/*
   *  linux/fs/fat/dir.c
   *
   *  directory handling functions for fat-based filesystems
   *
   *  Written 1992,1993 by Werner Almesberger
   *
   *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
   *
   *  VFAT extensions by Gordon Chaffee <chaffee@plateau.cs.berkeley.edu>
   *  Merged with msdos fs by Henrik Storner <storner@osiris.ping.dk>
   *  Rewritten for constant inumbers. Plugged buffer overrun in readdir(). AV
   *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
   */
  
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/time.h>

  #include <linux/buffer_head.h>

  #include <linux/compat.h>

  #include <asm/uaccess.h>

  #include <linux/kernel.h>

  #include "fat.h"

  /*
   * Maximum buffer size of short name.
   * [(MSDOS_NAME + '.') * max one char + nul]
   * For msdos style, ['.' (hidden) + MSDOS_NAME + '.' + nul]
   */
  #define FAT_MAX_SHORT_SIZE	((MSDOS_NAME + 1) * NLS_MAX_CHARSET_SIZE + 1)
  /*
   * Maximum buffer size of unicode chars from slots.
   * [(max longname slots * 13 (size in a slot) + nul) * sizeof(wchar_t)]
   */
  #define FAT_MAX_UNI_CHARS	((MSDOS_SLOTS - 1) * 13 + 1)
  #define FAT_MAX_UNI_SIZE	(FAT_MAX_UNI_CHARS * sizeof(wchar_t))

  static inline loff_t fat_make_i_pos(struct super_block *sb,
  				    struct buffer_head *bh,
  				    struct msdos_dir_entry *de)
  {
  	return ((loff_t)bh->b_blocknr << MSDOS_SB(sb)->dir_per_block_bits)
  		| (de - (struct msdos_dir_entry *)bh->b_data);
  }

  static inline void fat_dir_readahead(struct inode *dir, sector_t iblock,
  				     sector_t phys)
  {
  	struct super_block *sb = dir->i_sb;
  	struct msdos_sb_info *sbi = MSDOS_SB(sb);
  	struct buffer_head *bh;
  	int sec;
  
  	/* This is not a first sector of cluster, or sec_per_clus == 1 */
  	if ((iblock & (sbi->sec_per_clus - 1)) || sbi->sec_per_clus == 1)
  		return;
  	/* root dir of FAT12/FAT16 */
  	if ((sbi->fat_bits != 32) && (dir->i_ino == MSDOS_ROOT_INO))
  		return;

  	bh = sb_find_get_block(sb, phys);
  	if (bh == NULL || !buffer_uptodate(bh)) {

  		for (sec = 0; sec < sbi->sec_per_clus; sec++)
  			sb_breadahead(sb, phys + sec);
  	}
  	brelse(bh);
  }

  /* Returns the inode number of the directory entry at offset pos. If bh is
     non-NULL, it is brelse'd before. Pos is incremented. The buffer header is
     returned in bh.
     AV. Most often we do it item-by-item. Makes sense to optimize.
     AV. OK, there we go: if both bh and de are non-NULL we assume that we just
     AV. want the next entry (took one explicit de=NULL in vfat/namei.c).
     AV. It's done in fat_get_entry() (inlined), here the slow case lives.
     AV. Additionally, when we return -1 (i.e. reached the end of directory)
     AV. we make bh NULL.
   */
  static int fat__get_entry(struct inode *dir, loff_t *pos,
  			  struct buffer_head **bh, struct msdos_dir_entry **de)
  {
  	struct super_block *sb = dir->i_sb;
  	sector_t phys, iblock;

  	unsigned long mapped_blocks;
  	int err, offset;

  
  next:
  	if (*bh)
  		brelse(*bh);
  
  	*bh = NULL;
  	iblock = *pos >> sb->s_blocksize_bits;

  	err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0);

  	if (err || !phys)
  		return -1;	/* beyond EOF or error */

  	fat_dir_readahead(dir, iblock, phys);

  	*bh = sb_bread(sb, phys);
  	if (*bh == NULL) {

  		fat_msg(sb, KERN_ERR, "Directory bread(block %llu) failed",

  		       (llu)phys);

  		/* skip this block */
  		*pos = (iblock + 1) << sb->s_blocksize_bits;
  		goto next;
  	}
  
  	offset = *pos & (sb->s_blocksize - 1);
  	*pos += sizeof(struct msdos_dir_entry);
  	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
  
  	return 0;
  }
  
  static inline int fat_get_entry(struct inode *dir, loff_t *pos,
  				struct buffer_head **bh,
  				struct msdos_dir_entry **de)
  {
  	/* Fast stuff first */
  	if (*bh && *de &&
  	    (*de - (struct msdos_dir_entry *)(*bh)->b_data) < MSDOS_SB(dir->i_sb)->dir_per_block - 1) {
  		*pos += sizeof(struct msdos_dir_entry);
  		(*de)++;
  		return 0;
  	}
  	return fat__get_entry(dir, pos, bh, de);
  }
  
  /*

   * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.

