Initial import of modified Linux 2.6.28 tree

Original upstream URL:
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git | branch linux-2.6.28.y

10 files changed, 6728 insertions, 0 deletions

diff --git a/fs/fat/Makefile b/fs/fat/Makefile
new file mode 100644
index 0000000..e061903
--- /dev/null
+++ b/fs/fat/Makefile
@@ -0,0 +1,11 @@
+#
+# Makefile for the Linux fat filesystem support.
+#
+
+obj-$(CONFIG_FAT_FS) += fat.o
+obj-$(CONFIG_VFAT_FS) += vfat.o
+obj-$(CONFIG_MSDOS_FS) += msdos.o
+
+fat-y := cache.o dir.o fatent.o file.o inode.o misc.o
+vfat-y := namei_vfat.o
+msdos-y := namei_msdos.o
diff --git a/fs/fat/cache.c b/fs/fat/cache.c
new file mode 100644
index 0000000..b426022
--- /dev/null
+++ b/fs/fat/cache.c
@@ -0,0 +1,342 @@
+/*
+ *  linux/fs/fat/cache.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *
+ *  Mar 1999. AV. Changed cache, so that it uses the starting cluster instead
+ *	of inode number.
+ *  May 1999. AV. Fixed the bogosity with FAT32 (read "FAT28"). Fscking lusers.
+ */
+
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include "fat.h"
+
+/* this must be > 0. */
+#define FAT_MAX_CACHE	8
+
+struct fat_cache {
+	struct list_head cache_list;
+	int nr_contig;	/* number of contiguous clusters */
+	int fcluster;	/* cluster number in the file. */
+	int dcluster;	/* cluster number on disk. */
+};
+
+struct fat_cache_id {
+	unsigned int id;
+	int nr_contig;
+	int fcluster;
+	int dcluster;
+};
+
+static inline int fat_max_cache(struct inode *inode)
+{
+	return FAT_MAX_CACHE;
+}
+
+static struct kmem_cache *fat_cache_cachep;
+
+static void init_once(void *foo)
+{
+	struct fat_cache *cache = (struct fat_cache *)foo;
+
+	INIT_LIST_HEAD(&cache->cache_list);
+}
+
+int __init fat_cache_init(void)
+{
+	fat_cache_cachep = kmem_cache_create("fat_cache",
+				sizeof(struct fat_cache),
+				0, SLAB_RECLAIM_ACCOUNT|SLAB_MEM_SPREAD,
+				init_once);
+	if (fat_cache_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+void fat_cache_destroy(void)
+{
+	kmem_cache_destroy(fat_cache_cachep);
+}
+
+static inline struct fat_cache *fat_cache_alloc(struct inode *inode)
+{
+	return kmem_cache_alloc(fat_cache_cachep, GFP_NOFS);
+}
+
+static inline void fat_cache_free(struct fat_cache *cache)
+{
+	BUG_ON(!list_empty(&cache->cache_list));
+	kmem_cache_free(fat_cache_cachep, cache);
+}
+
+static inline void fat_cache_update_lru(struct inode *inode,
+					struct fat_cache *cache)
+{
+	if (MSDOS_I(inode)->cache_lru.next != &cache->cache_list)
+		list_move(&cache->cache_list, &MSDOS_I(inode)->cache_lru);
+}
+
+static int fat_cache_lookup(struct inode *inode, int fclus,
+			    struct fat_cache_id *cid,
+			    int *cached_fclus, int *cached_dclus)
+{
+	static struct fat_cache nohit = { .fcluster = 0, };
+
+	struct fat_cache *hit = &nohit, *p;
+	int offset = -1;
+
+	spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+	list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) {
+		/* Find the cache of "fclus" or nearest cache. */
+		if (p->fcluster <= fclus && hit->fcluster < p->fcluster) {
+			hit = p;
+			if ((hit->fcluster + hit->nr_contig) < fclus) {
+				offset = hit->nr_contig;
+			} else {
+				offset = fclus - hit->fcluster;
+				break;
+			}
+		}
+	}
+	if (hit != &nohit) {
+		fat_cache_update_lru(inode, hit);
+
+		cid->id = MSDOS_I(inode)->cache_valid_id;
+		cid->nr_contig = hit->nr_contig;
+		cid->fcluster = hit->fcluster;
+		cid->dcluster = hit->dcluster;
+		*cached_fclus = cid->fcluster + offset;
+		*cached_dclus = cid->dcluster + offset;
+	}
+	spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+
+	return offset;
+}
+
+static struct fat_cache *fat_cache_merge(struct inode *inode,
+					 struct fat_cache_id *new)
+{
+	struct fat_cache *p;
+
+	list_for_each_entry(p, &MSDOS_I(inode)->cache_lru, cache_list) {
+		/* Find the same part as "new" in cluster-chain. */
+		if (p->fcluster == new->fcluster) {
+			BUG_ON(p->dcluster != new->dcluster);
+			if (new->nr_contig > p->nr_contig)
+				p->nr_contig = new->nr_contig;
+			return p;
+		}
+	}
+	return NULL;
+}
+
+static void fat_cache_add(struct inode *inode, struct fat_cache_id *new)
+{
+	struct fat_cache *cache, *tmp;
+
+	if (new->fcluster == -1) /* dummy cache */
+		return;
+
+	spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+	if (new->id != FAT_CACHE_VALID &&
+	    new->id != MSDOS_I(inode)->cache_valid_id)
+		goto out;	/* this cache was invalidated */
+
+	cache = fat_cache_merge(inode, new);
+	if (cache == NULL) {
+		if (MSDOS_I(inode)->nr_caches < fat_max_cache(inode)) {
+			MSDOS_I(inode)->nr_caches++;
+			spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+
+			tmp = fat_cache_alloc(inode);
+			spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+			cache = fat_cache_merge(inode, new);
+			if (cache != NULL) {
+				MSDOS_I(inode)->nr_caches--;
+				fat_cache_free(tmp);
+				goto out_update_lru;
+			}
+			cache = tmp;
+		} else {
+			struct list_head *p = MSDOS_I(inode)->cache_lru.prev;
+			cache = list_entry(p, struct fat_cache, cache_list);
+		}
+		cache->fcluster = new->fcluster;
+		cache->dcluster = new->dcluster;
+		cache->nr_contig = new->nr_contig;
+	}
+out_update_lru:
+	fat_cache_update_lru(inode, cache);
+out:
+	spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+}
+
+/*
+ * Cache invalidation occurs rarely, thus the LRU chain is not updated. It
+ * fixes itself after a while.
+ */
+static void __fat_cache_inval_inode(struct inode *inode)
+{
+	struct msdos_inode_info *i = MSDOS_I(inode);
+	struct fat_cache *cache;
+
+	while (!list_empty(&i->cache_lru)) {
+		cache = list_entry(i->cache_lru.next, struct fat_cache, cache_list);
+		list_del_init(&cache->cache_list);
+		i->nr_caches--;
+		fat_cache_free(cache);
+	}
+	/* Update. The copy of caches before this id is discarded. */
+	i->cache_valid_id++;
+	if (i->cache_valid_id == FAT_CACHE_VALID)
+		i->cache_valid_id++;
+}
+
+void fat_cache_inval_inode(struct inode *inode)
+{
+	spin_lock(&MSDOS_I(inode)->cache_lru_lock);
+	__fat_cache_inval_inode(inode);
+	spin_unlock(&MSDOS_I(inode)->cache_lru_lock);
+}
+
+static inline int cache_contiguous(struct fat_cache_id *cid, int dclus)
+{
+	cid->nr_contig++;
+	return ((cid->dcluster + cid->nr_contig) == dclus);
+}
+
+static inline void cache_init(struct fat_cache_id *cid, int fclus, int dclus)
+{
+	cid->id = FAT_CACHE_VALID;
+	cid->fcluster = fclus;
+	cid->dcluster = dclus;
+	cid->nr_contig = 0;
+}
+
+int fat_get_cluster(struct inode *inode, int cluster, int *fclus, int *dclus)
+{
+	struct super_block *sb = inode->i_sb;
+	const int limit = sb->s_maxbytes >> MSDOS_SB(sb)->cluster_bits;
+	struct fat_entry fatent;
+	struct fat_cache_id cid;
+	int nr;
+
+	BUG_ON(MSDOS_I(inode)->i_start == 0);
+
+	*fclus = 0;
+	*dclus = MSDOS_I(inode)->i_start;
+	if (cluster == 0)
+		return 0;
+
+	if (fat_cache_lookup(inode, cluster, &cid, fclus, dclus) < 0) {
+		/*
+		 * dummy, always not contiguous
+		 * This is reinitialized by cache_init(), later.
+		 */
+		cache_init(&cid, -1, -1);
+	}
+
+	fatent_init(&fatent);
+	while (*fclus < cluster) {
+		/* prevent the infinite loop of cluster chain */
+		if (*fclus > limit) {
+			fat_fs_panic(sb, "%s: detected the cluster chain loop"
+				     " (i_pos %lld)", __func__,
+				     MSDOS_I(inode)->i_pos);
+			nr = -EIO;
+			goto out;
+		}
+
+		nr = fat_ent_read(inode, &fatent, *dclus);
+		if (nr < 0)
+			goto out;
+		else if (nr == FAT_ENT_FREE) {
+			fat_fs_panic(sb, "%s: invalid cluster chain"
+				     " (i_pos %lld)", __func__,
+				     MSDOS_I(inode)->i_pos);
+			nr = -EIO;
+			goto out;
+		} else if (nr == FAT_ENT_EOF) {
+			fat_cache_add(inode, &cid);
+			goto out;
+		}
+		(*fclus)++;
+		*dclus = nr;
+		if (!cache_contiguous(&cid, *dclus))
+			cache_init(&cid, *fclus, *dclus);
+	}
+	nr = 0;
+	fat_cache_add(inode, &cid);
+out:
+	fatent_brelse(&fatent);
+	return nr;
+}
+
+static int fat_bmap_cluster(struct inode *inode, int cluster)
+{
+	struct super_block *sb = inode->i_sb;
+	int ret, fclus, dclus;
+
+	if (MSDOS_I(inode)->i_start == 0)
+		return 0;
+
+	ret = fat_get_cluster(inode, cluster, &fclus, &dclus);
+	if (ret < 0)
+		return ret;
+	else if (ret == FAT_ENT_EOF) {
+		fat_fs_panic(sb, "%s: request beyond EOF (i_pos %lld)",
+			     __func__, MSDOS_I(inode)->i_pos);
+		return -EIO;
+	}
+	return dclus;
+}
+
+int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
+	     unsigned long *mapped_blocks, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	const unsigned long blocksize = sb->s_blocksize;
+	const unsigned char blocksize_bits = sb->s_blocksize_bits;
+	sector_t last_block;
+	int cluster, offset;
+
+	*phys = 0;
+	*mapped_blocks = 0;
+	if ((sbi->fat_bits != 32) && (inode->i_ino == MSDOS_ROOT_INO)) {
+		if (sector < (sbi->dir_entries >> sbi->dir_per_block_bits)) {
+			*phys = sector + sbi->dir_start;
+			*mapped_blocks = 1;
+		}
+		return 0;
+	}
+
+	last_block = (i_size_read(inode) + (blocksize - 1)) >> blocksize_bits;
+	if (sector >= last_block) {
+		if (!create)
+			return 0;
+
+		/*
+		 * ->mmu_private can access on only allocation path.
+		 * (caller must hold ->i_mutex)
+		 */
+		last_block = (MSDOS_I(inode)->mmu_private + (blocksize - 1))
+			>> blocksize_bits;
+		if (sector >= last_block)
+			return 0;
+	}
+
+	cluster = sector >> (sbi->cluster_bits - sb->s_blocksize_bits);
+	offset  = sector & (sbi->sec_per_clus - 1);
+	cluster = fat_bmap_cluster(inode, cluster);
+	if (cluster < 0)
+		return cluster;
+	else if (cluster) {
+		*phys = fat_clus_to_blknr(sbi, cluster) + offset;
+		*mapped_blocks = sbi->sec_per_clus - offset;
+		if (*mapped_blocks > last_block - sector)
+			*mapped_blocks = last_block - sector;
+	}
+	return 0;
+}
diff --git a/fs/fat/dir.c b/fs/fat/dir.c
new file mode 100644
index 0000000..67e0583
--- /dev/null
+++ b/fs/fat/dir.c
@@ -0,0 +1,1365 @@
+/*
+ *  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>
+#include <linux/compat.h>
+#include <asm/uaccess.h>
+#include "fat.h"
+
+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) {
+		printk(KERN_ERR "FAT: Directory bread(block %llu) failed\n",
+		       (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(unsigned char *ascii, const wchar_t *uni, int len,
+		       int uni_xlate, struct nls_table *nls)
+{
+	const wchar_t *ip;
+	wchar_t ec;
+	unsigned char *op, nc;
+	int charlen;
+	int k;
+
+	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 = ':';
+				for (k = 4; k > 0; k--) {
+					nc = ec & 0xF;
+					op[k] = nc > 9	? nc + ('a' - 10)
+							: nc + '0';
+					ec >>= 4;
+				}
+				op += 5;
+				len -= 5;
+			} else {
+				*op++ = '?';
+				len--;
+			}
+		}
+	}
+
+	if (unlikely(*ip)) {
+		printk(KERN_WARNING "FAT: filename was truncated while "
+		       "converting.");
+	}
+
+	*op = 0;
+	return (op - ascii);
+}
+
+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);
+}
+
+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;
+}
+
+/*
+ * 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))
+
+/*
+ * 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(sbi, 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(sbi, 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(sbi, 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(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:
+	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 int fat_dir_ioctl(struct inode *inode, struct file *filp,
+			 unsigned int cmd, unsigned long arg)
+{
+	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(inode, 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 -ENOIOCTLCMD;
+	}
+
+	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,
+	.ioctl		= fat_dir_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl	= fat_compat_dir_ioctl,
+#endif
+	.fsync		= file_fsync,
+	.llseek		= generic_file_llseek,
+};
+
+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(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;
+}
+
+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(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;
+	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(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;
+}
+
+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(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;
+}
+
+EXPORT_SYMBOL_GPL(fat_add_entries);
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
new file mode 100644
index 0000000..ea440d6
--- /dev/null
+++ b/fs/fat/fat.h
@@ -0,0 +1,329 @@
+#ifndef _FAT_H
+#define _FAT_H
+
+#include <linux/buffer_head.h>
+#include <linux/string.h>
+#include <linux/nls.h>
+#include <linux/fs.h>
+#include <linux/mutex.h>
+#include <linux/msdos_fs.h>
+
+/*
+ * vfat shortname flags
+ */
+#define VFAT_SFN_DISPLAY_LOWER	0x0001 /* convert to lowercase for display */
+#define VFAT_SFN_DISPLAY_WIN95	0x0002 /* emulate win95 rule for display */
+#define VFAT_SFN_DISPLAY_WINNT	0x0004 /* emulate winnt rule for display */
+#define VFAT_SFN_CREATE_WIN95	0x0100 /* emulate win95 rule for create */
+#define VFAT_SFN_CREATE_WINNT	0x0200 /* emulate winnt rule for create */
+
+struct fat_mount_options {
+	uid_t fs_uid;
+	gid_t fs_gid;
+	unsigned short fs_fmask;
+	unsigned short fs_dmask;
+	unsigned short codepage;  /* Codepage for shortname conversions */
+	char *iocharset;          /* Charset used for filename input/display */
+	unsigned short shortname; /* flags for shortname display/create rule */
+	unsigned char name_check; /* r = relaxed, n = normal, s = strict */
+	unsigned short allow_utime;/* permission for setting the [am]time */
+	unsigned quiet:1,         /* set = fake successful chmods and chowns */
+		 showexec:1,      /* set = only set x bit for com/exe/bat */
+		 sys_immutable:1, /* set = system files are immutable */
+		 dotsOK:1,        /* set = hidden and system files are named '.filename' */
+		 isvfat:1,        /* 0=no vfat long filename support, 1=vfat support */
+		 utf8:1,	  /* Use of UTF-8 character set (Default) */
+		 unicode_xlate:1, /* create escape sequences for unhandled Unicode */
+		 numtail:1,       /* Does first alias have a numeric '~1' type tail? */
+		 flush:1,	  /* write things quickly */
+		 nocase:1,	  /* Does this need case conversion? 0=need case conversion*/
+		 usefree:1,	  /* Use free_clusters for FAT32 */
+		 tz_utc:1,	  /* Filesystem timestamps are in UTC */
+		 rodir:1;	  /* allow ATTR_RO for directory */
+};
+
+#define FAT_HASH_BITS	8
+#define FAT_HASH_SIZE	(1UL << FAT_HASH_BITS)
+
+/*
+ * MS-DOS file system in-core superblock data
+ */
+struct msdos_sb_info {
+	unsigned short sec_per_clus; /* sectors/cluster */
+	unsigned short cluster_bits; /* log2(cluster_size) */
+	unsigned int cluster_size;   /* cluster size */
+	unsigned char fats,fat_bits; /* number of FATs, FAT bits (12 or 16) */
+	unsigned short fat_start;
+	unsigned long fat_length;    /* FAT start & length (sec.) */
+	unsigned long dir_start;
+	unsigned short dir_entries;  /* root dir start & entries */
+	unsigned long data_start;    /* first data sector */
+	unsigned long max_cluster;   /* maximum cluster number */
+	unsigned long root_cluster;  /* first cluster of the root directory */
+	unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
+	struct mutex fat_lock;
+	unsigned int prev_free;      /* previously allocated cluster number */
+	unsigned int free_clusters;  /* -1 if undefined */
+	unsigned int free_clus_valid; /* is free_clusters valid? */
+	struct fat_mount_options options;
+	struct nls_table *nls_disk;  /* Codepage used on disk */
+	struct nls_table *nls_io;    /* Charset used for input and display */
+	const void *dir_ops;		     /* Opaque; default directory operations */
+	int dir_per_block;	     /* dir entries per block */
+	int dir_per_block_bits;	     /* log2(dir_per_block) */
+
+	int fatent_shift;
+	struct fatent_operations *fatent_ops;
+
+	spinlock_t inode_hash_lock;
+	struct hlist_head inode_hashtable[FAT_HASH_SIZE];
+};
+
+#define FAT_CACHE_VALID	0	/* special case for valid cache */
+
+/*
+ * MS-DOS file system inode data in memory
+ */
+struct msdos_inode_info {
+	spinlock_t cache_lru_lock;
+	struct list_head cache_lru;
+	int nr_caches;
+	/* for avoiding the race between fat_free() and fat_get_cluster() */
+	unsigned int cache_valid_id;
+
+	/* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
+	loff_t mmu_private;	/* physically allocated size */
+
+	int i_start;		/* first cluster or 0 */
+	int i_logstart;		/* logical first cluster */
+	int i_attrs;		/* unused attribute bits */
+	loff_t i_pos;		/* on-disk position of directory entry or 0 */
+	struct hlist_node i_fat_hash;	/* hash by i_location */
+	struct inode vfs_inode;
+};
+
+struct fat_slot_info {
+	loff_t i_pos;		/* on-disk position of directory entry */
+	loff_t slot_off;	/* offset for slot or de start */
+	int nr_slots;		/* number of slots + 1(de) in filename */
+	struct msdos_dir_entry *de;
+	struct buffer_head *bh;
+};
+
+static inline struct msdos_sb_info *MSDOS_SB(struct super_block *sb)
+{
+	return sb->s_fs_info;
+}
+
+static inline struct msdos_inode_info *MSDOS_I(struct inode *inode)
+{
+	return container_of(inode, struct msdos_inode_info, vfs_inode);
+}
+
+/*
+ * If ->i_mode can't hold S_IWUGO (i.e. ATTR_RO), we use ->i_attrs to
+ * save ATTR_RO instead of ->i_mode.
+ *
+ * If it's directory and !sbi->options.rodir, ATTR_RO isn't read-only
+ * bit, it's just used as flag for app.
