1 // SPDX-License-Identifier: GPL-2.0-only
5 * directory handling functions for fat-based filesystems
7 * Written 1992,1993 by Werner Almesberger
9 * Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
11 * VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
12 * Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
13 * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
14 * Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
17 #include <linux/slab.h>
18 #include <linux/compat.h>
19 #include <linux/uaccess.h>
20 #include <linux/iversion.h>
24 * Maximum buffer size of short name.
25 * [(MSDOS_NAME + '.') * max one char + nul]
26 * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
28 #define FAT_MAX_SHORT_SIZE ((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
30 * Maximum buffer size of unicode chars from slots.
31 * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
33 #define FAT_MAX_UNI_CHARS ((MSDOS_SLOTS - 1) * 13 + 1)
34 #define FAT_MAX_UNI_SIZE (FAT_MAX_UNI_CHARS * sizeof(wchar_t))
36 static inline unsigned char fat_tolower(unsigned char c)
38 return ((c >= 'A') && (c <= 'Z')) ? c+32 : c;
41 static inline loff_t fat_make_i_pos(struct super_block *sb,
42 struct buffer_head *bh,
43 struct msdos_dir_entry *de)
45 return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
46 | (de - (struct msdos_dir_entry *)bh->b_data);
49 static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
52 struct super_block *sb = dir->i_sb;
53 struct msdos_sb_info *sbi = MSDOS_SB(sb);
54 struct buffer_head *bh;
57 /* This is not a first sector of cluster, or sec_per_clus == 1 */
58 if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
60 /* root dir of FAT12/FAT16 */
61 if (!is_fat32(sbi) && (dir->i_ino == MSDOS_ROOT_INO))
64 bh = sb_find_get_block(sb, phys);
65 if (bh == NULL || !buffer_uptodate(bh)) {
66 for (sec = 0; sec < sbi->sec_per_clus; sec++)
67 sb_breadahead(sb, phys + sec);
72 /* Returns the inode number of the directory entry at offset pos. If bh is
73 non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
75 AV. Most often we do it item-by-item. Makes sense to optimize.
76 AV. OK, there we go: if both bh and de are non-NULL we assume that we just
77 AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
78 AV. It's done in fat_get_entry() (inlined), here the slow case lives.
79 AV. Additionally, when we return -1 (i.e. reached the end of directory)
82 static int fat__get_entry(struct inode *dir, loff_t *pos,
83 struct buffer_head **bh, struct msdos_dir_entry **de)
85 struct super_block *sb = dir->i_sb;
86 sector_t phys, iblock;
87 unsigned long mapped_blocks;
93 iblock = *pos >> sb->s_blocksize_bits;
94 err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false);
96 return -1; /* beyond EOF or error */
98 fat_dir_readahead(dir, iblock, phys);
100 *bh = sb_bread(sb, phys);
102 fat_msg_ratelimit(sb, KERN_ERR,
103 "Directory bread(block %llu) failed", (llu)phys);
104 /* skip this block */
105 *pos = (iblock + 1) << sb->s_blocksize_bits;
109 offset = *pos & (sb->s_blocksize - 1);
110 *pos += sizeof(struct msdos_dir_entry);
111 *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
116 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
117 struct buffer_head **bh,
118 struct msdos_dir_entry **de)
120 /* Fast stuff first */
122 (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
123 MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
124 *pos += sizeof(struct msdos_dir_entry);
128 return fat__get_entry(dir, pos, bh, de);
132 * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
133 * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
134 * colon as an escape character since it is normally invalid on the vfat
135 * filesystem. The following four characters are the hexadecimal digits
136 * of Unicode value. This lets us do a full dump and restore of Unicode
137 * filenames. We could get into some trouble with long Unicode names,
138 * but ignore that right now.