   * If uni_xlate is enabled and we can't get a 1:1 conversion, use a
   * colon as an escape character since it is normally invalid on the vfat
   * filesystem. The following four characters are the hexadecimal digits
   * of Unicode value. This lets us do a full dump and restore of Unicode
   * filenames. We could get into some trouble with long Unicode names,
   * but ignore that right now.
   * Ahem... Stack smashing in ring 0 isn't fun. Fixed.
   */

  static int uni16_to_x8(struct super_block *sb, unsigned char *ascii,
  		       const wchar_t *uni, int len, struct nls_table *nls)

  {

  	int uni_xlate = MSDOS_SB(sb)->options.unicode_xlate;

  	const wchar_t *ip;
  	wchar_t ec;

  	unsigned char *op;

  	int charlen;

  
  	ip = uni;
  	op = ascii;

  	while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {

  		ec = *ip++;

  		if ((charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {

  			op += charlen;

  			len -= charlen;

  		} else {
  			if (uni_xlate == 1) {

  				*op++ = ':';

  				op = hex_byte_pack(op, ec >> 8);
  				op = hex_byte_pack(op, ec);

  				len -= 5;

  			} else {
  				*op++ = '?';

  				len--;

  			}
  		}

  	}

  
  	if (unlikely(*ip)) {

  		fat_msg(sb, KERN_WARNING, "filename was truncated while "
  			"converting.");

  	}

  	*op = 0;
  	return (op - ascii);
  }

  static inline int fat_uni_to_x8(struct super_block *sb, const wchar_t *uni,

  				unsigned char *buf, int size)
  {

  	struct msdos_sb_info *sbi = MSDOS_SB(sb);

  	if (sbi->options.utf8)

  		return utf16s_to_utf8s(uni, FAT_MAX_UNI_CHARS,
  				UTF16_HOST_ENDIAN, buf, size);

  	else

  		return uni16_to_x8(sb, buf, uni, size, sbi->nls_io);

  }

  static inline int
  fat_short2uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
  {
  	int charlen;
  
  	charlen = t->char2uni(c, clen, uni);
  	if (charlen < 0) {
  		*uni = 0x003f;	/* a question mark */
  		charlen = 1;
  	}
  	return charlen;
  }
  
  static inline int
  fat_short2lower_uni(struct nls_table *t, unsigned char *c, int clen, wchar_t *uni)
  {
  	int charlen;
  	wchar_t wc;
  
  	charlen = t->char2uni(c, clen, &wc);
  	if (charlen < 0) {
  		*uni = 0x003f;	/* a question mark */
  		charlen = 1;
  	} else if (charlen <= 1) {
  		unsigned char nc = t->charset2lower[*c];
  
  		if (!nc)
  			nc = *c;
  
  		if ( (charlen = t->char2uni(&nc, 1, uni)) < 0) {
  			*uni = 0x003f;	/* a question mark */
  			charlen = 1;
  		}
  	} else
  		*uni = wc;
  
  	return charlen;
  }
  
  static inline int
  fat_shortname2uni(struct nls_table *nls, unsigned char *buf, int buf_size,
  		  wchar_t *uni_buf, unsigned short opt, int lower)
  {
  	int len = 0;
  
  	if (opt & VFAT_SFN_DISPLAY_LOWER)
  		len =  fat_short2lower_uni(nls, buf, buf_size, uni_buf);
  	else if (opt & VFAT_SFN_DISPLAY_WIN95)
  		len = fat_short2uni(nls, buf, buf_size, uni_buf);
  	else if (opt & VFAT_SFN_DISPLAY_WINNT) {
  		if (lower)
  			len = fat_short2lower_uni(nls, buf, buf_size, uni_buf);
  		else
  			len = fat_short2uni(nls, buf, buf_size, uni_buf);
  	} else
  		len = fat_short2uni(nls, buf, buf_size, uni_buf);
  
  	return len;
  }

  static inline int fat_name_match(struct msdos_sb_info *sbi,
  				 const unsigned char *a, int a_len,
  				 const unsigned char *b, int b_len)
  {
  	if (a_len != b_len)
  		return 0;
  
  	if (sbi->options.name_check != 's')
  		return !nls_strnicmp(sbi->nls_io, a, b, a_len);
  	else
  		return !memcmp(a, b, a_len);
  }

  enum { PARSE_INVALID = 1, PARSE_NOT_LONGNAME, PARSE_EOF, };
  
  /**
   * fat_parse_long - Parse extended directory entry.
   *
   * This function returns zero on success, negative value on error, or one of
   * the following:
   *
   * %PARSE_INVALID - Directory entry is invalid.
   * %PARSE_NOT_LONGNAME - Directory entry does not contain longname.
   * %PARSE_EOF - Directory has no more entries.
   */
  static int fat_parse_long(struct inode *dir, loff_t *pos,
  			  struct buffer_head **bh, struct msdos_dir_entry **de,
  			  wchar_t **unicode, unsigned char *nr_slots)
  {
  	struct msdos_dir_slot *ds;
  	unsigned char id, slot, slots, alias_checksum;
  
  	if (!*unicode) {

  		*unicode = __getname();

  		if (!*unicode) {
  			brelse(*bh);
  			return -ENOMEM;
  		}
  	}
  parse_long:
  	slots = 0;
  	ds = (struct msdos_dir_slot *)*de;
  	id = ds->id;
  	if (!(id & 0x40))
  		return PARSE_INVALID;
  	slots = id & ~0x40;
  	if (slots > 20 || !slots)	/* ceil(256 * 2 / 26) */
  		return PARSE_INVALID;
  	*nr_slots = slots;
  	alias_checksum = ds->alias_checksum;
  
  	slot = slots;
  	while (1) {
  		int offset;
  
  		slot--;
  		offset = slot * 13;
  		fat16_towchar(*unicode + offset, ds->name0_4, 5);
  		fat16_towchar(*unicode + offset + 5, ds->name5_10, 6);
  		fat16_towchar(*unicode + offset + 11, ds->name11_12, 2);
  
  		if (ds->id & 0x40)
  			(*unicode)[offset + 13] = 0;
  		if (fat_get_entry(dir, pos, bh, de) < 0)
  			return PARSE_EOF;
  		if (slot == 0)
  			break;
  		ds = (struct msdos_dir_slot *)*de;
  		if (ds->attr != ATTR_EXT)
  			return PARSE_NOT_LONGNAME;
  		if ((ds->id & ~0x40) != slot)
  			goto parse_long;
  		if (ds->alias_checksum != alias_checksum)
  			goto parse_long;
  	}
  	if ((*de)->name[0] == DELETED_FLAG)
  		return PARSE_INVALID;
  	if ((*de)->attr == ATTR_EXT)
  		goto parse_long;
  	if (IS_FREE((*de)->name) || ((*de)->attr & ATTR_VOLUME))
  		return PARSE_INVALID;
  	if (fat_checksum((*de)->name) != alias_checksum)
  		*nr_slots = 0;
  