+ */
+static inline int fat_mode_can_hold_ro(struct inode *inode)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	mode_t mask;
+
+	if (S_ISDIR(inode->i_mode)) {
+		if (!sbi->options.rodir)
+			return 0;
+		mask = ~sbi->options.fs_dmask;
+	} else
+		mask = ~sbi->options.fs_fmask;
+
+	if (!(mask & S_IWUGO))
+		return 0;
+	return 1;
+}
+
+/* Convert attribute bits and a mask to the UNIX mode. */
+static inline mode_t fat_make_mode(struct msdos_sb_info *sbi,
+				   u8 attrs, mode_t mode)
+{
+	if (attrs & ATTR_RO && !((attrs & ATTR_DIR) && !sbi->options.rodir))
+		mode &= ~S_IWUGO;
+
+	if (attrs & ATTR_DIR)
+		return (mode & ~sbi->options.fs_dmask) | S_IFDIR;
+	else
+		return (mode & ~sbi->options.fs_fmask) | S_IFREG;
+}
+
+/* Return the FAT attribute byte for this inode */
+static inline u8 fat_make_attrs(struct inode *inode)
+{
+	u8 attrs = MSDOS_I(inode)->i_attrs;
+	if (S_ISDIR(inode->i_mode))
+		attrs |= ATTR_DIR;
+	if (fat_mode_can_hold_ro(inode) && !(inode->i_mode & S_IWUGO))
+		attrs |= ATTR_RO;
+	return attrs;
+}
+
+static inline void fat_save_attrs(struct inode *inode, u8 attrs)
+{
+	if (fat_mode_can_hold_ro(inode))
+		MSDOS_I(inode)->i_attrs = attrs & ATTR_UNUSED;
+	else
+		MSDOS_I(inode)->i_attrs = attrs & (ATTR_UNUSED | ATTR_RO);
+}
+
+static inline unsigned char fat_checksum(const __u8 *name)
+{
+	unsigned char s = name[0];
+	s = (s<<7) + (s>>1) + name[1];	s = (s<<7) + (s>>1) + name[2];
+	s = (s<<7) + (s>>1) + name[3];	s = (s<<7) + (s>>1) + name[4];
+	s = (s<<7) + (s>>1) + name[5];	s = (s<<7) + (s>>1) + name[6];
+	s = (s<<7) + (s>>1) + name[7];	s = (s<<7) + (s>>1) + name[8];
+	s = (s<<7) + (s>>1) + name[9];	s = (s<<7) + (s>>1) + name[10];
+	return s;
+}
+
+static inline sector_t fat_clus_to_blknr(struct msdos_sb_info *sbi, int clus)
+{
+	return ((sector_t)clus - FAT_START_ENT) * sbi->sec_per_clus
+		+ sbi->data_start;
+}
+
+static inline void fat16_towchar(wchar_t *dst, const __u8 *src, size_t len)
+{
+#ifdef __BIG_ENDIAN
+	while (len--) {
+		*dst++ = src[0] | (src[1] << 8);
+		src += 2;
+	}
+#else
+	memcpy(dst, src, len * 2);
+#endif
+}
+
+static inline void fatwchar_to16(__u8 *dst, const wchar_t *src, size_t len)
+{
+#ifdef __BIG_ENDIAN
+	while (len--) {
+		dst[0] = *src & 0x00FF;
+		dst[1] = (*src & 0xFF00) >> 8;
+		dst += 2;
+		src++;
+	}
+#else
+	memcpy(dst, src, len * 2);
+#endif
+}
+
+/* fat/cache.c */
+extern void fat_cache_inval_inode(struct inode *inode);
+extern int fat_get_cluster(struct inode *inode, int cluster,
+			   int *fclus, int *dclus);
+extern int fat_bmap(struct inode *inode, sector_t sector, sector_t *phys,
+		    unsigned long *mapped_blocks, int create);
+
+/* fat/dir.c */
+extern const struct file_operations fat_dir_operations;
+extern int fat_search_long(struct inode *inode, const unsigned char *name,
+			   int name_len, struct fat_slot_info *sinfo);
+extern int fat_dir_empty(struct inode *dir);
+extern int fat_subdirs(struct inode *dir);
+extern int fat_scan(struct inode *dir, const unsigned char *name,
+		    struct fat_slot_info *sinfo);
+extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head **bh,
+				struct msdos_dir_entry **de, loff_t *i_pos);
+extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts);
+extern int fat_add_entries(struct inode *dir, void *slots, int nr_slots,
+			   struct fat_slot_info *sinfo);
+extern int fat_remove_entries(struct inode *dir, struct fat_slot_info *sinfo);
+
+/* fat/fatent.c */
+struct fat_entry {
+	int entry;
+	union {
+		u8 *ent12_p[2];
+		__le16 *ent16_p;
+		__le32 *ent32_p;
+	} u;
+	int nr_bhs;
+	struct buffer_head *bhs[2];
+};
+
+static inline void fatent_init(struct fat_entry *fatent)
+{
+	fatent->nr_bhs = 0;
+	fatent->entry = 0;
+	fatent->u.ent32_p = NULL;
+	fatent->bhs[0] = fatent->bhs[1] = NULL;
+}
+
+static inline void fatent_set_entry(struct fat_entry *fatent, int entry)
+{
+	fatent->entry = entry;
+	fatent->u.ent32_p = NULL;
+}
+
+static inline void fatent_brelse(struct fat_entry *fatent)
+{
+	int i;
+	fatent->u.ent32_p = NULL;
+	for (i = 0; i < fatent->nr_bhs; i++)
+		brelse(fatent->bhs[i]);
+	fatent->nr_bhs = 0;
+	fatent->bhs[0] = fatent->bhs[1] = NULL;
+}
+
+extern void fat_ent_access_init(struct super_block *sb);
+extern int fat_ent_read(struct inode *inode, struct fat_entry *fatent,
+			int entry);
+extern int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
+			 int new, int wait);
+extern int fat_alloc_clusters(struct inode *inode, int *cluster,
+			      int nr_cluster);
+extern int fat_free_clusters(struct inode *inode, int cluster);
+extern int fat_count_free_clusters(struct super_block *sb);
+
+/* fat/file.c */
+extern int fat_generic_ioctl(struct inode *inode, struct file *filp,
+			     unsigned int cmd, unsigned long arg);
+extern const struct file_operations fat_file_operations;
+extern const struct inode_operations fat_file_inode_operations;
+extern int fat_setattr(struct dentry * dentry, struct iattr * attr);
+extern void fat_truncate(struct inode *inode);
+extern int fat_getattr(struct vfsmount *mnt, struct dentry *dentry,
+		       struct kstat *stat);
+
+/* fat/inode.c */
+extern void fat_attach(struct inode *inode, loff_t i_pos);
+extern void fat_detach(struct inode *inode);
+extern struct inode *fat_iget(struct super_block *sb, loff_t i_pos);
+extern struct inode *fat_build_inode(struct super_block *sb,
+			struct msdos_dir_entry *de, loff_t i_pos);
+extern int fat_sync_inode(struct inode *inode);
+extern int fat_fill_super(struct super_block *sb, void *data, int silent,
+			const struct inode_operations *fs_dir_inode_ops, int isvfat);
+
+extern int fat_flush_inodes(struct super_block *sb, struct inode *i1,
+		            struct inode *i2);
+/* fat/misc.c */
+extern void fat_fs_panic(struct super_block *s, const char *fmt, ...)
+	__attribute__ ((format (printf, 2, 3))) __cold;
+extern void fat_clusters_flush(struct super_block *sb);
+extern int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster);
+extern void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
+			      __le16 __time, __le16 __date, u8 time_cs);
+extern void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
+			      __le16 *time, __le16 *date, u8 *time_cs);
+extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs);
+
+int fat_cache_init(void);
+void fat_cache_destroy(void);
+
+/* helper for printk */
+typedef unsigned long long	llu;
+
+#endif /* !_FAT_H */
diff --git a/fs/fat/fatent.c b/fs/fat/fatent.c
new file mode 100644
index 0000000..da6eea4
--- /dev/null
+++ b/fs/fat/fatent.c
@@ -0,0 +1,676 @@
+/*
+ * Copyright (C) 2004, OGAWA Hirofumi
+ * Released under GPL v2.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/msdos_fs.h>
+#include <linux/blkdev.h>
+#include "fat.h"
+
+struct fatent_operations {
+	void (*ent_blocknr)(struct super_block *, int, int *, sector_t *);
+	void (*ent_set_ptr)(struct fat_entry *, int);
+	int (*ent_bread)(struct super_block *, struct fat_entry *,
+			 int, sector_t);
+	int (*ent_get)(struct fat_entry *);
+	void (*ent_put)(struct fat_entry *, int);
+	int (*ent_next)(struct fat_entry *);
+};
+
+static DEFINE_SPINLOCK(fat12_entry_lock);
+
+static void fat12_ent_blocknr(struct super_block *sb, int entry,
+			      int *offset, sector_t *blocknr)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	int bytes = entry + (entry >> 1);
+	WARN_ON(entry < FAT_START_ENT || sbi->max_cluster <= entry);
+	*offset = bytes & (sb->s_blocksize - 1);
+	*blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);
+}
+
+static void fat_ent_blocknr(struct super_block *sb, int entry,
+			    int *offset, sector_t *blocknr)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	int bytes = (entry << sbi->fatent_shift);
+	WARN_ON(entry < FAT_START_ENT || sbi->max_cluster <= entry);
+	*offset = bytes & (sb->s_blocksize - 1);
+	*blocknr = sbi->fat_start + (bytes >> sb->s_blocksize_bits);
+}
+
+static void fat12_ent_set_ptr(struct fat_entry *fatent, int offset)
+{
+	struct buffer_head **bhs = fatent->bhs;
+	if (fatent->nr_bhs == 1) {
+		WARN_ON(offset >= (bhs[0]->b_size - 1));
+		fatent->u.ent12_p[0] = bhs[0]->b_data + offset;
+		fatent->u.ent12_p[1] = bhs[0]->b_data + (offset + 1);
+	} else {
+		WARN_ON(offset != (bhs[0]->b_size - 1));
+		fatent->u.ent12_p[0] = bhs[0]->b_data + offset;
+		fatent->u.ent12_p[1] = bhs[1]->b_data;
+	}
+}
+
+static void fat16_ent_set_ptr(struct fat_entry *fatent, int offset)
+{
+	WARN_ON(offset & (2 - 1));
+	fatent->u.ent16_p = (__le16 *)(fatent->bhs[0]->b_data + offset);
+}
+
+static void fat32_ent_set_ptr(struct fat_entry *fatent, int offset)
+{
+	WARN_ON(offset & (4 - 1));
+	fatent->u.ent32_p = (__le32 *)(fatent->bhs[0]->b_data + offset);
+}
+
+static int fat12_ent_bread(struct super_block *sb, struct fat_entry *fatent,
+			   int offset, sector_t blocknr)
+{
+	struct buffer_head **bhs = fatent->bhs;
+
+	WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);
+	bhs[0] = sb_bread(sb, blocknr);
+	if (!bhs[0])
+		goto err;
+
+	if ((offset + 1) < sb->s_blocksize)
+		fatent->nr_bhs = 1;
+	else {
+		/* This entry is block boundary, it needs the next block */
+		blocknr++;
+		bhs[1] = sb_bread(sb, blocknr);
+		if (!bhs[1])
+			goto err_brelse;
+		fatent->nr_bhs = 2;
+	}
+	fat12_ent_set_ptr(fatent, offset);
+	return 0;
+
+err_brelse:
+	brelse(bhs[0]);
+err:
+	printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n", (llu)blocknr);
+	return -EIO;
+}
+
+static int fat_ent_bread(struct super_block *sb, struct fat_entry *fatent,
+			 int offset, sector_t blocknr)
+{
+	struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+
+	WARN_ON(blocknr < MSDOS_SB(sb)->fat_start);
+	fatent->bhs[0] = sb_bread(sb, blocknr);
+	if (!fatent->bhs[0]) {
+		printk(KERN_ERR "FAT: FAT read failed (blocknr %llu)\n",
+		       (llu)blocknr);
+		return -EIO;
+	}
+	fatent->nr_bhs = 1;
+	ops->ent_set_ptr(fatent, offset);
+	return 0;
+}
+
+static int fat12_ent_get(struct fat_entry *fatent)
+{
+	u8 **ent12_p = fatent->u.ent12_p;
+	int next;
+
+	spin_lock(&fat12_entry_lock);
+	if (fatent->entry & 1)
+		next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4);
+	else
+		next = (*ent12_p[1] << 8) | *ent12_p[0];
+	spin_unlock(&fat12_entry_lock);
+
+	next &= 0x0fff;
+	if (next >= BAD_FAT12)
+		next = FAT_ENT_EOF;
+	return next;
+}
+
+static int fat16_ent_get(struct fat_entry *fatent)
+{
+	int next = le16_to_cpu(*fatent->u.ent16_p);
+	WARN_ON((unsigned long)fatent->u.ent16_p & (2 - 1));
+	if (next >= BAD_FAT16)
+		next = FAT_ENT_EOF;
+	return next;
+}
+
+static int fat32_ent_get(struct fat_entry *fatent)
+{
+	int next = le32_to_cpu(*fatent->u.ent32_p) & 0x0fffffff;
+	WARN_ON((unsigned long)fatent->u.ent32_p & (4 - 1));
+	if (next >= BAD_FAT32)
+		next = FAT_ENT_EOF;
+	return next;
+}
+
+static void fat12_ent_put(struct fat_entry *fatent, int new)
+{
+	u8 **ent12_p = fatent->u.ent12_p;
+
+	if (new == FAT_ENT_EOF)
+		new = EOF_FAT12;
+
+	spin_lock(&fat12_entry_lock);
+	if (fatent->entry & 1) {
+		*ent12_p[0] = (new << 4) | (*ent12_p[0] & 0x0f);
+		*ent12_p[1] = new >> 4;
+	} else {
+		*ent12_p[0] = new & 0xff;
+		*ent12_p[1] = (*ent12_p[1] & 0xf0) | (new >> 8);
+	}
+	spin_unlock(&fat12_entry_lock);
+
+	mark_buffer_dirty(fatent->bhs[0]);
+	if (fatent->nr_bhs == 2)
+		mark_buffer_dirty(fatent->bhs[1]);
+}
+
+static void fat16_ent_put(struct fat_entry *fatent, int new)
+{
+	if (new == FAT_ENT_EOF)
+		new = EOF_FAT16;
+
+	*fatent->u.ent16_p = cpu_to_le16(new);
+	mark_buffer_dirty(fatent->bhs[0]);
+}
+
+static void fat32_ent_put(struct fat_entry *fatent, int new)
+{
+	if (new == FAT_ENT_EOF)
+		new = EOF_FAT32;
+
+	WARN_ON(new & 0xf0000000);
+	new |= le32_to_cpu(*fatent->u.ent32_p) & ~0x0fffffff;
+	*fatent->u.ent32_p = cpu_to_le32(new);
+	mark_buffer_dirty(fatent->bhs[0]);
+}
+
+static int fat12_ent_next(struct fat_entry *fatent)
+{
+	u8 **ent12_p = fatent->u.ent12_p;
+	struct buffer_head **bhs = fatent->bhs;
+	u8 *nextp = ent12_p[1] + 1 + (fatent->entry & 1);
+
+	fatent->entry++;
+	if (fatent->nr_bhs == 1) {
+		WARN_ON(ent12_p[0] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 2)));
+		WARN_ON(ent12_p[1] > (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1)));
+		if (nextp < (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1))) {
+			ent12_p[0] = nextp - 1;
+			ent12_p[1] = nextp;
+			return 1;
+		}
+	} else {
+		WARN_ON(ent12_p[0] != (u8 *)(bhs[0]->b_data + (bhs[0]->b_size - 1)));
+		WARN_ON(ent12_p[1] != (u8 *)bhs[1]->b_data);
+		ent12_p[0] = nextp - 1;
+		ent12_p[1] = nextp;
+		brelse(bhs[0]);
+		bhs[0] = bhs[1];
+		fatent->nr_bhs = 1;
+		return 1;
+	}
+	ent12_p[0] = NULL;
+	ent12_p[1] = NULL;
+	return 0;
+}
+
+static int fat16_ent_next(struct fat_entry *fatent)
+{
+	const struct buffer_head *bh = fatent->bhs[0];
+	fatent->entry++;
+	if (fatent->u.ent16_p < (__le16 *)(bh->b_data + (bh->b_size - 2))) {
+		fatent->u.ent16_p++;
+		return 1;
+	}
+	fatent->u.ent16_p = NULL;
+	return 0;
+}
+
+static int fat32_ent_next(struct fat_entry *fatent)
+{
+	const struct buffer_head *bh = fatent->bhs[0];
+	fatent->entry++;
+	if (fatent->u.ent32_p < (__le32 *)(bh->b_data + (bh->b_size - 4))) {
+		fatent->u.ent32_p++;
+		return 1;
+	}
+	fatent->u.ent32_p = NULL;
+	return 0;
+}
+
+static struct fatent_operations fat12_ops = {
+	.ent_blocknr	= fat12_ent_blocknr,
+	.ent_set_ptr	= fat12_ent_set_ptr,
+	.ent_bread	= fat12_ent_bread,
+	.ent_get	= fat12_ent_get,
+	.ent_put	= fat12_ent_put,
+	.ent_next	= fat12_ent_next,
+};
+
+static struct fatent_operations fat16_ops = {
+	.ent_blocknr	= fat_ent_blocknr,
+	.ent_set_ptr	= fat16_ent_set_ptr,
+	.ent_bread	= fat_ent_bread,
+	.ent_get	= fat16_ent_get,
+	.ent_put	= fat16_ent_put,
+	.ent_next	= fat16_ent_next,
+};
+
+static struct fatent_operations fat32_ops = {
+	.ent_blocknr	= fat_ent_blocknr,
+	.ent_set_ptr	= fat32_ent_set_ptr,
+	.ent_bread	= fat_ent_bread,
+	.ent_get	= fat32_ent_get,
+	.ent_put	= fat32_ent_put,
+	.ent_next	= fat32_ent_next,
+};
+
+static inline void lock_fat(struct msdos_sb_info *sbi)
+{
+	mutex_lock(&sbi->fat_lock);
+}
+
+static inline void unlock_fat(struct msdos_sb_info *sbi)
+{
+	mutex_unlock(&sbi->fat_lock);
+}
+
+void fat_ent_access_init(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+	mutex_init(&sbi->fat_lock);
+
+	switch (sbi->fat_bits) {
+	case 32:
+		sbi->fatent_shift = 2;
+		sbi->fatent_ops = &fat32_ops;
+		break;
+	case 16:
+		sbi->fatent_shift = 1;
+		sbi->fatent_ops = &fat16_ops;
+		break;
+	case 12:
+		sbi->fatent_shift = -1;
+		sbi->fatent_ops = &fat12_ops;
+		break;
+	}
+}
+
+static inline int fat_ent_update_ptr(struct super_block *sb,
+				     struct fat_entry *fatent,
+				     int offset, sector_t blocknr)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct fatent_operations *ops = sbi->fatent_ops;
+	struct buffer_head **bhs = fatent->bhs;
+
+	/* Is this fatent's blocks including this entry? */
+	if (!fatent->nr_bhs || bhs[0]->b_blocknr != blocknr)
+		return 0;
+	if (sbi->fat_bits == 12) {
+		if ((offset + 1) < sb->s_blocksize) {
+			/* This entry is on bhs[0]. */
+			if (fatent->nr_bhs == 2) {
+				brelse(bhs[1]);
+				fatent->nr_bhs = 1;
+			}
+		} else {
+			/* This entry needs the next block. */
+			if (fatent->nr_bhs != 2)
+				return 0;
+			if (bhs[1]->b_blocknr != (blocknr + 1))
+				return 0;
+		}
+	}
+	ops->ent_set_ptr(fatent, offset);
+	return 1;
+}
+
+int fat_ent_read(struct inode *inode, struct fat_entry *fatent, int entry)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	struct fatent_operations *ops = sbi->fatent_ops;
+	int err, offset;
+	sector_t blocknr;
+
+	if (entry < FAT_START_ENT || sbi->max_cluster <= entry) {
+		fatent_brelse(fatent);
+		fat_fs_panic(sb, "invalid access to FAT (entry 0x%08x)", entry);
+		return -EIO;
+	}
+
+	fatent_set_entry(fatent, entry);
+	ops->ent_blocknr(sb, entry, &offset, &blocknr);
+
+	if (!fat_ent_update_ptr(sb, fatent, offset, blocknr)) {
+		fatent_brelse(fatent);
+		err = ops->ent_bread(sb, fatent, offset, blocknr);
+		if (err)
+			return err;
+	}
+	return ops->ent_get(fatent);
+}
+
+/* FIXME: We can write the blocks as more big chunk. */
+static int fat_mirror_bhs(struct super_block *sb, struct buffer_head **bhs,
+			  int nr_bhs)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct buffer_head *c_bh;
+	int err, n, copy;
+
+	err = 0;
+	for (copy = 1; copy < sbi->fats; copy++) {
+		sector_t backup_fat = sbi->fat_length * copy;
+
+		for (n = 0; n < nr_bhs; n++) {
+			c_bh = sb_getblk(sb, backup_fat + bhs[n]->b_blocknr);
+			if (!c_bh) {
+				err = -ENOMEM;
+				goto error;
+			}
+			memcpy(c_bh->b_data, bhs[n]->b_data, sb->s_blocksize);
+			set_buffer_uptodate(c_bh);
+			mark_buffer_dirty(c_bh);
+			if (sb->s_flags & MS_SYNCHRONOUS)
+				err = sync_dirty_buffer(c_bh);
+			brelse(c_bh);
+			if (err)
+				goto error;
+		}
+	}
+error:
+	return err;
+}
+
+int fat_ent_write(struct inode *inode, struct fat_entry *fatent,
+		  int new, int wait)
+{
+	struct super_block *sb = inode->i_sb;
+	struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+	int err;
+
+	ops->ent_put(fatent, new);
+	if (wait) {
+		err = fat_sync_bhs(fatent->bhs, fatent->nr_bhs);
+		if (err)
+			return err;
+	}
+	return fat_mirror_bhs(sb, fatent->bhs, fatent->nr_bhs);
+}
+
+static inline int fat_ent_next(struct msdos_sb_info *sbi,
+			       struct fat_entry *fatent)
+{
+	if (sbi->fatent_ops->ent_next(fatent)) {
+		if (fatent->entry < sbi->max_cluster)
+			return 1;
+	}
+	return 0;
+}
+
+static inline int fat_ent_read_block(struct super_block *sb,
+				     struct fat_entry *fatent)
+{
+	struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+	sector_t blocknr;
+	int offset;
+
+	fatent_brelse(fatent);
+	ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
+	return ops->ent_bread(sb, fatent, offset, blocknr);
+}
+
+static void fat_collect_bhs(struct buffer_head **bhs, int *nr_bhs,
+			    struct fat_entry *fatent)
+{
+	int n, i;
+
+	for (n = 0; n < fatent->nr_bhs; n++) {
+		for (i = 0; i < *nr_bhs; i++) {
+			if (fatent->bhs[n] == bhs[i])
+				break;
+		}
+		if (i == *nr_bhs) {
+			get_bh(fatent->bhs[n]);
+			bhs[i] = fatent->bhs[n];
+			(*nr_bhs)++;
+		}
+	}
+}
+
+int fat_alloc_clusters(struct inode *inode, int *cluster, int nr_cluster)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct fatent_operations *ops = sbi->fatent_ops;
+	struct fat_entry fatent, prev_ent;
+	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
+	int i, count, err, nr_bhs, idx_clus;
+
+	BUG_ON(nr_cluster > (MAX_BUF_PER_PAGE / 2));	/* fixed limit */
+
+	lock_fat(sbi);
+	if (sbi->free_clusters != -1 && sbi->free_clus_valid &&
+	    sbi->free_clusters < nr_cluster) {
+		unlock_fat(sbi);
+		return -ENOSPC;
+	}
+
+	err = nr_bhs = idx_clus = 0;
+	count = FAT_START_ENT;
+	fatent_init(&prev_ent);
+	fatent_init(&fatent);
+	fatent_set_entry(&fatent, sbi->prev_free + 1);
+	while (count < sbi->max_cluster) {
+		if (fatent.entry >= sbi->max_cluster)
+			fatent.entry = FAT_START_ENT;
+		fatent_set_entry(&fatent, fatent.entry);
+		err = fat_ent_read_block(sb, &fatent);
+		if (err)
+			goto out;
+
+		/* Find the free entries in a block */
+		do {
+			if (ops->ent_get(&fatent) == FAT_ENT_FREE) {
+				int entry = fatent.entry;
+
+				/* make the cluster chain */
+				ops->ent_put(&fatent, FAT_ENT_EOF);
+				if (prev_ent.nr_bhs)
+					ops->ent_put(&prev_ent, entry);
+
+				fat_collect_bhs(bhs, &nr_bhs, &fatent);
+
+				sbi->prev_free = entry;
+				if (sbi->free_clusters != -1)
+					sbi->free_clusters--;
+				sb->s_dirt = 1;
+
+				cluster[idx_clus] = entry;
+				idx_clus++;
+				if (idx_clus == nr_cluster)
+					goto out;
+
+				/*
+				 * fat_collect_bhs() gets ref-count of bhs,
+				 * so we can still use the prev_ent.
