// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
 */

#include <linux/types.h>
#include <linux/buffer_head.h>
#include <linux/fs.h>
#include <linux/mutex.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include "exfat.h"

static void __set_sb_dirty(struct super_block *sb)
{
	struct exfat_sb_info *sbi = EXFAT_SB(sb);

	sbi->s_dirt = 1;
}

static u8 name_buf[MAX_PATH_LENGTH * MAX_CHARSET_SIZE];

static char *reserved_names[] = {
	"AUX     ", "CON     ", "NUL     ", "PRN     ",
	"COM1    ", "COM2    ", "COM3    ", "COM4    ",
	"COM5    ", "COM6    ", "COM7    ", "COM8    ", "COM9    ",
	"LPT1    ", "LPT2    ", "LPT3    ", "LPT4    ",
	"LPT5    ", "LPT6    ", "LPT7    ", "LPT8    ", "LPT9    ",
	NULL
};

static u8 free_bit[] = {
	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, /*   0 ~  19 */
	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, /*  20 ~  39 */
	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, /*  40 ~  59 */
	0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, /*  60 ~  79 */
	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 2, /*  80 ~  99 */
	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, /* 100 ~ 119 */
	0, 1, 0, 2, 0, 1, 0, 7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, /* 120 ~ 139 */
	0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 5, /* 140 ~ 159 */
	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, /* 160 ~ 179 */
	0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 6, 0, 1, 0, 2, 0, 1, 0, 3, /* 180 ~ 199 */
	0, 1, 0, 2, 0, 1, 0, 4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, /* 200 ~ 219 */
	0, 1, 0, 5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, 4, /* 220 ~ 239 */
	0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0                 /* 240 ~ 254 */
};

static u8 used_bit[] = {
	0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3, 4, 1, 2, 2, 3, /*   0 ~  19 */
	2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3, 3, 4, /*  20 ~  39 */
	2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, /*  40 ~  59 */
	4, 5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, /*  60 ~  79 */
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, /*  80 ~  99 */
	3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, /* 100 ~ 119 */
	4, 5, 5, 6, 5, 6, 6, 7, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, /* 120 ~ 139 */
	3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, /* 140 ~ 159 */
	2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, /* 160 ~ 179 */
	4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4, 5, /* 180 ~ 199 */
	3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, /* 200 ~ 219 */
	5, 6, 6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, /* 220 ~ 239 */
	4, 5, 5, 6, 5, 6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8              /* 240 ~ 255 */
};

#define BITMAP_LOC(v)           ((v) >> 3)
#define BITMAP_SHIFT(v)         ((v) & 0x07)

static inline s32 exfat_bitmap_test(u8 *bitmap, int i)
{
	u8 data;

	data = bitmap[BITMAP_LOC(i)];
	if ((data >> BITMAP_SHIFT(i)) & 0x01)
		return 1;
	return 0;
}

static inline void exfat_bitmap_set(u8 *bitmap, int i)
{
	bitmap[BITMAP_LOC(i)] |= (0x01 << BITMAP_SHIFT(i));
}

static inline void exfat_bitmap_clear(u8 *bitmap, int i)
{
	bitmap[BITMAP_LOC(i)] &= ~(0x01 << BITMAP_SHIFT(i));
}

/*
 *  File System Management Functions
 */

void fs_set_vol_flags(struct super_block *sb, u32 new_flag)
{
	struct pbr_sector_t *p_pbr;
	struct bpbex_t *p_bpb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (p_fs->vol_flag == new_flag)
		return;

	p_fs->vol_flag = new_flag;

	if (p_fs->vol_type == EXFAT) {
		if (!p_fs->pbr_bh) {
			if (sector_read(sb, p_fs->PBR_sector,
					&p_fs->pbr_bh, 1) != FFS_SUCCESS)
				return;
		}

		p_pbr = (struct pbr_sector_t *)p_fs->pbr_bh->b_data;
		p_bpb = (struct bpbex_t *)p_pbr->bpb;
		SET16(p_bpb->vol_flags, (u16)new_flag);

		/* XXX duyoung
		 * what can we do here? (cuz fs_set_vol_flags() is void)
		 */
		if ((new_flag == VOL_DIRTY) && (!buffer_dirty(p_fs->pbr_bh)))
			sector_write(sb, p_fs->PBR_sector, p_fs->pbr_bh, 1);
		else
			sector_write(sb, p_fs->PBR_sector, p_fs->pbr_bh, 0);
	}
}

void fs_error(struct super_block *sb)
{
	struct exfat_mount_options *opts = &EXFAT_SB(sb)->options;

	if (opts->errors == EXFAT_ERRORS_PANIC) {
		panic("[EXFAT] Filesystem panic from previous error\n");
	} else if ((opts->errors == EXFAT_ERRORS_RO) && !sb_rdonly(sb)) {
		sb->s_flags |= SB_RDONLY;
		pr_err("[EXFAT] Filesystem has been set read-only\n");
	}
}

