1 // SPDX-License-Identifier: GPL-2.0-only
5 * directory handling functions for fat-based filesystems
7 * Written 1992,1993 by Werner Almesberger
13 * Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
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;
95 iblock = *pos >> sb->s_blocksize_bits;
96 err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0, false);
98 return -1; /* beyond EOF or error */
100 fat_dir_readahead(dir, iblock, phys);
102 *bh = sb_bread(sb, phys);
104 fat_msg_ratelimit(sb, KERN_ERR,
105 "Directory bread(block %llu) failed", (llu)phys);
106 /* skip this block */
107 *pos = (iblock + 1) << sb->s_blocksize_bits;
111 offset = *pos & (sb->s_blocksize - 1);
112 *pos += sizeof(struct msdos_dir_entry);
113 *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
118 static inline int fat_get_entry(struct inode *dir, loff_t *pos,
119 struct buffer_head **bh,
120 struct msdos_dir_entry **de)
122 /* Fast stuff first */
124 (*de - (struct msdos_dir_entry *)(*bh)->b_data) <
125 MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
126 *pos += sizeof(struct msdos_dir_entry);
130 return fat__get_entry(dir, pos, bh, de);
134 * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
135 * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
136 * colon as an escape character since it is normally invalid on the vfat
137 * filesystem. The following four characters are the hexadecimal digits
138 * of Unicode value. This lets us do a full dump and restore of Unicode
139 * filenames. We could get into some trouble with long Unicode names,
140 * but ignore that right now.
141 * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
143 static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
144 const wchar_t *uni, int len, struct nls_table *nls)
146 int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;
155 while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
157 charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE);
162 if (uni_xlate == 1) {
164 op = hex_byte_pack(op, ec >> 8);
165 op = hex_byte_pack(op, ec);
175 fat_msg(sb, KERN_WARNING,
176 "filename was truncated while converting.");
183 static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,
184 unsigned char *buf, int size)
186 struct msdos_sb_info *sbi = MSDOS_SB(sb);
187 if (sbi->options.utf8)
188 return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
189 UTF16_HOST_ENDIAN, buf, size);
191 return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);
195 fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
199 charlen = t->char2uni(c, clen, uni);
201 *uni = 0x003f; /* a question mark */
208 fat_short2lower_uni(struct nls_table *t, unsigned char *c,
209 int clen, wchar_t *uni)
214 charlen = t->char2uni(c, clen, &wc);
216 *uni = 0x003f; /* a question mark */
218 } else if (charlen <= 1) {
219 unsigned char nc = t->charset2lower[*c];
224 charlen = t->char2uni(&nc, 1, uni);
226 *uni = 0x003f; /* a question mark */
236 fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
237 wchar_t *uni_buf, unsigned short opt, int lower)
241 if (opt & VFAT_SFN_DISPLAY_LOWER)
242 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
243 else if (opt & VFAT_SFN_DISPLAY_WIN95)
244 len = fat_short2uni(nls, buf, buf_size, uni_buf);
245 else if (opt & VFAT_SFN_DISPLAY_WINNT) {
247 len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
249 len = fat_short2uni(nls, buf, buf_size, uni_buf);
251 len = fat_short2uni(nls, buf, buf_size, uni_buf);
256 static inline int fat_name_match(struct msdos_sb_info *sbi,
257 const unsigned char *a, int a_len,
258 const unsigned char *b, int b_len)
263 if (sbi->options.name_check != 's')
264 return !nls_strnicmp(sbi->nls_io, a, b, a_len);
266 return !memcmp(a, b, a_len);
269 enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
272 * fat_parse_long - Parse extended directory entry.
274 * This function returns zero on success, negative value on error, or one of
277 * %PARSE_INVALID - Directory entry is invalid.
278 * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
279 * %PARSE_EOF - Directory has no more entries.
