dir.c 33.7 KB
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/*
 *  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/smp_lock.h>
#include <linux/buffer_head.h>
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#include <linux/compat.h>
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#include <asm/uaccess.h>
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#include "fat.h"
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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);
}

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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;

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	bh = sb_find_get_block(sb, phys);
	if (bh == NULL || !buffer_uptodate(bh)) {
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		for (sec = 0; sec < sbi->sec_per_clus; sec++)
			sb_breadahead(sb, phys + sec);
	}
	brelse(bh);
}

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/* 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;
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	unsigned long mapped_blocks;
	int err, offset;
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next:
	if (*bh)
		brelse(*bh);

	*bh = NULL;
	iblock = *pos >> sb->s_blocksize_bits;
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	err = fat_bmap(dir, iblock, &phys, &mapped_blocks, 0);
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	if (err || !phys)
		return -1;	/* beyond EOF or error */

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	fat_dir_readahead(dir, iblock, phys);

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	*bh = sb_bread(sb, phys);
	if (*bh == NULL) {
		printk(KERN_ERR "FAT: Directory bread(block %llu) failed\n",
		       (unsigned long long)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);
}

/*
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 * Convert Unicode 16 to UTF-8, translated Unicode, or ASCII.
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 * 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.
 */
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static int uni16_to_x8(unsigned char *ascii, const wchar_t *uni, int len,
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		       int uni_xlate, struct nls_table *nls)
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{
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	const wchar_t *ip;
	wchar_t ec;
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	unsigned char *op, nc;
	int charlen;
	int k;

	ip = uni;
	op = ascii;

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	while (*ip && ((len - NLS_MAX_CHARSET_SIZE) > 0)) {
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		ec = *ip++;
		if ( (charlen = nls->uni2char(ec, op, NLS_MAX_CHARSET_SIZE)) > 0) {
			op += charlen;
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			len -= charlen;
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		} else {
			if (uni_xlate == 1) {
				*op = ':';
				for (k = 4; k > 0; k--) {
					nc = ec & 0xF;
					op[k] = nc > 9	? nc + ('a' - 10)
							: nc + '0';
					ec >>= 4;
				}
				op += 5;
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				len -= 5;
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			} else {
				*op++ = '?';
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				len--;
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			}
		}
	}
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	if (unlikely(*ip)) {
		printk(KERN_WARNING "FAT: filename was truncated while "
		       "converting.");
	}

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

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static inline int fat_uni_to_x8(struct msdos_sb_info *sbi, const wchar_t *uni,
				unsigned char *buf, int size)
{
	if (sbi->options.utf8)
		return utf8_wcstombs(buf, uni, size);
	else
		return uni16_to_x8(buf, uni, size, sbi->options.unicode_xlate,
				   sbi->nls_io);
}

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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;
}

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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);
}

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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) {
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		*unicode = __getname();
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		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;
}

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/*
 * 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))

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/*
 * 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;
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	unsigned char nr_slots;
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	wchar_t bufuname[14];
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	wchar_t *unicode = NULL;
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	unsigned char work[MSDOS_NAME];
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	unsigned char bufname[FAT_MAX_SHORT_SIZE];
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	unsigned short opt_shortname = sbi->options.shortname;
	loff_t cpos = 0;
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	int chl, i, j, last_u, err, len;
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	err = -ENOENT;
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	while (1) {
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		if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
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			goto end_of_dir;
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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) {
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			int status = fat_parse_long(inode, &cpos, &bh, &de,
						    &unicode, &nr_slots);
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			if (status < 0) {
				err = status;
				goto end_of_dir;
			} else if (status == PARSE_INVALID)
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				continue;
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			else if (status == PARSE_NOT_LONGNAME)
				goto parse_record;
			else if (status == PARSE_EOF)
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				goto end_of_dir;
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		}

		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;) {
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			if (!work[i])
				break;
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			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++]);
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		for (i = 8; i < MSDOS_NAME;) {
			if (!work[i])
				break;
			chl = fat_shortname2uni(nls_disk, &work[i],
						MSDOS_NAME - i,
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						&bufuname[j++], opt_shortname,
						de->lcase & CASE_LOWER_EXT);
			if (chl <= 1) {
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				if (work[i] != ' ')
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					last_u = j;
			} else {
				last_u = j;
			}
			i += chl;
		}
		if (!last_u)
			continue;

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		/* Compare shortname */
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		bufuname[last_u] = 0x0000;
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		len = fat_uni_to_x8(sbi, bufuname, bufname, sizeof(bufname));
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		if (fat_name_match(sbi, name, name_len, bufname, len))
			goto found;
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		if (nr_slots) {
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			void *longname = unicode + FAT_MAX_UNI_CHARS;
			int size = PATH_MAX - FAT_MAX_UNI_SIZE;

