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(struct dentry
*dentry
, struct qstr
*qstr
)
153 struct fat_mount_options
*options
= &MSDOS_SB(dentry
->d_sb
)->options
;
154 unsigned char msdos_name
[MSDOS_NAME
];
157 error
= msdos_format_name(qstr
->name
, qstr
->len
, msdos_name
, options
);
159 qstr
->hash
= full_name_hash(msdos_name
, MSDOS_NAME
);
164 * Compare two msdos names. If either of the names are invalid,
165 * we fall back to doing the standard name comparison.
167 static int msdos_cmp(struct dentry
*dentry
, struct qstr
*a
, struct qstr
*b
)
169 struct fat_mount_options
*options
= &MSDOS_SB(dentry
->d_sb
)->options
;
170 unsigned char a_msdos_name
[MSDOS_NAME
], b_msdos_name
[MSDOS_NAME
];
173 error
= msdos_format_name(a
->name
, a
->len
, a_msdos_name
, options
);
176 error
= msdos_format_name(b
->name
, b
->len
, b_msdos_name
, options
);
179 error
= memcmp(a_msdos_name
, b_msdos_name
, MSDOS_NAME
);
185 if (a
->len
== b
->len
)
186 error
= memcmp(a
->name
, b
->name
, a
->len
);
190 static const struct dentry_operations msdos_dentry_operations
= {
191 .d_hash
= msdos_hash
,
192 .d_compare
= msdos_cmp
,
196 * AV. Wrappers for FAT sb operations. Is it wise?
199 /***** Get inode using directory and name */
200 static struct dentry
*msdos_lookup(struct inode
*dir
, struct dentry
*dentry
,
201 struct nameidata
*nd
)
203 struct super_block
*sb
= dir
->i_sb
;
204 struct fat_slot_info sinfo
;
210 err
= msdos_find(dir
, dentry
->d_name
.name
, dentry
->d_name
.len
, &sinfo
);
212 if (err
== -ENOENT
) {
219 inode
= fat_build_inode(sb
, sinfo
.de
, sinfo
.i_pos
);
222 err
= PTR_ERR(inode
);
227 dentry
->d_op
= &msdos_dentry_operations
;
228 dentry
= d_splice_alias(inode
, dentry
);
230 dentry
->d_op
= &msdos_dentry_operations
;
238 /***** Creates a directory entry (name is already formatted). */
239 static int msdos_add_entry(struct inode
*dir
, const unsigned char *name
,
240 int is_dir
, int is_hid
, int cluster
,
241 struct timespec
*ts
, struct fat_slot_info
*sinfo
)
243 struct msdos_sb_info
*sbi
= MSDOS_SB(dir
->i_sb
);
244 struct msdos_dir_entry de
;
248 memcpy(de
.name
, name
, MSDOS_NAME
);
249 de
.attr
= is_dir
? ATTR_DIR
: ATTR_ARCH
;
251 de
.attr
|= ATTR_HIDDEN
;
253 fat_time_unix2fat(sbi
, ts
, &time
, &date
, NULL
);
254 de
.cdate
= de
.adate
= 0;
259 de
.start
= cpu_to_le16(cluster
);
260 de
.starthi
= cpu_to_le16(cluster
>> 16);
263 err
= fat_add_entries(dir
, &de
, 1, sinfo
);
267 dir
->i_ctime
= dir
->i_mtime
= *ts
;
269 (void)fat_sync_inode(dir
);
271 mark_inode_dirty(dir
);
276 /***** Create a file */
277 static int msdos_create(struct inode
*dir
, struct dentry
*dentry
, int mode
,
278 struct nameidata
*nd
)
280 struct super_block
*sb
= dir
->i_sb
;
281 struct inode
*inode
= NULL
;
282 struct fat_slot_info sinfo
;
284 unsigned char msdos_name
[MSDOS_NAME
];
289 err
= msdos_format_name(dentry
->d_name
.name
, dentry
->d_name
.len
,
290 msdos_name
, &MSDOS_SB(sb
)->options
);
293 is_hid
= (dentry
->d_name
.name
[0] == '.') && (msdos_name
[0] != '.');
294 /* Have to do it due to foo vs. .foo conflicts */
295 if (!fat_scan(dir
, msdos_name
, &sinfo
)) {
301 ts
= CURRENT_TIME_SEC
;
302 err
= msdos_add_entry(dir
, msdos_name
, 0, is_hid
, 0, &ts
, &sinfo
);
305 inode
= fat_build_inode(sb
, sinfo
.de
, sinfo
.i_pos
);
308 err
= PTR_ERR(inode
);
311 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= ts
;
312 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
314 d_instantiate(dentry
, inode
);
318 err
= fat_flush_inodes(sb
, dir
, inode
);
322 /***** Remove a directory */
323 static int msdos_rmdir(struct inode
*dir
, struct dentry
*dentry
)
325 struct super_block
*sb
= dir
->i_sb
;
326 struct inode
*inode
= dentry
->d_inode
;
327 struct fat_slot_info sinfo
;
332 * Check whether the directory is not in use, then check
333 * whether it is empty.