281 static int fat_parse_long(struct inode *dir, loff_t *pos,
282 struct buffer_head **bh, struct msdos_dir_entry **de,
283 wchar_t **unicode, unsigned char *nr_slots)
285 struct msdos_dir_slot *ds;
286 unsigned char id, slot, slots, alias_checksum;
289 *unicode = __getname();
296 ds = (struct msdos_dir_slot *)*de;
299 return PARSE_INVALID;
301 if (slots > 20 || !slots) /* ceil(256 * 2 / 26) */
302 return PARSE_INVALID;
304 alias_checksum = ds->alias_checksum;
312 fat16_towchar(*unicode + offset, ds->name0_4, 5);
313 fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
314 fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
317 (*unicode)[offset + 13] = 0;
318 if (fat_get_entry(dir, pos, bh, de) < 0)
322 ds = (struct msdos_dir_slot *)*de;
323 if (ds->attr != ATTR_EXT)
324 return PARSE_NOT_LONGNAME;
325 if ((ds->id & ~0x40) != slot)
327 if (ds->alias_checksum != alias_checksum)
330 if ((*de)->name[0] == DELETED_FLAG)
331 return PARSE_INVALID;
332 if ((*de)->attr == ATTR_EXT)
334 if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
335 return PARSE_INVALID;
336 if (fat_checksum((*de)->name) != alias_checksum)
343 * fat_parse_short - Parse MS-DOS (short) directory entry.
345 * @de: directory entry to parse
346 * @name: FAT_MAX_SHORT_SIZE array in which to place extracted name
347 * @dot_hidden: Nonzero == prepend '.' to names with ATTR_HIDDEN
349 * Returns the number of characters extracted into 'name'.
351 static int fat_parse_short(struct super_block *sb,
352 const struct msdos_dir_entry *de,
353 unsigned char *name, int dot_hidden)
355 const struct msdos_sb_info *sbi = MSDOS_SB(sb);
356 int isvfat = sbi->options.isvfat;
357 int nocase = sbi->options.nocase;
358 unsigned short opt_shortname = sbi->options.shortname;
359 struct nls_table *nls_disk = sbi->nls_disk;
360 wchar_t uni_name[14];
361 unsigned char c, work[MSDOS_NAME];
362 unsigned char *ptname = name;
363 int chi, chl, i, j, k;
365 int name_len = 0, uni_len = 0;
367 if (!isvfat && dot_hidden && (de->attr & ATTR_HIDDEN)) {
372 memcpy(work, de->name, sizeof(work));
373 /* For an explanation of the special treatment of 0x05 in
374 * filenames, see msdos_format_name in namei_msdos.c
380 for (i = 0, j = 0; i < 8;) {
384 chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
385 &uni_name[j++], opt_shortname,
386 de->lcase & CASE_LOWER_BASE);
389 ptname[i] = nocase ? c : fat_tolower(c);
400 for (chi = 0; chi < chl && i < 8; chi++, i++)
410 fat_short2uni(nls_disk, ".", 1, &uni_name[j++]);
416 for (k = 8; k < MSDOS_NAME;) {
420 chl = fat_shortname2uni(nls_disk, &work[k], MSDOS_NAME - k,
421 &uni_name[j++], opt_shortname,
422 de->lcase & CASE_LOWER_EXT);
426 ptname[i] = nocase ? c : fat_tolower(c);
435 int offset = min(chl, MSDOS_NAME-k);
439 for (chi = 0; chi < chl && k < MSDOS_NAME;
450 name_len += dotoffset;
452 if (sbi->options.isvfat) {
453 uni_name[uni_len] = 0x0000;
454 name_len = fat_uni_to_x8(sb, uni_name, name,
463 * Return values: negative -> error/not found, 0 -> found.
465 int fat_search_long(struct inode *inode, const unsigned char *name,
466 int name_len, struct fat_slot_info *sinfo)
468 struct super_block *sb = inode->i_sb;
469 struct msdos_sb_info *sbi = MSDOS_SB(sb);
470 struct buffer_head *bh = NULL;
471 struct msdos_dir_entry *de;
472 unsigned char nr_slots;
473 wchar_t *unicode = NULL;
474 unsigned char bufname[FAT_MAX_SHORT_SIZE];
480 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
484 if (de->name[0] == DELETED_FLAG)
486 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
488 if (de->attr != ATTR_EXT && IS_FREE(de->name))
490 if (de->attr == ATTR_EXT) {
491 int status = fat_parse_long(inode, &cpos, &bh, &de,
492 &unicode, &nr_slots);
496 } else if (status == PARSE_INVALID)
498 else if (status == PARSE_NOT_LONGNAME)
500 else if (status == PARSE_EOF)
504 /* Never prepend '.' to hidden files here.
