Creation of Cybook 2416 (actually Gen4) repository

fs/fat/Makefile

@@ -0,0 +1,7 @@
+#
+# Makefile for the Linux fat filesystem support.
+#
+
+obj-$(CONFIG_FAT_FS) += fat.o
+
+fat-objs := cache.o dir.o fatent.o file.o inode.o misc.o

fs/fat/cache.c

@@ -0,0 +1,331 @@
+/*
+ *  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/msdos_fs.h>
+#include <linux/buffer_head.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 kmem_cache *cachep, unsigned long flags)
+{
+	struct fat_cache *cache = (struct fat_cache *)foo;
+
+	if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) ==
+	    SLAB_CTOR_CONSTRUCTOR)
+		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, NULL);
+	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_KERNEL);
+}
+
+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)", __FUNCTION__,
+				     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)", __FUNCTION__,
+				     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)",
+			     __FUNCTION__, 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)
+{
+	struct super_block *sb = inode->i_sb;
+	struct msdos_sb_info *sbi = MSDOS_SB(sb);
+	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 = (MSDOS_I(inode)->mmu_private + (sb->s_blocksize - 1))
+		>> sb->s_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;
+}

fs/fat/fatent.c

@@ -0,0 +1,616 @@
+/*
+ * Copyright (C) 2004, OGAWA Hirofumi
+ * Released under GPL v2.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/msdos_fs.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 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",
+	       (unsigned long long)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",
+		       (unsigned long long)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;
+
+	if (fatent->entry & 1)
+		next = (*ent12_p[0] >> 4) | (*ent12_p[1] << 4);
+	else
+		next = (*ent12_p[1] << 8) | *ent12_p[0];
+	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;
+
+	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);
+	}
+
+	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;
+	/* Does this entry need the next block? */
+	if (sbi->fat_bits == 12 && (offset + 1) >= sb->s_blocksize) {
+		if (fatent->nr_bhs != 2 || 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_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;
+	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;
+
+	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",
+				     __FUNCTION__);
+			err = -EIO;
+			goto error;
+		}
+
+		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);
+
+	fat_clusters_flush(sb);
+
+	return err;
+}
+
+EXPORT_SYMBOL_GPL(fat_free_clusters);
+
+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;
+	int err = 0, free;
+
+	lock_fat(sbi);
+	if (sbi->free_clusters != -1)
+		goto out;
+
+	free = 0;
+	fatent_init(&fatent);
+	fatent_set_entry(&fatent, FAT_START_ENT);
+	while (fatent.entry < sbi->max_cluster) {
+		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;
+	sb->s_dirt = 1;
+	fatent_brelse(&fatent);
+out:
+	unlock_fat(sbi);
+	return err;
+}

fs/fat/file.c

@@ -0,0 +1,319 @@
+/*
+ *  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/time.h>
+#include <linux/msdos_fs.h>
+#include <linux/smp_lock.h>
+#include <linux/buffer_head.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/blkdev.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;
+
+		if (inode->i_ino == MSDOS_ROOT_INO)
+			attr = ATTR_DIR;
+		else
+			attr = fat_attr(inode);
+
+		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);
+
+		if (IS_RDONLY(inode)) {
+			err = -EROFS;
+			goto up;
+		}
+
+		/*
+		 * 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_attr(inode);
+
+		/* Equivalent to a chmod() */
+		ia.ia_valid = ATTR_MODE | ATTR_CTIME;
+		if (is_dir) {
+			ia.ia_mode = MSDOS_MKMODE(attr,
+				S_IRWXUGO & ~sbi->options.fs_dmask)
+				| S_IFDIR;
+		} else {
+			ia.ia_mode = MSDOS_MKMODE(attr,
+				(S_IRUGO | S_IWUGO | (inode->i_mode & S_IXUGO))
+				& ~sbi->options.fs_fmask)
+				| S_IFREG;
+		}
+
+		/* 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;
+				}
+			}
+		}
+
+		/* This MUST be done before doing anything irreversible... */
+		err = notify_change(filp->f_path.dentry, &ia);
+		if (err)
+			goto up;
+
+		if (sbi->options.sys_immutable) {
+			if (attr & ATTR_SYS)
+				inode->i_flags |= S_IMMUTABLE;
+			else
+				inode->i_flags &= S_IMMUTABLE;
+		}
+
+		MSDOS_I(inode)->i_attrs = attr & ATTR_UNUSED;
+		mark_inode_dirty(inode);
+	up:
+		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,
+	.sendfile	= generic_file_sendfile,
+};
+
+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;
+}
+
+int fat_notify_change(struct dentry *dentry, struct iattr *attr)
+{
+	struct msdos_sb_info *sbi = MSDOS_SB(dentry->d_sb);
+	struct inode *inode = dentry->d_inode;
+	int mask, error = 0;
+
+	lock_kernel();
+
+	/*
+	 * 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;
+		}
+	}
+
+	error = inode_change_ok(inode, attr);
+	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 & ~MSDOS_VALID_MODE)))
+		error = -EPERM;
+
+	if (error) {
+		if (sbi->options.quiet)
+			error = 0;
+		goto out;
+	}
+	error = inode_setattr(inode, attr);
+	if (error)
+		goto out;
+
+	if (S_ISDIR(inode->i_mode))
+		mask = sbi->options.fs_dmask;
+	else
+		mask = sbi->options.fs_fmask;
+	inode->i_mode &= S_IFMT | (S_IRWXUGO & ~mask);
+out:
+	unlock_kernel();
+	return error;
+}
+
+EXPORT_SYMBOL_GPL(fat_notify_change);
+
+/* 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)",
+				     __FUNCTION__, 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;
+
+	lock_kernel();
+	fat_free(inode, nr_clusters);
+	unlock_kernel();
+	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);
+
+const struct inode_operations fat_file_inode_operations = {
+	.truncate	= fat_truncate,
+	.setattr	= fat_notify_change,
+	.getattr	= fat_getattr,
+};