139 * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
141 static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
142 const wchar_t *uni, int len, struct nls_table *nls)
144 int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
153 while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
155 charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
160 if (uni_xlate == 1) {
162 op = hex_byte_pack(op, ec >> 8);
163 op = hex_byte_pack(op, ec);
173 fat_msg(sb, KERN_WARNING,
174 "filename was truncated while converting.");
181 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
182 unsigned char *buf, int size)
184 struct msdos_sb_info *sbi = MSDOS_SB(sb);
185 if (sbi->options.utf8)
186 return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
187 UTF16_HOST_ENDIAN, buf, size);
189 return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
193 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
197 charlen = t->char2uni(c, clen, uni);
199 *uni = 0x003f; /* a question mark */
206 fat_short2lower_uni(struct nls_table *t, unsigned char *c,
207 int clen, wchar_t *uni)
212 charlen = t->char2uni(c, clen, &wc);
214 *uni = 0x003f; /* a question mark */
216 } else if (charlen <= 1) {
217 unsigned char nc = t->charset2lower[*c];
222 charlen = t->char2uni(&nc, 1, uni);
224 *uni = 0x003f; /* a question mark */
234 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
235 wchar_t *uni_buf, unsigned short opt, int lower)
239 if (opt & VFAT_SFN_DISPLAY_LOWER)
240 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
241 else if (opt & VFAT_SFN_DISPLAY_WIN95)
242 len = fat_short2uni(nls, buf, buf_size, uni_buf);
243 else if (opt & VFAT_SFN_DISPLAY_WINNT) {
245 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
247 len = fat_short2uni(nls, buf, buf_size, uni_buf);
249 len = fat_short2uni(nls, buf, buf_size, uni_buf);
254 static inline int fat_name_match(struct msdos_sb_info *sbi,
255 const unsigned char *a, int a_len,
256 const unsigned char *b, int b_len)
261 if (sbi->options.name_check != 's')
262 return !nls_strnicmp(sbi->nls_io, a, b, a_len);
264 return !memcmp(a, b, a_len);
267 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
270 * fat_parse_long - Parse extended directory entry.
272 * This function returns zero on success, negative value on error, or one of
275 * %PARSE_INVALID - Directory entry is invalid.
276 * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
277 * %PARSE_EOF - Directory has no more entries.
279 static int fat_parse_long(struct inode *dir, loff_t *pos,
280 struct buffer_head **bh, struct msdos_dir_entry **de,
281 wchar_t **unicode, unsigned char *nr_slots)
283 struct msdos_dir_slot *ds;
284 unsigned char id, slot, slots, alias_checksum;
287 *unicode = __getname();
294 ds = (struct msdos_dir_slot *)*de;
297 return PARSE_INVALID;
299 if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */
300 return PARSE_INVALID;
302 alias_checksum = ds->alias_checksum;
310 fat16_towchar(*unicode + offset, ds->name0_4, 5);
311 fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
312 fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
315 (*unicode)[offset + 13] = 0;
316 if (fat_get_entry(dir, pos, bh, de) < 0)
320 ds = (struct msdos_dir_slot *)*de;
321 if (ds->attr != ATTR_EXT)
322 return PARSE_NOT_LONGNAME;
323 if ((ds->id & ~0x40) != slot)
325 if (ds->alias_checksum != alias_checksum)
328 if ((*de)->name[0] == DELETED_FLAG)
329 return PARSE_INVALID;
330 if ((*de)->attr == ATTR_EXT)
332 if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
333 return PARSE_INVALID;
334 if (fat_checksum((*de)->name) != alias_checksum)
341 * fat_parse_short - Parse MS-DOS (short) directory entry.
343 * @de: directory entry to parse
344 * @name: FAT_MAX_SHORT_SIZE array in which to place extracted name
345 * @dot_hidden: Nonzero == prepend '.' to names with ATTR_HIDDEN
347 * Returns the number of characters extracted into 'name'.