  	return 0;
  }

  /*
   * Return values: negative -> error, 0 -> not found, positive -> found,
   * value is the total amount of slots, including the shortname entry.
   */
  int fat_search_long(struct inode *inode, const unsigned char *name,
  		    int name_len, struct fat_slot_info *sinfo)
  {
  	struct super_block *sb = inode->i_sb;
  	struct msdos_sb_info *sbi = MSDOS_SB(sb);
  	struct buffer_head *bh = NULL;
  	struct msdos_dir_entry *de;

  	struct nls_table *nls_disk = sbi->nls_disk;

  	unsigned char nr_slots;

  	wchar_t bufuname[14];

  	wchar_t *unicode = NULL;

  	unsigned char work[MSDOS_NAME];

  	unsigned char bufname[FAT_MAX_SHORT_SIZE];

  	unsigned short opt_shortname = sbi->options.shortname;
  	loff_t cpos = 0;

  	int chl, i, j, last_u, err, len;

  
  	err = -ENOENT;

  	while (1) {

  		if (fat_get_entry(inode, &cpos, &bh, &de) == -1)

  			goto end_of_dir;

  parse_record:
  		nr_slots = 0;
  		if (de->name[0] == DELETED_FLAG)
  			continue;
  		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
  			continue;
  		if (de->attr != ATTR_EXT && IS_FREE(de->name))
  			continue;
  		if (de->attr == ATTR_EXT) {

  			int status = fat_parse_long(inode, &cpos, &bh, &de,
  						    &unicode, &nr_slots);

  			if (status < 0) {
  				err = status;
  				goto end_of_dir;
  			} else if (status == PARSE_INVALID)

  				continue;

  			else if (status == PARSE_NOT_LONGNAME)
  				goto parse_record;
  			else if (status == PARSE_EOF)

  				goto end_of_dir;

  		}
  
  		memcpy(work, de->name, sizeof(de->name));
  		/* see namei.c, msdos_format_name */
  		if (work[0] == 0x05)
  			work[0] = 0xE5;
  		for (i = 0, j = 0, last_u = 0; i < 8;) {

  			if (!work[i])
  				break;

  			chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
  						&bufuname[j++], opt_shortname,
  						de->lcase & CASE_LOWER_BASE);
  			if (chl <= 1) {
  				if (work[i] != ' ')
  					last_u = j;
  			} else {
  				last_u = j;
  			}
  			i += chl;
  		}
  		j = last_u;
  		fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);

  		for (i = 8; i < MSDOS_NAME;) {
  			if (!work[i])
  				break;
  			chl = fat_shortname2uni(nls_disk, &work[i],
  						MSDOS_NAME - i,

  						&bufuname[j++], opt_shortname,
  						de->lcase & CASE_LOWER_EXT);
  			if (chl <= 1) {

  				if (work[i] != ' ')

  					last_u = j;
  			} else {
  				last_u = j;
  			}
  			i += chl;
  		}
  		if (!last_u)
  			continue;

  		/* Compare shortname */

  		bufuname[last_u] = 0x0000;

  		len = fat_uni_to_x8(sb, bufuname, bufname, sizeof(bufname));

  		if (fat_name_match(sbi, name, name_len, bufname, len))
  			goto found;

  
  		if (nr_slots) {

  			void *longname = unicode + FAT_MAX_UNI_CHARS;
  			int size = PATH_MAX - FAT_MAX_UNI_SIZE;

  			/* Compare longname */

  			len = fat_uni_to_x8(sb, unicode, longname, size);

  			if (fat_name_match(sbi, name, name_len, longname, len))

  				goto found;

  		}
  	}

  found:

  	nr_slots++;	/* include the de */
  	sinfo->slot_off = cpos - nr_slots * sizeof(*de);
  	sinfo->nr_slots = nr_slots;
  	sinfo->de = de;
  	sinfo->bh = bh;
  	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
  	err = 0;

  end_of_dir:

  	if (unicode)

  		__putname(unicode);

  
  	return err;
  }

  EXPORT_SYMBOL_GPL(fat_search_long);

  
  struct fat_ioctl_filldir_callback {

  	void __user *dirent;

  	int result;
  	/* for dir ioctl */
  	const char *longname;
  	int long_len;
  	const char *shortname;
  	int short_len;
  };

  static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
  			 filldir_t filldir, int short_only, int both)

  {
  	struct super_block *sb = inode->i_sb;
  	struct msdos_sb_info *sbi = MSDOS_SB(sb);
  	struct buffer_head *bh;
  	struct msdos_dir_entry *de;

  	struct nls_table *nls_disk = sbi->nls_disk;

  	unsigned char nr_slots;

  	wchar_t bufuname[14];
  	wchar_t *unicode = NULL;

  	unsigned char c, work[MSDOS_NAME];
  	unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname;

  	unsigned short opt_shortname = sbi->options.shortname;

  	int isvfat = sbi->options.isvfat;

  	int nocase = sbi->options.nocase;

  	const char *fill_name = NULL;

  	unsigned long inum;

  	unsigned long lpos, dummy, *furrfu = &lpos;

  	loff_t cpos;

  	int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;

  	int ret = 0;

  	lock_super(sb);

  
  	cpos = filp->f_pos;
  	/* Fake . and .. for the root directory. */
  	if (inode->i_ino == MSDOS_ROOT_INO) {
  		while (cpos < 2) {
  			if (filldir(dirent, "..", cpos+1, cpos, MSDOS_ROOT_INO, DT_DIR) < 0)
  				goto out;
  			cpos++;
  			filp->f_pos++;
  		}
  		if (cpos == 2) {
  			dummy = 2;
  			furrfu = &dummy;
  			cpos = 0;
  		}
  	}

  	if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {

  		ret = -ENOENT;
  		goto out;
  	}
  
  	bh = NULL;

  get_new:

  	if (fat_get_entry(inode, &cpos, &bh, &de) == -1)

  		goto end_of_dir;

  parse_record:

  	nr_slots = 0;