+				 */
+				prev_ent = fatent;
+			}
+			count++;
+			if (count == sbi->max_cluster)
+				break;
+		} while (fat_ent_next(sbi, &fatent));
+	}
+
+	/* Couldn't allocate the free entries */
+	sbi->free_clusters = 0;
+	sbi->free_clus_valid = 1;
+	sb->s_dirt = 1;
+	err = -ENOSPC;
+
+out:
+	unlock_fat(sbi);
+	fatent_brelse(&fatent);
+	if (!err) {
+		if (inode_needs_sync(inode))
+			err = fat_sync_bhs(bhs, nr_bhs);
+		if (!err)
+			err = fat_mirror_bhs(sb, bhs, nr_bhs);
+	}
+	for (i = 0; i < nr_bhs; i++)
+		brelse(bhs[i]);
+
+	if (err && idx_clus)
+		fat_free_clusters(inode, cluster[0]);
+
+	return err;
+}
+
+int fat_free_clusters(struct inode *inode, int cluster)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct fatent_operations *ops = sbi->fatent_ops;
+	struct fat_entry fatent;
+	struct buffer_head *bhs[MAX_BUF_PER_PAGE];
+	int i, err, nr_bhs;
+	int first_cl = cluster;
+
+	nr_bhs = 0;
+	fatent_init(&fatent);
+	lock_fat(sbi);
+	do {
+		cluster = fat_ent_read(inode, &fatent, cluster);
+		if (cluster < 0) {
+			err = cluster;
+			goto error;
+		} else if (cluster == FAT_ENT_FREE) {
+			fat_fs_panic(sb, "%s: deleting FAT entry beyond EOF",
+				     __func__);
+			err = -EIO;
+			goto error;
+		}
+
+		/* 
+		 * Issue discard for the sectors we no longer care about,
+		 * batching contiguous clusters into one request
+		 */
+		if (cluster != fatent.entry + 1) {
+			int nr_clus = fatent.entry - first_cl + 1;
+
+			sb_issue_discard(sb, fat_clus_to_blknr(sbi, first_cl),
+					 nr_clus * sbi->sec_per_clus);
+			first_cl = cluster;
+		}
+
+		ops->ent_put(&fatent, FAT_ENT_FREE);
+		if (sbi->free_clusters != -1) {
+			sbi->free_clusters++;
+			sb->s_dirt = 1;
+		}
+
+		if (nr_bhs + fatent.nr_bhs > MAX_BUF_PER_PAGE) {
+			if (sb->s_flags & MS_SYNCHRONOUS) {
+				err = fat_sync_bhs(bhs, nr_bhs);
+				if (err)
+					goto error;
+			}
+			err = fat_mirror_bhs(sb, bhs, nr_bhs);
+			if (err)
+				goto error;
+			for (i = 0; i < nr_bhs; i++)
+				brelse(bhs[i]);
+			nr_bhs = 0;
+		}
+		fat_collect_bhs(bhs, &nr_bhs, &fatent);
+	} while (cluster != FAT_ENT_EOF);
+
+	if (sb->s_flags & MS_SYNCHRONOUS) {
+		err = fat_sync_bhs(bhs, nr_bhs);
+		if (err)
+			goto error;
+	}
+	err = fat_mirror_bhs(sb, bhs, nr_bhs);
+error:
+	fatent_brelse(&fatent);
+	for (i = 0; i < nr_bhs; i++)
+		brelse(bhs[i]);
+	unlock_fat(sbi);
+
+	return err;
+}
+
+EXPORT_SYMBOL_GPL(fat_free_clusters);
+
+/* 128kb is the whole sectors for FAT12 and FAT16 */
+#define FAT_READA_SIZE		(128 * 1024)
+
+static void fat_ent_reada(struct super_block *sb, struct fat_entry *fatent,
+			  unsigned long reada_blocks)
+{
+	struct fatent_operations *ops = MSDOS_SB(sb)->fatent_ops;
+	sector_t blocknr;
+	int i, offset;
+
+	ops->ent_blocknr(sb, fatent->entry, &offset, &blocknr);
+
+	for (i = 0; i < reada_blocks; i++)
+		sb_breadahead(sb, blocknr + i);
+}
+
+int fat_count_free_clusters(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct fatent_operations *ops = sbi->fatent_ops;
+	struct fat_entry fatent;
+	unsigned long reada_blocks, reada_mask, cur_block;
+	int err = 0, free;
+
+	lock_fat(sbi);
+	if (sbi->free_clusters != -1 && sbi->free_clus_valid)
+		goto out;
+
+	reada_blocks = FAT_READA_SIZE >> sb->s_blocksize_bits;
+	reada_mask = reada_blocks - 1;
+	cur_block = 0;
+
+	free = 0;
+	fatent_init(&fatent);
+	fatent_set_entry(&fatent, FAT_START_ENT);
+	while (fatent.entry < sbi->max_cluster) {
+		/* readahead of fat blocks */
+		if ((cur_block & reada_mask) == 0) {
+			unsigned long rest = sbi->fat_length - cur_block;
+			fat_ent_reada(sb, &fatent, min(reada_blocks, rest));
+		}
+		cur_block++;
+
+		err = fat_ent_read_block(sb, &fatent);
+		if (err)
+			goto out;
+
+		do {
+			if (ops->ent_get(&fatent) == FAT_ENT_FREE)
+				free++;
+		} while (fat_ent_next(sbi, &fatent));
+	}
+	sbi->free_clusters = free;
+	sbi->free_clus_valid = 1;
+	sb->s_dirt = 1;
+	fatent_brelse(&fatent);
+out:
+	unlock_fat(sbi);
+	return err;
+}
diff --git a/fs/fat/file.c b/fs/fat/file.c
new file mode 100644
index 0000000..f06a4e5
--- /dev/null
+++ b/fs/fat/file.c
@@ -0,0 +1,392 @@
+/*
+ *  linux/fs/fat/file.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *
+ *  regular file handling primitives for fat-based filesystems
+ */
+
+#include <linux/capability.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/time.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/blkdev.h>
+#include <linux/fsnotify.h>
+#include <linux/security.h>
+#include "fat.h"
+
+int fat_generic_ioctl(struct inode *inode, struct file *filp,
+		      unsigned int cmd, unsigned long arg)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	u32 __user *user_attr = (u32 __user *)arg;
+
+	switch (cmd) {
+	case FAT_IOCTL_GET_ATTRIBUTES:
+	{
+		u32 attr;
+
+		mutex_lock(&inode->i_mutex);
+		attr = fat_make_attrs(inode);
+		mutex_unlock(&inode->i_mutex);
+
+		return put_user(attr, user_attr);
+	}
+	case FAT_IOCTL_SET_ATTRIBUTES:
+	{
+		u32 attr, oldattr;
+		int err, is_dir = S_ISDIR(inode->i_mode);
+		struct iattr ia;
+
+		err = get_user(attr, user_attr);
+		if (err)
+			return err;
+
+		mutex_lock(&inode->i_mutex);
+
+		err = mnt_want_write(filp->f_path.mnt);
+		if (err)
+			goto up_no_drop_write;
+
+		/*
+		 * ATTR_VOLUME and ATTR_DIR cannot be changed; this also
+		 * prevents the user from turning us into a VFAT
+		 * longname entry.  Also, we obviously can't set
+		 * any of the NTFS attributes in the high 24 bits.
+		 */
+		attr &= 0xff & ~(ATTR_VOLUME | ATTR_DIR);
+		/* Merge in ATTR_VOLUME and ATTR_DIR */
+		attr |= (MSDOS_I(inode)->i_attrs & ATTR_VOLUME) |
+			(is_dir ? ATTR_DIR : 0);
+		oldattr = fat_make_attrs(inode);
+
+		/* Equivalent to a chmod() */
+		ia.ia_valid = ATTR_MODE | ATTR_CTIME;
+		ia.ia_ctime = current_fs_time(inode->i_sb);
+		if (is_dir)
+			ia.ia_mode = fat_make_mode(sbi, attr, S_IRWXUGO);
+		else {
+			ia.ia_mode = fat_make_mode(sbi, attr,
+				S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO));
+		}
+
+		/* The root directory has no attributes */
+		if (inode->i_ino == MSDOS_ROOT_INO && attr != ATTR_DIR) {
+			err = -EINVAL;
+			goto up;
+		}
+
+		if (sbi->options.sys_immutable) {
+			if ((attr | oldattr) & ATTR_SYS) {
+				if (!capable(CAP_LINUX_IMMUTABLE)) {
+					err = -EPERM;
+					goto up;
+				}
+			}
+		}
+
+		/*
+		 * The security check is questionable...  We single
+		 * out the RO attribute for checking by the security
+		 * module, just because it maps to a file mode.
+		 */
+		err = security_inode_setattr(filp->f_path.dentry, &ia);
+		if (err)
+			goto up;
+
+		/* This MUST be done before doing anything irreversible... */
+		err = fat_setattr(filp->f_path.dentry, &ia);
+		if (err)
+			goto up;
+
+		fsnotify_change(filp->f_path.dentry, ia.ia_valid);
+		if (sbi->options.sys_immutable) {
+			if (attr & ATTR_SYS)
+				inode->i_flags |= S_IMMUTABLE;
+			else
+				inode->i_flags &= S_IMMUTABLE;
+		}
+
+		fat_save_attrs(inode, attr);
+		mark_inode_dirty(inode);
+up:
+		mnt_drop_write(filp->f_path.mnt);
+up_no_drop_write:
+		mutex_unlock(&inode->i_mutex);
+		return err;
+	}
+	default:
+		return -ENOTTY;	/* Inappropriate ioctl for device */
+	}
+}
+
+static int fat_file_release(struct inode *inode, struct file *filp)
+{
+	if ((filp->f_mode & FMODE_WRITE) &&
+	     MSDOS_SB(inode->i_sb)->options.flush) {
+		fat_flush_inodes(inode->i_sb, inode, NULL);
+		congestion_wait(WRITE, HZ/10);
+	}
+	return 0;
+}
+
+const struct file_operations fat_file_operations = {
+	.llseek		= generic_file_llseek,
+	.read		= do_sync_read,
+	.write		= do_sync_write,
+	.aio_read	= generic_file_aio_read,
+	.aio_write	= generic_file_aio_write,
+	.mmap		= generic_file_mmap,
+	.release	= fat_file_release,
+	.ioctl		= fat_generic_ioctl,
+	.fsync		= file_fsync,
+	.splice_read	= generic_file_splice_read,
+};
+
+static int fat_cont_expand(struct inode *inode, loff_t size)
+{
+	struct address_space *mapping = inode->i_mapping;
+	loff_t start = inode->i_size, count = size - inode->i_size;
+	int err;
+
+	err = generic_cont_expand_simple(inode, size);
+	if (err)
+		goto out;
+
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
+	mark_inode_dirty(inode);
+	if (IS_SYNC(inode))
+		err = sync_page_range_nolock(inode, mapping, start, count);
+out:
+	return err;
+}
+
+/* Free all clusters after the skip'th cluster. */
+static int fat_free(struct inode *inode, int skip)
+{
+	struct super_block *sb = inode->i_sb;
+	int err, wait, free_start, i_start, i_logstart;
+
+	if (MSDOS_I(inode)->i_start == 0)
+		return 0;
+
+	fat_cache_inval_inode(inode);
+
+	wait = IS_DIRSYNC(inode);
+	i_start = free_start = MSDOS_I(inode)->i_start;
+	i_logstart = MSDOS_I(inode)->i_logstart;
+
+	/* First, we write the new file size. */
+	if (!skip) {
+		MSDOS_I(inode)->i_start = 0;
+		MSDOS_I(inode)->i_logstart = 0;
+	}
+	MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
+	inode->i_ctime = inode->i_mtime = CURRENT_TIME_SEC;
+	if (wait) {
+		err = fat_sync_inode(inode);
+		if (err) {
+			MSDOS_I(inode)->i_start = i_start;
+			MSDOS_I(inode)->i_logstart = i_logstart;
+			return err;
+		}
+	} else
+		mark_inode_dirty(inode);
+
+	/* Write a new EOF, and get the remaining cluster chain for freeing. */
+	if (skip) {
+		struct fat_entry fatent;
+		int ret, fclus, dclus;
+
+		ret = fat_get_cluster(inode, skip - 1, &fclus, &dclus);
+		if (ret < 0)
+			return ret;
+		else if (ret == FAT_ENT_EOF)
+			return 0;
+
+		fatent_init(&fatent);
+		ret = fat_ent_read(inode, &fatent, dclus);
+		if (ret == FAT_ENT_EOF) {
+			fatent_brelse(&fatent);
+			return 0;
+		} else if (ret == FAT_ENT_FREE) {
+			fat_fs_panic(sb,
+				     "%s: invalid cluster chain (i_pos %lld)",
+				     __func__, MSDOS_I(inode)->i_pos);
+			ret = -EIO;
+		} else if (ret > 0) {
+			err = fat_ent_write(inode, &fatent, FAT_ENT_EOF, wait);
+			if (err)
+				ret = err;
+		}
+		fatent_brelse(&fatent);
+		if (ret < 0)
+			return ret;
+
+		free_start = ret;
+	}
+	inode->i_blocks = skip << (MSDOS_SB(sb)->cluster_bits - 9);
+
+	/* Freeing the remained cluster chain */
+	return fat_free_clusters(inode, free_start);
+}
+
+void fat_truncate(struct inode *inode)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	const unsigned int cluster_size = sbi->cluster_size;
+	int nr_clusters;
+
+	/*
+	 * This protects against truncating a file bigger than it was then
+	 * trying to write into the hole.
+	 */
+	if (MSDOS_I(inode)->mmu_private > inode->i_size)
+		MSDOS_I(inode)->mmu_private = inode->i_size;
+
+	nr_clusters = (inode->i_size + (cluster_size - 1)) >> sbi->cluster_bits;
+
+	fat_free(inode, nr_clusters);
+	fat_flush_inodes(inode->i_sb, inode, NULL);
+}
+
+int fat_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+	struct inode *inode = dentry->d_inode;
+	generic_fillattr(inode, stat);
+	stat->blksize = MSDOS_SB(inode->i_sb)->cluster_size;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fat_getattr);
+
+static int fat_sanitize_mode(const struct msdos_sb_info *sbi,
+			     struct inode *inode, umode_t *mode_ptr)
+{
+	mode_t mask, perm;
+
+	/*
+	 * Note, the basic check is already done by a caller of
+	 * (attr->ia_mode & ~FAT_VALID_MODE)
+	 */
+
+	if (S_ISREG(inode->i_mode))
+		mask = sbi->options.fs_fmask;
+	else
+		mask = sbi->options.fs_dmask;
+
+	perm = *mode_ptr & ~(S_IFMT | mask);
+
+	/*
+	 * Of the r and x bits, all (subject to umask) must be present. Of the
+	 * w bits, either all (subject to umask) or none must be present.
+	 *
+	 * If fat_mode_can_hold_ro(inode) is false, can't change w bits.
+	 */
+	if ((perm & (S_IRUGO | S_IXUGO)) != (inode->i_mode & (S_IRUGO|S_IXUGO)))
+		return -EPERM;
+	if (fat_mode_can_hold_ro(inode)) {
+		if ((perm & S_IWUGO) && ((perm & S_IWUGO) != (S_IWUGO & ~mask)))
+			return -EPERM;
+	} else {
+		if ((perm & S_IWUGO) != (S_IWUGO & ~mask))
+			return -EPERM;
+	}
+
+	*mode_ptr &= S_IFMT | perm;
+
+	return 0;
+}
+
+static int fat_allow_set_time(struct msdos_sb_info *sbi, struct inode *inode)
+{
+	mode_t allow_utime = sbi->options.allow_utime;
+
+	if (current->fsuid != inode->i_uid) {
+		if (in_group_p(inode->i_gid))
+			allow_utime >>= 3;
+		if (allow_utime & MAY_WRITE)
+			return 1;
+	}
+
+	/* use a default check */
+	return 0;
+}
+
+#define TIMES_SET_FLAGS	(ATTR_MTIME_SET | ATTR_ATIME_SET | ATTR_TIMES_SET)
+/* valid file mode bits */
+#define FAT_VALID_MODE	(S_IFREG | S_IFDIR | S_IRWXUGO)
+
+int fat_setattr(struct dentry *dentry, struct iattr *attr)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
+	struct inode *inode = dentry->d_inode;
+	unsigned int ia_valid;
+	int error;
+
+	/*
+	 * Expand the file. Since inode_setattr() updates ->i_size
+	 * before calling the ->truncate(), but FAT needs to fill the
+	 * hole before it.
+	 */
+	if (attr->ia_valid & ATTR_SIZE) {
+		if (attr->ia_size > inode->i_size) {
+			error = fat_cont_expand(inode, attr->ia_size);
+			if (error || attr->ia_valid == ATTR_SIZE)
+				goto out;
+			attr->ia_valid &= ~ATTR_SIZE;
+		}
+	}
+
+	/* Check for setting the inode time. */
+	ia_valid = attr->ia_valid;
+	if (ia_valid & TIMES_SET_FLAGS) {
+		if (fat_allow_set_time(sbi, inode))
+			attr->ia_valid &= ~TIMES_SET_FLAGS;
+	}
+
+	error = inode_change_ok(inode, attr);
+	attr->ia_valid = ia_valid;
+	if (error) {
+		if (sbi->options.quiet)
+			error = 0;
+		goto out;
+	}
+
+	if (((attr->ia_valid & ATTR_UID) &&
+	     (attr->ia_uid != sbi->options.fs_uid)) ||
+	    ((attr->ia_valid & ATTR_GID) &&
+	     (attr->ia_gid != sbi->options.fs_gid)) ||
+	    ((attr->ia_valid & ATTR_MODE) &&
+	     (attr->ia_mode & ~FAT_VALID_MODE)))
+		error = -EPERM;
+
+	if (error) {
+		if (sbi->options.quiet)
+			error = 0;
+		goto out;
+	}
+
+	/*
+	 * We don't return -EPERM here. Yes, strange, but this is too
+	 * old behavior.
+	 */
+	if (attr->ia_valid & ATTR_MODE) {
+		if (fat_sanitize_mode(sbi, inode, &attr->ia_mode) < 0)
+			attr->ia_valid &= ~ATTR_MODE;
+	}
+
+	if (attr->ia_valid)
+		error = inode_setattr(inode, attr);
+out:
+	return error;
+}
+EXPORT_SYMBOL_GPL(fat_setattr);
+
+const struct inode_operations fat_file_inode_operations = {
+	.truncate	= fat_truncate,
+	.setattr	= fat_setattr,
+	.getattr	= fat_getattr,
+};
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
new file mode 100644
index 0000000..bdd8fb7
--- /dev/null
+++ b/fs/fat/inode.c
@@ -0,0 +1,1529 @@
+/*
+ *  linux/fs/fat/inode.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *  VFAT extensions by Gordon Chaffee, merged with msdos fs by Henrik Storner
+ *  Rewritten for the constant inumbers support by Al Viro
+ *
+ *  Fixes:
+ *
+ *	Max Cohan: Fixed invalid FSINFO offset when info_sector is 0
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/time.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/seq_file.h>
+#include <linux/pagemap.h>
+#include <linux/mpage.h>
+#include <linux/buffer_head.h>
+#include <linux/exportfs.h>
+#include <linux/mount.h>
+#include <linux/vfs.h>
+#include <linux/parser.h>
+#include <linux/uio.h>
+#include <linux/writeback.h>
+#include <linux/log2.h>
+#include <linux/hash.h>
+#include <asm/unaligned.h>
+#include "fat.h"
+
+#ifndef CONFIG_FAT_DEFAULT_IOCHARSET
+/* if user don't select VFAT, this is undefined. */
+#define CONFIG_FAT_DEFAULT_IOCHARSET	""
+#endif
+
+static int fat_default_codepage = CONFIG_FAT_DEFAULT_CODEPAGE;
+static char fat_default_iocharset[] = CONFIG_FAT_DEFAULT_IOCHARSET;
+
+
+static int fat_add_cluster(struct inode *inode)
+{
+	int err, cluster;
+
+	err = fat_alloc_clusters(inode, &cluster, 1);
+	if (err)
+		return err;
+	/* FIXME: this cluster should be added after data of this
+	 * cluster is writed */
+	err = fat_chain_add(inode, cluster, 1);
+	if (err)
+		fat_free_clusters(inode, cluster);
+	return err;
+}
+
+static inline int __fat_get_block(struct inode *inode, sector_t iblock,
+				  unsigned long *max_blocks,
+				  struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	unsigned long mapped_blocks;
+	sector_t phys;
+	int err, offset;
+
+	err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
+	if (err)
+		return err;
+	if (phys) {
+		map_bh(bh_result, sb, phys);
+		*max_blocks = min(mapped_blocks, *max_blocks);
+		return 0;
+	}
+	if (!create)
+		return 0;
+
+	if (iblock != MSDOS_I(inode)->mmu_private >> sb->s_blocksize_bits) {
+		fat_fs_panic(sb, "corrupted file size (i_pos %lld, %lld)",
+			MSDOS_I(inode)->i_pos, MSDOS_I(inode)->mmu_private);
+		return -EIO;
+	}
+
+	offset = (unsigned long)iblock & (sbi->sec_per_clus - 1);
+	if (!offset) {
+		/* TODO: multiple cluster allocation would be desirable. */
+		err = fat_add_cluster(inode);
+		if (err)
+			return err;
+	}
+	/* available blocks on this cluster */
+	mapped_blocks = sbi->sec_per_clus - offset;
+
+	*max_blocks = min(mapped_blocks, *max_blocks);
+	MSDOS_I(inode)->mmu_private += *max_blocks << sb->s_blocksize_bits;
+
+	err = fat_bmap(inode, iblock, &phys, &mapped_blocks, create);
+	if (err)
+		return err;
+
+	BUG_ON(!phys);
+	BUG_ON(*max_blocks != mapped_blocks);
+	set_buffer_new(bh_result);
+	map_bh(bh_result, sb, phys);
+
+	return 0;
+}
+
+static int fat_get_block(struct inode *inode, sector_t iblock,
+			 struct buffer_head *bh_result, int create)
+{
+	struct super_block *sb = inode->i_sb;
+	unsigned long max_blocks = bh_result->b_size >> inode->i_blkbits;
+	int err;
+
+	err = __fat_get_block(inode, iblock, &max_blocks, bh_result, create);
+	if (err)
+		return err;
+	bh_result->b_size = max_blocks << sb->s_blocksize_bits;
+	return 0;
+}
+
+static int fat_writepage(struct page *page, struct writeback_control *wbc)
+{
+	return block_write_full_page(page, fat_get_block, wbc);
+}
+
+static int fat_writepages(struct address_space *mapping,
+			  struct writeback_control *wbc)
+{
+	return mpage_writepages(mapping, wbc, fat_get_block);
+}
+
+static int fat_readpage(struct file *file, struct page *page)
+{
+	return mpage_readpage(page, fat_get_block);
+}
+
+static int fat_readpages(struct file *file, struct address_space *mapping,
+			 struct list_head *pages, unsigned nr_pages)
+{
+	return mpage_readpages(mapping, pages, nr_pages, fat_get_block);
+}
+
+static int fat_write_begin(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned flags,
+			struct page **pagep, void **fsdata)
+{
+	*pagep = NULL;
+	return cont_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+				fat_get_block,
+				&MSDOS_I(mapping->host)->mmu_private);
+}
+
+static int fat_write_end(struct file *file, struct address_space *mapping,
+			loff_t pos, unsigned len, unsigned copied,
+			struct page *pagep, void *fsdata)
+{
+	struct inode *inode = mapping->host;
+	int err;
+	err = generic_write_end(file, mapping, pos, len, copied, pagep, fsdata);
+	if (!(err < 0) && !(MSDOS_I(inode)->i_attrs & ATTR_ARCH)) {
+		inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
+		MSDOS_I(inode)->i_attrs |= ATTR_ARCH;
+		mark_inode_dirty(inode);
+	}
+	return err;
+}
+
+static ssize_t fat_direct_IO(int rw, struct kiocb *iocb,
+			     const struct iovec *iov,
+			     loff_t offset, unsigned long nr_segs)
+{
+	struct file *file = iocb->ki_filp;
+	struct inode *inode = file->f_mapping->host;
+
+	if (rw == WRITE) {
+		/*
+		 * FIXME: blockdev_direct_IO() doesn't use ->write_begin(),
+		 * so we need to update the ->mmu_private to block boundary.