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			/* Compare longname */
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			len = fat_uni_to_x8(sbi, unicode, longname, size);
			if (fat_name_match(sbi, name, name_len, longname, len))
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				goto found;
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		}
	}

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found:
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	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;
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end_of_dir:
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	if (unicode)
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		__putname(unicode);
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	return err;
}

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EXPORT_SYMBOL_GPL(fat_search_long);
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struct fat_ioctl_filldir_callback {
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	void __user *dirent;
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	int result;
	/* for dir ioctl */
	const char *longname;
	int long_len;
	const char *shortname;
	int short_len;
};

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static int __fat_readdir(struct inode *inode, struct file *filp, void *dirent,
			 filldir_t filldir, int short_only, int both)
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{
	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;
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	unsigned char nr_slots;
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	wchar_t bufuname[14];
	wchar_t *unicode = NULL;
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	unsigned char c, work[MSDOS_NAME];
	unsigned char bufname[FAT_MAX_SHORT_SIZE], *ptname = bufname;
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	unsigned short opt_shortname = sbi->options.shortname;
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	int isvfat = sbi->options.isvfat;
	int nocase = sbi->options.nocase;
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	const char *fill_name = NULL;
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	unsigned long inum;
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	unsigned long lpos, dummy, *furrfu = &lpos;
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	loff_t cpos;
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	int chi, chl, i, i2, j, last, last_u, dotoffset = 0, fill_len = 0;
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	int ret = 0;

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	lock_super(sb);
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	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;
		}
	}
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	if (cpos & (sizeof(struct msdos_dir_entry) - 1)) {
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		ret = -ENOENT;
		goto out;
	}

	bh = NULL;
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get_new:
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	if (fat_get_entry(inode, &cpos, &bh, &de) == -1)
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		goto end_of_dir;
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parse_record:
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	nr_slots = 0;
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	/*
	 * Check for long filename entry, but if short_only, we don't
	 * need to parse long filename.
	 */
	if (isvfat && !short_only) {
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		if (de->name[0] == DELETED_FLAG)
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			goto record_end;
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		if (de->attr != ATTR_EXT && (de->attr & ATTR_VOLUME))
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			goto record_end;
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		if (de->attr != ATTR_EXT && IS_FREE(de->name))
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			goto record_end;
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	} else {
		if ((de->attr & ATTR_VOLUME) || IS_FREE(de->name))
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			goto record_end;
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	}

	if (isvfat && de->attr == ATTR_EXT) {
537
		int status = fat_parse_long(inode, &cpos, &bh, &de,
O
OGAWA Hirofumi 已提交
538
					    &unicode, &nr_slots);
539 540 541 542 543
		if (status < 0) {
			filp->f_pos = cpos;
			ret = status;
			goto out;
		} else if (status == PARSE_INVALID)
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			goto record_end;
545 546 547
		else if (status == PARSE_NOT_LONGNAME)
			goto parse_record;
		else if (status == PARSE_EOF)
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			goto end_of_dir;
549 550 551 552 553 554 555 556 557 558 559 560

		if (nr_slots) {
			void *longname = unicode + FAT_MAX_UNI_CHARS;
			int size = PATH_MAX - FAT_MAX_UNI_SIZE;
			int len = fat_uni_to_x8(sbi, unicode, longname, size);

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

	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;) {
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		if (!(c = work[i]))
			break;
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		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++] = '.';
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	for (i2 = 8; i2 < MSDOS_NAME;) {
		if (!(c = work[i2]))
			break;
		chl = fat_shortname2uni(nls_disk, &work[i2], MSDOS_NAME - i2,
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					&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;
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			for (chi = 0; chi < chl && i2 < MSDOS_NAME; chi++) {
				ptname[i++] = work[i2++];
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				last = i;
			}
		}
	}
	if (!last)
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		goto record_end;
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	i = last + dotoffset;
	j = last_u;