505 * That is done only for msdos mounts (and only when
506 * 'dotsOK=yes'); if we are executing here, it is in the
507 * context of a vfat mount.
509 len = fat_parse_short(sb, de, bufname, 0);
513 /* Compare shortname */
514 if (fat_name_match(sbi, name, name_len, bufname, len))
518 void *longname = unicode + FAT_MAX_UNI_CHARS;
519 int size = PATH_MAX - FAT_MAX_UNI_SIZE;
521 /* Compare longname */
522 len = fat_uni_to_x8(sb, unicode, longname, size);
523 if (fat_name_match(sbi, name, name_len, longname, len))
529 nr_slots++; /* include the de */
530 sinfo->slot_off = cpos - nr_slots * sizeof(*de);
531 sinfo->nr_slots = nr_slots;
534 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
542 EXPORT_SYMBOL_GPL(fat_search_long);
544 struct fat_ioctl_filldir_callback {
545 struct dir_context ctx;
549 const char *longname;
551 const char *shortname;
555 static int __fat_readdir(struct inode *inode, struct file *file,
556 struct dir_context *ctx, int short_only,
557 struct fat_ioctl_filldir_callback *both)
559 struct super_block *sb = inode->i_sb;
560 struct msdos_sb_info *sbi = MSDOS_SB(sb);
561 struct buffer_head *bh;
562 struct msdos_dir_entry *de;
563 unsigned char nr_slots;
564 wchar_t *unicode = NULL;
565 unsigned char bufname[FAT_MAX_SHORT_SIZE];
566 int isvfat = sbi->options.isvfat;
567 const char *fill_name = NULL;
570 int short_len = 0, fill_len = 0;
573 mutex_lock(&sbi->s_lock);
576 /* Fake . and .. for the root directory. */
577 if (inode->i_ino == MSDOS_ROOT_INO) {
578 if (!dir_emit_dots(file, ctx))
585 if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
592 if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
597 * Check for long filename entry, but if short_only, we don't
598 * need to parse long filename.
600 if (isvfat && !short_only) {
601 if (de->name[0] == DELETED_FLAG)
603 if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
605 if (de->attr != ATTR_EXT && IS_FREE(de->name))
608 if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
612 if (isvfat && de->attr == ATTR_EXT) {
613 int status = fat_parse_long(inode, &cpos, &bh, &de,
614 &unicode, &nr_slots);
619 } else if (status == PARSE_INVALID)
621 else if (status == PARSE_NOT_LONGNAME)
623 else if (status == PARSE_EOF)
627 void *longname = unicode + FAT_MAX_UNI_CHARS;
628 int size = PATH_MAX - FAT_MAX_UNI_SIZE;
629 int len = fat_uni_to_x8(sb, unicode, longname, size);
631 fill_name = longname;
633 /* !both && !short_only, so we don't need shortname. */
637 short_len = fat_parse_short(sb, de, bufname,
638 sbi->options.dotsOK);
641 /* hack for fat_ioctl_filldir() */
642 both->longname = fill_name;
643 both->long_len = fill_len;
644 both->shortname = bufname;
645 both->short_len = short_len;
652 short_len = fat_parse_short(sb, de, bufname, sbi->options.dotsOK);
657 fill_len = short_len;
660 ctx->pos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
661 if (fake_offset && ctx->pos < 2)
664 if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME)) {
665 if (!dir_emit_dot(file, ctx))
667 } else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
668 if (!dir_emit_dotdot(file, ctx))
672 loff_t i_pos = fat_make_i_pos(sb, bh, de);
673 struct inode *tmp = fat_iget(sb, i_pos);
678 inum = iunique(sb, MSDOS_ROOT_INO);
679 if (!dir_emit(ctx, fill_name, fill_len, inum,
680 (de->attr & ATTR_DIR) ? DT_DIR : DT_REG))
690 if (fake_offset && cpos < 2)
699 mutex_unlock(&sbi->s_lock);
704 static int fat_readdir(struct file *file, struct dir_context *ctx)
