
442 struct inode *new_dir, unsigned char *new_name,
443 struct dentry *new_dentry, int is_hid)
445 struct buffer_head *dotdot_bh;
446 struct msdos_dir_entry *dotdot_de;
447 struct inode *old_inode, *new_inode;
448 struct fat_slot_info old_sinfo, sinfo;
450 loff_t dotdot_i_pos, new_i_pos;
451 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
453 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
454 old_inode = old_dentry->d_inode;
455 new_inode = new_dentry->d_inode;
457 err = fat_scan(old_dir, old_name, &old_sinfo);
463 is_dir = S_ISDIR(old_inode->i_mode);
464 update_dotdot = (is_dir && old_dir != new_dir);
466 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
467 &dotdot_i_pos) < 0) {
473 old_attrs = MSDOS_I(old_inode)->i_attrs;
474 err = fat_scan(new_dir, new_name, &sinfo);
477 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
478 if (sinfo.de != old_sinfo.de) {
483 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
485 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
486 if (IS_DIRSYNC(old_dir)) {
487 err = fat_sync_inode(old_inode);
489 MSDOS_I(old_inode)->i_attrs = old_attrs;
493 mark_inode_dirty(old_inode);
495 old_dir->i_version++;
496 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
497 if (IS_DIRSYNC(old_dir))
498 (void)fat_sync_inode(old_dir);
500 mark_inode_dirty(old_dir);
505 ts = CURRENT_TIME_SEC;
510 err = fat_dir_empty(new_inode);
514 new_i_pos = MSDOS_I(new_inode)->i_pos;
515 fat_detach(new_inode);
517 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
521 new_i_pos = sinfo.i_pos;
523 new_dir->i_version++;
525 fat_detach(old_inode);
526 fat_attach(old_inode, new_i_pos);
528 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
530 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
531 if (IS_DIRSYNC(new_dir)) {
532 err = fat_sync_inode(old_inode);
536 mark_inode_dirty(old_inode);
539 int start = MSDOS_I(new_dir)->i_logstart;
540 dotdot_de->start = cpu_to_le16(start);
541 dotdot_de->starthi = cpu_to_le16(start >> 16);
542 mark_buffer_dirty(dotdot_bh);
543 if (IS_DIRSYNC(new_dir)) {
544 err = sync_dirty_buffer(dotdot_bh);
553 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
557 old_dir->i_version++;
558 old_dir->i_ctime = old_dir->i_mtime = ts;
559 if (IS_DIRSYNC(old_dir))
560 (void)fat_sync_inode(old_dir);
562 mark_inode_dirty(old_dir);
565 drop_nlink(new_inode);
567 drop_nlink(new_inode);
568 new_inode->i_ctime = ts;
573 brelse(old_sinfo.bh);
577 /* data cluster is shared, serious corruption */
581 int start = MSDOS_I(old_dir)->i_logstart;
582 dotdot_de->start = cpu_to_le16(start);
583 dotdot_de->starthi = cpu_to_le16(start >> 16);
584 mark_buffer_dirty(dotdot_bh);
585 corrupt |= sync_dirty_buffer(dotdot_bh);
588 fat_detach(old_inode);
589 fat_attach(old_inode, old_sinfo.i_pos);
590 MSDOS_I(old_inode)->i_attrs = old_attrs;
592 fat_attach(new_inode, new_i_pos);
594 corrupt |= fat_sync_inode(new_inode);
597 * If new entry was not sharing the data cluster, it
598 * shouldn't be serious corruption.
600 int err2 = fat_remove_entries(new_dir, &sinfo);
606 fat_fs_panic(new_dir->i_sb,
607 "%s: Filesystem corrupted (i_pos %lld)",
608 __func__, sinfo.i_pos);
613 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
614 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
615 struct inode *new_dir, struct dentry *new_dentry)
617 struct super_block *sb = old_dir->i_sb;
618 unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
623 err = msdos_format_name(old_dentry->d_name.name,
624 old_dentry->d_name.len, old_msdos_name,
625 &MSDOS_SB(old_dir->i_sb)->options);
628 err = msdos_format_name(new_dentry->d_name.name,
629 new_dentry->d_name.len, new_msdos_name,
630 &MSDOS_SB(new_dir->i_sb)->options);
635 (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
637 err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
638 new_dir, new_msdos_name, new_dentry, is_hid);
642 err = fat_flush_inodes(sb, old_dir, new_dir);
646 static const struct inode_operations msdos_dir_inode_operations = {
647 .create = msdos_create,
648 .lookup = msdos_lookup,
649 .unlink = msdos_unlink,
650 .mkdir = msdos_mkdir,
651 .rmdir = msdos_rmdir,
652 .rename = msdos_rename,
653 .setattr = fat_setattr,
654 .getattr = fat_getattr,
657 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
661 res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
665 sb->s_flags |= MS_NOATIME;
666 sb->s_root->d_op = &msdos_dentry_operations;
670 static int msdos_get_sb(struct file_system_type *fs_type,
671 int flags, const char *dev_name,
672 void *data, struct vfsmount *mnt)
674 return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
678 static struct file_system_type msdos_fs_type = {
679 .owner = THIS_MODULE,
681 .get_sb = msdos_get_sb,
682 .kill_sb = kill_block_super,
683 .fs_flags = FS_REQUIRES_DEV,
686 static int __init init_msdos_fs(void)
688 return register_filesystem(&msdos_fs_type);
691 static void __exit exit_msdos_fs(void)
693 unregister_filesystem(&msdos_fs_type);
696 MODULE_LICENSE("GPL");
697 MODULE_AUTHOR("Werner Almesberger");
698 MODULE_DESCRIPTION("MS-DOS filesystem support");
700 module_init(init_msdos_fs)
701 module_exit(exit_msdos_fs)