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_pc[] = "+=,; ";
18 /* GEMDOS is less restrictive */
19 static unsigned char bad_if_strict_atari[] = " ";
21 #define bad_if_strict(opts) \
22 ((opts)->atari ? bad_if_strict_atari : bad_if_strict_pc)
24 /***** Formats an MS-DOS file name. Rejects invalid names. */
25 static int msdos_format_name(const unsigned char *name, int len,
26 unsigned char *res, struct fat_mount_options *opts)
28 * name is the proposed name, len is its length, res is
29 * the resulting name, opts->name_check is either (r)elaxed,
30 * (n)ormal or (s)trict, opts->dotsOK allows dots at the
31 * beginning of name (for hidden files)
38 if (name[0] == '.') { /* dotfile because . and .. already done */
40 /* Get rid of dot - test for it elsewhere */
43 } else if (!opts->atari)
47 * disallow names that _really_ start with a dot for MS-DOS,
48 * GEMDOS does not care
52 for (walk = res; len && walk - res < 8; walk++) {
55 if (opts->name_check != 'r' && strchr(bad_chars, c))
57 if (opts->name_check == 's' && strchr(bad_if_strict(opts), c))
59 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
61 if (c < ' ' || c == ':' || c == '\\')
64 * 0xE5 is legal as a first character, but we must substitute
65 * 0x05 because 0xE5 marks deleted files. Yes, DOS really
67 * It seems that Microsoft hacked DOS to support non-US
68 * characters after the 0xE5 character was already in use to
71 if ((res == walk) && (c == 0xE5))
76 *walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
80 if (opts->name_check == 's' && len && c != '.') {
86 while (c != '.' && len--)
89 while (walk - res < 8)
91 while (len > 0 && walk - res < MSDOS_NAME) {
94 if (opts->name_check != 'r' && strchr(bad_chars, c))
96 if (opts->name_check == 's' &&
97 strchr(bad_if_strict(opts), c))
99 if (c < ' ' || c == ':' || c == '\\')
102 if (opts->name_check == 's')
106 if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
109 if (!opts->nocase && c >= 'a' && c <= 'z')
116 if (opts->name_check == 's' && len)
119 while (walk - res < MSDOS_NAME)
125 /***** Locates a directory entry. Uses unformatted name. */
126 static int msdos_find(struct inode *dir, const unsigned char *name, int len,
127 struct fat_slot_info *sinfo)
129 struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
130 unsigned char msdos_name[MSDOS_NAME];
133 err = msdos_format_name(name, len, msdos_name, &sbi->options);
137 err = fat_scan(dir, msdos_name, sinfo);
138 if (!err && sbi->options.dotsOK) {
139 if (name[0] == '.') {
140 if (!(sinfo->de->attr & ATTR_HIDDEN))
143 if (sinfo->de->attr & ATTR_HIDDEN)
153 * Compute the hash for the msdos name corresponding to the dentry.
154 * Note: if the name is invalid, we leave the hash code unchanged so
155 * that the existing dentry can be used. The msdos fs routines will
156 * return ENOENT or EINVAL as appropriate.
158 static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
160 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
161 unsigned char msdos_name[MSDOS_NAME];
164 error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
166 qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
171 * Compare two msdos names. If either of the names are invalid,
172 * we fall back to doing the standard name comparison.
174 static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
176 struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
177 unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
180 error = msdos_format_name(a->name, a->len, a_msdos_name, options);
183 error = msdos_format_name(b->name, b->len, b_msdos_name, options);
186 error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
192 if (a->len == b->len)
193 error = memcmp(a->name, b->name, a->len);
197 static struct dentry_operations msdos_dentry_operations = {
198 .d_hash = msdos_hash,
199 .d_compare = msdos_cmp,
203 * AV. Wrappers for FAT sb operations. Is it wise?
206 /***** Get inode using directory and name */
207 static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
208 struct nameidata *nd)
210 struct super_block *sb = dir->i_sb;
211 struct fat_slot_info sinfo;
212 struct inode *inode = NULL;
215 dentry->d_op = &msdos_dentry_operations;
218 res = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
223 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
226 res = PTR_ERR(inode);
231 dentry = d_splice_alias(inode, dentry);
233 dentry->d_op = &msdos_dentry_operations;
241 /***** Creates a directory entry (name is already formatted). */
242 static int msdos_add_entry(struct inode *dir, const unsigned char *name,
243 int is_dir, int is_hid, int cluster,
244 struct timespec *ts, struct fat_slot_info *sinfo)
246 struct msdos_dir_entry de;
250 memcpy(de.name, name, MSDOS_NAME);
251 de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
253 de.attr |= ATTR_HIDDEN;
255 fat_date_unix2dos(ts->tv_sec, &time, &date);
256 de.cdate = de.adate = 0;
261 de.start = cpu_to_le16(cluster);
262 de.starthi = cpu_to_le16(cluster >> 16);
265 err = fat_add_entries(dir, &de, 1, sinfo);
269 dir->i_ctime = dir->i_mtime = *ts;
271 (void)fat_sync_inode(dir);
273 mark_inode_dirty(dir);
278 /***** Create a file */
279 static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
280 struct nameidata *nd)
282 struct super_block *sb = dir->i_sb;
283 struct inode *inode = NULL;
284 struct fat_slot_info sinfo;
286 unsigned char msdos_name[MSDOS_NAME];
291 err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
292 msdos_name, &MSDOS_SB(sb)->options);
295 is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