+		 *
+		 * But we must fill the remaining area or hole by nul for
+		 * updating ->mmu_private.
+		 *
+		 * Return 0, and fallback to normal buffered write.
+		 */
+		loff_t size = offset + iov_length(iov, nr_segs);
+		if (MSDOS_I(inode)->mmu_private < size)
+			return 0;
+	}
+
+	/*
+	 * FAT need to use the DIO_LOCKING for avoiding the race
+	 * condition of fat_get_block() and ->truncate().
+	 */
+	return blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
+				  offset, nr_segs, fat_get_block, NULL);
+}
+
+static sector_t _fat_bmap(struct address_space *mapping, sector_t block)
+{
+	sector_t blocknr;
+
+	/* fat_get_cluster() assumes the requested blocknr isn't truncated. */
+	mutex_lock(&mapping->host->i_mutex);
+	blocknr = generic_block_bmap(mapping, block, fat_get_block);
+	mutex_unlock(&mapping->host->i_mutex);
+
+	return blocknr;
+}
+
+static const struct address_space_operations fat_aops = {
+	.readpage	= fat_readpage,
+	.readpages	= fat_readpages,
+	.writepage	= fat_writepage,
+	.writepages	= fat_writepages,
+	.sync_page	= block_sync_page,
+	.write_begin	= fat_write_begin,
+	.write_end	= fat_write_end,
+	.direct_IO	= fat_direct_IO,
+	.bmap		= _fat_bmap
+};
+
+/*
+ * New FAT inode stuff. We do the following:
+ *	a) i_ino is constant and has nothing with on-disk location.
+ *	b) FAT manages its own cache of directory entries.
+ *	c) *This* cache is indexed by on-disk location.
+ *	d) inode has an associated directory entry, all right, but
+ *		it may be unhashed.
+ *	e) currently entries are stored within struct inode. That should
+ *		change.
+ *	f) we deal with races in the following way:
+ *		1. readdir() and lookup() do FAT-dir-cache lookup.
+ *		2. rename() unhashes the F-d-c entry and rehashes it in
+ *			a new place.
+ *		3. unlink() and rmdir() unhash F-d-c entry.
+ *		4. fat_write_inode() checks whether the thing is unhashed.
+ *			If it is we silently return. If it isn't we do bread(),
+ *			check if the location is still valid and retry if it
+ *			isn't. Otherwise we do changes.
+ *		5. Spinlock is used to protect hash/unhash/location check/lookup
+ *		6. fat_clear_inode() unhashes the F-d-c entry.
+ *		7. lookup() and readdir() do igrab() if they find a F-d-c entry
+ *			and consider negative result as cache miss.
+ */
+
+static void fat_hash_init(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	int i;
+
+	spin_lock_init(&sbi->inode_hash_lock);
+	for (i = 0; i < FAT_HASH_SIZE; i++)
+		INIT_HLIST_HEAD(&sbi->inode_hashtable[i]);
+}
+
+static inline unsigned long fat_hash(loff_t i_pos)
+{
+	return hash_32(i_pos, FAT_HASH_BITS);
+}
+
+void fat_attach(struct inode *inode, loff_t i_pos)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
+
+	spin_lock(&sbi->inode_hash_lock);
+	MSDOS_I(inode)->i_pos = i_pos;
+	hlist_add_head(&MSDOS_I(inode)->i_fat_hash, head);
+	spin_unlock(&sbi->inode_hash_lock);
+}
+EXPORT_SYMBOL_GPL(fat_attach);
+
+void fat_detach(struct inode *inode)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	spin_lock(&sbi->inode_hash_lock);
+	MSDOS_I(inode)->i_pos = 0;
+	hlist_del_init(&MSDOS_I(inode)->i_fat_hash);
+	spin_unlock(&sbi->inode_hash_lock);
+}
+EXPORT_SYMBOL_GPL(fat_detach);
+
+struct inode *fat_iget(struct super_block *sb, loff_t i_pos)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct hlist_head *head = sbi->inode_hashtable + fat_hash(i_pos);
+	struct hlist_node *_p;
+	struct msdos_inode_info *i;
+	struct inode *inode = NULL;
+
+	spin_lock(&sbi->inode_hash_lock);
+	hlist_for_each_entry(i, _p, head, i_fat_hash) {
+		BUG_ON(i->vfs_inode.i_sb != sb);
+		if (i->i_pos != i_pos)
+			continue;
+		inode = igrab(&i->vfs_inode);
+		if (inode)
+			break;
+	}
+	spin_unlock(&sbi->inode_hash_lock);
+	return inode;
+}
+
+static int is_exec(unsigned char *extension)
+{
+	unsigned char *exe_extensions = "EXECOMBAT", *walk;
+
+	for (walk = exe_extensions; *walk; walk += 3)
+		if (!strncmp(extension, walk, 3))
+			return 1;
+	return 0;
+}
+
+static int fat_calc_dir_size(struct inode *inode)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	int ret, fclus, dclus;
+
+	inode->i_size = 0;
+	if (MSDOS_I(inode)->i_start == 0)
+		return 0;
+
+	ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
+	if (ret < 0)
+		return ret;
+	inode->i_size = (fclus + 1) << sbi->cluster_bits;
+
+	return 0;
+}
+
+/* doesn't deal with root inode */
+static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb);
+	int error;
+
+	MSDOS_I(inode)->i_pos = 0;
+	inode->i_uid = sbi->options.fs_uid;
+	inode->i_gid = sbi->options.fs_gid;
+	inode->i_version++;
+	inode->i_generation = get_seconds();
+
+	if ((de->attr & ATTR_DIR) && !IS_FREE(de->name)) {
+		inode->i_generation &= ~1;
+		inode->i_mode = fat_make_mode(sbi, de->attr, S_IRWXUGO);
+		inode->i_op = sbi->dir_ops;
+		inode->i_fop = &fat_dir_operations;
+
+		MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
+		if (sbi->fat_bits == 32)
+			MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
+
+		MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
+		error = fat_calc_dir_size(inode);
+		if (error < 0)
+			return error;
+		MSDOS_I(inode)->mmu_private = inode->i_size;
+
+		inode->i_nlink = fat_subdirs(inode);
+	} else { /* not a directory */
+		inode->i_generation |= 1;
+		inode->i_mode = fat_make_mode(sbi, de->attr,
+			((sbi->options.showexec && !is_exec(de->name + 8))
+			 ? S_IRUGO|S_IWUGO : S_IRWXUGO));
+		MSDOS_I(inode)->i_start = le16_to_cpu(de->start);
+		if (sbi->fat_bits == 32)
+			MSDOS_I(inode)->i_start |= (le16_to_cpu(de->starthi) << 16);
+
+		MSDOS_I(inode)->i_logstart = MSDOS_I(inode)->i_start;
+		inode->i_size = le32_to_cpu(de->size);
+		inode->i_op = &fat_file_inode_operations;
+		inode->i_fop = &fat_file_operations;
+		inode->i_mapping->a_ops = &fat_aops;
+		MSDOS_I(inode)->mmu_private = inode->i_size;
+	}
+	if (de->attr & ATTR_SYS) {
+		if (sbi->options.sys_immutable)
+			inode->i_flags |= S_IMMUTABLE;
+	}
+	fat_save_attrs(inode, de->attr);
+
+	inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
+			   & ~((loff_t)sbi->cluster_size - 1)) >> 9;
+
+	fat_time_fat2unix(sbi, &inode->i_mtime, de->time, de->date, 0);
+	if (sbi->options.isvfat) {
+		fat_time_fat2unix(sbi, &inode->i_ctime, de->ctime,
+				  de->cdate, de->ctime_cs);
+		fat_time_fat2unix(sbi, &inode->i_atime, 0, de->adate, 0);
+	} else
+		inode->i_ctime = inode->i_atime = inode->i_mtime;
+
+	return 0;
+}
+
+struct inode *fat_build_inode(struct super_block *sb,
+			struct msdos_dir_entry *de, loff_t i_pos)
+{
+	struct inode *inode;
+	int err;
+
+	inode = fat_iget(sb, i_pos);
+	if (inode)
+		goto out;
+	inode = new_inode(sb);
+	if (!inode) {
+		inode = ERR_PTR(-ENOMEM);
+		goto out;
+	}
+	inode->i_ino = iunique(sb, MSDOS_ROOT_INO);
+	inode->i_version = 1;
+	err = fat_fill_inode(inode, de);
+	if (err) {
+		iput(inode);
+		inode = ERR_PTR(err);
+		goto out;
+	}
+	fat_attach(inode, i_pos);
+	insert_inode_hash(inode);
+out:
+	return inode;
+}
+
+EXPORT_SYMBOL_GPL(fat_build_inode);
+
+static void fat_delete_inode(struct inode *inode)
+{
+	truncate_inode_pages(&inode->i_data, 0);
+	inode->i_size = 0;
+	fat_truncate(inode);
+	clear_inode(inode);
+}
+
+static void fat_clear_inode(struct inode *inode)
+{
+	fat_cache_inval_inode(inode);
+	fat_detach(inode);
+}
+
+static void fat_write_super(struct super_block *sb)
+{
+	sb->s_dirt = 0;
+
+	if (!(sb->s_flags & MS_RDONLY))
+		fat_clusters_flush(sb);
+}
+
+static void fat_put_super(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+
+	if (sbi->nls_disk) {
+		unload_nls(sbi->nls_disk);
+		sbi->nls_disk = NULL;
+		sbi->options.codepage = fat_default_codepage;
+	}
+	if (sbi->nls_io) {
+		unload_nls(sbi->nls_io);
+		sbi->nls_io = NULL;
+	}
+	if (sbi->options.iocharset != fat_default_iocharset) {
+		kfree(sbi->options.iocharset);
+		sbi->options.iocharset = fat_default_iocharset;
+	}
+
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+}
+
+static struct kmem_cache *fat_inode_cachep;
+
+static struct inode *fat_alloc_inode(struct super_block *sb)
+{
+	struct msdos_inode_info *ei;
+	ei = kmem_cache_alloc(fat_inode_cachep, GFP_NOFS);
+	if (!ei)
+		return NULL;
+	return &ei->vfs_inode;
+}
+
+static void fat_destroy_inode(struct inode *inode)
+{
+	kmem_cache_free(fat_inode_cachep, MSDOS_I(inode));
+}
+
+static void init_once(void *foo)
+{
+	struct msdos_inode_info *ei = (struct msdos_inode_info *)foo;
+
+	spin_lock_init(&ei->cache_lru_lock);
+	ei->nr_caches = 0;
+	ei->cache_valid_id = FAT_CACHE_VALID + 1;
+	INIT_LIST_HEAD(&ei->cache_lru);
+	INIT_HLIST_NODE(&ei->i_fat_hash);
+	inode_init_once(&ei->vfs_inode);
+}
+
+static int __init fat_init_inodecache(void)
+{
+	fat_inode_cachep = kmem_cache_create("fat_inode_cache",
+					     sizeof(struct msdos_inode_info),
+					     0, (SLAB_RECLAIM_ACCOUNT|
+						SLAB_MEM_SPREAD),
+					     init_once);
+	if (fat_inode_cachep == NULL)
+		return -ENOMEM;
+	return 0;
+}
+
+static void __exit fat_destroy_inodecache(void)
+{
+	kmem_cache_destroy(fat_inode_cachep);
+}
+
+static int fat_remount(struct super_block *sb, int *flags, char *data)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	*flags |= MS_NODIRATIME | (sbi->options.isvfat ? 0 : MS_NOATIME);
+	return 0;
+}
+
+static int fat_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
+
+	/* If the count of free cluster is still unknown, counts it here. */
+	if (sbi->free_clusters == -1 || !sbi->free_clus_valid) {
+		int err = fat_count_free_clusters(dentry->d_sb);
+		if (err)
+			return err;
+	}
+
+	buf->f_type = dentry->d_sb->s_magic;
+	buf->f_bsize = sbi->cluster_size;
+	buf->f_blocks = sbi->max_cluster - FAT_START_ENT;
+	buf->f_bfree = sbi->free_clusters;
+	buf->f_bavail = sbi->free_clusters;
+	buf->f_namelen = sbi->options.isvfat ? 260 : 12;
+
+	return 0;
+}
+
+static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi,
+				    struct inode *inode)
+{
+	loff_t i_pos;
+#if BITS_PER_LONG == 32
+	spin_lock(&sbi->inode_hash_lock);
+#endif
+	i_pos = MSDOS_I(inode)->i_pos;
+#if BITS_PER_LONG == 32
+	spin_unlock(&sbi->inode_hash_lock);
+#endif
+	return i_pos;
+}
+
+static int fat_write_inode(struct inode *inode, int wait)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct buffer_head *bh;
+	struct msdos_dir_entry *raw_entry;
+	loff_t i_pos;
+	int err;
+
+	if (inode->i_ino == MSDOS_ROOT_INO)
+		return 0;
+
+retry:
+	i_pos = fat_i_pos_read(sbi, inode);
+	if (!i_pos)
+		return 0;
+
+	bh = sb_bread(sb, i_pos >> sbi->dir_per_block_bits);
+	if (!bh) {
+		printk(KERN_ERR "FAT: unable to read inode block "
+		       "for updating (i_pos %lld)\n", i_pos);
+		return -EIO;
+	}
+	spin_lock(&sbi->inode_hash_lock);
+	if (i_pos != MSDOS_I(inode)->i_pos) {
+		spin_unlock(&sbi->inode_hash_lock);
+		brelse(bh);
+		goto retry;
+	}
+
+	raw_entry = &((struct msdos_dir_entry *) (bh->b_data))
+	    [i_pos & (sbi->dir_per_block - 1)];
+	if (S_ISDIR(inode->i_mode))
+		raw_entry->size = 0;
+	else
+		raw_entry->size = cpu_to_le32(inode->i_size);
+	raw_entry->attr = fat_make_attrs(inode);
+	raw_entry->start = cpu_to_le16(MSDOS_I(inode)->i_logstart);
+	raw_entry->starthi = cpu_to_le16(MSDOS_I(inode)->i_logstart >> 16);
+	fat_time_unix2fat(sbi, &inode->i_mtime, &raw_entry->time,
+			  &raw_entry->date, NULL);
+	if (sbi->options.isvfat) {
+		__le16 atime;
+		fat_time_unix2fat(sbi, &inode->i_ctime, &raw_entry->ctime,
+				  &raw_entry->cdate, &raw_entry->ctime_cs);
+		fat_time_unix2fat(sbi, &inode->i_atime, &atime,
+				  &raw_entry->adate, NULL);
+	}
+	spin_unlock(&sbi->inode_hash_lock);
+	mark_buffer_dirty(bh);
+	err = 0;
+	if (wait)
+		err = sync_dirty_buffer(bh);
+	brelse(bh);
+	return err;
+}
+
+int fat_sync_inode(struct inode *inode)
+{
+	return fat_write_inode(inode, 1);
+}
+
+EXPORT_SYMBOL_GPL(fat_sync_inode);
+
+static int fat_show_options(struct seq_file *m, struct vfsmount *mnt);
+static const struct super_operations fat_sops = {
+	.alloc_inode	= fat_alloc_inode,
+	.destroy_inode	= fat_destroy_inode,
+	.write_inode	= fat_write_inode,
+	.delete_inode	= fat_delete_inode,
+	.put_super	= fat_put_super,
+	.write_super	= fat_write_super,
+	.statfs		= fat_statfs,
+	.clear_inode	= fat_clear_inode,
+	.remount_fs	= fat_remount,
+
+	.show_options	= fat_show_options,
+};
+
+/*
+ * a FAT file handle with fhtype 3 is
+ *  0/  i_ino - for fast, reliable lookup if still in the cache
+ *  1/  i_generation - to see if i_ino is still valid
+ *          bit 0 == 0 iff directory
+ *  2/  i_pos(8-39) - if ino has changed, but still in cache
+ *  3/  i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos
+ *  4/  i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc
+ *
+ * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum
+ * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits
+ * of i_logstart is used to store the directory entry offset.
+ */
+
+static struct dentry *fat_fh_to_dentry(struct super_block *sb,
+		struct fid *fid, int fh_len, int fh_type)
+{
+	struct inode *inode = NULL;
+	struct dentry *result;
+	u32 *fh = fid->raw;
+
+	if (fh_len < 5 || fh_type != 3)
+		return NULL;
+
+	inode = ilookup(sb, fh[0]);
+	if (!inode || inode->i_generation != fh[1]) {
+		if (inode)
+			iput(inode);
+		inode = NULL;
+	}
+	if (!inode) {
+		loff_t i_pos;
+		int i_logstart = fh[3] & 0x0fffffff;
+
+		i_pos = (loff_t)fh[2] << 8;
+		i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28);
+
+		/* try 2 - see if i_pos is in F-d-c
+		 * require i_logstart to be the same
+		 * Will fail if you truncate and then re-write
+		 */
+
+		inode = fat_iget(sb, i_pos);
+		if (inode && MSDOS_I(inode)->i_logstart != i_logstart) {
+			iput(inode);
+			inode = NULL;
+		}
+	}
+
+	/*
+	 * For now, do nothing if the inode is not found.
+	 *
+	 * What we could do is:
+	 *
+	 *	- follow the file starting at fh[4], and record the ".." entry,
+	 *	  and the name of the fh[2] entry.
+	 *	- then follow the ".." file finding the next step up.