335 err
= fat_dir_empty(inode
);
338 err
= msdos_find(dir
, dentry
->d_name
.name
, dentry
->d_name
.len
, &sinfo
);
342 err
= fat_remove_entries(dir
, &sinfo
); /* and releases bh */
348 inode
->i_ctime
= CURRENT_TIME_SEC
;
353 err
= fat_flush_inodes(sb
, dir
, inode
);
358 /***** Make a directory */
359 static int msdos_mkdir(struct inode
*dir
, struct dentry
*dentry
, int mode
)
361 struct super_block
*sb
= dir
->i_sb
;
362 struct fat_slot_info sinfo
;
364 unsigned char msdos_name
[MSDOS_NAME
];
366 int err
, is_hid
, cluster
;
370 err
= msdos_format_name(dentry
->d_name
.name
, dentry
->d_name
.len
,
371 msdos_name
, &MSDOS_SB(sb
)->options
);
374 is_hid
= (dentry
->d_name
.name
[0] == '.') && (msdos_name
[0] != '.');
375 /* foo vs .foo situation */
376 if (!fat_scan(dir
, msdos_name
, &sinfo
)) {
382 ts
= CURRENT_TIME_SEC
;
383 cluster
= fat_alloc_new_dir(dir
, &ts
);
388 err
= msdos_add_entry(dir
, msdos_name
, 1, is_hid
, cluster
, &ts
, &sinfo
);
393 inode
= fat_build_inode(sb
, sinfo
.de
, sinfo
.i_pos
);
396 err
= PTR_ERR(inode
);
397 /* the directory was completed, just return a error */
401 inode
->i_mtime
= inode
->i_atime
= inode
->i_ctime
= ts
;
402 /* timestamp is already written, so mark_inode_dirty() is unneeded. */
404 d_instantiate(dentry
, inode
);
407 fat_flush_inodes(sb
, dir
, inode
);
411 fat_free_clusters(dir
, cluster
);
417 /***** Unlink a file */
418 static int msdos_unlink(struct inode
*dir
, struct dentry
*dentry
)
420 struct inode
*inode
= dentry
->d_inode
;
421 struct super_block
*sb
= inode
->i_sb
;
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(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_inode(dotdot_bh
, old_inode
);
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_inode(dotdot_bh
, old_inode
);
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_error(new_dir
->i_sb
,
611 "%s: Filesystem corrupted (i_pos %lld)",
612 __func__
, 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 struct super_block
*sb
= old_dir
->i_sb
;
622 unsigned char old_msdos_name
[MSDOS_NAME
], new_msdos_name
[MSDOS_NAME
];
627 err
= msdos_format_name(old_dentry
->d_name
.name
,
628 old_dentry
->d_name
.len
, old_msdos_name
,
629 &MSDOS_SB(old_dir
->i_sb
)->options
);
632 err
= msdos_format_name(new_dentry
->d_name
.name
,
633 new_dentry
->d_name
.len
, new_msdos_name
,
634 &MSDOS_SB(new_dir
->i_sb
)->options
);
639 (new_dentry
->d_name
.name
[0] == '.') && (new_msdos_name
[0] != '.');
641 err
= do_msdos_rename(old_dir
, old_msdos_name
, old_dentry
,
642 new_dir
, new_msdos_name
, new_dentry
, is_hid
);
646 err
= fat_flush_inodes(sb
, old_dir
, new_dir
);
650 static const struct inode_operations msdos_dir_inode_operations
= {
651 .create
= msdos_create
,
652 .lookup
= msdos_lookup
,
653 .unlink
= msdos_unlink
,
654 .mkdir
= msdos_mkdir
,
655 .rmdir
= msdos_rmdir
,
656 .rename
= msdos_rename
,
657 .setattr
= fat_setattr
,
658 .getattr
= fat_getattr
,
661 static int msdos_fill_super(struct super_block
*sb
, void *data
, int silent
)
665 res
= fat_fill_super(sb
, data
, silent
, &msdos_dir_inode_operations
, 0);
669 sb
->s_flags
|= MS_NOATIME
;
670 sb
->s_root
->d_op
= &msdos_dentry_operations
;
674 static int msdos_get_sb(struct file_system_type
*fs_type
,
675 int flags
, const char *dev_name
,
676 void *data
, struct vfsmount
*mnt
)
678 return get_sb_bdev(fs_type
, flags
, dev_name
, data
, msdos_fill_super
,
682 static struct file_system_type msdos_fs_type
= {
683 .owner
= THIS_MODULE
,
685 .get_sb
= msdos_get_sb
,
686 .kill_sb
= kill_block_super
,
687 .fs_flags
= FS_REQUIRES_DEV
,
690 static int __init
init_msdos_fs(void)
692 return register_filesystem(&msdos_fs_type
);
695 static void __exit
exit_msdos_fs(void)
697 unregister_filesystem(&msdos_fs_type
);
700 MODULE_LICENSE("GPL");
701 MODULE_AUTHOR("Werner Almesberger");
702 MODULE_DESCRIPTION("MS-DOS filesystem support");
704 module_init(init_msdos_fs
)
705 module_exit(exit_msdos_fs
)