296 /* Have to do it due to foo vs. .foo conflicts */
297 if (!fat_scan(dir, msdos_name, &sinfo)) {
303 ts = CURRENT_TIME_SEC;
304 err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
307 inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
310 err = PTR_ERR(inode);
313 inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
314 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
316 d_instantiate(dentry, inode);
320 err = fat_flush_inodes(sb, dir, inode);
324 /***** Remove a directory */
325 static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
327 struct inode *inode = dentry->d_inode;
328 struct fat_slot_info sinfo;
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(inode->i_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 fat_slot_info sinfo;
426 err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
430 err = fat_remove_entries(dir, &sinfo); /* and releases bh */
434 inode->i_ctime = CURRENT_TIME_SEC;
439 err = fat_flush_inodes(inode->i_sb, dir, inode);
444 static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
445 struct dentry *old_dentry,
446 struct inode *new_dir, unsigned char *new_name,
447 struct dentry *new_dentry, int is_hid)
449 struct buffer_head *dotdot_bh;
450 struct msdos_dir_entry *dotdot_de;
451 struct inode *old_inode, *new_inode;
452 struct fat_slot_info old_sinfo, sinfo;
454 loff_t dotdot_i_pos, new_i_pos;
455 int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
457 old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
458 old_inode = old_dentry->d_inode;
459 new_inode = new_dentry->d_inode;
461 err = fat_scan(old_dir, old_name, &old_sinfo);
467 is_dir = S_ISDIR(old_inode->i_mode);
468 update_dotdot = (is_dir && old_dir != new_dir);
470 if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
471 &dotdot_i_pos) < 0) {
477 old_attrs = MSDOS_I(old_inode)->i_attrs;
478 err = fat_scan(new_dir, new_name, &sinfo);
481 /* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
482 if (sinfo.de != old_sinfo.de) {
487 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
489 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
490 if (IS_DIRSYNC(old_dir)) {
491 err = fat_sync_inode(old_inode);
493 MSDOS_I(old_inode)->i_attrs = old_attrs;
497 mark_inode_dirty(old_inode);
499 old_dir->i_version++;
500 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
501 if (IS_DIRSYNC(old_dir))
502 (void)fat_sync_inode(old_dir);
504 mark_inode_dirty(old_dir);
509 ts = CURRENT_TIME_SEC;
514 err = fat_dir_empty(new_inode);
518 new_i_pos = MSDOS_I(new_inode)->i_pos;
519 fat_detach(new_inode);
521 err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
525 new_i_pos = sinfo.i_pos;
527 new_dir->i_version++;
529 fat_detach(old_inode);
530 fat_attach(old_inode, new_i_pos);
532 MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
534 MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
535 if (IS_DIRSYNC(new_dir)) {
536 err = fat_sync_inode(old_inode);
540 mark_inode_dirty(old_inode);
543 int start = MSDOS_I(new_dir)->i_logstart;
544 dotdot_de->start = cpu_to_le16(start);
545 dotdot_de->starthi = cpu_to_le16(start >> 16);
546 mark_buffer_dirty(dotdot_bh);
547 if (IS_DIRSYNC(new_dir)) {
548 err = sync_dirty_buffer(dotdot_bh);
557 err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */
561 old_dir->i_version++;
562 old_dir->i_ctime = old_dir->i_mtime = ts;
563 if (IS_DIRSYNC(old_dir))
564 (void)fat_sync_inode(old_dir);
566 mark_inode_dirty(old_dir);
569 drop_nlink(new_inode);
571 drop_nlink(new_inode);
572 new_inode->i_ctime = ts;
577 brelse(old_sinfo.bh);
581 /* data cluster is shared, serious corruption */
585 int start = MSDOS_I(old_dir)->i_logstart;
586 dotdot_de->start = cpu_to_le16(start);
587 dotdot_de->starthi = cpu_to_le16(start >> 16);
588 mark_buffer_dirty(dotdot_bh);
589 corrupt |= sync_dirty_buffer(dotdot_bh);
592 fat_detach(old_inode);
593 fat_attach(old_inode, old_sinfo.i_pos);
594 MSDOS_I(old_inode)->i_attrs = old_attrs;
596 fat_attach(new_inode, new_i_pos);
598 corrupt |= fat_sync_inode(new_inode);
601 * If new entry was not sharing the data cluster, it
602 * shouldn't be serious corruption.
604 int err2 = fat_remove_entries(new_dir, &sinfo);
610 fat_fs_panic(new_dir->i_sb,
611 "%s: Filesystem corrupted (i_pos %lld)",
612 __FUNCTION__, sinfo.i_pos);
617 /***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
618 static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
619 struct inode *new_dir, struct dentry *new_dentry)
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(old_dir->i_sb, old_dir, new_dir);
649 static 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_notify_change,
659 static int msdos_fill_super(struct super_block *sb, void *data, int silent)
663 res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
667 sb->s_flags |= MS_NOATIME;
668 sb->s_root->d_op = &msdos_dentry_operations;
672 static int msdos_get_sb(struct file_system_type *fs_type,
673 int flags, const char *dev_name,
674 void *data, struct vfsmount *mnt)
676 return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
680 static struct file_system_type msdos_fs_type = {
681 .owner = THIS_MODULE,
683 .get_sb = msdos_get_sb,
684 .kill_sb = kill_block_super,
685 .fs_flags = FS_REQUIRES_DEV,
688 static int __init init_msdos_fs(void)
690 return register_filesystem(&msdos_fs_type);
693 static void __exit exit_msdos_fs(void)
695 unregister_filesystem(&msdos_fs_type);
698 MODULE_LICENSE("GPL");
699 MODULE_AUTHOR("Werner Almesberger");
700 MODULE_DESCRIPTION("MS-DOS filesystem support");
702 module_init(init_msdos_fs)
703 module_exit(exit_msdos_fs)