/*
 *  Cluster Management Functions
 */

s32 clear_cluster(struct super_block *sb, u32 clu)
{
	sector_t s, n;
	s32 ret = FFS_SUCCESS;
	struct buffer_head *tmp_bh = NULL;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	if (clu == CLUSTER_32(0)) { /* FAT16 root_dir */
		s = p_fs->root_start_sector;
		n = p_fs->data_start_sector;
	} else {
		s = START_SECTOR(clu);
		n = s + p_fs->sectors_per_clu;
	}

	for (; s < n; s++) {
		ret = sector_read(sb, s, &tmp_bh, 0);
		if (ret != FFS_SUCCESS)
			return ret;

		memset((char *)tmp_bh->b_data, 0x0, p_bd->sector_size);
		ret = sector_write(sb, s, tmp_bh, 0);
		if (ret != FFS_SUCCESS)
			break;
	}

	brelse(tmp_bh);
	return ret;
}

s32 fat_alloc_cluster(struct super_block *sb, s32 num_alloc,
		      struct chain_t *p_chain)
{
	int i, num_clusters = 0;
	u32 new_clu, last_clu = CLUSTER_32(~0), read_clu;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	new_clu = p_chain->dir;
	if (new_clu == CLUSTER_32(~0))
		new_clu = p_fs->clu_srch_ptr;
	else if (new_clu >= p_fs->num_clusters)
		new_clu = 2;

	__set_sb_dirty(sb);

	p_chain->dir = CLUSTER_32(~0);

	for (i = 2; i < p_fs->num_clusters; i++) {
		if (FAT_read(sb, new_clu, &read_clu) != 0)
			return -1;

		if (read_clu == CLUSTER_32(0)) {
			if (FAT_write(sb, new_clu, CLUSTER_32(~0)) < 0)
				return -1;
			num_clusters++;

			if (p_chain->dir == CLUSTER_32(~0)) {
				p_chain->dir = new_clu;
			} else {
				if (FAT_write(sb, last_clu, new_clu) < 0)
					return -1;
			}

			last_clu = new_clu;

			if ((--num_alloc) == 0) {
				p_fs->clu_srch_ptr = new_clu;
				if (p_fs->used_clusters != UINT_MAX)
					p_fs->used_clusters += num_clusters;

				return num_clusters;
			}
		}
		if ((++new_clu) >= p_fs->num_clusters)
			new_clu = 2;
	}

	p_fs->clu_srch_ptr = new_clu;
	if (p_fs->used_clusters != UINT_MAX)
		p_fs->used_clusters += num_clusters;

	return num_clusters;
}

s32 exfat_alloc_cluster(struct super_block *sb, s32 num_alloc,
			struct chain_t *p_chain)
{
	s32 num_clusters = 0;
	u32 hint_clu, new_clu, last_clu = CLUSTER_32(~0);
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	hint_clu = p_chain->dir;
	if (hint_clu == CLUSTER_32(~0)) {
		hint_clu = test_alloc_bitmap(sb, p_fs->clu_srch_ptr - 2);
		if (hint_clu == CLUSTER_32(~0))
			return 0;
	} else if (hint_clu >= p_fs->num_clusters) {
		hint_clu = 2;
		p_chain->flags = 0x01;
	}

	__set_sb_dirty(sb);

	p_chain->dir = CLUSTER_32(~0);

	while ((new_clu = test_alloc_bitmap(sb, hint_clu - 2)) != CLUSTER_32(~0)) {
		if (new_clu != hint_clu) {
			if (p_chain->flags == 0x03) {
				exfat_chain_cont_cluster(sb, p_chain->dir,
							 num_clusters);
				p_chain->flags = 0x01;
			}
		}

		if (set_alloc_bitmap(sb, new_clu - 2) != FFS_SUCCESS)
			return -1;

		num_clusters++;

		if (p_chain->flags == 0x01) {
			if (FAT_write(sb, new_clu, CLUSTER_32(~0)) < 0)
				return -1;
		}

		if (p_chain->dir == CLUSTER_32(~0)) {
			p_chain->dir = new_clu;
		} else {
			if (p_chain->flags == 0x01) {
				if (FAT_write(sb, last_clu, new_clu) < 0)
					return -1;
			}
		}
		last_clu = new_clu;