  	/*
  	 * Check for long filename entry, but if short_only, we don't
  	 * need to parse long filename.
  	 */
  	if (isvfat && !short_only) {

  		if (de->name[0] == DELETED_FLAG)

  			goto record_end;

  		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))

  			goto record_end;

  		if (de->attr != ATTR_EXT && IS_FREE(de->name))

  			goto record_end;

  	} else {
  		if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))

  			goto record_end;

  	}
  
  	if (isvfat && de->attr == ATTR_EXT) {

  		int status = fat_parse_long(inode, &cpos, &bh, &de,

  					    &unicode, &nr_slots);

  		if (status < 0) {
  			filp->f_pos = cpos;
  			ret = status;
  			goto out;
  		} else if (status == PARSE_INVALID)

  			goto record_end;

  		else if (status == PARSE_NOT_LONGNAME)
  			goto parse_record;
  		else if (status == PARSE_EOF)

  			goto end_of_dir;

  
  		if (nr_slots) {
  			void *longname = unicode + FAT_MAX_UNI_CHARS;
  			int size = PATH_MAX - FAT_MAX_UNI_SIZE;

  			int len = fat_uni_to_x8(sb, unicode, longname, size);

  
  			fill_name = longname;
  			fill_len = len;
  			/* !both && !short_only, so we don't need shortname. */
  			if (!both)
  				goto start_filldir;
  		}

  	}
  
  	if (sbi->options.dotsOK) {
  		ptname = bufname;
  		dotoffset = 0;
  		if (de->attr & ATTR_HIDDEN) {
  			*ptname++ = '.';
  			dotoffset = 1;
  		}
  	}
  
  	memcpy(work, de->name, sizeof(de->name));
  	/* see namei.c, msdos_format_name */
  	if (work[0] == 0x05)
  		work[0] = 0xE5;
  	for (i = 0, j = 0, last = 0, last_u = 0; i < 8;) {

  		if (!(c = work[i]))
  			break;

  		chl = fat_shortname2uni(nls_disk, &work[i], 8 - i,
  					&bufuname[j++], opt_shortname,
  					de->lcase & CASE_LOWER_BASE);
  		if (chl <= 1) {
  			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
  			if (c != ' ') {
  				last = i;
  				last_u = j;
  			}
  		} else {
  			last_u = j;
  			for (chi = 0; chi < chl && i < 8; chi++) {
  				ptname[i] = work[i];
  				i++; last = i;
  			}
  		}
  	}
  	i = last;
  	j = last_u;
  	fat_short2uni(nls_disk, ".", 1, &bufuname[j++]);
  	ptname[i++] = '.';

  	for (i2 = 8; i2 < MSDOS_NAME;) {
  		if (!(c = work[i2]))
  			break;
  		chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2,

  					&bufuname[j++], opt_shortname,
  					de->lcase & CASE_LOWER_EXT);
  		if (chl <= 1) {
  			i2++;
  			ptname[i++] = (!nocase && c>='A' && c<='Z') ? c+32 : c;
  			if (c != ' ') {
  				last = i;
  				last_u = j;
  			}
  		} else {
  			last_u = j;

  			for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) {
  				ptname[i++] = work[i2++];

  				last = i;
  			}
  		}
  	}
  	if (!last)

  		goto record_end;

  
  	i = last + dotoffset;
  	j = last_u;

  	if (isvfat) {
  		bufuname[j] = 0x0000;

  		i = fat_uni_to_x8(sb, bufuname, bufname, sizeof(bufname));

  	}
  	if (nr_slots) {
  		/* hack for fat_ioctl_filldir() */
  		struct fat_ioctl_filldir_callback *p = dirent;
  
  		p->longname = fill_name;
  		p->long_len = fill_len;
  		p->shortname = bufname;
  		p->short_len = i;
  		fill_name = NULL;
  		fill_len = 0;
  	} else {
  		fill_name = bufname;
  		fill_len = i;
  	}
  
  start_filldir:

  	lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);

  	if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
  		inum = inode->i_ino;
  	else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {

  		inum = parent_ino(filp->f_path.dentry);

  	} else {
  		loff_t i_pos = fat_make_i_pos(sb, bh, de);
  		struct inode *tmp = fat_iget(sb, i_pos);
  		if (tmp) {
  			inum = tmp->i_ino;
  			iput(tmp);
  		} else
  			inum = iunique(sb, MSDOS_ROOT_INO);
  	}

  	if (filldir(dirent, fill_name, fill_len, *furrfu, inum,
  		    (de->attr & ATTR_DIR) ? DT_DIR : DT_REG) < 0)

  		goto fill_failed;

  record_end:

  	furrfu = &lpos;
  	filp->f_pos = cpos;

  	goto get_new;
  end_of_dir:

  	filp->f_pos = cpos;

  fill_failed:

  	brelse(bh);

  	if (unicode)

  		__putname(unicode);

  out:

  	unlock_super(sb);

  	return ret;
  }
  
  static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
  {

  	struct inode *inode = filp->f_path.dentry->d_inode;

  	return __fat_readdir(inode, filp, dirent, filldir, 0, 0);