+	 *
+	 * This way we build a path to the root of the tree. If this works, we
+	 * lookup the path and so get this inode into the cache.  Finally try
+	 * the fat_iget lookup again.  If that fails, then we are totally out
+	 * of luck.  But all that is for another day
+	 */
+	result = d_obtain_alias(inode);
+	if (!IS_ERR(result))
+		result->d_op = sb->s_root->d_op;
+	return result;
+}
+
+static int
+fat_encode_fh(struct dentry *de, __u32 *fh, int *lenp, int connectable)
+{
+	int len = *lenp;
+	struct inode *inode =  de->d_inode;
+	u32 ipos_h, ipos_m, ipos_l;
+
+	if (len < 5)
+		return 255; /* no room */
+
+	ipos_h = MSDOS_I(inode)->i_pos >> 8;
+	ipos_m = (MSDOS_I(inode)->i_pos & 0xf0) << 24;
+	ipos_l = (MSDOS_I(inode)->i_pos & 0x0f) << 28;
+	*lenp = 5;
+	fh[0] = inode->i_ino;
+	fh[1] = inode->i_generation;
+	fh[2] = ipos_h;
+	fh[3] = ipos_m | MSDOS_I(inode)->i_logstart;
+	spin_lock(&de->d_lock);
+	fh[4] = ipos_l | MSDOS_I(de->d_parent->d_inode)->i_logstart;
+	spin_unlock(&de->d_lock);
+	return 3;
+}
+
+static struct dentry *fat_get_parent(struct dentry *child)
+{
+	struct super_block *sb = child->d_sb;
+	struct buffer_head *bh;
+	struct msdos_dir_entry *de;
+	loff_t i_pos;
+	struct dentry *parent;
+	struct inode *inode;
+	int err;
+
+	lock_super(sb);
+
+	err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos);
+	if (err) {
+		parent = ERR_PTR(err);
+		goto out;
+	}
+	inode = fat_build_inode(sb, de, i_pos);
+	brelse(bh);
+
+	parent = d_obtain_alias(inode);
+out:
+	unlock_super(sb);
+
+	return parent;
+}
+
+static const struct export_operations fat_export_ops = {
+	.encode_fh	= fat_encode_fh,
+	.fh_to_dentry	= fat_fh_to_dentry,
+	.get_parent	= fat_get_parent,
+};
+
+static int fat_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(mnt->mnt_sb);
+	struct fat_mount_options *opts = &sbi->options;
+	int isvfat = opts->isvfat;
+
+	if (opts->fs_uid != 0)
+		seq_printf(m, ",uid=%u", opts->fs_uid);
+	if (opts->fs_gid != 0)
+		seq_printf(m, ",gid=%u", opts->fs_gid);
+	seq_printf(m, ",fmask=%04o", opts->fs_fmask);
+	seq_printf(m, ",dmask=%04o", opts->fs_dmask);
+	if (opts->allow_utime)
+		seq_printf(m, ",allow_utime=%04o", opts->allow_utime);
+	if (sbi->nls_disk)
+		seq_printf(m, ",codepage=%s", sbi->nls_disk->charset);
+	if (isvfat) {
+		if (sbi->nls_io)
+			seq_printf(m, ",iocharset=%s", sbi->nls_io->charset);
+
+		switch (opts->shortname) {
+		case VFAT_SFN_DISPLAY_WIN95 | VFAT_SFN_CREATE_WIN95:
+			seq_puts(m, ",shortname=win95");
+			break;
+		case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WINNT:
+			seq_puts(m, ",shortname=winnt");
+			break;
+		case VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95:
+			seq_puts(m, ",shortname=mixed");
+			break;
+		case VFAT_SFN_DISPLAY_LOWER | VFAT_SFN_CREATE_WIN95:
+			/* seq_puts(m, ",shortname=lower"); */
+			break;
+		default:
+			seq_puts(m, ",shortname=unknown");
+			break;
+		}
+	}
+	if (opts->name_check != 'n')
+		seq_printf(m, ",check=%c", opts->name_check);
+	if (opts->usefree)
+		seq_puts(m, ",usefree");
+	if (opts->quiet)
+		seq_puts(m, ",quiet");
+	if (opts->showexec)
+		seq_puts(m, ",showexec");
+	if (opts->sys_immutable)
+		seq_puts(m, ",sys_immutable");
+	if (!isvfat) {
+		if (opts->dotsOK)
+			seq_puts(m, ",dotsOK=yes");
+		if (opts->nocase)
+			seq_puts(m, ",nocase");
+	} else {
+		if (opts->utf8)
+			seq_puts(m, ",utf8");
+		if (opts->unicode_xlate)
+			seq_puts(m, ",uni_xlate");
+		if (!opts->numtail)
+			seq_puts(m, ",nonumtail");
+		if (opts->rodir)
+			seq_puts(m, ",rodir");
+	}
+	if (opts->flush)
+		seq_puts(m, ",flush");
+	if (opts->tz_utc)
+		seq_puts(m, ",tz=UTC");
+
+	return 0;
+}
+
+enum {
+	Opt_check_n, Opt_check_r, Opt_check_s, Opt_uid, Opt_gid,
+	Opt_umask, Opt_dmask, Opt_fmask, Opt_allow_utime, Opt_codepage,
+	Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug,
+	Opt_immutable, Opt_dots, Opt_nodots,
+	Opt_charset, Opt_shortname_lower, Opt_shortname_win95,
+	Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes,
+	Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
+	Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err,
+};
+
+static const match_table_t fat_tokens = {
+	{Opt_check_r, "check=relaxed"},
+	{Opt_check_s, "check=strict"},
+	{Opt_check_n, "check=normal"},
+	{Opt_check_r, "check=r"},
+	{Opt_check_s, "check=s"},
+	{Opt_check_n, "check=n"},
+	{Opt_uid, "uid=%u"},
+	{Opt_gid, "gid=%u"},
+	{Opt_umask, "umask=%o"},
+	{Opt_dmask, "dmask=%o"},
+	{Opt_fmask, "fmask=%o"},
+	{Opt_allow_utime, "allow_utime=%o"},
+	{Opt_codepage, "codepage=%u"},
+	{Opt_usefree, "usefree"},
+	{Opt_nocase, "nocase"},
+	{Opt_quiet, "quiet"},
+	{Opt_showexec, "showexec"},
+	{Opt_debug, "debug"},
+	{Opt_immutable, "sys_immutable"},
+	{Opt_obsolate, "conv=binary"},
+	{Opt_obsolate, "conv=text"},
+	{Opt_obsolate, "conv=auto"},
+	{Opt_obsolate, "conv=b"},
+	{Opt_obsolate, "conv=t"},
+	{Opt_obsolate, "conv=a"},
+	{Opt_obsolate, "fat=%u"},
+	{Opt_obsolate, "blocksize=%u"},
+	{Opt_obsolate, "cvf_format=%20s"},
+	{Opt_obsolate, "cvf_options=%100s"},
+	{Opt_obsolate, "posix"},
+	{Opt_flush, "flush"},
+	{Opt_tz_utc, "tz=UTC"},
+	{Opt_err, NULL},
+};
+static const match_table_t msdos_tokens = {
+	{Opt_nodots, "nodots"},
+	{Opt_nodots, "dotsOK=no"},
+	{Opt_dots, "dots"},
+	{Opt_dots, "dotsOK=yes"},
+	{Opt_err, NULL}
+};
+static const match_table_t vfat_tokens = {
+	{Opt_charset, "iocharset=%s"},
+	{Opt_shortname_lower, "shortname=lower"},
+	{Opt_shortname_win95, "shortname=win95"},
+	{Opt_shortname_winnt, "shortname=winnt"},
+	{Opt_shortname_mixed, "shortname=mixed"},
+	{Opt_utf8_no, "utf8=0"},		/* 0 or no or false */
+	{Opt_utf8_no, "utf8=no"},
+	{Opt_utf8_no, "utf8=false"},
+	{Opt_utf8_yes, "utf8=1"},		/* empty or 1 or yes or true */
+	{Opt_utf8_yes, "utf8=yes"},
+	{Opt_utf8_yes, "utf8=true"},
+	{Opt_utf8_yes, "utf8"},
+	{Opt_uni_xl_no, "uni_xlate=0"},		/* 0 or no or false */
+	{Opt_uni_xl_no, "uni_xlate=no"},
+	{Opt_uni_xl_no, "uni_xlate=false"},
+	{Opt_uni_xl_yes, "uni_xlate=1"},	/* empty or 1 or yes or true */
+	{Opt_uni_xl_yes, "uni_xlate=yes"},
+	{Opt_uni_xl_yes, "uni_xlate=true"},
+	{Opt_uni_xl_yes, "uni_xlate"},
+	{Opt_nonumtail_no, "nonumtail=0"},	/* 0 or no or false */
+	{Opt_nonumtail_no, "nonumtail=no"},
+	{Opt_nonumtail_no, "nonumtail=false"},
+	{Opt_nonumtail_yes, "nonumtail=1"},	/* empty or 1 or yes or true */
+	{Opt_nonumtail_yes, "nonumtail=yes"},
+	{Opt_nonumtail_yes, "nonumtail=true"},
+	{Opt_nonumtail_yes, "nonumtail"},
+	{Opt_rodir, "rodir"},
+	{Opt_err, NULL}
+};
+
+static int parse_options(char *options, int is_vfat, int silent, int *debug,
+			 struct fat_mount_options *opts)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	char *iocharset;
+
+	opts->isvfat = is_vfat;
+
+	opts->fs_uid = current->uid;
+	opts->fs_gid = current->gid;
+	opts->fs_fmask = opts->fs_dmask = current->fs->umask;
+	opts->allow_utime = -1;
+	opts->codepage = fat_default_codepage;
+	opts->iocharset = fat_default_iocharset;
+	if (is_vfat) {
+		opts->shortname = VFAT_SFN_DISPLAY_LOWER|VFAT_SFN_CREATE_WIN95;
+		opts->rodir = 0;
+	} else {
+		opts->shortname = 0;
+		opts->rodir = 1;
+	}
+	opts->name_check = 'n';
+	opts->quiet = opts->showexec = opts->sys_immutable = opts->dotsOK =  0;
+	opts->utf8 = opts->unicode_xlate = 0;
+	opts->numtail = 1;
+	opts->usefree = opts->nocase = 0;
+	opts->tz_utc = 0;
+	*debug = 0;
+
+	if (!options)
+		goto out;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token;
+		if (!*p)
+			continue;
+
+		token = match_token(p, fat_tokens, args);
+		if (token == Opt_err) {
+			if (is_vfat)
+				token = match_token(p, vfat_tokens, args);
+			else
+				token = match_token(p, msdos_tokens, args);
+		}
+		switch (token) {
+		case Opt_check_s:
+			opts->name_check = 's';
+			break;
+		case Opt_check_r:
+			opts->name_check = 'r';
+			break;
+		case Opt_check_n:
+			opts->name_check = 'n';
+			break;
+		case Opt_usefree:
+			opts->usefree = 1;
+			break;
+		case Opt_nocase:
+			if (!is_vfat)
+				opts->nocase = 1;
+			else {
+				/* for backward compatibility */
+				opts->shortname = VFAT_SFN_DISPLAY_WIN95
+					| VFAT_SFN_CREATE_WIN95;
+			}
+			break;
+		case Opt_quiet:
+			opts->quiet = 1;
+			break;
+		case Opt_showexec:
+			opts->showexec = 1;
+			break;
+		case Opt_debug:
+			*debug = 1;
+			break;
+		case Opt_immutable:
+			opts->sys_immutable = 1;
+			break;
+		case Opt_uid:
+			if (match_int(&args[0], &option))
+				return 0;
+			opts->fs_uid = option;
+			break;
+		case Opt_gid:
+			if (match_int(&args[0], &option))
+				return 0;
+			opts->fs_gid = option;
+			break;
+		case Opt_umask:
+			if (match_octal(&args[0], &option))
+				return 0;
+			opts->fs_fmask = opts->fs_dmask = option;
+			break;
+		case Opt_dmask:
+			if (match_octal(&args[0], &option))
+				return 0;
+			opts->fs_dmask = option;
+			break;
+		case Opt_fmask:
+			if (match_octal(&args[0], &option))
+				return 0;
+			opts->fs_fmask = option;
+			break;
+		case Opt_allow_utime:
+			if (match_octal(&args[0], &option))
+				return 0;
+			opts->allow_utime = option & (S_IWGRP | S_IWOTH);
+			break;
+		case Opt_codepage:
+			if (match_int(&args[0], &option))
+				return 0;
+			opts->codepage = option;
+			break;
+		case Opt_flush:
+			opts->flush = 1;
+			break;
+		case Opt_tz_utc:
+			opts->tz_utc = 1;
+			break;
+
+		/* msdos specific */
+		case Opt_dots:
+			opts->dotsOK = 1;
+			break;
+		case Opt_nodots:
+			opts->dotsOK = 0;
+			break;
+
+		/* vfat specific */
+		case Opt_charset:
+			if (opts->iocharset != fat_default_iocharset)
+				kfree(opts->iocharset);
+			iocharset = match_strdup(&args[0]);
+			if (!iocharset)
+				return -ENOMEM;
+			opts->iocharset = iocharset;
+			break;
+		case Opt_shortname_lower:
+			opts->shortname = VFAT_SFN_DISPLAY_LOWER
+					| VFAT_SFN_CREATE_WIN95;
+			break;
+		case Opt_shortname_win95:
+			opts->shortname = VFAT_SFN_DISPLAY_WIN95
+					| VFAT_SFN_CREATE_WIN95;
+			break;
+		case Opt_shortname_winnt:
+			opts->shortname = VFAT_SFN_DISPLAY_WINNT
+					| VFAT_SFN_CREATE_WINNT;
+			break;
+		case Opt_shortname_mixed:
+			opts->shortname = VFAT_SFN_DISPLAY_WINNT
+					| VFAT_SFN_CREATE_WIN95;
+			break;
+		case Opt_utf8_no:		/* 0 or no or false */
+			opts->utf8 = 0;
+			break;
+		case Opt_utf8_yes:		/* empty or 1 or yes or true */
+			opts->utf8 = 1;
+			break;
+		case Opt_uni_xl_no:		/* 0 or no or false */
+			opts->unicode_xlate = 0;
+			break;
+		case Opt_uni_xl_yes:		/* empty or 1 or yes or true */
+			opts->unicode_xlate = 1;
+			break;
+		case Opt_nonumtail_no:		/* 0 or no or false */
+			opts->numtail = 1;	/* negated option */
+			break;
+		case Opt_nonumtail_yes:		/* empty or 1 or yes or true */
+			opts->numtail = 0;	/* negated option */
+			break;
+		case Opt_rodir:
+			opts->rodir = 1;
+			break;
+
+		/* obsolete mount options */
+		case Opt_obsolate:
+			printk(KERN_INFO "FAT: \"%s\" option is obsolete, "
+			       "not supported now\n", p);
+			break;
+		/* unknown option */
+		default:
+			if (!silent) {
+				printk(KERN_ERR
+				       "FAT: Unrecognized mount option \"%s\" "
+				       "or missing value\n", p);
+			}
+			return -EINVAL;
+		}
+	}
+
+out:
+	/* UTF-8 doesn't provide FAT semantics */
+	if (!strcmp(opts->iocharset, "utf8")) {
+		printk(KERN_ERR "FAT: utf8 is not a recommended IO charset"
+		       " for FAT filesystems, filesystem will be "
+		       "case sensitive!\n");
+	}
+
+	/* If user doesn't specify allow_utime, it's initialized from dmask. */
+	if (opts->allow_utime == (unsigned short)-1)
+		opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
+	if (opts->unicode_xlate)
+		opts->utf8 = 0;
+
+	return 0;
+}
+
+static int fat_read_root(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	int error;
+
+	MSDOS_I(inode)->i_pos = 0;
+	inode->i_uid = sbi->options.fs_uid;
+	inode->i_gid = sbi->options.fs_gid;
+	inode->i_version++;
+	inode->i_generation = 0;
+	inode->i_mode = fat_make_mode(sbi, ATTR_DIR, S_IRWXUGO);
+	inode->i_op = sbi->dir_ops;
+	inode->i_fop = &fat_dir_operations;
+	if (sbi->fat_bits == 32) {
+		MSDOS_I(inode)->i_start = sbi->root_cluster;
+		error = fat_calc_dir_size(inode);
+		if (error < 0)
+			return error;
+	} else {
+		MSDOS_I(inode)->i_start = 0;
+		inode->i_size = sbi->dir_entries * sizeof(struct msdos_dir_entry);
+	}
+	inode->i_blocks = ((inode->i_size + (sbi->cluster_size - 1))
+			   & ~((loff_t)sbi->cluster_size - 1)) >> 9;
+	MSDOS_I(inode)->i_logstart = 0;
+	MSDOS_I(inode)->mmu_private = inode->i_size;
+
+	fat_save_attrs(inode, ATTR_DIR);
+	inode->i_mtime.tv_sec = inode->i_atime.tv_sec = inode->i_ctime.tv_sec = 0;
+	inode->i_mtime.tv_nsec = inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = 0;
+	inode->i_nlink = fat_subdirs(inode)+2;
+
+	return 0;
+}
+
+/*
+ * Read the super block of an MS-DOS FS.
+ */
+int fat_fill_super(struct super_block *sb, void *data, int silent,
+		   const struct inode_operations *fs_dir_inode_ops, int isvfat)
+{
+	struct inode *root_inode = NULL;
+	struct buffer_head *bh;
+	struct fat_boot_sector *b;
+	struct msdos_sb_info *sbi;
+	u16 logical_sector_size;
+	u32 total_sectors, total_clusters, fat_clusters, rootdir_sectors;
+	int debug;
+	unsigned int media;
+	long error;
+	char buf[50];
+
+	/*
+	 * GFP_KERNEL is ok here, because while we do hold the
+	 * supeblock lock, memory pressure can't call back into
+	 * the filesystem, since we're only just about to mount
+	 * it and have no inodes etc active!
+	 */
+	sbi = kzalloc(sizeof(struct msdos_sb_info), GFP_KERNEL);
+	if (!sbi)
+		return -ENOMEM;
+	sb->s_fs_info = sbi;
+
+	sb->s_flags |= MS_NODIRATIME;
+	sb->s_magic = MSDOS_SUPER_MAGIC;
+	sb->s_op = &fat_sops;
+	sb->s_export_op = &fat_export_ops;
+	sbi->dir_ops = fs_dir_inode_ops;
+
+	error = parse_options(data, isvfat, silent, &debug, &sbi->options);
+	if (error)
+		goto out_fail;
+
+	error = -EIO;
+	sb_min_blocksize(sb, 512);
+	bh = sb_bread(sb, 0);
+	if (bh == NULL) {
+		printk(KERN_ERR "FAT: unable to read boot sector\n");
+		goto out_fail;
+	}
+
+	b = (struct fat_boot_sector *) bh->b_data;
+	if (!b->reserved) {
+		if (!silent)
+			printk(KERN_ERR "FAT: bogus number of reserved sectors\n");
+		brelse(bh);
+		goto out_invalid;
+	}
+	if (!b->fats) {
+		if (!silent)
+			printk(KERN_ERR "FAT: bogus number of FAT structure\n");
+		brelse(bh);
+		goto out_invalid;
+	}
+
+	/*
+	 * Earlier we checked here that b->secs_track and b->head are nonzero,
+	 * but it turns out valid FAT filesystems can have zero there.
+	 */
+
+	media = b->media;
+	if (!fat_valid_media(media)) {
+		if (!silent)
+			printk(KERN_ERR "FAT: invalid media value (0x%02x)\n",
+			       media);
+		brelse(bh);
+		goto out_invalid;
+	}
+	logical_sector_size = get_unaligned_le16(&b->sector_size);
+	if (!is_power_of_2(logical_sector_size)
+	    || (logical_sector_size < 512)
+	    || (logical_sector_size > 4096)) {
+		if (!silent)
+			printk(KERN_ERR "FAT: bogus logical sector size %u\n",
+			       logical_sector_size);
+		brelse(bh);
+		goto out_invalid;
+	}
+	sbi->sec_per_clus = b->sec_per_clus;
+	if (!is_power_of_2(sbi->sec_per_clus)) {
+		if (!silent)
+			printk(KERN_ERR "FAT: bogus sectors per cluster %u\n",
+			       sbi->sec_per_clus);
+		brelse(bh);
+		goto out_invalid;
+	}
+
+	if (logical_sector_size < sb->s_blocksize) {
+		printk(KERN_ERR "FAT: logical sector size too small for device"
+		       " (logical sector size = %u)\n", logical_sector_size);
+		brelse(bh);
+		goto out_fail;
+	}
+	if (logical_sector_size > sb->s_blocksize) {
+		brelse(bh);
+
+		if (!sb_set_blocksize(sb, logical_sector_size)) {
+			printk(KERN_ERR "FAT: unable to set blocksize %u\n",
+			       logical_sector_size);
+			goto out_fail;
+		}
+		bh = sb_bread(sb, 0);
+		if (bh == NULL) {
+			printk(KERN_ERR "FAT: unable to read boot sector"
+			       " (logical sector size = %lu)\n",
+			       sb->s_blocksize);
+			goto out_fail;
+		}
+		b = (struct fat_boot_sector *) bh->b_data;
+	}
+
+	sbi->cluster_size = sb->s_blocksize * sbi->sec_per_clus;
+	sbi->cluster_bits = ffs(sbi->cluster_size) - 1;
+	sbi->fats = b->fats;
+	sbi->fat_bits = 0;		/* Don't know yet */
+	sbi->fat_start = le16_to_cpu(b->reserved);
+	sbi->fat_length = le16_to_cpu(b->fat_length);
+	sbi->root_cluster = 0;
+	sbi->free_clusters = -1;	/* Don't know yet */
+	sbi->free_clus_valid = 0;
+	sbi->prev_free = FAT_START_ENT;
+
+	if (!sbi->fat_length && b->fat32_length) {
+		struct fat_boot_fsinfo *fsinfo;
+		struct buffer_head *fsinfo_bh;
+
+		/* Must be FAT32 */
+		sbi->fat_bits = 32;
+		sbi->fat_length = le32_to_cpu(b->fat32_length);
+		sbi->root_cluster = le32_to_cpu(b->root_cluster);
+
+		sb->s_maxbytes = 0xffffffff;
+
+		/* MC - if info_sector is 0, don't multiply by 0 */
+		sbi->fsinfo_sector = le16_to_cpu(b->info_sector);
+		if (sbi->fsinfo_sector == 0)
+			sbi->fsinfo_sector = 1;
+
+		fsinfo_bh = sb_bread(sb, sbi->fsinfo_sector);
+		if (fsinfo_bh == NULL) {
+			printk(KERN_ERR "FAT: bread failed, FSINFO block"
+			       " (sector = %lu)\n", sbi->fsinfo_sector);
+			brelse(bh);
+			goto out_fail;
+		}
+
+		fsinfo = (struct fat_boot_fsinfo *)fsinfo_bh->b_data;
+		if (!IS_FSINFO(fsinfo)) {
+			printk(KERN_WARNING "FAT: Invalid FSINFO signature: "
+			       "0x%08x, 0x%08x (sector = %lu)\n",
+			       le32_to_cpu(fsinfo->signature1),
+			       le32_to_cpu(fsinfo->signature2),
+			       sbi->fsinfo_sector);
+		} else {
+			if (sbi->options.usefree)
+				sbi->free_clus_valid = 1;
+			sbi->free_clusters = le32_to_cpu(fsinfo->free_clusters);
+			sbi->prev_free = le32_to_cpu(fsinfo->next_cluster);
+		}
+
+		brelse(fsinfo_bh);
+	}
+
+	sbi->dir_per_block = sb->s_blocksize / sizeof(struct msdos_dir_entry);
+	sbi->dir_per_block_bits = ffs(sbi->dir_per_block) - 1;
+
+	sbi->dir_start = sbi->fat_start + sbi->fats * sbi->fat_length;
+	sbi->dir_entries = get_unaligned_le16(&b->dir_entries);
+	if (sbi->dir_entries & (sbi->dir_per_block - 1)) {
+		if (!silent)
+			printk(KERN_ERR "FAT: bogus directroy-entries per block"
+			       " (%u)\n", sbi->dir_entries);
+		brelse(bh);
+		goto out_invalid;
+	}
+
+	rootdir_sectors = sbi->dir_entries
+		* sizeof(struct msdos_dir_entry) / sb->s_blocksize;
+	sbi->data_start = sbi->dir_start + rootdir_sectors;
+	total_sectors = get_unaligned_le16(&b->sectors);
+	if (total_sectors == 0)
+		total_sectors = le32_to_cpu(b->total_sect);
+
+	total_clusters = (total_sectors - sbi->data_start) / sbi->sec_per_clus;
+
+	if (sbi->fat_bits != 32)
+		sbi->fat_bits = (total_clusters > MAX_FAT12) ? 16 : 12;
+
+	/* check that FAT table does not overflow */
+	fat_clusters = sbi->fat_length * sb->s_blocksize * 8 / sbi->fat_bits;
+	total_clusters = min(total_clusters, fat_clusters - FAT_START_ENT);
+	if (total_clusters > MAX_FAT(sb)) {
+		if (!silent)
+			printk(KERN_ERR "FAT: count of clusters too big (%u)\n",
+			       total_clusters);
+		brelse(bh);
+		goto out_invalid;
+	}
+
+	sbi->max_cluster = total_clusters + FAT_START_ENT;
+	/* check the free_clusters, it's not necessarily correct */
+	if (sbi->free_clusters != -1 && sbi->free_clusters > total_clusters)
+		sbi->free_clusters = -1;
+	/* check the prev_free, it's not necessarily correct */
+	sbi->prev_free %= sbi->max_cluster;
+	if (sbi->prev_free < FAT_START_ENT)
+		sbi->prev_free = FAT_START_ENT;
+
+	brelse(bh);
+
+	/* set up enough so that it can read an inode */
+	fat_hash_init(sb);
+	fat_ent_access_init(sb);
+
+	/*
+	 * The low byte of FAT's first entry must have same value with
+	 * media-field.  But in real world, too many devices is
+	 * writing wrong value.  So, removed that validity check.