706 return __fat_readdir(file_inode(file), file, ctx, 0, NULL);
709 #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type) \
710 static int func(struct dir_context *ctx, const char *name, int name_len, \
711 loff_t offset, u64 ino, unsigned int d_type) \
713 struct fat_ioctl_filldir_callback *buf = \
714 container_of(ctx, struct fat_ioctl_filldir_callback, ctx); \
715 struct dirent_type __user *d1 = buf->dirent; \
716 struct dirent_type __user *d2 = d1 + 1; \
722 if (name != NULL) { \
723 /* dirent has only short name */ \
724 if (name_len >= sizeof(d1->d_name)) \
725 name_len = sizeof(d1->d_name) - 1; \
727 if (put_user(0, d2->d_name) || \
728 put_user(0, &d2->d_reclen) || \
729 copy_to_user(d1->d_name, name, name_len) || \
730 put_user(0, d1->d_name + name_len) || \
731 put_user(name_len, &d1->d_reclen)) \
734 /* dirent has short and long name */ \
735 const char *longname = buf->longname; \
736 int long_len = buf->long_len; \
737 const char *shortname = buf->shortname; \
738 int short_len = buf->short_len; \
740 if (long_len >= sizeof(d1->d_name)) \
741 long_len = sizeof(d1->d_name) - 1; \
742 if (short_len >= sizeof(d1->d_name)) \
743 short_len = sizeof(d1->d_name) - 1; \
745 if (copy_to_user(d2->d_name, longname, long_len) || \
746 put_user(0, d2->d_name + long_len) || \
747 put_user(long_len, &d2->d_reclen) || \
748 put_user(ino, &d2->d_ino) || \
749 put_user(offset, &d2->d_off) || \
750 copy_to_user(d1->d_name, shortname, short_len) || \
751 put_user(0, d1->d_name + short_len) || \
752 put_user(short_len, &d1->d_reclen)) \
757 buf->result = -EFAULT; \
761 FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
763 static int fat_ioctl_readdir(struct inode *inode, struct file *file,
764 void __user *dirent, filldir_t filldir,
765 int short_only, int both)
767 struct fat_ioctl_filldir_callback buf = {
768 .ctx.actor = filldir,
775 inode_lock_shared(inode);
776 buf.ctx.pos = file->f_pos;
778 if (!IS_DEADDIR(inode)) {
779 ret = __fat_readdir(inode, file, &buf.ctx,
780 short_only, both ? &buf : NULL);
781 file->f_pos = buf.ctx.pos;
783 inode_unlock_shared(inode);
789 static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
792 struct inode *inode = file_inode(filp);
793 struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
794 int short_only, both;
797 case VFAT_IOCTL_READDIR_SHORT:
801 case VFAT_IOCTL_READDIR_BOTH:
806 return fat_generic_ioctl(filp, cmd, arg);
809 if (!access_ok(d1, sizeof(struct __fat_dirent[2])))
812 * Yes, we don't need this put_user() absolutely. However old
813 * code didn't return the right value. So, app use this value,
814 * in order to check whether it is EOF.
816 if (put_user(0, &d1->d_reclen))
819 return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
824 #define VFAT_IOCTL_READDIR_BOTH32 _IOR('r', 1, struct compat_dirent[2])
825 #define VFAT_IOCTL_READDIR_SHORT32 _IOR('r', 2, struct compat_dirent[2])
827 FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
829 static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
832 struct inode *inode = file_inode(filp);
833 struct compat_dirent __user *d1 = compat_ptr(arg);
834 int short_only, both;
837 case VFAT_IOCTL_READDIR_SHORT32:
841 case VFAT_IOCTL_READDIR_BOTH32:
846 return fat_generic_ioctl(filp, cmd, (unsigned long)arg);
849 if (!access_ok(d1, sizeof(struct compat_dirent[2])))
852 * Yes, we don't need this put_user() absolutely. However old
853 * code didn't return the right value. So, app use this value,
854 * in order to check whether it is EOF.