  }

  #define FAT_IOCTL_FILLDIR_FUNC(func, dirent_type)			   \
  static int func(void *__buf, const char *name, int name_len,		   \
  			     loff_t offset, u64 ino, unsigned int d_type)  \
  {									   \
  	struct fat_ioctl_filldir_callback *buf = __buf;			   \
  	struct dirent_type __user *d1 = buf->dirent;			   \
  	struct dirent_type __user *d2 = d1 + 1;				   \
  									   \
  	if (buf->result)						   \
  		return -EINVAL;						   \
  	buf->result++;							   \
  									   \
  	if (name != NULL) {						   \
  		/* dirent has only short name */			   \
  		if (name_len >= sizeof(d1->d_name))			   \
  			name_len = sizeof(d1->d_name) - 1;		   \
  									   \
  		if (put_user(0, d2->d_name)			||	   \
  		    put_user(0, &d2->d_reclen)			||	   \
  		    copy_to_user(d1->d_name, name, name_len)	||	   \
  		    put_user(0, d1->d_name + name_len)		||	   \
  		    put_user(name_len, &d1->d_reclen))			   \
  			goto efault;					   \
  	} else {							   \
  		/* dirent has short and long name */			   \
  		const char *longname = buf->longname;			   \
  		int long_len = buf->long_len;				   \
  		const char *shortname = buf->shortname;			   \
  		int short_len = buf->short_len;				   \
  									   \
  		if (long_len >= sizeof(d1->d_name))			   \
  			long_len = sizeof(d1->d_name) - 1;		   \
  		if (short_len >= sizeof(d1->d_name))			   \
  			short_len = sizeof(d1->d_name) - 1;		   \
  									   \
  		if (copy_to_user(d2->d_name, longname, long_len)	|| \
  		    put_user(0, d2->d_name + long_len)			|| \
  		    put_user(long_len, &d2->d_reclen)			|| \
  		    put_user(ino, &d2->d_ino)				|| \
  		    put_user(offset, &d2->d_off)			|| \
  		    copy_to_user(d1->d_name, shortname, short_len)	|| \
  		    put_user(0, d1->d_name + short_len)			|| \
  		    put_user(short_len, &d1->d_reclen))			   \
  			goto efault;					   \
  	}								   \
  	return 0;							   \
  efault:									   \
  	buf->result = -EFAULT;						   \
  	return -EFAULT;							   \
  }

  FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)

  
  static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
  			     void __user *dirent, filldir_t filldir,
  			     int short_only, int both)

  {

  	struct fat_ioctl_filldir_callback buf;
  	int ret;
  
  	buf.dirent = dirent;
  	buf.result = 0;
  	mutex_lock(&inode->i_mutex);
  	ret = -ENOENT;
  	if (!IS_DEADDIR(inode)) {
  		ret = __fat_readdir(inode, filp, &buf, filldir,
  				    short_only, both);

  	}

  	mutex_unlock(&inode->i_mutex);
  	if (ret >= 0)
  		ret = buf.result;
  	return ret;

  }

  static long fat_dir_ioctl(struct file *filp, unsigned int cmd,
  			  unsigned long arg)

  {

  	struct inode *inode = filp->f_path.dentry->d_inode;

  	struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;

  	int short_only, both;

  
  	switch (cmd) {
  	case VFAT_IOCTL_READDIR_SHORT:
  		short_only = 1;
  		both = 0;
  		break;
  	case VFAT_IOCTL_READDIR_BOTH:
  		short_only = 0;
  		both = 1;
  		break;
  	default:

  		return fat_generic_ioctl(filp, cmd, arg);

  	}

  	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))

  		return -EFAULT;
  	/*
  	 * Yes, we don't need this put_user() absolutely. However old
  	 * code didn't return the right value. So, app use this value,
  	 * in order to check whether it is EOF.
  	 */
  	if (put_user(0, &d1->d_reclen))
  		return -EFAULT;

  	return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
  				 short_only, both);

  }

  #ifdef CONFIG_COMPAT
  #define	VFAT_IOCTL_READDIR_BOTH32	_IOR('r', 1, struct compat_dirent[2])
  #define	VFAT_IOCTL_READDIR_SHORT32	_IOR('r', 2, struct compat_dirent[2])

  FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)

  static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,

  				 unsigned long arg)
  {

  	struct inode *inode = filp->f_path.dentry->d_inode;
  	struct compat_dirent __user *d1 = compat_ptr(arg);
  	int short_only, both;

  
  	switch (cmd) {

  	case VFAT_IOCTL_READDIR_SHORT32:

  		short_only = 1;
  		both = 0;
  		break;
  	case VFAT_IOCTL_READDIR_BOTH32:
  		short_only = 0;
  		both = 1;

  		break;
  	default:

  		return fat_generic_ioctl(filp, cmd, (unsigned long)arg);

  	}

  	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct compat_dirent[2])))
  		return -EFAULT;
  	/*
  	 * Yes, we don't need this put_user() absolutely. However old
  	 * code didn't return the right value. So, app use this value,
  	 * in order to check whether it is EOF.
  	 */
  	if (put_user(0, &d1->d_reclen))
  		return -EFAULT;
  
  	return fat_ioctl_readdir(inode, filp, d1, fat_compat_ioctl_filldir,
  				 short_only, both);

  }
  #endif /* CONFIG_COMPAT */

  const struct file_operations fat_dir_operations = {

  	.llseek		= generic_file_llseek,

  	.read		= generic_read_dir,
  	.readdir	= fat_readdir,

  	.unlocked_ioctl	= fat_dir_ioctl,

  #ifdef CONFIG_COMPAT
  	.compat_ioctl	= fat_compat_dir_ioctl,
  #endif

  	.fsync		= fat_file_fsync,

  };
  
  static int fat_get_short_entry(struct inode *dir, loff_t *pos,
  			       struct buffer_head **bh,
  			       struct msdos_dir_entry **de)
  {
  	while (fat_get_entry(dir, pos, bh, de) >= 0) {
  		/* free entry or long name entry or volume label */
  		if (!IS_FREE((*de)->name) && !((*de)->attr & ATTR_VOLUME))
  			return 0;
  	}
  	return -ENOENT;
  }
  