+	 *
+	 * if (FAT_FIRST_ENT(sb, media) != first)
+	 */
+
+	error = -EINVAL;
+	sprintf(buf, "cp%d", sbi->options.codepage);
+	sbi->nls_disk = load_nls(buf);
+	if (!sbi->nls_disk) {
+		printk(KERN_ERR "FAT: codepage %s not found\n", buf);
+		goto out_fail;
+	}
+
+	/* FIXME: utf8 is using iocharset for upper/lower conversion */
+	if (sbi->options.isvfat) {
+		sbi->nls_io = load_nls(sbi->options.iocharset);
+		if (!sbi->nls_io) {
+			printk(KERN_ERR "FAT: IO charset %s not found\n",
+			       sbi->options.iocharset);
+			goto out_fail;
+		}
+	}
+
+	error = -ENOMEM;
+	root_inode = new_inode(sb);
+	if (!root_inode)
+		goto out_fail;
+	root_inode->i_ino = MSDOS_ROOT_INO;
+	root_inode->i_version = 1;
+	error = fat_read_root(root_inode);
+	if (error < 0)
+		goto out_fail;
+	error = -ENOMEM;
+	insert_inode_hash(root_inode);
+	sb->s_root = d_alloc_root(root_inode);
+	if (!sb->s_root) {
+		printk(KERN_ERR "FAT: get root inode failed\n");
+		goto out_fail;
+	}
+
+	return 0;
+
+out_invalid:
+	error = -EINVAL;
+	if (!silent)
+		printk(KERN_INFO "VFS: Can't find a valid FAT filesystem"
+		       " on dev %s.\n", sb->s_id);
+
+out_fail:
+	if (root_inode)
+		iput(root_inode);
+	if (sbi->nls_io)
+		unload_nls(sbi->nls_io);
+	if (sbi->nls_disk)
+		unload_nls(sbi->nls_disk);
+	if (sbi->options.iocharset != fat_default_iocharset)
+		kfree(sbi->options.iocharset);
+	sb->s_fs_info = NULL;
+	kfree(sbi);
+	return error;
+}
+
+EXPORT_SYMBOL_GPL(fat_fill_super);
+
+/*
+ * helper function for fat_flush_inodes.  This writes both the inode
+ * and the file data blocks, waiting for in flight data blocks before
+ * the start of the call.  It does not wait for any io started
+ * during the call
+ */
+static int writeback_inode(struct inode *inode)
+{
+
+	int ret;
+	struct address_space *mapping = inode->i_mapping;
+	struct writeback_control wbc = {
+	       .sync_mode = WB_SYNC_NONE,
+	      .nr_to_write = 0,
+	};
+	/* if we used WB_SYNC_ALL, sync_inode waits for the io for the
+	* inode to finish.  So WB_SYNC_NONE is sent down to sync_inode
+	* and filemap_fdatawrite is used for the data blocks
+	*/
+	ret = sync_inode(inode, &wbc);
+	if (!ret)
+	       ret = filemap_fdatawrite(mapping);
+	return ret;
+}
+
+/*
+ * write data and metadata corresponding to i1 and i2.  The io is
+ * started but we do not wait for any of it to finish.
+ *
+ * filemap_flush is used for the block device, so if there is a dirty
+ * page for a block already in flight, we will not wait and start the
+ * io over again
+ */
+int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2)
+{
+	int ret = 0;
+	if (!MSDOS_SB(sb)->options.flush)
+		return 0;
+	if (i1)
+		ret = writeback_inode(i1);
+	if (!ret && i2)
+		ret = writeback_inode(i2);
+	if (!ret) {
+		struct address_space *mapping = sb->s_bdev->bd_inode->i_mapping;
+		ret = filemap_flush(mapping);
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(fat_flush_inodes);
+
+static int __init init_fat_fs(void)
+{
+	int err;
+
+	err = fat_cache_init();
+	if (err)
+		return err;
+
+	err = fat_init_inodecache();
+	if (err)
+		goto failed;
+
+	return 0;
+
+failed:
+	fat_cache_destroy();
+	return err;
+}
+
+static void __exit exit_fat_fs(void)
+{
+	fat_cache_destroy();
+	fat_destroy_inodecache();
+}
+
+module_init(init_fat_fs)
+module_exit(exit_fat_fs)
+
+MODULE_LICENSE("GPL");
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
new file mode 100644
index 0000000..ac39ebc
--- /dev/null
+++ b/fs/fat/misc.c
@@ -0,0 +1,280 @@
+/*
+ *  linux/fs/fat/misc.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *  22/11/2000 - Fixed fat_date_unix2dos for dates earlier than 01/01/1980
+ *		 and date_dos2unix for date==0 by Igor Zhbanov(bsg@uniyar.ac.ru)
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/buffer_head.h>
+#include "fat.h"
+
+/*
+ * fat_fs_panic reports a severe file system problem and sets the file system
+ * read-only. The file system can be made writable again by remounting it.
+ */
+void fat_fs_panic(struct super_block *s, const char *fmt, ...)
+{
+	va_list args;
+
+	printk(KERN_ERR "FAT: Filesystem panic (dev %s)\n", s->s_id);
+
+	printk(KERN_ERR "    ");
+	va_start(args, fmt);
+	vprintk(fmt, args);
+	va_end(args);
+	printk("\n");
+
+	if (!(s->s_flags & MS_RDONLY)) {
+		s->s_flags |= MS_RDONLY;
+		printk(KERN_ERR "    File system has been set read-only\n");
+	}
+}
+
+EXPORT_SYMBOL_GPL(fat_fs_panic);
+
+/* Flushes the number of free clusters on FAT32 */
+/* XXX: Need to write one per FSINFO block.  Currently only writes 1 */
+void fat_clusters_flush(struct super_block *sb)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	struct buffer_head *bh;
+	struct fat_boot_fsinfo *fsinfo;
+
+	if (sbi->fat_bits != 32)
+		return;
+
+	bh = sb_bread(sb, sbi->fsinfo_sector);
+	if (bh == NULL) {
+		printk(KERN_ERR "FAT: bread failed in fat_clusters_flush\n");
+		return;
+	}
+
+	fsinfo = (struct fat_boot_fsinfo *)bh->b_data;
+	/* Sanity check */
+	if (!IS_FSINFO(fsinfo)) {
+		printk(KERN_ERR "FAT: Invalid FSINFO signature: "
+		       "0x%08x, 0x%08x (sector = %lu)\n",
+		       le32_to_cpu(fsinfo->signature1),
+		       le32_to_cpu(fsinfo->signature2),
+		       sbi->fsinfo_sector);
+	} else {
+		if (sbi->free_clusters != -1)
+			fsinfo->free_clusters = cpu_to_le32(sbi->free_clusters);
+		if (sbi->prev_free != -1)
+			fsinfo->next_cluster = cpu_to_le32(sbi->prev_free);
+		mark_buffer_dirty(bh);
+	}
+	brelse(bh);
+}
+
+/*
+ * fat_chain_add() adds a new cluster to the chain of clusters represented
+ * by inode.
+ */
+int fat_chain_add(struct inode *inode, int new_dclus, int nr_cluster)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	int ret, new_fclus, last;
+
+	/*
+	 * We must locate the last cluster of the file to add this new
+	 * one (new_dclus) to the end of the link list (the FAT).
+	 */
+	last = new_fclus = 0;
+	if (MSDOS_I(inode)->i_start) {
+		int fclus, dclus;
+
+		ret = fat_get_cluster(inode, FAT_ENT_EOF, &fclus, &dclus);
+		if (ret < 0)
+			return ret;
+		new_fclus = fclus + 1;
+		last = dclus;
+	}
+
+	/* add new one to the last of the cluster chain */
+	if (last) {
+		struct fat_entry fatent;
+
+		fatent_init(&fatent);
+		ret = fat_ent_read(inode, &fatent, last);
+		if (ret >= 0) {
+			int wait = inode_needs_sync(inode);
+			ret = fat_ent_write(inode, &fatent, new_dclus, wait);
+			fatent_brelse(&fatent);
+		}
+		if (ret < 0)
+			return ret;
+//		fat_cache_add(inode, new_fclus, new_dclus);
+	} else {
+		MSDOS_I(inode)->i_start = new_dclus;
+		MSDOS_I(inode)->i_logstart = new_dclus;
+		/*
+		 * Since generic_osync_inode() synchronize later if
+		 * this is not directory, we don't here.
+		 */
+		if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode)) {
+			ret = fat_sync_inode(inode);
+			if (ret)
+				return ret;
+		} else
+			mark_inode_dirty(inode);
+	}
+	if (new_fclus != (inode->i_blocks >> (sbi->cluster_bits - 9))) {
+		fat_fs_panic(sb, "clusters badly computed (%d != %llu)",
+			     new_fclus,
+			     (llu)(inode->i_blocks >> (sbi->cluster_bits - 9)));
+		fat_cache_inval_inode(inode);
+	}
+	inode->i_blocks += nr_cluster << (sbi->cluster_bits - 9);
+
+	return 0;
+}
+
+extern struct timezone sys_tz;
+
+/*
+ * The epoch of FAT timestamp is 1980.
+ *     :  bits :     value
+ * date:  0 -  4: day	(1 -  31)
+ * date:  5 -  8: month	(1 -  12)
+ * date:  9 - 15: year	(0 - 127) from 1980
+ * time:  0 -  4: sec	(0 -  29) 2sec counts
+ * time:  5 - 10: min	(0 -  59)
+ * time: 11 - 15: hour	(0 -  23)
+ */
+#define SECS_PER_MIN	60
+#define SECS_PER_HOUR	(60 * 60)
+#define SECS_PER_DAY	(SECS_PER_HOUR * 24)
+#define UNIX_SECS_1980	315532800L
+#if BITS_PER_LONG == 64
+#define UNIX_SECS_2108	4354819200L
+#endif
+/* days between 1.1.70 and 1.1.80 (2 leap days) */
+#define DAYS_DELTA	(365 * 10 + 2)
+/* 120 (2100 - 1980) isn't leap year */
+#define YEAR_2100	120
+#define IS_LEAP_YEAR(y)	(!((y) & 3) && (y) != YEAR_2100)
+
+/* Linear day numbers of the respective 1sts in non-leap years. */
+static time_t days_in_year[] = {
+	/* Jan  Feb  Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec */
+	0,   0,  31,  59,  90, 120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0,
+};
+
+/* Convert a FAT time/date pair to a UNIX date (seconds since 1 1 70). */
+void fat_time_fat2unix(struct msdos_sb_info *sbi, struct timespec *ts,
+		       __le16 __time, __le16 __date, u8 time_cs)
+{
+	u16 time = le16_to_cpu(__time), date = le16_to_cpu(__date);
+	time_t second, day, leap_day, month, year;
+
+	year  = date >> 9;
+	month = max(1, (date >> 5) & 0xf);
+	day   = max(1, date & 0x1f) - 1;
+
+	leap_day = (year + 3) / 4;
+	if (year > YEAR_2100)		/* 2100 isn't leap year */
+		leap_day--;
+	if (IS_LEAP_YEAR(year) && month > 2)
+		leap_day++;
+
+	second =  (time & 0x1f) << 1;
+	second += ((time >> 5) & 0x3f) * SECS_PER_MIN;
+	second += (time >> 11) * SECS_PER_HOUR;
+	second += (year * 365 + leap_day
+		   + days_in_year[month] + day
+		   + DAYS_DELTA) * SECS_PER_DAY;
+
+	if (!sbi->options.tz_utc)
+		second += sys_tz.tz_minuteswest * SECS_PER_MIN;
+
+	if (time_cs) {
+		ts->tv_sec = second + (time_cs / 100);
+		ts->tv_nsec = (time_cs % 100) * 10000000;
+	} else {
+		ts->tv_sec = second;
+		ts->tv_nsec = 0;
+	}
+}
+
+/* Convert linear UNIX date to a FAT time/date pair. */
+void fat_time_unix2fat(struct msdos_sb_info *sbi, struct timespec *ts,
+		       __le16 *time, __le16 *date, u8 *time_cs)
+{
+	time_t second = ts->tv_sec;
+	time_t day, leap_day, month, year;
+
+	if (!sbi->options.tz_utc)
+		second -= sys_tz.tz_minuteswest * SECS_PER_MIN;
+
+	/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
+	if (second < UNIX_SECS_1980) {
+		*time = 0;
+		*date = cpu_to_le16((0 << 9) | (1 << 5) | 1);
+		if (time_cs)
+			*time_cs = 0;
+		return;
+	}
+#if BITS_PER_LONG == 64
+	if (second >= UNIX_SECS_2108) {
+		*time = cpu_to_le16((23 << 11) | (59 << 5) | 29);
+		*date = cpu_to_le16((127 << 9) | (12 << 5) | 31);
+		if (time_cs)
+			*time_cs = 199;
+		return;
+	}
+#endif
+
+	day = second / SECS_PER_DAY - DAYS_DELTA;
+	year = day / 365;
+	leap_day = (year + 3) / 4;
+	if (year > YEAR_2100)		/* 2100 isn't leap year */
+		leap_day--;
+	if (year * 365 + leap_day > day)
+		year--;
+	leap_day = (year + 3) / 4;
+	if (year > YEAR_2100)		/* 2100 isn't leap year */
+		leap_day--;
+	day -= year * 365 + leap_day;
+
+	if (IS_LEAP_YEAR(year) && day == days_in_year[3]) {
+		month = 2;
+	} else {
+		if (IS_LEAP_YEAR(year) && day > days_in_year[3])
+			day--;
+		for (month = 1; month < 12; month++) {
+			if (days_in_year[month + 1] > day)
+				break;
+		}
+	}
+	day -= days_in_year[month];
+
+	*time = cpu_to_le16(((second / SECS_PER_HOUR) % 24) << 11
+			    | ((second / SECS_PER_MIN) % 60) << 5
+			    | (second % SECS_PER_MIN) >> 1);
+	*date = cpu_to_le16((year << 9) | (month << 5) | (day + 1));
+	if (time_cs)
+		*time_cs = (ts->tv_sec & 1) * 100 + ts->tv_nsec / 10000000;
+}
+EXPORT_SYMBOL_GPL(fat_time_unix2fat);
+
+int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs)
+{
+	int i, err = 0;
+
+	ll_rw_block(SWRITE, nr_bhs, bhs);
+	for (i = 0; i < nr_bhs; i++) {
+		wait_on_buffer(bhs[i]);
+		if (buffer_eopnotsupp(bhs[i])) {
+			clear_buffer_eopnotsupp(bhs[i]);
+			err = -EOPNOTSUPP;
+		} else if (!err && !buffer_uptodate(bhs[i]))
+			err = -EIO;
+	}
+	return err;
+}
+
diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c
new file mode 100644
index 0000000..7ba03a4
--- /dev/null
+++ b/fs/fat/namei_msdos.c
@@ -0,0 +1,706 @@
+/*
+ *  linux/fs/msdos/namei.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *  Hidden files 1995 by Albert Cahalan <albert@ccs.neu.edu> <adc@coe.neu.edu>
+ *  Rewritten for constant inumbers 1999 by Al Viro
+ */
+
+#include <linux/module.h>
+#include <linux/time.h>
+#include <linux/buffer_head.h>
+#include <linux/smp_lock.h>
+#include "fat.h"
+
+/* Characters that are undesirable in an MS-DOS file name */
+static unsigned char bad_chars[] = "*?<>|\"";
+static unsigned char bad_if_strict[] = "+=,; ";
+
+/***** Formats an MS-DOS file name. Rejects invalid names. */
+static int msdos_format_name(const unsigned char *name, int len,
+			     unsigned char *res, struct fat_mount_options *opts)
+	/*
+	 * name is the proposed name, len is its length, res is
+	 * the resulting name, opts->name_check is either (r)elaxed,
+	 * (n)ormal or (s)trict, opts->dotsOK allows dots at the
+	 * beginning of name (for hidden files)
+	 */
+{
+	unsigned char *walk;
+	unsigned char c;
+	int space;
+
+	if (name[0] == '.') {	/* dotfile because . and .. already done */
+		if (opts->dotsOK) {
+			/* Get rid of dot - test for it elsewhere */
+			name++;
+			len--;
+		} else
+			return -EINVAL;
+	}
+	/*
+	 * disallow names that _really_ start with a dot
+	 */
+	space = 1;
+	c = 0;
+	for (walk = res; len && walk - res < 8; walk++) {
+		c = *name++;
+		len--;
+		if (opts->name_check != 'r' && strchr(bad_chars, c))
+			return -EINVAL;
+		if (opts->name_check == 's' && strchr(bad_if_strict, c))
+			return -EINVAL;
+		if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
+			return -EINVAL;
+		if (c < ' ' || c == ':' || c == '\\')
+			return -EINVAL;
+	/*
+	 * 0xE5 is legal as a first character, but we must substitute
+	 * 0x05 because 0xE5 marks deleted files.  Yes, DOS really
+	 * does this.
+	 * It seems that Microsoft hacked DOS to support non-US
+	 * characters after the 0xE5 character was already in use to
+	 * mark deleted files.
+	 */
+		if ((res == walk) && (c == 0xE5))
+			c = 0x05;
+		if (c == '.')
+			break;
+		space = (c == ' ');
+		*walk = (!opts->nocase && c >= 'a' && c <= 'z') ? c - 32 : c;
+	}
+	if (space)
+		return -EINVAL;
+	if (opts->name_check == 's' && len && c != '.') {
+		c = *name++;
+		len--;
+		if (c != '.')
+			return -EINVAL;
+	}
+	while (c != '.' && len--)
+		c = *name++;
+	if (c == '.') {
+		while (walk - res < 8)
+			*walk++ = ' ';
+		while (len > 0 && walk - res < MSDOS_NAME) {
+			c = *name++;
+			len--;
+			if (opts->name_check != 'r' && strchr(bad_chars, c))
+				return -EINVAL;
+			if (opts->name_check == 's' &&
+			    strchr(bad_if_strict, c))
+				return -EINVAL;
+			if (c < ' ' || c == ':' || c == '\\')
+				return -EINVAL;
+			if (c == '.') {
+				if (opts->name_check == 's')
+					return -EINVAL;
+				break;
+			}
+			if (c >= 'A' && c <= 'Z' && opts->name_check == 's')
+				return -EINVAL;
+			space = c == ' ';
+			if (!opts->nocase && c >= 'a' && c <= 'z')
+				*walk++ = c - 32;
+			else
+				*walk++ = c;
+		}
+		if (space)
+			return -EINVAL;
+		if (opts->name_check == 's' && len)
+			return -EINVAL;
+	}
+	while (walk - res < MSDOS_NAME)
+		*walk++ = ' ';
+
+	return 0;
+}
+
+/***** Locates a directory entry.  Uses unformatted name. */
+static int msdos_find(struct inode *dir, const unsigned char *name, int len,
+		      struct fat_slot_info *sinfo)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
+	unsigned char msdos_name[MSDOS_NAME];
+	int err;
+
+	err = msdos_format_name(name, len, msdos_name, &sbi->options);
+	if (err)
+		return -ENOENT;
+
+	err = fat_scan(dir, msdos_name, sinfo);
+	if (!err && sbi->options.dotsOK) {
+		if (name[0] == '.') {
+			if (!(sinfo->de->attr & ATTR_HIDDEN))
+				err = -ENOENT;
+		} else {
+			if (sinfo->de->attr & ATTR_HIDDEN)
+				err = -ENOENT;
+		}
+		if (err)
+			brelse(sinfo->bh);
+	}
+	return err;
+}
+
+/*
+ * Compute the hash for the msdos name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The msdos fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int msdos_hash(struct dentry *dentry, struct qstr *qstr)
+{
+	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
+	unsigned char msdos_name[MSDOS_NAME];
+	int error;
+
+	error = msdos_format_name(qstr->name, qstr->len, msdos_name, options);
+	if (!error)
+		qstr->hash = full_name_hash(msdos_name, MSDOS_NAME);
+	return 0;
+}
+
+/*
+ * Compare two msdos names. If either of the names are invalid,
+ * we fall back to doing the standard name comparison.
+ */
+static int msdos_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
+{
+	struct fat_mount_options *options = &MSDOS_SB(dentry->d_sb)->options;
+	unsigned char a_msdos_name[MSDOS_NAME], b_msdos_name[MSDOS_NAME];
+	int error;
+
+	error = msdos_format_name(a->name, a->len, a_msdos_name, options);
+	if (error)
+		goto old_compare;
+	error = msdos_format_name(b->name, b->len, b_msdos_name, options);
+	if (error)
+		goto old_compare;
+	error = memcmp(a_msdos_name, b_msdos_name, MSDOS_NAME);
+out:
+	return error;
+
+old_compare:
+	error = 1;
+	if (a->len == b->len)
+		error = memcmp(a->name, b->name, a->len);
+	goto out;
+}
+
+static struct dentry_operations msdos_dentry_operations = {
+	.d_hash		= msdos_hash,
+	.d_compare	= msdos_cmp,
+};
+
+/*
+ * AV. Wrappers for FAT sb operations. Is it wise?
+ */
+
+/***** Get inode using directory and name */
+static struct dentry *msdos_lookup(struct inode *dir, struct dentry *dentry,
+				   struct nameidata *nd)
+{
+	struct super_block *sb = dir->i_sb;
+	struct fat_slot_info sinfo;
+	struct inode *inode;
+	int err;
+
+	lock_super(sb);
+
+	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
+	if (err) {
+		if (err == -ENOENT) {
+			inode = NULL;
+			goto out;
+		}
+		goto error;
+	}
+
+	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+	brelse(sinfo.bh);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto error;
+	}
+out:
+	unlock_super(sb);
+	dentry->d_op = &msdos_dentry_operations;
+	dentry = d_splice_alias(inode, dentry);
+	if (dentry)
+		dentry->d_op = &msdos_dentry_operations;
+	return dentry;
+
+error:
+	unlock_super(sb);
+	return ERR_PTR(err);
+}
+
+/***** Creates a directory entry (name is already formatted). */
+static int msdos_add_entry(struct inode *dir, const unsigned char *name,
+			   int is_dir, int is_hid, int cluster,
+			   struct timespec *ts, struct fat_slot_info *sinfo)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
+	struct msdos_dir_entry de;
+	__le16 time, date;
+	int err;
+
+	memcpy(de.name, name, MSDOS_NAME);
+	de.attr = is_dir ? ATTR_DIR : ATTR_ARCH;
+	if (is_hid)
+		de.attr |= ATTR_HIDDEN;
+	de.lcase = 0;
+	fat_time_unix2fat(sbi, ts, &time, &date, NULL);
+	de.cdate = de.adate = 0;
+	de.ctime = 0;
+	de.ctime_cs = 0;
+	de.time = time;
+	de.date = date;
+	de.start = cpu_to_le16(cluster);
+	de.starthi = cpu_to_le16(cluster >> 16);
+	de.size = 0;
+
+	err = fat_add_entries(dir, &de, 1, sinfo);
+	if (err)
+		return err;
+
+	dir->i_ctime = dir->i_mtime = *ts;
+	if (IS_DIRSYNC(dir))
+		(void)fat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+
+	return 0;
+}
+
+/***** Create a file */
+static int msdos_create(struct inode *dir, struct dentry *dentry, int mode,
+			struct nameidata *nd)
+{
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode = NULL;
+	struct fat_slot_info sinfo;
+	struct timespec ts;
+	unsigned char msdos_name[MSDOS_NAME];
+	int err, is_hid;
+
+	lock_super(sb);
+
+	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
+				msdos_name, &MSDOS_SB(sb)->options);
+	if (err)
+		goto out;
+	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
+	/* Have to do it due to foo vs. .foo conflicts */
+	if (!fat_scan(dir, msdos_name, &sinfo)) {
+		brelse(sinfo.bh);
+		err = -EINVAL;
+		goto out;
+	}
+
+	ts = CURRENT_TIME_SEC;
+	err = msdos_add_entry(dir, msdos_name, 0, is_hid, 0, &ts, &sinfo);
+	if (err)
+		goto out;
+	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+	brelse(sinfo.bh);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out;
+	}
+	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+	d_instantiate(dentry, inode);
+out:
+	unlock_super(sb);
+	if (!err)
+		err = fat_flush_inodes(sb, dir, inode);
+	return err;
+}
+
+/***** Remove a directory */
+static int msdos_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode = dentry->d_inode;
+	struct fat_slot_info sinfo;
+	int err;
+
+	lock_super(sb);
+	/*
+	 * Check whether the directory is not in use, then check
+	 * whether it is empty.