856 if (put_user(0, &d1->d_reclen))
859 return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
862 #endif /* CONFIG_COMPAT */
864 const struct file_operations fat_dir_operations = {
865 .llseek = generic_file_llseek,
866 .read = generic_read_dir,
867 .iterate_shared = fat_readdir,
868 .unlocked_ioctl = fat_dir_ioctl,
870 .compat_ioctl = fat_compat_dir_ioctl,
872 .fsync = fat_file_fsync,
875 static int fat_get_short_entry(struct inode *dir, loff_t *pos,
876 struct buffer_head **bh,
877 struct msdos_dir_entry **de)
879 while (fat_get_entry(dir, pos, bh, de) >= 0) {
880 /* free entry or long name entry or volume label */
881 if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
888 * The ".." entry can not provide the "struct fat_slot_info" information
889 * for inode, nor a usable i_pos. So, this function provides some information
892 * Since this function walks through the on-disk inodes within a directory,
893 * callers are responsible for taking any locks necessary to prevent the
894 * directory from changing.
896 int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
897 struct msdos_dir_entry **de)
902 while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
903 if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME))
908 EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
910 /* See if directory is empty */
911 int fat_dir_empty(struct inode *dir)
913 struct buffer_head *bh;
914 struct msdos_dir_entry *de;
920 while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
921 if (strncmp(de->name, MSDOS_DOT , MSDOS_NAME) &&
922 strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
930 EXPORT_SYMBOL_GPL(fat_dir_empty);
933 * fat_subdirs counts the number of sub-directories of dir. It can be run
934 * on directories being created.
936 int fat_subdirs(struct inode *dir)
938 struct buffer_head *bh;
939 struct msdos_dir_entry *de;
945 while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
946 if (de->attr & ATTR_DIR)
954 * Scans a directory for a given file (name points to its formatted name).
955 * Returns an error code or zero.
957 int fat_scan(struct inode *dir, const unsigned char *name,
958 struct fat_slot_info *sinfo)
960 struct super_block *sb = dir->i_sb;
964 while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
966 if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
967 sinfo->slot_off -= sizeof(*sinfo->de);
969 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
975 EXPORT_SYMBOL_GPL(fat_scan);
978 * Scans a directory for a given logstart.
979 * Returns an error code or zero.
981 int fat_scan_logstart(struct inode *dir, int i_logstart,
982 struct fat_slot_info *sinfo)
984 struct super_block *sb = dir->i_sb;
988 while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
990 if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) {
991 sinfo->slot_off -= sizeof(*sinfo->de);
993 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1000 static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
1002 struct super_block *sb = dir->i_sb;
1003 struct buffer_head *bh;
1004 struct msdos_dir_entry *de, *endp;
1005 int err = 0, orig_slots;
1009 if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
1014 orig_slots = nr_slots;
1015 endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
1016 while (nr_slots && de < endp) {
1017 de->name[0] = DELETED_FLAG;
1021 mark_buffer_dirty_inode(bh, dir);
1022 if (IS_DIRSYNC(dir))
1023 err = sync_dirty_buffer(bh);
1028 /* pos is *next* de's position, so this does `- sizeof(de)' */
1029 pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
1035 int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
1037 struct super_block *sb = dir->i_sb;
1038 struct msdos_dir_entry *de;
1039 struct buffer_head *bh;
1040 int err = 0, nr_slots;
1043 * First stage: Remove the shortname. By this, the directory
1046 nr_slots = sinfo->nr_slots;
1051 while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
1052 de->name[0] = DELETED_FLAG;
1056 mark_buffer_dirty_inode(bh, dir);
1057 if (IS_DIRSYNC(dir))
1058 err = sync_dirty_buffer(bh);
1062 inode_inc_iversion(dir);
1066 * Second stage: remove the remaining longname slots.