  /*
   * The ".." entry can not provide the "struct fat_slot_info" informations
   * for inode. So, this function provide the some informations only.
   */
  int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
  			 struct msdos_dir_entry **de, loff_t *i_pos)
  {
  	loff_t offset;
  
  	offset = 0;
  	*bh = NULL;
  	while (fat_get_short_entry(dir, &offset, bh, de) >= 0) {
  		if (!strncmp((*de)->name, MSDOS_DOTDOT, MSDOS_NAME)) {
  			*i_pos = fat_make_i_pos(dir->i_sb, *bh, *de);
  			return 0;
  		}
  	}
  	return -ENOENT;
  }

  EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);

  
  /* See if directory is empty */
  int fat_dir_empty(struct inode *dir)
  {
  	struct buffer_head *bh;
  	struct msdos_dir_entry *de;
  	loff_t cpos;
  	int result = 0;
  
  	bh = NULL;
  	cpos = 0;
  	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
  		if (strncmp(de->name, MSDOS_DOT   , MSDOS_NAME) &&
  		    strncmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
  			result = -ENOTEMPTY;
  			break;
  		}
  	}
  	brelse(bh);
  	return result;
  }

  EXPORT_SYMBOL_GPL(fat_dir_empty);

  
  /*
   * fat_subdirs counts the number of sub-directories of dir. It can be run
   * on directories being created.
   */
  int fat_subdirs(struct inode *dir)
  {
  	struct buffer_head *bh;
  	struct msdos_dir_entry *de;
  	loff_t cpos;
  	int count = 0;
  
  	bh = NULL;
  	cpos = 0;
  	while (fat_get_short_entry(dir, &cpos, &bh, &de) >= 0) {
  		if (de->attr & ATTR_DIR)
  			count++;
  	}
  	brelse(bh);
  	return count;
  }
  
  /*
   * Scans a directory for a given file (name points to its formatted name).
   * Returns an error code or zero.
   */
  int fat_scan(struct inode *dir, const unsigned char *name,
  	     struct fat_slot_info *sinfo)
  {
  	struct super_block *sb = dir->i_sb;
  
  	sinfo->slot_off = 0;
  	sinfo->bh = NULL;
  	while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh,
  				   &sinfo->de) >= 0) {
  		if (!strncmp(sinfo->de->name, name, MSDOS_NAME)) {
  			sinfo->slot_off -= sizeof(*sinfo->de);
  			sinfo->nr_slots = 1;
  			sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
  			return 0;
  		}
  	}
  	return -ENOENT;
  }

  EXPORT_SYMBOL_GPL(fat_scan);

  
  static int __fat_remove_entries(struct inode *dir, loff_t pos, int nr_slots)
  {
  	struct super_block *sb = dir->i_sb;
  	struct buffer_head *bh;
  	struct msdos_dir_entry *de, *endp;
  	int err = 0, orig_slots;
  
  	while (nr_slots) {
  		bh = NULL;
  		if (fat_get_entry(dir, &pos, &bh, &de) < 0) {
  			err = -EIO;
  			break;
  		}
  
  		orig_slots = nr_slots;
  		endp = (struct msdos_dir_entry *)(bh->b_data + sb->s_blocksize);
  		while (nr_slots && de < endp) {
  			de->name[0] = DELETED_FLAG;
  			de++;
  			nr_slots--;
  		}

  		mark_buffer_dirty_inode(bh, dir);

  		if (IS_DIRSYNC(dir))
  			err = sync_dirty_buffer(bh);
  		brelse(bh);
  		if (err)
  			break;
  
  		/* pos is *next* de's position, so this does `- sizeof(de)' */
  		pos += ((orig_slots - nr_slots) * sizeof(*de)) - sizeof(*de);
  	}
  
  	return err;
  }
  
  int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo)
  {

  	struct super_block *sb = dir->i_sb;

  	struct msdos_dir_entry *de;
  	struct buffer_head *bh;
  	int err = 0, nr_slots;
  
  	/*
  	 * First stage: Remove the shortname. By this, the directory
  	 * entry is removed.
  	 */
  	nr_slots = sinfo->nr_slots;
  	de = sinfo->de;
  	sinfo->de = NULL;
  	bh = sinfo->bh;
  	sinfo->bh = NULL;
  	while (nr_slots && de >= (struct msdos_dir_entry *)bh->b_data) {
  		de->name[0] = DELETED_FLAG;
  		de--;
  		nr_slots--;
  	}

  	mark_buffer_dirty_inode(bh, dir);

  	if (IS_DIRSYNC(dir))
  		err = sync_dirty_buffer(bh);
  	brelse(bh);
  	if (err)
  		return err;
  	dir->i_version++;
  
  	if (nr_slots) {
  		/*
  		 * Second stage: remove the remaining longname slots.
  		 * (This directory entry is already removed, and so return
  		 * the success)
  		 */
  		err = __fat_remove_entries(dir, sinfo->slot_off, nr_slots);
  		if (err) {

  			fat_msg(sb, KERN_WARNING,
  			       "Couldn't remove the long name slots");

  		}
  	}
  
  	dir->i_mtime = dir->i_atime = CURRENT_TIME_SEC;
  	if (IS_DIRSYNC(dir))
  		(void)fat_sync_inode(dir);
  	else
  		mark_inode_dirty(dir);
  
  	return 0;
  }

  EXPORT_SYMBOL_GPL(fat_remove_entries);

  
  static int fat_zeroed_cluster(struct inode *dir, sector_t blknr, int nr_used,
  			      struct buffer_head **bhs, int nr_bhs)
  {
  	struct super_block *sb = dir->i_sb;
  	sector_t last_blknr = blknr + MSDOS_SB(sb)->sec_per_clus;
  	int err, i, n;
  