+	 */
+	err = fat_dir_empty(inode);
+	if (err)
+		goto out;
+	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
+	if (err)
+		goto out;
+
+	err = fat_remove_entries(dir, &sinfo);	/* and releases bh */
+	if (err)
+		goto out;
+	drop_nlink(dir);
+
+	clear_nlink(inode);
+	inode->i_ctime = CURRENT_TIME_SEC;
+	fat_detach(inode);
+out:
+	unlock_super(sb);
+	if (!err)
+		err = fat_flush_inodes(sb, dir, inode);
+
+	return err;
+}
+
+/***** Make a directory */
+static int msdos_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	struct super_block *sb = dir->i_sb;
+	struct fat_slot_info sinfo;
+	struct inode *inode;
+	unsigned char msdos_name[MSDOS_NAME];
+	struct timespec ts;
+	int err, is_hid, cluster;
+
+	lock_super(sb);
+
+	err = msdos_format_name(dentry->d_name.name, dentry->d_name.len,
+				msdos_name, &MSDOS_SB(sb)->options);
+	if (err)
+		goto out;
+	is_hid = (dentry->d_name.name[0] == '.') && (msdos_name[0] != '.');
+	/* foo vs .foo situation */
+	if (!fat_scan(dir, msdos_name, &sinfo)) {
+		brelse(sinfo.bh);
+		err = -EINVAL;
+		goto out;
+	}
+
+	ts = CURRENT_TIME_SEC;
+	cluster = fat_alloc_new_dir(dir, &ts);
+	if (cluster < 0) {
+		err = cluster;
+		goto out;
+	}
+	err = msdos_add_entry(dir, msdos_name, 1, is_hid, cluster, &ts, &sinfo);
+	if (err)
+		goto out_free;
+	inc_nlink(dir);
+
+	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+	brelse(sinfo.bh);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		/* the directory was completed, just return a error */
+		goto out;
+	}
+	inode->i_nlink = 2;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+	d_instantiate(dentry, inode);
+
+	unlock_super(sb);
+	fat_flush_inodes(sb, dir, inode);
+	return 0;
+
+out_free:
+	fat_free_clusters(dir, cluster);
+out:
+	unlock_super(sb);
+	return err;
+}
+
+/***** Unlink a file */
+static int msdos_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	struct super_block *sb= inode->i_sb;
+	struct fat_slot_info sinfo;
+	int err;
+
+	lock_super(sb);
+	err = msdos_find(dir, dentry->d_name.name, dentry->d_name.len, &sinfo);
+	if (err)
+		goto out;
+
+	err = fat_remove_entries(dir, &sinfo);	/* and releases bh */
+	if (err)
+		goto out;
+	clear_nlink(inode);
+	inode->i_ctime = CURRENT_TIME_SEC;
+	fat_detach(inode);
+out:
+	unlock_super(sb);
+	if (!err)
+		err = fat_flush_inodes(sb, dir, inode);
+
+	return err;
+}
+
+static int do_msdos_rename(struct inode *old_dir, unsigned char *old_name,
+			   struct dentry *old_dentry,
+			   struct inode *new_dir, unsigned char *new_name,
+			   struct dentry *new_dentry, int is_hid)
+{
+	struct buffer_head *dotdot_bh;
+	struct msdos_dir_entry *dotdot_de;
+	struct inode *old_inode, *new_inode;
+	struct fat_slot_info old_sinfo, sinfo;
+	struct timespec ts;
+	loff_t dotdot_i_pos, new_i_pos;
+	int err, old_attrs, is_dir, update_dotdot, corrupt = 0;
+
+	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
+	old_inode = old_dentry->d_inode;
+	new_inode = new_dentry->d_inode;
+
+	err = fat_scan(old_dir, old_name, &old_sinfo);
+	if (err) {
+		err = -EIO;
+		goto out;
+	}
+
+	is_dir = S_ISDIR(old_inode->i_mode);
+	update_dotdot = (is_dir && old_dir != new_dir);
+	if (update_dotdot) {
+		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
+					 &dotdot_i_pos) < 0) {
+			err = -EIO;
+			goto out;
+		}
+	}
+
+	old_attrs = MSDOS_I(old_inode)->i_attrs;
+	err = fat_scan(new_dir, new_name, &sinfo);
+	if (!err) {
+		if (!new_inode) {
+			/* "foo" -> ".foo" case. just change the ATTR_HIDDEN */
+			if (sinfo.de != old_sinfo.de) {
+				err = -EINVAL;
+				goto out;
+			}
+			if (is_hid)
+				MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
+			else
+				MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
+			if (IS_DIRSYNC(old_dir)) {
+				err = fat_sync_inode(old_inode);
+				if (err) {
+					MSDOS_I(old_inode)->i_attrs = old_attrs;
+					goto out;
+				}
+			} else
+				mark_inode_dirty(old_inode);
+
+			old_dir->i_version++;
+			old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
+			if (IS_DIRSYNC(old_dir))
+				(void)fat_sync_inode(old_dir);
+			else
+				mark_inode_dirty(old_dir);
+			goto out;
+		}
+	}
+
+	ts = CURRENT_TIME_SEC;
+	if (new_inode) {
+		if (err)
+			goto out;
+		if (is_dir) {
+			err = fat_dir_empty(new_inode);
+			if (err)
+				goto out;
+		}
+		new_i_pos = MSDOS_I(new_inode)->i_pos;
+		fat_detach(new_inode);
+	} else {
+		err = msdos_add_entry(new_dir, new_name, is_dir, is_hid, 0,
+				      &ts, &sinfo);
+		if (err)
+			goto out;
+		new_i_pos = sinfo.i_pos;
+	}
+	new_dir->i_version++;
+
+	fat_detach(old_inode);
+	fat_attach(old_inode, new_i_pos);
+	if (is_hid)
+		MSDOS_I(old_inode)->i_attrs |= ATTR_HIDDEN;
+	else
+		MSDOS_I(old_inode)->i_attrs &= ~ATTR_HIDDEN;
+	if (IS_DIRSYNC(new_dir)) {
+		err = fat_sync_inode(old_inode);
+		if (err)
+			goto error_inode;
+	} else
+		mark_inode_dirty(old_inode);
+
+	if (update_dotdot) {
+		int start = MSDOS_I(new_dir)->i_logstart;
+		dotdot_de->start = cpu_to_le16(start);
+		dotdot_de->starthi = cpu_to_le16(start >> 16);
+		mark_buffer_dirty(dotdot_bh);
+		if (IS_DIRSYNC(new_dir)) {
+			err = sync_dirty_buffer(dotdot_bh);
+			if (err)
+				goto error_dotdot;
+		}
+		drop_nlink(old_dir);
+		if (!new_inode)
+			inc_nlink(new_dir);
+	}
+
+	err = fat_remove_entries(old_dir, &old_sinfo);	/* and releases bh */
+	old_sinfo.bh = NULL;
+	if (err)
+		goto error_dotdot;
+	old_dir->i_version++;
+	old_dir->i_ctime = old_dir->i_mtime = ts;
+	if (IS_DIRSYNC(old_dir))
+		(void)fat_sync_inode(old_dir);
+	else
+		mark_inode_dirty(old_dir);
+
+	if (new_inode) {
+		drop_nlink(new_inode);
+		if (is_dir)
+			drop_nlink(new_inode);
+		new_inode->i_ctime = ts;
+	}
+out:
+	brelse(sinfo.bh);
+	brelse(dotdot_bh);
+	brelse(old_sinfo.bh);
+	return err;
+
+error_dotdot:
+	/* data cluster is shared, serious corruption */
+	corrupt = 1;
+
+	if (update_dotdot) {
+		int start = MSDOS_I(old_dir)->i_logstart;
+		dotdot_de->start = cpu_to_le16(start);
+		dotdot_de->starthi = cpu_to_le16(start >> 16);
+		mark_buffer_dirty(dotdot_bh);
+		corrupt |= sync_dirty_buffer(dotdot_bh);
+	}
+error_inode:
+	fat_detach(old_inode);
+	fat_attach(old_inode, old_sinfo.i_pos);
+	MSDOS_I(old_inode)->i_attrs = old_attrs;
+	if (new_inode) {
+		fat_attach(new_inode, new_i_pos);
+		if (corrupt)
+			corrupt |= fat_sync_inode(new_inode);
+	} else {
+		/*
+		 * If new entry was not sharing the data cluster, it
+		 * shouldn't be serious corruption.
+		 */
+		int err2 = fat_remove_entries(new_dir, &sinfo);
+		if (corrupt)
+			corrupt |= err2;
+		sinfo.bh = NULL;
+	}
+	if (corrupt < 0) {
+		fat_fs_panic(new_dir->i_sb,
+			     "%s: Filesystem corrupted (i_pos %lld)",
+			     __func__, sinfo.i_pos);
+	}
+	goto out;
+}
+
+/***** Rename, a wrapper for rename_same_dir & rename_diff_dir */
+static int msdos_rename(struct inode *old_dir, struct dentry *old_dentry,
+			struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct super_block *sb = old_dir->i_sb;
+	unsigned char old_msdos_name[MSDOS_NAME], new_msdos_name[MSDOS_NAME];
+	int err, is_hid;
+
+	lock_super(sb);
+
+	err = msdos_format_name(old_dentry->d_name.name,
+				old_dentry->d_name.len, old_msdos_name,
+				&MSDOS_SB(old_dir->i_sb)->options);
+	if (err)
+		goto out;
+	err = msdos_format_name(new_dentry->d_name.name,
+				new_dentry->d_name.len, new_msdos_name,
+				&MSDOS_SB(new_dir->i_sb)->options);
+	if (err)
+		goto out;
+
+	is_hid =
+	     (new_dentry->d_name.name[0] == '.') && (new_msdos_name[0] != '.');
+
+	err = do_msdos_rename(old_dir, old_msdos_name, old_dentry,
+			      new_dir, new_msdos_name, new_dentry, is_hid);
+out:
+	unlock_super(sb);
+	if (!err)
+		err = fat_flush_inodes(sb, old_dir, new_dir);
+	return err;
+}
+
+static const struct inode_operations msdos_dir_inode_operations = {
+	.create		= msdos_create,
+	.lookup		= msdos_lookup,
+	.unlink		= msdos_unlink,
+	.mkdir		= msdos_mkdir,
+	.rmdir		= msdos_rmdir,
+	.rename		= msdos_rename,
+	.setattr	= fat_setattr,
+	.getattr	= fat_getattr,
+};
+
+static int msdos_fill_super(struct super_block *sb, void *data, int silent)
+{
+	int res;
+
+	res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0);
+	if (res)
+		return res;
+
+	sb->s_flags |= MS_NOATIME;
+	sb->s_root->d_op = &msdos_dentry_operations;
+	return 0;
+}
+
+static int msdos_get_sb(struct file_system_type *fs_type,
+			int flags, const char *dev_name,
+			void *data, struct vfsmount *mnt)
+{
+	return get_sb_bdev(fs_type, flags, dev_name, data, msdos_fill_super,
+			   mnt);
+}
+
+static struct file_system_type msdos_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "msdos",
+	.get_sb		= msdos_get_sb,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+
+static int __init init_msdos_fs(void)
+{
+	return register_filesystem(&msdos_fs_type);
+}
+
+static void __exit exit_msdos_fs(void)
+{
+	unregister_filesystem(&msdos_fs_type);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Werner Almesberger");
+MODULE_DESCRIPTION("MS-DOS filesystem support");
+
+module_init(init_msdos_fs)
+module_exit(exit_msdos_fs)
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c
new file mode 100644
index 0000000..bf326d4
--- /dev/null
+++ b/fs/fat/namei_vfat.c
@@ -0,0 +1,1098 @@
+/*
+ *  linux/fs/vfat/namei.c
+ *
+ *  Written 1992,1993 by Werner Almesberger
+ *
+ *  Windows95/Windows NT compatible extended MSDOS filesystem
+ *    by Gordon Chaffee Copyright (C) 1995.  Send bug reports for the
+ *    VFAT filesystem to <chaffee@cs.berkeley.edu>.  Specify
+ *    what file operation caused you trouble and if you can duplicate
+ *    the problem, send a script that demonstrates it.
+ *
+ *  Short name translation 1999, 2001 by Wolfram Pienkoss <wp@bszh.de>
+ *
+ *  Support Multibyte characters and cleanup by
+ *				OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
+ */
+
+#include <linux/module.h>
+#include <linux/jiffies.h>
+#include <linux/ctype.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/buffer_head.h>
+#include <linux/namei.h>
+#include "fat.h"
+
+/*
+ * If new entry was created in the parent, it could create the 8.3
+ * alias (the shortname of logname).  So, the parent may have the
+ * negative-dentry which matches the created 8.3 alias.
+ *
+ * If it happened, the negative dentry isn't actually negative
+ * anymore.  So, drop it.
+ */
+static int vfat_revalidate_shortname(struct dentry *dentry)
+{
+	int ret = 1;
+	spin_lock(&dentry->d_lock);
+	if (dentry->d_time != dentry->d_parent->d_inode->i_version)
+		ret = 0;
+	spin_unlock(&dentry->d_lock);
+	return ret;
+}
+
+static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+	/* This is not negative dentry. Always valid. */
+	if (dentry->d_inode)
+		return 1;
+	return vfat_revalidate_shortname(dentry);
+}
+
+static int vfat_revalidate_ci(struct dentry *dentry, struct nameidata *nd)
+{
+	/*
+	 * This is not negative dentry. Always valid.
+	 *
+	 * Note, rename() to existing directory entry will have ->d_inode,
+	 * and will use existing name which isn't specified name by user.
+	 *
+	 * We may be able to drop this positive dentry here. But dropping
+	 * positive dentry isn't good idea. So it's unsupported like
+	 * rename("filename", "FILENAME") for now.
+	 */
+	if (dentry->d_inode)
+		return 1;
+
+	/*
+	 * This may be nfsd (or something), anyway, we can't see the
+	 * intent of this. So, since this can be for creation, drop it.
+	 */
+	if (!nd)
+		return 0;
+
+	/*
+	 * Drop the negative dentry, in order to make sure to use the
+	 * case sensitive name which is specified by user if this is
+	 * for creation.
+	 */
+	if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) {
+		if (nd->flags & LOOKUP_CREATE)
+			return 0;
+	}
+
+	return vfat_revalidate_shortname(dentry);
+}
+
+/* returns the length of a struct qstr, ignoring trailing dots */
+static unsigned int vfat_striptail_len(struct qstr *qstr)
+{
+	unsigned int len = qstr->len;
+
+	while (len && qstr->name[len - 1] == '.')
+		len--;
+	return len;
+}
+
+/*
+ * Compute the hash for the vfat name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The vfat fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int vfat_hash(struct dentry *dentry, struct qstr *qstr)
+{
+	qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr));
+	return 0;
+}
+
+/*
+ * Compute the hash for the vfat name corresponding to the dentry.
+ * Note: if the name is invalid, we leave the hash code unchanged so
+ * that the existing dentry can be used. The vfat fs routines will
+ * return ENOENT or EINVAL as appropriate.
+ */
+static int vfat_hashi(struct dentry *dentry, struct qstr *qstr)
+{
+	struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io;
+	const unsigned char *name;
+	unsigned int len;
+	unsigned long hash;
+
+	name = qstr->name;
+	len = vfat_striptail_len(qstr);
+
+	hash = init_name_hash();
+	while (len--)
+		hash = partial_name_hash(nls_tolower(t, *name++), hash);
+	qstr->hash = end_name_hash(hash);
+
+	return 0;
+}
+
+/*
+ * Case insensitive compare of two vfat names.
+ */
+static int vfat_cmpi(struct dentry *dentry, struct qstr *a, struct qstr *b)
+{
+	struct nls_table *t = MSDOS_SB(dentry->d_inode->i_sb)->nls_io;
+	unsigned int alen, blen;
+
+	/* A filename cannot end in '.' or we treat it like it has none */
+	alen = vfat_striptail_len(a);
+	blen = vfat_striptail_len(b);
+	if (alen == blen) {
+		if (nls_strnicmp(t, a->name, b->name, alen) == 0)
+			return 0;
+	}
+	return 1;
+}
+
+/*
+ * Case sensitive compare of two vfat names.
+ */
+static int vfat_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b)
+{
+	unsigned int alen, blen;
+
+	/* A filename cannot end in '.' or we treat it like it has none */
+	alen = vfat_striptail_len(a);
+	blen = vfat_striptail_len(b);
+	if (alen == blen) {
+		if (strncmp(a->name, b->name, alen) == 0)
+			return 0;
+	}
+	return 1;
+}
+
+static struct dentry_operations vfat_ci_dentry_ops = {
+	.d_revalidate	= vfat_revalidate_ci,
+	.d_hash		= vfat_hashi,
+	.d_compare	= vfat_cmpi,
+};
+
+static struct dentry_operations vfat_dentry_ops = {
+	.d_revalidate	= vfat_revalidate,
+	.d_hash		= vfat_hash,
+	.d_compare	= vfat_cmp,
+};
+
+/* Characters that are undesirable in an MS-DOS file name */
+
+static inline wchar_t vfat_bad_char(wchar_t w)
+{
+	return (w < 0x0020)
+	    || (w == '*') || (w == '?') || (w == '<') || (w == '>')
+	    || (w == '|') || (w == '"') || (w == ':') || (w == '/')
+	    || (w == '\\');
+}
+
+static inline wchar_t vfat_replace_char(wchar_t w)
+{
+	return (w == '[') || (w == ']') || (w == ';') || (w == ',')
+	    || (w == '+') || (w == '=');
+}
+
+static wchar_t vfat_skip_char(wchar_t w)
+{
+	return (w == '.') || (w == ' ');
+}
+
+static inline int vfat_is_used_badchars(const wchar_t *s, int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++)
+		if (vfat_bad_char(s[i]))
+			return -EINVAL;
+
+	if (s[i - 1] == ' ') /* last character cannot be space */
+		return -EINVAL;
+
+	return 0;
+}
+
+static int vfat_find_form(struct inode *dir, unsigned char *name)
+{
+	struct fat_slot_info sinfo;
+	int err = fat_scan(dir, name, &sinfo);
+	if (err)
+		return -ENOENT;
+	brelse(sinfo.bh);
+	return 0;
+}
+
+/*
+ * 1) Valid characters for the 8.3 format alias are any combination of
+ * letters, uppercase alphabets, digits, any of the
+ * following special characters:
+ *     $ % ' ` - @ { } ~ ! # ( ) & _ ^
+ * In this case Longfilename is not stored in disk.
+ *
+ * WinNT's Extension:
+ * File name and extension name is contain uppercase/lowercase
+ * only. And it is expressed by CASE_LOWER_BASE and CASE_LOWER_EXT.
+ *
+ * 2) File name is 8.3 format, but it contain the uppercase and
+ * lowercase char, muliti bytes char, etc. In this case numtail is not
+ * added, but Longfilename is stored.
+ *
+ * 3) When the one except for the above, or the following special
+ * character are contained:
+ *        .   [ ] ; , + =
+ * numtail is added, and Longfilename must be stored in disk .
+ */
+struct shortname_info {
+	unsigned char lower:1,
+		      upper:1,
+		      valid:1;
+};
+#define INIT_SHORTNAME_INFO(x)	do {		\
+	(x)->lower = 1;				\
+	(x)->upper = 1;				\
+	(x)->valid = 1;				\
+} while (0)
+
+static inline int to_shortname_char(struct nls_table *nls,
+				    unsigned char *buf, int buf_size,
+				    wchar_t *src, struct shortname_info *info)
+{
+	int len;
+
+	if (vfat_skip_char(*src)) {
+		info->valid = 0;
+		return 0;
+	}
+	if (vfat_replace_char(*src)) {
+		info->valid = 0;
+		buf[0] = '_';
+		return 1;
+	}
+
+	len = nls->uni2char(*src, buf, buf_size);
+	if (len <= 0) {
+		info->valid = 0;
+		buf[0] = '_';
+		len = 1;
+	} else if (len == 1) {
+		unsigned char prev = buf[0];
+
+		if (buf[0] >= 0x7F) {
+			info->lower = 0;
+			info->upper = 0;
+		}
+
+		buf[0] = nls_toupper(nls, buf[0]);
+		if (isalpha(buf[0])) {
+			if (buf[0] == prev)
+				info->lower = 0;
+			else
+				info->upper = 0;
+		}
+	} else {
+		info->lower = 0;
+		info->upper = 0;
+	}
+
+	return len;
+}
+
+/*
+ * Given a valid longname, create a unique shortname.  Make sure the
+ * shortname does not exist
+ * Returns negative number on error, 0 for a normal
+ * return, and 1 for valid shortname
+ */
+static int vfat_create_shortname(struct inode *dir, struct nls_table *nls,
+				 wchar_t *uname, int ulen,
+				 unsigned char *name_res, unsigned char *lcase)
+{
+	struct fat_mount_options *opts = &MSDOS_SB(dir->i_sb)->options;
+	wchar_t *ip, *ext_start, *end, *name_start;
+	unsigned char base[9], ext[4], buf[8], *p;
+	unsigned char charbuf[NLS_MAX_CHARSET_SIZE];
+	int chl, chi;
+	int sz = 0, extlen, baselen, i, numtail_baselen, numtail2_baselen;
+	int is_shortname;
+	struct shortname_info base_info, ext_info;
+
+	is_shortname = 1;
+	INIT_SHORTNAME_INFO(&base_info);
+	INIT_SHORTNAME_INFO(&ext_info);
+
+	/* Now, we need to create a shortname from the long name */
+	ext_start = end = &uname[ulen];
+	while (--ext_start >= uname) {
+		if (*ext_start == 0x002E) {	/* is `.' */
+			if (ext_start == end - 1) {
+				sz = ulen;
+				ext_start = NULL;
+			}
+			break;
+		}
+	}
+
+	if (ext_start == uname - 1) {
+		sz = ulen;
+		ext_start = NULL;
+	} else if (ext_start) {
+		/*
+		 * Names which start with a dot could be just
+		 * an extension eg. "...test".  In this case Win95
+		 * uses the extension as the name and sets no extension.