1067 * (This directory entry is already removed, and so return
1070 err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
1072 fat_msg(sb, KERN_WARNING,
1073 "Couldn't remove the long name slots");
1077 fat_truncate_time(dir, NULL, S_ATIME|S_MTIME);
1078 if (IS_DIRSYNC(dir))
1079 (void)fat_sync_inode(dir);
1081 mark_inode_dirty(dir);
1085 EXPORT_SYMBOL_GPL(fat_remove_entries);
1087 static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
1088 struct buffer_head **bhs, int nr_bhs)
1090 struct super_block *sb = dir->i_sb;
1091 sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
1094 /* Zeroing the unused blocks on this cluster */
1097 while (blknr < last_blknr) {
1098 bhs[n] = sb_getblk(sb, blknr);
1103 memset(bhs[n]->b_data, 0, sb->s_blocksize);
1104 set_buffer_uptodate(bhs[n]);
1105 mark_buffer_dirty_inode(bhs[n], dir);
1110 if (IS_DIRSYNC(dir)) {
1111 err = fat_sync_bhs(bhs, n);
1115 for (i = 0; i < n; i++)
1120 if (IS_DIRSYNC(dir)) {
1121 err = fat_sync_bhs(bhs, n);
1125 for (i = 0; i < n; i++)
1131 for (i = 0; i < n; i++)
1136 int fat_alloc_new_dir(struct inode *dir, struct timespec64 *ts)
1138 struct super_block *sb = dir->i_sb;
1139 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1140 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1141 struct msdos_dir_entry *de;
1147 err = fat_alloc_clusters(dir, &cluster, 1);
1151 blknr = fat_clus_to_blknr(sbi, cluster);
1152 bhs[0] = sb_getblk(sb, blknr);
1158 fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
1160 de = (struct msdos_dir_entry *)bhs[0]->b_data;
1161 /* filling the new directory slots ("." and ".." entries) */
1162 memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
1163 memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
1164 de->attr = de[1].attr = ATTR_DIR;
1165 de[0].lcase = de[1].lcase = 0;
1166 de[0].time = de[1].time = time;
1167 de[0].date = de[1].date = date;
1168 if (sbi->options.isvfat) {
1169 /* extra timestamps */
1170 de[0].ctime = de[1].ctime = time;
1171 de[0].ctime_cs = de[1].ctime_cs = time_cs;
1172 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
1174 de[0].ctime = de[1].ctime = 0;
1175 de[0].ctime_cs = de[1].ctime_cs = 0;
1176 de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
1178 fat_set_start(&de[0], cluster);
1179 fat_set_start(&de[1], MSDOS_I(dir)->i_logstart);
1180 de[0].size = de[1].size = 0;
1181 memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
1182 set_buffer_uptodate(bhs[0]);
1183 mark_buffer_dirty_inode(bhs[0], dir);
1185 err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
1192 fat_free_clusters(dir, cluster);
1196 EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
1198 static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
1199 int *nr_cluster, struct msdos_dir_entry **de,
1200 struct buffer_head **bh, loff_t *i_pos)
1202 struct super_block *sb = dir->i_sb;
1203 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1204 struct buffer_head *bhs[MAX_BUF_PER_PAGE];
1205 sector_t blknr, start_blknr, last_blknr;
1206 unsigned long size, copy;
1207 int err, i, n, offset, cluster[2];
1210 * The minimum cluster size is 512bytes, and maximum entry
1211 * size is 32*slots (672bytes). So, iff the cluster size is
1212 * 512bytes, we may need two clusters.