		if ((--num_alloc) == 0) {
			p_fs->clu_srch_ptr = hint_clu;
			if (p_fs->used_clusters != UINT_MAX)
				p_fs->used_clusters += num_clusters;

			p_chain->size += num_clusters;
			return num_clusters;
		}

		hint_clu = new_clu + 1;
		if (hint_clu >= p_fs->num_clusters) {
			hint_clu = 2;

			if (p_chain->flags == 0x03) {
				exfat_chain_cont_cluster(sb, p_chain->dir,
							 num_clusters);
				p_chain->flags = 0x01;
			}
		}
	}

	p_fs->clu_srch_ptr = hint_clu;
	if (p_fs->used_clusters != UINT_MAX)
		p_fs->used_clusters += num_clusters;

	p_chain->size += num_clusters;
	return num_clusters;
}

void fat_free_cluster(struct super_block *sb, struct chain_t *p_chain,
		      s32 do_relse)
{
	s32 num_clusters = 0;
	u32 clu, prev;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	int i;
	sector_t sector;

	if ((p_chain->dir == CLUSTER_32(0)) || (p_chain->dir == CLUSTER_32(~0)))
		return;
	__set_sb_dirty(sb);
	clu = p_chain->dir;

	if (p_chain->size <= 0)
		return;

	do {
		if (p_fs->dev_ejected)
			break;

		if (do_relse) {
			sector = START_SECTOR(clu);
			for (i = 0; i < p_fs->sectors_per_clu; i++)
				buf_release(sb, sector + i);
		}

		prev = clu;
		if (FAT_read(sb, clu, &clu) == -1)
			break;

		if (FAT_write(sb, prev, CLUSTER_32(0)) < 0)
			break;
		num_clusters++;

	} while (clu != CLUSTER_32(~0));

	if (p_fs->used_clusters != UINT_MAX)
		p_fs->used_clusters -= num_clusters;
}

void exfat_free_cluster(struct super_block *sb, struct chain_t *p_chain,
			s32 do_relse)
{
	s32 num_clusters = 0;
	u32 clu;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	int i;
	sector_t sector;

	if ((p_chain->dir == CLUSTER_32(0)) || (p_chain->dir == CLUSTER_32(~0)))
		return;

	if (p_chain->size <= 0) {
		pr_err("[EXFAT] free_cluster : skip free-req clu:%u, because of zero-size truncation\n",
		       p_chain->dir);
		return;
	}

	__set_sb_dirty(sb);
	clu = p_chain->dir;

	if (p_chain->flags == 0x03) {
		do {
			if (do_relse) {
				sector = START_SECTOR(clu);
				for (i = 0; i < p_fs->sectors_per_clu; i++)
					buf_release(sb, sector + i);
			}

			if (clr_alloc_bitmap(sb, clu - 2) != FFS_SUCCESS)
				break;
			clu++;

			num_clusters++;
		} while (num_clusters < p_chain->size);
	} else {
		do {
			if (p_fs->dev_ejected)
				break;

			if (do_relse) {
				sector = START_SECTOR(clu);
				for (i = 0; i < p_fs->sectors_per_clu; i++)
					buf_release(sb, sector + i);
			}

			if (clr_alloc_bitmap(sb, clu - 2) != FFS_SUCCESS)
				break;

			if (FAT_read(sb, clu, &clu) == -1)
				break;
			num_clusters++;
		} while ((clu != CLUSTER_32(0)) && (clu != CLUSTER_32(~0)));
	}

	if (p_fs->used_clusters != UINT_MAX)
		p_fs->used_clusters -= num_clusters;
}

u32 find_last_cluster(struct super_block *sb, struct chain_t *p_chain)
{
	u32 clu, next;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	clu = p_chain->dir;

	if (p_chain->flags == 0x03) {
		clu += p_chain->size - 1;
	} else {
		while ((FAT_read(sb, clu, &next) == 0) &&
		       (next != CLUSTER_32(~0))) {
			if (p_fs->dev_ejected)
				break;
			clu = next;
		}
	}

	return clu;
}

s32 count_num_clusters(struct super_block *sb, struct chain_t *p_chain)
{
	int i, count = 0;
	u32 clu;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if ((p_chain->dir == CLUSTER_32(0)) || (p_chain->dir == CLUSTER_32(~0)))
		return 0;

	clu = p_chain->dir;