  	/* Zeroing the unused blocks on this cluster */
  	blknr += nr_used;
  	n = nr_used;
  	while (blknr < last_blknr) {
  		bhs[n] = sb_getblk(sb, blknr);
  		if (!bhs[n]) {
  			err = -ENOMEM;
  			goto error;
  		}
  		memset(bhs[n]->b_data, 0, sb->s_blocksize);
  		set_buffer_uptodate(bhs[n]);

  		mark_buffer_dirty_inode(bhs[n], dir);

  
  		n++;
  		blknr++;
  		if (n == nr_bhs) {
  			if (IS_DIRSYNC(dir)) {
  				err = fat_sync_bhs(bhs, n);
  				if (err)
  					goto error;
  			}
  			for (i = 0; i < n; i++)
  				brelse(bhs[i]);
  			n = 0;
  		}
  	}
  	if (IS_DIRSYNC(dir)) {
  		err = fat_sync_bhs(bhs, n);
  		if (err)
  			goto error;
  	}
  	for (i = 0; i < n; i++)
  		brelse(bhs[i]);
  
  	return 0;
  
  error:
  	for (i = 0; i < n; i++)
  		bforget(bhs[i]);
  	return err;
  }
  
  int fat_alloc_new_dir(struct inode *dir, struct timespec *ts)
  {
  	struct super_block *sb = dir->i_sb;
  	struct msdos_sb_info *sbi = MSDOS_SB(sb);
  	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
  	struct msdos_dir_entry *de;
  	sector_t blknr;
  	__le16 date, time;

  	u8 time_cs;

  	int err, cluster;
  
  	err = fat_alloc_clusters(dir, &cluster, 1);
  	if (err)
  		goto error;
  
  	blknr = fat_clus_to_blknr(sbi, cluster);
  	bhs[0] = sb_getblk(sb, blknr);
  	if (!bhs[0]) {
  		err = -ENOMEM;
  		goto error_free;
  	}

  	fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);

  
  	de = (struct msdos_dir_entry *)bhs[0]->b_data;
  	/* filling the new directory slots ("." and ".." entries) */
  	memcpy(de[0].name, MSDOS_DOT, MSDOS_NAME);
  	memcpy(de[1].name, MSDOS_DOTDOT, MSDOS_NAME);
  	de->attr = de[1].attr = ATTR_DIR;
  	de[0].lcase = de[1].lcase = 0;
  	de[0].time = de[1].time = time;
  	de[0].date = de[1].date = date;

  	if (sbi->options.isvfat) {
  		/* extra timestamps */
  		de[0].ctime = de[1].ctime = time;

  		de[0].ctime_cs = de[1].ctime_cs = time_cs;

  		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
  	} else {
  		de[0].ctime = de[1].ctime = 0;

  		de[0].ctime_cs = de[1].ctime_cs = 0;

  		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = 0;
  	}
  	de[0].start = cpu_to_le16(cluster);
  	de[0].starthi = cpu_to_le16(cluster >> 16);
  	de[1].start = cpu_to_le16(MSDOS_I(dir)->i_logstart);
  	de[1].starthi = cpu_to_le16(MSDOS_I(dir)->i_logstart >> 16);
  	de[0].size = de[1].size = 0;
  	memset(de + 2, 0, sb->s_blocksize - 2 * sizeof(*de));
  	set_buffer_uptodate(bhs[0]);

  	mark_buffer_dirty_inode(bhs[0], dir);

  
  	err = fat_zeroed_cluster(dir, blknr, 1, bhs, MAX_BUF_PER_PAGE);
  	if (err)
  		goto error_free;
  
  	return cluster;
  
  error_free:
  	fat_free_clusters(dir, cluster);
  error:
  	return err;
  }

  EXPORT_SYMBOL_GPL(fat_alloc_new_dir);

  
  static int fat_add_new_entries(struct inode *dir, void *slots, int nr_slots,
  			       int *nr_cluster, struct msdos_dir_entry **de,
  			       struct buffer_head **bh, loff_t *i_pos)
  {
  	struct super_block *sb = dir->i_sb;
  	struct msdos_sb_info *sbi = MSDOS_SB(sb);
  	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
  	sector_t blknr, start_blknr, last_blknr;
  	unsigned long size, copy;
  	int err, i, n, offset, cluster[2];
  
  	/*
  	 * The minimum cluster size is 512bytes, and maximum entry
  	 * size is 32*slots (672bytes).  So, iff the cluster size is
  	 * 512bytes, we may need two clusters.
  	 */
  	size = nr_slots * sizeof(struct msdos_dir_entry);
  	*nr_cluster = (size + (sbi->cluster_size - 1)) >> sbi->cluster_bits;
  	BUG_ON(*nr_cluster > 2);
  
  	err = fat_alloc_clusters(dir, cluster, *nr_cluster);
  	if (err)
  		goto error;
  
  	/*
  	 * First stage: Fill the directory entry.  NOTE: This cluster
  	 * is not referenced from any inode yet, so updates order is
  	 * not important.
  	 */
  	i = n = copy = 0;
  	do {
  		start_blknr = blknr = fat_clus_to_blknr(sbi, cluster[i]);
  		last_blknr = start_blknr + sbi->sec_per_clus;
  		while (blknr < last_blknr) {
  			bhs[n] = sb_getblk(sb, blknr);
  			if (!bhs[n]) {
  				err = -ENOMEM;
  				goto error_nomem;
  			}
  
  			/* fill the directory entry */
  			copy = min(size, sb->s_blocksize);
  			memcpy(bhs[n]->b_data, slots, copy);
  			slots += copy;
  			size -= copy;
  			set_buffer_uptodate(bhs[n]);

  			mark_buffer_dirty_inode(bhs[n], dir);

  			if (!size)
  				break;
  			n++;
  			blknr++;
  		}
  	} while (++i < *nr_cluster);
  
  	memset(bhs[n]->b_data + copy, 0, sb->s_blocksize - copy);
  	offset = copy - sizeof(struct msdos_dir_entry);
  	get_bh(bhs[n]);
  	*bh = bhs[n];
  	*de = (struct msdos_dir_entry *)((*bh)->b_data + offset);
  	*i_pos = fat_make_i_pos(sb, *bh, *de);
  