627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646
	if (isvfat) {
		bufuname[j] = 0x0000;
		i = fat_uni_to_x8(sbi, 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:
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	lpos = cpos - (nr_slots + 1) * sizeof(struct msdos_dir_entry);
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	if (!memcmp(de->name, MSDOS_DOT, MSDOS_NAME))
		inum = inode->i_ino;
	else if (!memcmp(de->name, MSDOS_DOTDOT, MSDOS_NAME)) {
651
		inum = parent_ino(filp->f_path.dentry);
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	} 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)
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		goto fill_failed;
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record_end:
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	furrfu = &lpos;
	filp->f_pos = cpos;
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	goto get_new;
end_of_dir:
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	filp->f_pos = cpos;
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fill_failed:
673
	brelse(bh);
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	if (unicode)
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		__putname(unicode);
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out:
677
	unlock_super(sb);
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	return ret;
}

static int fat_readdir(struct file *filp, void *dirent, filldir_t filldir)
{
683
	struct inode *inode = filp->f_path.dentry->d_inode;
684
	return __fat_readdir(inode, filp, dirent, filldir, 0, 0);
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}

687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737
#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;							   \
}

738
FAT_IOCTL_FILLDIR_FUNC(fat_ioctl_filldir, __fat_dirent)
739 740 741 742

static int fat_ioctl_readdir(struct inode *inode, struct file *filp,
			     void __user *dirent, filldir_t filldir,
			     int short_only, int both)
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{
744 745 746 747 748 749 750 751 752 753
	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);
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	}
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	mutex_unlock(&inode->i_mutex);
	if (ret >= 0)
		ret = buf.result;
	return ret;
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}

761 762
static int fat_dir_ioctl(struct inode *inode, struct file *filp,
			 unsigned int cmd, unsigned long arg)
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{
764
	struct __fat_dirent __user *d1 = (struct __fat_dirent __user *)arg;
765
	int short_only, both;
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	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(inode, filp, cmd, arg);
	}

780
	if (!access_ok(VERIFY_WRITE, d1, sizeof(struct __fat_dirent[2])))
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		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;

790 791
	return fat_ioctl_readdir(inode, filp, d1, fat_ioctl_filldir,
				 short_only, both);
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}

794 795 796 797
#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])

798
FAT_IOCTL_FILLDIR_FUNC(fat_compat_ioctl_filldir, compat_dirent)
799

800
static long fat_compat_dir_ioctl(struct file *filp, unsigned cmd,
801 802
				 unsigned long arg)
{
803 804 805
	struct inode *inode = filp->f_path.dentry->d_inode;
	struct compat_dirent __user *d1 = compat_ptr(arg);
	int short_only, both;
806 807 808

	switch (cmd) {
	case VFAT_IOCTL_READDIR_SHORT32:
809 810 811 812 813 814
		short_only = 1;
		both = 0;
		break;
	case VFAT_IOCTL_READDIR_BOTH32:
		short_only = 0;
		both = 1;
815 816 817 818 819
		break;
	default:
		return -ENOIOCTLCMD;
	}

820 821 822 823 824 825 826 827 828 829 830 831
	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);
832 833 834
}
#endif /* CONFIG_COMPAT */

835
const struct file_operations fat_dir_operations = {
836
	.llseek		= generic_file_llseek,
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	.read		= generic_read_dir,
	.readdir	= fat_readdir,
	.ioctl		= fat_dir_ioctl,
840 841 842
#ifdef CONFIG_COMPAT
	.compat_ioctl	= fat_compat_dir_ioctl,
#endif
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	.fsync		= file_fsync,
844
	.llseek		= generic_file_llseek,
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};

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;
}

879
EXPORT_SYMBOL_GPL(fat_get_dotdot_entry);
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880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901

/* 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;
}

902
EXPORT_SYMBOL_GPL(fat_dir_empty);
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903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947

/*
 * 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;
}

948
EXPORT_SYMBOL_GPL(fat_scan);
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949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034

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(bh);
		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 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(bh);
	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) {
			printk(KERN_WARNING
			       "FAT: Couldn't remove the long name slots\n");
		}
	}

	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;
}

1035
EXPORT_SYMBOL_GPL(fat_remove_entries);
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1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093

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(bhs[n]);

		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;
1094
	u8 time_cs;
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	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;
	}

1108
	fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
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	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;
1121
		de[0].ctime_cs = de[1].ctime_cs = time_cs;
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		de[0].adate = de[0].cdate = de[1].adate = de[1].cdate = date;
	} else {
		de[0].ctime = de[1].ctime = 0;
1125
		de[0].ctime_cs = de[1].ctime_cs = 0;
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		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(bhs[0]);

	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;
}

1149
EXPORT_SYMBOL_GPL(fat_alloc_new_dir);
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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(bhs[n]);
			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 *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) {
		printk(KERN_ERR "FAT: Corrupted directory (i_pos %lld)\n",
		       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(bhs[i]);
			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(bhs[i]);
			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_panic(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;
}

1365
EXPORT_SYMBOL_GPL(fat_add_entries);