349 static int fat_parse_short(struct super_block *sb,
350 const struct msdos_dir_entry *de,
351 unsigned char *name, int dot_hidden)
353 const struct msdos_sb_info *sbi = MSDOS_SB(sb);
354 int isvfat = sbi->options.isvfat;
355 int nocase = sbi->options.nocase;
356 unsigned short opt_shortname = sbi->options.shortname;
357 struct nls_table *nls_disk = sbi->nls_disk;
358 wchar_t uni_name[14];
359 unsigned char c, work[MSDOS_NAME];
360 unsigned char *ptname = name;
361 int chi, chl, i, j, k;
363 int name_len = 0, uni_len = 0;
365 if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {
370 memcpy(work, de->name, sizeof(work));
371 /* For an explanation of the special treatment of 0x05 in
372 * filenames, see msdos_format_name in namei_msdos.c
378 for (i = 0, j = 0; i < 8;) {
382 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
383 &uni_name[j++], opt_shortname,
384 de->lcase & CASE_LOWER_BASE);
387 ptname[i] = nocase ? c : fat_tolower(c);
398 for (chi = 0; chi < chl && i < 8; chi++, i++)
408 fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
414 for (k = 8; k < MSDOS_NAME;) {
418 chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
419 &uni_name[j++], opt_shortname,
420 de->lcase & CASE_LOWER_EXT);
424 ptname[i] = nocase ? c : fat_tolower(c);
433 int offset = min(chl, MSDOS_NAME-k);
437 for (chi = 0; chi < chl && k < MSDOS_NAME;
448 name_len += dotoffset;
450 if (sbi->options.isvfat) {
451 uni_name[uni_len] = 0x0000;
452 name_len = fat_uni_to_x8(sb, uni_name, name,
461 * Return values: negative -> error/not found, 0 -> found.
463 int fat_search_long(struct inode *inode, const unsigned char *name,
464 int name_len, struct fat_slot_info *sinfo)
466 struct super_block *sb = inode->i_sb;
467 struct msdos_sb_info *sbi = MSDOS_SB(sb);
468 struct buffer_head *bh = NULL;
469 struct msdos_dir_entry *de;
470 unsigned char nr_slots;
471 wchar_t *unicode = NULL;
472 unsigned char bufname[FAT_MAX_SHORT_SIZE];
478 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
482 if (de->name[0] == DELETED_FLAG)
484 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
486 if (de->attr != ATTR_EXT && IS_FREE(de->name))
488 if (de->attr == ATTR_EXT) {
489 int status = fat_parse_long(inode, &cpos, &bh, &de,
490 &unicode, &nr_slots);
494 } else if (status == PARSE_INVALID)
496 else if (status == PARSE_NOT_LONGNAME)
498 else if (status == PARSE_EOF)
502 /* Never prepend '.' to hidden files here.
503 * That is done only for msdos mounts (and only when
504 * 'dotsOK=yes'); if we are executing here, it is in the
505 * context of a vfat mount.
507 len = fat_parse_short(sb, de, bufname, 0);
511 /* Compare shortname */
512 if (fat_name_match(sbi, name, name_len, bufname, len))
516 void *longname = unicode + FAT_MAX_UNI_CHARS;
517 int size = PATH_MAX - FAT_MAX_UNI_SIZE;
519 /* Compare longname */
520 len = fat_uni_to_x8(sb, unicode, longname, size);
521 if (fat_name_match(sbi, name, name_len, longname, len))
527 nr_slots++; /* include the de */
528 sinfo->slot_off = cpos - nr_slots * sizeof(*de);
529 sinfo->nr_slots = nr_slots;
532 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
540 EXPORT_SYMBOL_GPL(fat_search_long);
542 struct fat_ioctl_filldir_callback {
543 struct dir_context ctx;
547 const char *longname;
549 const char *shortname;
553 static int __fat_readdir(struct inode *inode, struct file *file,
554 struct dir_context *ctx, int short_only,
555 struct fat_ioctl_filldir_callback *both)
557 struct super_block *sb = inode->i_sb;
558 struct msdos_sb_info *sbi = MSDOS_SB(sb);
559 struct buffer_head *bh;
560 struct msdos_dir_entry *de;
561 unsigned char nr_slots;
562 wchar_t *unicode = NULL;
563 unsigned char bufname[FAT_MAX_SHORT_SIZE];
564 int isvfat = sbi->options.isvfat;
565 const char *fill_name = NULL;
568 int short_len = 0, fill_len = 0;
571 mutex_lock(&sbi->s_lock);
574 /* Fake . and .. for the root directory. */
575 if (inode->i_ino == MSDOS_ROOT_INO) {
576 if (!dir_emit_dots(file, ctx))
583 if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
590 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
595 * Check for long filename entry, but if short_only, we don't
596 * need to parse long filename.