1214 size = nr_slots * sizeof(struct msdos_dir_entry);
1215 *nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
1216 BUG_ON(*nr_cluster > 2);
1218 err = fat_alloc_clusters(dir, cluster, *nr_cluster);
1223 * First stage: Fill the directory entry. NOTE: This cluster
1224 * is not referenced from any inode yet, so updates order is
1229 start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
1230 last_blknr = start_blknr + sbi->sec_per_clus;
1231 while (blknr < last_blknr) {
1232 bhs[n] = sb_getblk(sb, blknr);
1238 /* fill the directory entry */
1239 copy = min(size, sb->s_blocksize);
1240 memcpy(bhs[n]->b_data, slots, copy);
1243 set_buffer_uptodate(bhs[n]);
1244 mark_buffer_dirty_inode(bhs[n], dir);
1250 } while (++i < *nr_cluster);
1252 memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
1253 offset = copy - sizeof(struct msdos_dir_entry);
1256 *de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
1257 *i_pos = fat_make_i_pos(sb, *bh, *de);
1259 /* Second stage: clear the rest of cluster, and write outs */
1260 err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
1271 for (i = 0; i < n; i++)
1273 fat_free_clusters(dir, cluster[0]);
1278 int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
1279 struct fat_slot_info *sinfo)
1281 struct super_block *sb = dir->i_sb;
1282 struct msdos_sb_info *sbi = MSDOS_SB(sb);
1283 struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */
1284 struct msdos_dir_entry *uninitialized_var(de);
1285 int err, free_slots, i, nr_bhs;
1288 sinfo->nr_slots = nr_slots;
1290 /* First stage: search free directory entries */
1291 free_slots = nr_bhs = 0;
1295 while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
1296 /* check the maximum size of directory */
1297 if (pos >= FAT_MAX_DIR_SIZE)
1300 if (IS_FREE(de->name)) {
1303 bhs[nr_bhs] = prev = bh;
1307 if (free_slots == nr_slots)
1310 for (i = 0; i < nr_bhs; i++)
1313 free_slots = nr_bhs = 0;
1316 if (dir->i_ino == MSDOS_ROOT_INO) {
1319 } else if (MSDOS_I(dir)->i_start == 0) {
1320 fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",
1321 MSDOS_I(dir)->i_pos);
1328 pos -= free_slots * sizeof(*de);
1329 nr_slots -= free_slots;
1332 * Second stage: filling the free entries with new entries.
1333 * NOTE: If this slots has shortname, first, we write
1334 * the long name slots, then write the short name.
1336 int size = free_slots * sizeof(*de);
1337 int offset = pos & (sb->s_blocksize - 1);
1338 int long_bhs = nr_bhs - (nr_slots == 0);
1340 /* Fill the long name slots. */
1341 for (i = 0; i < long_bhs; i++) {
1342 int copy = min_t(int, sb->s_blocksize - offset, size);
1343 memcpy(bhs[i]->b_data + offset, slots, copy);
1344 mark_buffer_dirty_inode(bhs[i], dir);
1349 if (long_bhs && IS_DIRSYNC(dir))
1350 err = fat_sync_bhs(bhs, long_bhs);
1351 if (!err && i < nr_bhs) {
1352 /* Fill the short name slot. */
1353 int copy = min_t(int, sb->s_blocksize - offset, size);
1354 memcpy(bhs[i]->b_data + offset, slots, copy);
1355 mark_buffer_dirty_inode(bhs[i], dir);
1356 if (IS_DIRSYNC(dir))
1357 err = sync_dirty_buffer(bhs[i]);
1359 for (i = 0; i < nr_bhs; i++)
1366 int cluster, nr_cluster;
1369 * Third stage: allocate the cluster for new entries.
1370 * And initialize the cluster with new entries, then
1371 * add the cluster to dir.
1373 cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
1379 err = fat_chain_add(dir, cluster, nr_cluster);
1381 fat_free_clusters(dir, cluster);
1384 if (dir->i_size & (sbi->cluster_size - 1)) {
1385 fat_fs_error(sb, "Odd directory size");
1386 dir->i_size = (dir->i_size + sbi->cluster_size - 1)
1387 & ~((loff_t)sbi->cluster_size - 1);
1389 dir->i_size += nr_cluster << sbi->cluster_bits;
1390 MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
1392 sinfo->slot_off = pos;
1395 sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
1401 for (i = 0; i < nr_bhs; i++)
1408 __fat_remove_entries(dir, pos, free_slots);
1411 EXPORT_SYMBOL_GPL(fat_add_entries);