+		 */
+		name_start = &uname[0];
+		while (name_start < ext_start) {
+			if (!vfat_skip_char(*name_start))
+				break;
+			name_start++;
+		}
+		if (name_start != ext_start) {
+			sz = ext_start - uname;
+			ext_start++;
+		} else {
+			sz = ulen;
+			ext_start = NULL;
+		}
+	}
+
+	numtail_baselen = 6;
+	numtail2_baselen = 2;
+	for (baselen = i = 0, p = base, ip = uname; i < sz; i++, ip++) {
+		chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
+					ip, &base_info);
+		if (chl == 0)
+			continue;
+
+		if (baselen < 2 && (baselen + chl) > 2)
+			numtail2_baselen = baselen;
+		if (baselen < 6 && (baselen + chl) > 6)
+			numtail_baselen = baselen;
+		for (chi = 0; chi < chl; chi++) {
+			*p++ = charbuf[chi];
+			baselen++;
+			if (baselen >= 8)
+				break;
+		}
+		if (baselen >= 8) {
+			if ((chi < chl - 1) || (ip + 1) - uname < sz)
+				is_shortname = 0;
+			break;
+		}
+	}
+	if (baselen == 0) {
+		return -EINVAL;
+	}
+
+	extlen = 0;
+	if (ext_start) {
+		for (p = ext, ip = ext_start; extlen < 3 && ip < end; ip++) {
+			chl = to_shortname_char(nls, charbuf, sizeof(charbuf),
+						ip, &ext_info);
+			if (chl == 0)
+				continue;
+
+			if ((extlen + chl) > 3) {
+				is_shortname = 0;
+				break;
+			}
+			for (chi = 0; chi < chl; chi++) {
+				*p++ = charbuf[chi];
+				extlen++;
+			}
+			if (extlen >= 3) {
+				if (ip + 1 != end)
+					is_shortname = 0;
+				break;
+			}
+		}
+	}
+	ext[extlen] = '\0';
+	base[baselen] = '\0';
+
+	/* Yes, it can happen. ".\xe5" would do it. */
+	if (base[0] == DELETED_FLAG)
+		base[0] = 0x05;
+
+	/* OK, at this point we know that base is not longer than 8 symbols,
+	 * ext is not longer than 3, base is nonempty, both don't contain
+	 * any bad symbols (lowercase transformed to uppercase).
+	 */
+
+	memset(name_res, ' ', MSDOS_NAME);
+	memcpy(name_res, base, baselen);
+	memcpy(name_res + 8, ext, extlen);
+	*lcase = 0;
+	if (is_shortname && base_info.valid && ext_info.valid) {
+		if (vfat_find_form(dir, name_res) == 0)
+			return -EEXIST;
+
+		if (opts->shortname & VFAT_SFN_CREATE_WIN95) {
+			return (base_info.upper && ext_info.upper);
+		} else if (opts->shortname & VFAT_SFN_CREATE_WINNT) {
+			if ((base_info.upper || base_info.lower) &&
+			    (ext_info.upper || ext_info.lower)) {
+				if (!base_info.upper && base_info.lower)
+					*lcase |= CASE_LOWER_BASE;
+				if (!ext_info.upper && ext_info.lower)
+					*lcase |= CASE_LOWER_EXT;
+				return 1;
+			}
+			return 0;
+		} else {
+			BUG();
+		}
+	}
+
+	if (opts->numtail == 0)
+		if (vfat_find_form(dir, name_res) < 0)
+			return 0;
+
+	/*
+	 * Try to find a unique extension.  This used to
+	 * iterate through all possibilities sequentially,
+	 * but that gave extremely bad performance.  Windows
+	 * only tries a few cases before using random
+	 * values for part of the base.
+	 */
+
+	if (baselen > 6) {
+		baselen = numtail_baselen;
+		name_res[7] = ' ';
+	}
+	name_res[baselen] = '~';
+	for (i = 1; i < 10; i++) {
+		name_res[baselen + 1] = i + '0';
+		if (vfat_find_form(dir, name_res) < 0)
+			return 0;
+	}
+
+	i = jiffies & 0xffff;
+	sz = (jiffies >> 16) & 0x7;
+	if (baselen > 2) {
+		baselen = numtail2_baselen;
+		name_res[7] = ' ';
+	}
+	name_res[baselen + 4] = '~';
+	name_res[baselen + 5] = '1' + sz;
+	while (1) {
+		sprintf(buf, "%04X", i);
+		memcpy(&name_res[baselen], buf, 4);
+		if (vfat_find_form(dir, name_res) < 0)
+			break;
+		i -= 11;
+	}
+	return 0;
+}
+
+/* Translate a string, including coded sequences into Unicode */
+static int
+xlate_to_uni(const unsigned char *name, int len, unsigned char *outname,
+	     int *longlen, int *outlen, int escape, int utf8,
+	     struct nls_table *nls)
+{
+	const unsigned char *ip;
+	unsigned char nc;
+	unsigned char *op;
+	unsigned int ec;
+	int i, k, fill;
+	int charlen;
+
+	if (utf8) {
+		int name_len = strlen(name);
+
+		*outlen = utf8_mbstowcs((wchar_t *)outname, name, PATH_MAX);
+
+		/*
+		 * We stripped '.'s before and set len appropriately,
+		 * but utf8_mbstowcs doesn't care about len
+		 */
+		*outlen -= (name_len - len);
+
+		if (*outlen > 255)
+			return -ENAMETOOLONG;
+
+		op = &outname[*outlen * sizeof(wchar_t)];
+	} else {
+		if (nls) {
+			for (i = 0, ip = name, op = outname, *outlen = 0;
+			     i < len && *outlen <= 255;
+			     *outlen += 1)
+			{
+				if (escape && (*ip == ':')) {
+					if (i > len - 5)
+						return -EINVAL;
+					ec = 0;
+					for (k = 1; k < 5; k++) {
+						nc = ip[k];
+						ec <<= 4;
+						if (nc >= '0' && nc <= '9') {
+							ec |= nc - '0';
+							continue;
+						}
+						if (nc >= 'a' && nc <= 'f') {
+							ec |= nc - ('a' - 10);
+							continue;
+						}
+						if (nc >= 'A' && nc <= 'F') {
+							ec |= nc - ('A' - 10);
+							continue;
+						}
+						return -EINVAL;
+					}
+					*op++ = ec & 0xFF;
+					*op++ = ec >> 8;
+					ip += 5;
+					i += 5;
+				} else {
+					if ((charlen = nls->char2uni(ip, len - i, (wchar_t *)op)) < 0)
+						return -EINVAL;
+					ip += charlen;
+					i += charlen;
+					op += 2;
+				}
+			}
+			if (i < len)
+				return -ENAMETOOLONG;
+		} else {
+			for (i = 0, ip = name, op = outname, *outlen = 0;
+			     i < len && *outlen <= 255;
+			     i++, *outlen += 1)
+			{
+				*op++ = *ip++;
+				*op++ = 0;
+			}
+			if (i < len)
+				return -ENAMETOOLONG;
+		}
+	}
+
+	*longlen = *outlen;
+	if (*outlen % 13) {
+		*op++ = 0;
+		*op++ = 0;
+		*outlen += 1;
+		if (*outlen % 13) {
+			fill = 13 - (*outlen % 13);
+			for (i = 0; i < fill; i++) {
+				*op++ = 0xff;
+				*op++ = 0xff;
+			}
+			*outlen += fill;
+		}
+	}
+
+	return 0;
+}
+
+static int vfat_build_slots(struct inode *dir, const unsigned char *name,
+			    int len, int is_dir, int cluster,
+			    struct timespec *ts,
+			    struct msdos_dir_slot *slots, int *nr_slots)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(dir->i_sb);
+	struct fat_mount_options *opts = &sbi->options;
+	struct msdos_dir_slot *ps;
+	struct msdos_dir_entry *de;
+	unsigned char cksum, lcase;
+	unsigned char msdos_name[MSDOS_NAME];
+	wchar_t *uname;
+	__le16 time, date;
+	u8 time_cs;
+	int err, ulen, usize, i;
+	loff_t offset;
+
+	*nr_slots = 0;
+
+	uname = __getname();
+	if (!uname)
+		return -ENOMEM;
+
+	err = xlate_to_uni(name, len, (unsigned char *)uname, &ulen, &usize,
+			   opts->unicode_xlate, opts->utf8, sbi->nls_io);
+	if (err)
+		goto out_free;
+
+	err = vfat_is_used_badchars(uname, ulen);
+	if (err)
+		goto out_free;
+
+	err = vfat_create_shortname(dir, sbi->nls_disk, uname, ulen,
+				    msdos_name, &lcase);
+	if (err < 0)
+		goto out_free;
+	else if (err == 1) {
+		de = (struct msdos_dir_entry *)slots;
+		err = 0;
+		goto shortname;
+	}
+
+	/* build the entry of long file name */
+	cksum = fat_checksum(msdos_name);
+
+	*nr_slots = usize / 13;
+	for (ps = slots, i = *nr_slots; i > 0; i--, ps++) {
+		ps->id = i;
+		ps->attr = ATTR_EXT;
+		ps->reserved = 0;
+		ps->alias_checksum = cksum;
+		ps->start = 0;
+		offset = (i - 1) * 13;
+		fatwchar_to16(ps->name0_4, uname + offset, 5);
+		fatwchar_to16(ps->name5_10, uname + offset + 5, 6);
+		fatwchar_to16(ps->name11_12, uname + offset + 11, 2);
+	}
+	slots[0].id |= 0x40;
+	de = (struct msdos_dir_entry *)ps;
+
+shortname:
+	/* build the entry of 8.3 alias name */
+	(*nr_slots)++;
+	memcpy(de->name, msdos_name, MSDOS_NAME);
+	de->attr = is_dir ? ATTR_DIR : ATTR_ARCH;
+	de->lcase = lcase;
+	fat_time_unix2fat(sbi, ts, &time, &date, &time_cs);
+	de->time = de->ctime = time;
+	de->date = de->cdate = de->adate = date;
+	de->ctime_cs = time_cs;
+	de->start = cpu_to_le16(cluster);
+	de->starthi = cpu_to_le16(cluster >> 16);
+	de->size = 0;
+out_free:
+	__putname(uname);
+	return err;
+}
+
+static int vfat_add_entry(struct inode *dir, struct qstr *qname, int is_dir,
+			  int cluster, struct timespec *ts,
+			  struct fat_slot_info *sinfo)
+{
+	struct msdos_dir_slot *slots;
+	unsigned int len;
+	int err, nr_slots;
+
+	len = vfat_striptail_len(qname);
+	if (len == 0)
+		return -ENOENT;
+
+	slots = kmalloc(sizeof(*slots) * MSDOS_SLOTS, GFP_NOFS);
+	if (slots == NULL)
+		return -ENOMEM;
+
+	err = vfat_build_slots(dir, qname->name, len, is_dir, cluster, ts,
+			       slots, &nr_slots);
+	if (err)
+		goto cleanup;
+
+	err = fat_add_entries(dir, slots, nr_slots, sinfo);
+	if (err)
+		goto cleanup;
+
+	/* update timestamp */
+	dir->i_ctime = dir->i_mtime = dir->i_atime = *ts;
+	if (IS_DIRSYNC(dir))
+		(void)fat_sync_inode(dir);
+	else
+		mark_inode_dirty(dir);
+cleanup:
+	kfree(slots);
+	return err;
+}
+
+static int vfat_find(struct inode *dir, struct qstr *qname,
+		     struct fat_slot_info *sinfo)
+{
+	unsigned int len = vfat_striptail_len(qname);
+	if (len == 0)
+		return -ENOENT;
+	return fat_search_long(dir, qname->name, len, sinfo);
+}
+
+static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
+				  struct nameidata *nd)
+{
+	struct super_block *sb = dir->i_sb;
+	struct fat_slot_info sinfo;
+	struct inode *inode;
+	struct dentry *alias;
+	int err;
+
+	lock_super(sb);
+
+	err = vfat_find(dir, &dentry->d_name, &sinfo);
+	if (err) {
+		if (err == -ENOENT) {
+			inode = NULL;
+			goto out;
+		}
+		goto error;
+	}
+
+	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+	brelse(sinfo.bh);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto error;
+	}
+
+	alias = d_find_alias(inode);
+	if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {
+		/*
+		 * This inode has non DCACHE_DISCONNECTED dentry. This
+		 * means, the user did ->lookup() by an another name
+		 * (longname vs 8.3 alias of it) in past.
+		 *
+		 * Switch to new one for reason of locality if possible.
+		 */
+		BUG_ON(d_unhashed(alias));
+		if (!S_ISDIR(inode->i_mode))
+			d_move(alias, dentry);
+		iput(inode);
+		unlock_super(sb);
+		return alias;
+	}
+out:
+	unlock_super(sb);
+	dentry->d_op = sb->s_root->d_op;
+	dentry->d_time = dentry->d_parent->d_inode->i_version;
+	dentry = d_splice_alias(inode, dentry);
+	if (dentry) {
+		dentry->d_op = sb->s_root->d_op;
+		dentry->d_time = dentry->d_parent->d_inode->i_version;
+	}
+	return dentry;
+
+error:
+	unlock_super(sb);
+	return ERR_PTR(err);
+}
+
+static int vfat_create(struct inode *dir, struct dentry *dentry, int mode,
+		       struct nameidata *nd)
+{
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode;
+	struct fat_slot_info sinfo;
+	struct timespec ts;
+	int err;
+
+	lock_super(sb);
+
+	ts = CURRENT_TIME_SEC;
+	err = vfat_add_entry(dir, &dentry->d_name, 0, 0, &ts, &sinfo);
+	if (err)
+		goto out;
+	dir->i_version++;
+
+	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+	brelse(sinfo.bh);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out;
+	}
+	inode->i_version++;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+	dentry->d_time = dentry->d_parent->d_inode->i_version;
+	d_instantiate(dentry, inode);
+out:
+	unlock_super(sb);
+	return err;
+}
+
+static int vfat_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	struct super_block *sb = dir->i_sb;
+	struct fat_slot_info sinfo;
+	int err;
+
+	lock_super(sb);
+
+	err = fat_dir_empty(inode);
+	if (err)
+		goto out;
+	err = vfat_find(dir, &dentry->d_name, &sinfo);
+	if (err)
+		goto out;
+
+	err = fat_remove_entries(dir, &sinfo);	/* and releases bh */
+	if (err)
+		goto out;
+	drop_nlink(dir);
+
+	clear_nlink(inode);
+	inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
+	fat_detach(inode);
+out:
+	unlock_super(sb);
+
+	return err;
+}
+
+static int vfat_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct inode *inode = dentry->d_inode;
+	struct super_block *sb = dir->i_sb;
+	struct fat_slot_info sinfo;
+	int err;
+
+	lock_super(sb);
+
+	err = vfat_find(dir, &dentry->d_name, &sinfo);
+	if (err)
+		goto out;
+
+	err = fat_remove_entries(dir, &sinfo);	/* and releases bh */
+	if (err)
+		goto out;
+	clear_nlink(inode);
+	inode->i_mtime = inode->i_atime = CURRENT_TIME_SEC;
+	fat_detach(inode);
+out:
+	unlock_super(sb);
+
+	return err;
+}
+
+static int vfat_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+	struct super_block *sb = dir->i_sb;
+	struct inode *inode;
+	struct fat_slot_info sinfo;
+	struct timespec ts;
+	int err, cluster;
+
+	lock_super(sb);
+
+	ts = CURRENT_TIME_SEC;
+	cluster = fat_alloc_new_dir(dir, &ts);
+	if (cluster < 0) {
+		err = cluster;
+		goto out;
+	}
+	err = vfat_add_entry(dir, &dentry->d_name, 1, cluster, &ts, &sinfo);
+	if (err)
+		goto out_free;
+	dir->i_version++;
+	inc_nlink(dir);
+
+	inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos);
+	brelse(sinfo.bh);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		/* the directory was completed, just return a error */
+		goto out;
+	}
+	inode->i_version++;
+	inode->i_nlink = 2;
+	inode->i_mtime = inode->i_atime = inode->i_ctime = ts;
+	/* timestamp is already written, so mark_inode_dirty() is unneeded. */
+
+	dentry->d_time = dentry->d_parent->d_inode->i_version;
+	d_instantiate(dentry, inode);
+
+	unlock_super(sb);
+	return 0;
+
+out_free:
+	fat_free_clusters(dir, cluster);
+out:
+	unlock_super(sb);
+	return err;
+}
+
+static int vfat_rename(struct inode *old_dir, struct dentry *old_dentry,
+		       struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct buffer_head *dotdot_bh;
+	struct msdos_dir_entry *dotdot_de;
+	struct inode *old_inode, *new_inode;
+	struct fat_slot_info old_sinfo, sinfo;
+	struct timespec ts;
+	loff_t dotdot_i_pos, new_i_pos;
+	int err, is_dir, update_dotdot, corrupt = 0;
+	struct super_block *sb = old_dir->i_sb;
+
+	old_sinfo.bh = sinfo.bh = dotdot_bh = NULL;
+	old_inode = old_dentry->d_inode;
+	new_inode = new_dentry->d_inode;
+	lock_super(sb);
+	err = vfat_find(old_dir, &old_dentry->d_name, &old_sinfo);
+	if (err)
+		goto out;
+
+	is_dir = S_ISDIR(old_inode->i_mode);
+	update_dotdot = (is_dir && old_dir != new_dir);
+	if (update_dotdot) {
+		if (fat_get_dotdot_entry(old_inode, &dotdot_bh, &dotdot_de,
+					 &dotdot_i_pos) < 0) {
+			err = -EIO;
+			goto out;
+		}
+	}
+
+	ts = CURRENT_TIME_SEC;
+	if (new_inode) {
+		if (is_dir) {
+			err = fat_dir_empty(new_inode);
+			if (err)
+				goto out;
+		}
+		new_i_pos = MSDOS_I(new_inode)->i_pos;
+		fat_detach(new_inode);
+	} else {
+		err = vfat_add_entry(new_dir, &new_dentry->d_name, is_dir, 0,
+				     &ts, &sinfo);
+		if (err)
+			goto out;
+		new_i_pos = sinfo.i_pos;
+	}
+	new_dir->i_version++;
+
+	fat_detach(old_inode);
+	fat_attach(old_inode, new_i_pos);
+	if (IS_DIRSYNC(new_dir)) {
+		err = fat_sync_inode(old_inode);
+		if (err)
+			goto error_inode;
+	} else
+		mark_inode_dirty(old_inode);
+
+	if (update_dotdot) {
+		int start = MSDOS_I(new_dir)->i_logstart;
+		dotdot_de->start = cpu_to_le16(start);
+		dotdot_de->starthi = cpu_to_le16(start >> 16);
+		mark_buffer_dirty(dotdot_bh);
+		if (IS_DIRSYNC(new_dir)) {
+			err = sync_dirty_buffer(dotdot_bh);
+			if (err)
+				goto error_dotdot;
+		}
+		drop_nlink(old_dir);
+		if (!new_inode)
+ 			inc_nlink(new_dir);
+	}
+
+	err = fat_remove_entries(old_dir, &old_sinfo);	/* and releases bh */
+	old_sinfo.bh = NULL;
+	if (err)
+		goto error_dotdot;
+	old_dir->i_version++;
+	old_dir->i_ctime = old_dir->i_mtime = ts;
+	if (IS_DIRSYNC(old_dir))
+		(void)fat_sync_inode(old_dir);
+	else
+		mark_inode_dirty(old_dir);
+
+	if (new_inode) {
+		drop_nlink(new_inode);
+		if (is_dir)
+			drop_nlink(new_inode);
+		new_inode->i_ctime = ts;
+	}
+out:
+	brelse(sinfo.bh);
+	brelse(dotdot_bh);
+	brelse(old_sinfo.bh);
+	unlock_super(sb);
+
+	return err;
+
+error_dotdot:
+	/* data cluster is shared, serious corruption */
+	corrupt = 1;
+
+	if (update_dotdot) {
+		int start = MSDOS_I(old_dir)->i_logstart;
+		dotdot_de->start = cpu_to_le16(start);
+		dotdot_de->starthi = cpu_to_le16(start >> 16);
+		mark_buffer_dirty(dotdot_bh);
+		corrupt |= sync_dirty_buffer(dotdot_bh);
+	}
+error_inode:
+	fat_detach(old_inode);
+	fat_attach(old_inode, old_sinfo.i_pos);
+	if (new_inode) {
+		fat_attach(new_inode, new_i_pos);
+		if (corrupt)
+			corrupt |= fat_sync_inode(new_inode);
+	} else {
+		/*
+		 * If new entry was not sharing the data cluster, it
+		 * shouldn't be serious corruption.
+		 */
+		int err2 = fat_remove_entries(new_dir, &sinfo);
+		if (corrupt)
+			corrupt |= err2;
+		sinfo.bh = NULL;
+	}
+	if (corrupt < 0) {
+		fat_fs_panic(new_dir->i_sb,
+			     "%s: Filesystem corrupted (i_pos %lld)",
+			     __func__, sinfo.i_pos);
+	}
+	goto out;
+}
+
+static const struct inode_operations vfat_dir_inode_operations = {
+	.create		= vfat_create,
+	.lookup		= vfat_lookup,
+	.unlink		= vfat_unlink,
+	.mkdir		= vfat_mkdir,
+	.rmdir		= vfat_rmdir,
+	.rename		= vfat_rename,
+	.setattr	= fat_setattr,
+	.getattr	= fat_getattr,
+};
+
+static int vfat_fill_super(struct super_block *sb, void *data, int silent)
+{
+	int res;
+
+	res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1);
+	if (res)
+		return res;
+
+	if (MSDOS_SB(sb)->options.name_check != 's')
+		sb->s_root->d_op = &vfat_ci_dentry_ops;
+	else
+		sb->s_root->d_op = &vfat_dentry_ops;
+
+	return 0;
+}
+
+static int vfat_get_sb(struct file_system_type *fs_type,
+		       int flags, const char *dev_name,
+		       void *data, struct vfsmount *mnt)
+{
+	return get_sb_bdev(fs_type, flags, dev_name, data, vfat_fill_super,
+			   mnt);
+}
+
+static struct file_system_type vfat_fs_type = {
+	.owner		= THIS_MODULE,
+	.name		= "vfat",
+	.get_sb		= vfat_get_sb,
+	.kill_sb	= kill_block_super,
+	.fs_flags	= FS_REQUIRES_DEV,
+};
+
+static int __init init_vfat_fs(void)
+{
+	return register_filesystem(&vfat_fs_type);
+}
+
+static void __exit exit_vfat_fs(void)
+{
+	unregister_filesystem(&vfat_fs_type);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("VFAT filesystem support");
+MODULE_AUTHOR("Gordon Chaffee");
+
+module_init(init_vfat_fs)
+module_exit(exit_vfat_fs)