598 if (isvfat && !short_only) {
599 if (de->name[0] == DELETED_FLAG)
601 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
603 if (de->attr != ATTR_EXT && IS_FREE(de->name))
606 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
610 if (isvfat && de->attr == ATTR_EXT) {
611 int status = fat_parse_long(inode, &cpos, &bh, &de,
612 &unicode, &nr_slots);
617 } else if (status == PARSE_INVALID)
619 else if (status == PARSE_NOT_LONGNAME)
621 else if (status == PARSE_EOF)
625 void *longname = unicode + FAT_MAX_UNI_CHARS;
626 int size = PATH_MAX - FAT_MAX_UNI_SIZE;
627 int len = fat_uni_to_x8(sb, unicode, longname, size);
629 fill_name = longname;
631 /* !both && !short_only, so we don't need shortname. */
635 short_len = fat_parse_short(sb, de, bufname,
636 sbi->options.dotsOK);
639 /* hack for fat_ioctl_filldir() */
640 both->longname = fill_name;
641 both->long_len = fill_len;
642 both->shortname = bufname;
643 both->short_len = short_len;
650 short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
655 fill_len = short_len;
658 ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
659 if (fake_offset && ctx->pos < 2)
662 if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {
663 if (!dir_emit_dot(file, ctx))
665 } else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
666 if (!dir_emit_dotdot(file, ctx))
670 loff_t i_pos = fat_make_i_pos(sb, bh, de);
671 struct inode *tmp = fat_iget(sb, i_pos);
676 inum = iunique(sb, MSDOS_ROOT_INO);
677 if (!dir_emit(ctx, fill_name, fill_len, inum,
678 (de->attr & ATTR_DIR) ? DT_DIR : DT_REG))
688 if (fake_offset && cpos < 2)
697 mutex_unlock(&sbi->s_lock);
702 static int fat_readdir(struct file *file, struct dir_context *ctx)
704 return __fat_readdir(file_inode(file), file, ctx, 0, NULL);
707 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \
708 static int func(struct dir_context *ctx, const char *name, int name_len, \
709 loff_t offset, u64 ino, unsigned int d_type) \
711 struct fat_ioctl_filldir_callback *buf = \
712 container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \
713 struct dirent_type __user *d1 = buf->dirent; \
714 struct dirent_type __user *d2 = d1 + 1; \
720 if (name != NULL) { \
721 /* dirent has only short name */ \
722 if (name_len >= sizeof(d1->d_name)) \
723 name_len = sizeof(d1->d_name) - 1; \
725 if (put_user(0, d2->d_name) || \
726 put_user(0, &d2->d_reclen) || \
727 copy_to_user(d1->d_name, name, name_len) || \
728 put_user(0, d1->d_name + name_len) || \
729 put_user(name_len, &d1->d_reclen)) \
732 /* dirent has short and long name */ \
733 const char *longname = buf->longname; \
734 int long_len = buf->long_len; \
735 const char *shortname = buf->shortname; \
736 int short_len = buf->short_len; \
738 if (long_len >= sizeof(d1->d_name)) \
739 long_len = sizeof(d1->d_name) - 1; \
740 if (short_len >= sizeof(d1->d_name)) \
741 short_len = sizeof(d1->d_name) - 1; \
743 if (copy_to_user(d2->d_name, longname, long_len) || \
744 put_user(0, d2->d_name + long_len) || \
745 put_user(long_len, &d2->d_reclen) || \
746 put_user(ino, &d2->d_ino) || \
747 put_user(offset, &d2->d_off) || \
748 copy_to_user(d1->d_name, shortname, short_len) || \
749 put_user(0, d1->d_name + short_len) || \
750 put_user(short_len, &d1->d_reclen)) \
755 buf->result = -EFAULT; \
759 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
761 static int fat_ioctl_readdir(struct inode *inode, struct file *file,
762 void __user *dirent, filldir_t filldir,
763 int short_only, int both)
765 struct fat_ioctl_filldir_callback buf = {
766 .ctx.actor = filldir,
773 inode_lock_shared(inode);
774 buf.ctx.pos = file->f_pos;
776 if (!IS_DEADDIR(inode)) {
777 ret = __fat_readdir(inode, file, &buf.ctx,
778 short_only, both ? &buf : NULL);
779 file->f_pos = buf.ctx.pos;
781 inode_unlock_shared(inode);
787 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
790 struct inode *inode = file_inode(filp);
791 struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
792 int short_only, both;
795 case VFAT_IOCTL_READDIR_SHORT:
799 case VFAT_IOCTL_READDIR_BOTH:
804 return fat_generic_ioctl(filp, cmd, arg);
807 if (!access_ok(d1, sizeof(struct __fat_dirent[2])))
810 * Yes, we don't need this put_user() absolutely. However old
811 * code didn't return the right value. So, app use this value,
812 * in order to check whether it is EOF.