fs/fat/misc.c

@@ -0,0 +1,212 @@
+/*
+ *  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/msdos_fs.h>
+#include <linux/buffer_head.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: Did not find valid FSINFO signature.\n"
+		       "     Found signature1 0x%08x signature2 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 != %lu)",
+			new_fclus, 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;
+
+/* Linear day numbers of the respective 1sts in non-leap years. */
+static int day_n[] = {
+   /* Jan  Feb  Mar  Apr   May  Jun  Jul  Aug  Sep  Oct  Nov  Dec */
+	0,  31,  59,  90,  120, 151, 181, 212, 243, 273, 304, 334, 0, 0, 0, 0
+};
+
+/* Convert a MS-DOS time/date pair to a UNIX date (seconds since 1 1 70). */
+int date_dos2unix(unsigned short time, unsigned short date)
+{
+	int month, year, secs;
+
+	/*
+	 * first subtract and mask after that... Otherwise, if
+	 * date == 0, bad things happen
+	 */
+	month = ((date >> 5) - 1) & 15;
+	year = date >> 9;
+	secs = (time & 31)*2+60*((time >> 5) & 63)+(time >> 11)*3600+86400*
+	    ((date & 31)-1+day_n[month]+(year/4)+year*365-((year & 3) == 0 &&
+	    month < 2 ? 1 : 0)+3653);
+			/* days since 1.1.70 plus 80's leap day */
+	secs += sys_tz.tz_minuteswest*60;
+	return secs;
+}
+
+/* Convert linear UNIX date to a MS-DOS time/date pair. */
+void fat_date_unix2dos(int unix_date, __le16 *time, __le16 *date)
+{
+	int day, year, nl_day, month;
+
+	unix_date -= sys_tz.tz_minuteswest*60;
+
+	/* Jan 1 GMT 00:00:00 1980. But what about another time zone? */
+	if (unix_date < 315532800)
+		unix_date = 315532800;
+
+	*time = cpu_to_le16((unix_date % 60)/2+(((unix_date/60) % 60) << 5)+
+	    (((unix_date/3600) % 24) << 11));
+	day = unix_date/86400-3652;
+	year = day/365;
+	if ((year+3)/4+365*year > day)
+		year--;
+	day -= (year+3)/4+365*year;
+	if (day == 59 && !(year & 3)) {
+		nl_day = day;
+		month = 2;
+	} else {
+		nl_day = (year & 3) || day <= 59 ? day : day-1;
+		for (month = 0; month < 12; month++) {
+			if (day_n[month] > nl_day)
+				break;
+		}
+	}
+	*date = cpu_to_le16(nl_day-day_n[month-1]+1+(month << 5)+(year << 9));
+}
+
+EXPORT_SYMBOL_GPL(fat_date_unix2dos);
+
+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;
+}
+