  	/* Second stage: clear the rest of cluster, and write outs */
  	err = fat_zeroed_cluster(dir, start_blknr, ++n, bhs, MAX_BUF_PER_PAGE);
  	if (err)
  		goto error_free;
  
  	return cluster[0];
  
  error_free:
  	brelse(*bh);
  	*bh = NULL;
  	n = 0;
  error_nomem:
  	for (i = 0; i < n; i++)
  		bforget(bhs[i]);
  	fat_free_clusters(dir, cluster[0]);
  error:
  	return err;
  }
  
  int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
  		    struct fat_slot_info *sinfo)
  {
  	struct super_block *sb = dir->i_sb;
  	struct msdos_sb_info *sbi = MSDOS_SB(sb);
  	struct buffer_head *bh, *prev, *bhs[3]; /* 32*slots (672bytes) */

  	struct msdos_dir_entry *uninitialized_var(de);

  	int err, free_slots, i, nr_bhs;
  	loff_t pos, i_pos;
  
  	sinfo->nr_slots = nr_slots;
  
  	/* First stage: search free direcotry entries */
  	free_slots = nr_bhs = 0;
  	bh = prev = NULL;
  	pos = 0;
  	err = -ENOSPC;
  	while (fat_get_entry(dir, &pos, &bh, &de) > -1) {
  		/* check the maximum size of directory */
  		if (pos >= FAT_MAX_DIR_SIZE)
  			goto error;
  
  		if (IS_FREE(de->name)) {
  			if (prev != bh) {
  				get_bh(bh);
  				bhs[nr_bhs] = prev = bh;
  				nr_bhs++;
  			}
  			free_slots++;
  			if (free_slots == nr_slots)
  				goto found;
  		} else {
  			for (i = 0; i < nr_bhs; i++)
  				brelse(bhs[i]);
  			prev = NULL;
  			free_slots = nr_bhs = 0;
  		}
  	}
  	if (dir->i_ino == MSDOS_ROOT_INO) {
  		if (sbi->fat_bits != 32)
  			goto error;
  	} else if (MSDOS_I(dir)->i_start == 0) {

  		fat_msg(sb, KERN_ERR, "Corrupted directory (i_pos %lld)",

  		       MSDOS_I(dir)->i_pos);
  		err = -EIO;
  		goto error;
  	}
  
  found:
  	err = 0;
  	pos -= free_slots * sizeof(*de);
  	nr_slots -= free_slots;
  	if (free_slots) {
  		/*
  		 * Second stage: filling the free entries with new entries.
  		 * NOTE: If this slots has shortname, first, we write
  		 * the long name slots, then write the short name.
  		 */
  		int size = free_slots * sizeof(*de);
  		int offset = pos & (sb->s_blocksize - 1);
  		int long_bhs = nr_bhs - (nr_slots == 0);
  
  		/* Fill the long name slots. */
  		for (i = 0; i < long_bhs; i++) {
  			int copy = min_t(int, sb->s_blocksize - offset, size);
  			memcpy(bhs[i]->b_data + offset, slots, copy);

  			mark_buffer_dirty_inode(bhs[i], dir);

  			offset = 0;
  			slots += copy;
  			size -= copy;
  		}
  		if (long_bhs && IS_DIRSYNC(dir))
  			err = fat_sync_bhs(bhs, long_bhs);
  		if (!err && i < nr_bhs) {
  			/* Fill the short name slot. */
  			int copy = min_t(int, sb->s_blocksize - offset, size);
  			memcpy(bhs[i]->b_data + offset, slots, copy);

  			mark_buffer_dirty_inode(bhs[i], dir);

  			if (IS_DIRSYNC(dir))
  				err = sync_dirty_buffer(bhs[i]);
  		}
  		for (i = 0; i < nr_bhs; i++)
  			brelse(bhs[i]);
  		if (err)
  			goto error_remove;
  	}
  
  	if (nr_slots) {
  		int cluster, nr_cluster;
  
  		/*
  		 * Third stage: allocate the cluster for new entries.
  		 * And initialize the cluster with new entries, then
  		 * add the cluster to dir.
  		 */
  		cluster = fat_add_new_entries(dir, slots, nr_slots, &nr_cluster,
  					      &de, &bh, &i_pos);
  		if (cluster < 0) {
  			err = cluster;
  			goto error_remove;
  		}
  		err = fat_chain_add(dir, cluster, nr_cluster);
  		if (err) {
  			fat_free_clusters(dir, cluster);
  			goto error_remove;
  		}
  		if (dir->i_size & (sbi->cluster_size - 1)) {

  			fat_fs_error(sb, "Odd directory size");

  			dir->i_size = (dir->i_size + sbi->cluster_size - 1)
  				& ~((loff_t)sbi->cluster_size - 1);
  		}
  		dir->i_size += nr_cluster << sbi->cluster_bits;
  		MSDOS_I(dir)->mmu_private += nr_cluster << sbi->cluster_bits;
  	}
  	sinfo->slot_off = pos;
  	sinfo->de = de;
  	sinfo->bh = bh;
  	sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de);
  
  	return 0;
  
  error:
  	brelse(bh);
  	for (i = 0; i < nr_bhs; i++)
  		brelse(bhs[i]);
  	return err;
  
  error_remove:
  	brelse(bh);
  	if (free_slots)
  		__fat_remove_entries(dir, pos, free_slots);
  	return err;
  }

  EXPORT_SYMBOL_GPL(fat_add_entries);