814 if (put_user(0, &d1->d_reclen))
817 return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
822 #define VFAT_IOCTL_READDIR_BOTH32 _IOR('r', 1, struct compat_dirent[2])
823 #define VFAT_IOCTL_READDIR_SHORT32 _IOR('r', 2, struct compat_dirent[2])
825 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
827 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
830 struct inode *inode = file_inode(filp);
831 struct compat_dirent __user *d1 = compat_ptr(arg);
832 int short_only, both;
835 case VFAT_IOCTL_READDIR_SHORT32:
839 case VFAT_IOCTL_READDIR_BOTH32:
844 return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
847 if (!access_ok(d1, sizeof(struct compat_dirent[2])))
850 * Yes, we don't need this put_user() absolutely. However old
851 * code didn't return the right value. So, app use this value,
852 * in order to check whether it is EOF.
854 if (put_user(0, &d1->d_reclen))
857 return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
860 #endif /* CONFIG_COMPAT */
862 const struct file_operations fat_dir_operations = {
863 .llseek = generic_file_llseek,
864 .read = generic_read_dir,
865 .iterate_shared = fat_readdir,
866 .unlocked_ioctl = fat_dir_ioctl,
868 .compat_ioctl = fat_compat_dir_ioctl,
870 .fsync = fat_file_fsync,
873 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
874 struct buffer_head **bh,
875 struct msdos_dir_entry **de)
877 while (fat_get_entry(dir, pos, bh, de) >= 0) {
878 /* free entry or long name entry or volume label */
879 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
886 * The ".." entry can not provide the "struct fat_slot_info" information
887 * for inode, nor a usable i_pos. So, this function provides some information
890 * Since this function walks through the on-disk inodes within a directory,
891 * callers are responsible for taking any locks necessary to prevent the
892 * directory from changing.
894 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
895 struct msdos_dir_entry **de)
900 while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
901 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
906 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
908 /* See if directory is empty */
909 int fat_dir_empty(struct inode *dir)
911 struct buffer_head *bh;
912 struct msdos_dir_entry *de;
918 while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
919 if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) &&
920 strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
928 EXPORT_SYMBOL_GPL(fat_dir_empty);
931 * fat_subdirs counts the number of sub-directories of dir. It can be run
932 * on directories being created.
934 int fat_subdirs(struct inode *dir)
936 struct buffer_head *bh;
937 struct msdos_dir_entry *de;
943 while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
944 if (de->attr & ATTR_DIR)
952 * Scans a directory for a given file (name points to its formatted name).
953 * Returns an error code or zero.
955 int fat_scan(struct inode *dir, const unsigned char *name,
956 struct fat_slot_info *sinfo)
958 struct super_block *sb = dir->i_sb;
962 while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
964 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
965 sinfo->slot_off -= sizeof(*sinfo->de);
967 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
973 EXPORT_SYMBOL_GPL(fat_scan);
976 * Scans a directory for a given logstart.
977 * Returns an error code or zero.
979 int fat_scan_logstart(struct inode *dir, int i_logstart,
980 struct fat_slot_info *sinfo)
982 struct super_block *sb = dir->i_sb;
986 while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
988 if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {
989 sinfo->slot_off -= sizeof(*sinfo->de);
991 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
998 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
1000 struct super_block *sb = dir->i_sb;
1001 struct buffer_head *bh;
1002 struct msdos_dir_entry *de, *endp;
1003 int err = 0, orig_slots;
1007 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
1012 orig_slots = nr_slots;
1013 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
1014 while (nr_slots && de < endp) {
1015 de->name[0] = DELETED_FLAG;
1019 mark_buffer_dirty_inode(bh, dir);
1020 if (IS_DIRSYNC(dir))
1021 err = sync_dirty_buffer(bh);
1026 /* pos is *next* de's position, so this does `- sizeof(de)' */
1027 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
1033 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
1035 struct super_block *sb = dir->i_sb;
1036 struct msdos_dir_entry *de;
1037 struct buffer_head *bh;
1038 int err = 0, nr_slots;
1041 * First stage: Remove the shortname. By this, the directory
1044 nr_slots = sinfo->nr_slots;
1049 while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
1050 de->name[0] = DELETED_FLAG;
1054 mark_buffer_dirty_inode(bh, dir);
1055 if (IS_DIRSYNC(dir))
1056 err = sync_dirty_buffer(bh);
1060 inode_inc_iversion(dir);
1064 * Second stage: remove the remaining longname slots.
1065 * (This directory entry is already removed, and so return
1068 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1070 fat_msg(sb, KERN_WARNING,
1071 "Couldn't remove the long name slots");
1075 fat_truncate_time(dir, NULL, S_ATIME|S_MTIME);
1076 if (IS_DIRSYNC(dir))
1077 (void)fat_sync_inode(dir);
1079 mark_inode_dirty(dir);
1083 EXPORT_SYMBOL_GPL(fat_remove_entries);
1085 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1086 struct buffer_head **bhs, int nr_bhs)
1088 struct super_block *sb = dir->i_sb;
1089 sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1092 /* Zeroing the unused blocks on this cluster */
1095 while (blknr < last_blknr) {
1096 bhs[n] = sb_getblk(sb, blknr);
1101 /* Avoid race with userspace read via bdev */
1102 lock_buffer(bhs[n]);
1103 memset(bhs[n]->b_data, 0, sb->s_blocksize);
1104 set_buffer_uptodate(bhs[n]);
1105 unlock_buffer(bhs[n]);
1106 mark_buffer_dirty_inode(bhs[n], dir);
1111 if (IS_DIRSYNC(dir)) {
1112 err = fat_sync_bhs(bhs, n);
1116 for (i = 0; i < n; i++)
1121 if (IS_DIRSYNC(dir)) {
1122 err = fat_sync_bhs(bhs, n);
1126 for (i = 0; i < n; i++)
1132 for (i = 0; i < n; i++)
1137 int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts)
1139 struct super_block *sb = dir->i_sb;
1140 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1141 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1142 struct msdos_dir_entry *de;
1148 err = fat_alloc_clusters(dir, &cluster, 1);
1152 blknr = fat_clus_to_blknr(sbi, cluster);
1153 bhs[0] = sb_getblk(sb, blknr);
1159 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1161 de = (struct msdos_dir_entry *)bhs[0]->b_data;
1162 /* Avoid race with userspace read via bdev */
1163 lock_buffer(bhs[0]);
1164 /* filling the new directory slots ("." and ".." entries) */
1165 memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1166 memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1167 de->attr = de[1].attr = ATTR_DIR;
1168 de[0].lcase = de[1].lcase = 0;
1169 de[0].time = de[1].time = time;
1170 de[0].date = de[1].date = date;
1171 if (sbi->options.isvfat) {
1172 /* extra timestamps */
1173 de[0].ctime = de[1].ctime = time;
1174 de[0].ctime_cs = de[1].ctime_cs = time_cs;
1175 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1177 de[0].ctime = de[1].ctime = 0;
1178 de[0].ctime_cs = de[1].ctime_cs = 0;
1179 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1181 fat_set_start(&de[0], cluster);
1182 fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
1183 de[0].size = de[1].size = 0;
1184 memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1185 set_buffer_uptodate(bhs[0]);
1186 unlock_buffer(bhs[0]);
1187 mark_buffer_dirty_inode(bhs[0], dir);
1189 err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1196 fat_free_clusters(dir, cluster);
1200 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1202 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1203 int *nr_cluster, struct msdos_dir_entry **de,
1204 struct buffer_head **bh, loff_t *i_pos)
1206 struct super_block *sb = dir->i_sb;
1207 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1208 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1209 sector_t blknr, start_blknr, last_blknr;
1210 unsigned long size, copy;
1211 int err, i, n, offset, cluster[2];
1214 * The minimum cluster size is 512bytes, and maximum entry
1215 * size is 32*slots (672bytes). So, iff the cluster size is
1216 * 512bytes, we may need two clusters.
1218 size = nr_slots * sizeof(struct msdos_dir_entry);
1219 *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1220 BUG_ON(*nr_cluster > 2);
1222 err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1227 * First stage: Fill the directory entry. NOTE: This cluster
1228 * is not referenced from any inode yet, so updates order is
1233 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1234 last_blknr = start_blknr + sbi->sec_per_clus;
1235 while (blknr < last_blknr) {
1236 bhs[n] = sb_getblk(sb, blknr);
1242 /* fill the directory entry */
1243 copy = min(size, sb->s_blocksize);
1244 /* Avoid race with userspace read via bdev */
1245 lock_buffer(bhs[n]);
1246 memcpy(bhs[n]->b_data, slots, copy);
1247 set_buffer_uptodate(bhs[n]);
1248 unlock_buffer(bhs[n]);
1249 mark_buffer_dirty_inode(bhs[n], dir);
1257 } while (++i < *nr_cluster);
1259 memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1260 offset = copy - sizeof(struct msdos_dir_entry);
1263 *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1264 *i_pos = fat_make_i_pos(sb, *bh, *de);
1266 /* Second stage: clear the rest of cluster, and write outs */
1267 err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1278 for (i = 0; i < n; i++)
1280 fat_free_clusters(dir, cluster[0]);
1285 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1286 struct fat_slot_info *sinfo)
1288 struct super_block *sb = dir->i_sb;
1289 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1290 struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1291 struct msdos_dir_entry *uninitialized_var(de);
1292 int err, free_slots, i, nr_bhs;
1295 sinfo->nr_slots = nr_slots;
1297 /* First stage: search free directory entries */
1298 free_slots = nr_bhs = 0;
1302 while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1303 /* check the maximum size of directory */
1304 if (pos >= FAT_MAX_DIR_SIZE)
1307 if (IS_FREE(de->name)) {
1310 bhs[nr_bhs] = prev = bh;
1314 if (free_slots == nr_slots)
1317 for (i = 0; i < nr_bhs; i++)
1320 free_slots = nr_bhs = 0;
1323 if (dir->i_ino == MSDOS_ROOT_INO) {
1326 } else if (MSDOS_I(dir)->i_start == 0) {
1327 fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1328 MSDOS_I(dir)->i_pos);
1335 pos -= free_slots * sizeof(*de);
1336 nr_slots -= free_slots;
1339 * Second stage: filling the free entries with new entries.
1340 * NOTE: If this slots has shortname, first, we write
1341 * the long name slots, then write the short name.
1343 int size = free_slots * sizeof(*de);
1344 int offset = pos & (sb->s_blocksize - 1);
1345 int long_bhs = nr_bhs - (nr_slots == 0);
1347 /* Fill the long name slots. */
1348 for (i = 0; i < long_bhs; i++) {
1349 int copy = min_t(int, sb->s_blocksize - offset, size);
1350 memcpy(bhs[i]->b_data + offset, slots, copy);
1351 mark_buffer_dirty_inode(bhs[i], dir);
1356 if (long_bhs && IS_DIRSYNC(dir))
1357 err = fat_sync_bhs(bhs, long_bhs);
1358 if (!err && i < nr_bhs) {
1359 /* Fill the short name slot. */
1360 int copy = min_t(int, sb->s_blocksize - offset, size);
1361 memcpy(bhs[i]->b_data + offset, slots, copy);
1362 mark_buffer_dirty_inode(bhs[i], dir);
1363 if (IS_DIRSYNC(dir))
1364 err = sync_dirty_buffer(bhs[i]);
1366 for (i = 0; i < nr_bhs; i++)
1373 int cluster, nr_cluster;
1376 * Third stage: allocate the cluster for new entries.
1377 * And initialize the cluster with new entries, then
1378 * add the cluster to dir.
1380 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1386 err = fat_chain_add(dir, cluster, nr_cluster);
1388 fat_free_clusters(dir, cluster);
1391 if (dir->i_size & (sbi->cluster_size - 1)) {
1392 fat_fs_error(sb, "Odd directory size");
1393 dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1394 & ~((loff_t)sbi->cluster_size - 1);
1396 dir->i_size += nr_cluster << sbi->cluster_bits;
1397 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1399 sinfo->slot_off = pos;
1402 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1408 for (i = 0; i < nr_bhs; i++)
1415 __fat_remove_entries(dir, pos, free_slots);
1418 EXPORT_SYMBOL_GPL(fat_add_entries);