	if (p_chain->flags == 0x03) {
		count = p_chain->size;
	} else {
		for (i = 2; i < p_fs->num_clusters; i++) {
			count++;
			if (FAT_read(sb, clu, &clu) != 0)
				return 0;
			if (clu == CLUSTER_32(~0))
				break;
		}
	}

	return count;
}

s32 fat_count_used_clusters(struct super_block *sb)
{
	int i, count = 0;
	u32 clu;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	for (i = 2; i < p_fs->num_clusters; i++) {
		if (FAT_read(sb, i, &clu) != 0)
			break;
		if (clu != CLUSTER_32(0))
			count++;
	}

	return count;
}

s32 exfat_count_used_clusters(struct super_block *sb)
{
	int i, map_i, map_b, count = 0;
	u8 k;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	map_i = map_b = 0;

	for (i = 2; i < p_fs->num_clusters; i += 8) {
		k = *(((u8 *)p_fs->vol_amap[map_i]->b_data) + map_b);
		count += used_bit[k];

		if ((++map_b) >= p_bd->sector_size) {
			map_i++;
			map_b = 0;
		}
	}

	return count;
}

void exfat_chain_cont_cluster(struct super_block *sb, u32 chain, s32 len)
{
	if (len == 0)
		return;

	while (len > 1) {
		if (FAT_write(sb, chain, chain + 1) < 0)
			break;
		chain++;
		len--;
	}
	FAT_write(sb, chain, CLUSTER_32(~0));
}

/*
 *  Allocation Bitmap Management Functions
 */

s32 load_alloc_bitmap(struct super_block *sb)
{
	int i, j, ret;
	u32 map_size;
	u32 type;
	sector_t sector;
	struct chain_t clu;
	struct bmap_dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	clu.dir = p_fs->root_dir;
	clu.flags = 0x01;

	while (clu.dir != CLUSTER_32(~0)) {
		if (p_fs->dev_ejected)
			break;

		for (i = 0; i < p_fs->dentries_per_clu; i++) {
			ep = (struct bmap_dentry_t *)get_entry_in_dir(sb, &clu,
								      i, NULL);
			if (!ep)
				return FFS_MEDIAERR;

			type = p_fs->fs_func->get_entry_type((struct dentry_t *)ep);

			if (type == TYPE_UNUSED)
				break;
			if (type != TYPE_BITMAP)
				continue;

			if (ep->flags == 0x0) {
				p_fs->map_clu  = GET32_A(ep->start_clu);
				map_size = (u32)GET64_A(ep->size);

				p_fs->map_sectors = ((map_size - 1) >> p_bd->sector_size_bits) + 1;

				p_fs->vol_amap = kmalloc_array(p_fs->map_sectors,
							       sizeof(struct buffer_head *),
							       GFP_KERNEL);
				if (!p_fs->vol_amap)
					return FFS_MEMORYERR;

				sector = START_SECTOR(p_fs->map_clu);

				for (j = 0; j < p_fs->map_sectors; j++) {
					p_fs->vol_amap[j] = NULL;
					ret = sector_read(sb, sector + j, &(p_fs->vol_amap[j]), 1);
					if (ret != FFS_SUCCESS) {
						/*  release all buffers and free vol_amap */
						i = 0;
						while (i < j)
							brelse(p_fs->vol_amap[i++]);

						kfree(p_fs->vol_amap);
						p_fs->vol_amap = NULL;
						return ret;
					}
				}

				p_fs->pbr_bh = NULL;
				return FFS_SUCCESS;
			}
		}

		if (FAT_read(sb, clu.dir, &clu.dir) != 0)
			return FFS_MEDIAERR;
	}

	return FFS_FORMATERR;
}

void free_alloc_bitmap(struct super_block *sb)
{
	int i;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	brelse(p_fs->pbr_bh);

	for (i = 0; i < p_fs->map_sectors; i++)
		__brelse(p_fs->vol_amap[i]);

	kfree(p_fs->vol_amap);
	p_fs->vol_amap = NULL;
}

s32 set_alloc_bitmap(struct super_block *sb, u32 clu)
{
	int i, b;
	sector_t sector;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	i = clu >> (p_bd->sector_size_bits + 3);
	b = clu & ((p_bd->sector_size << 3) - 1);

	sector = START_SECTOR(p_fs->map_clu) + i;

	exfat_bitmap_set((u8 *)p_fs->vol_amap[i]->b_data, b);

	return sector_write(sb, sector, p_fs->vol_amap[i], 0);
}

s32 clr_alloc_bitmap(struct super_block *sb, u32 clu)
{
	int i, b;
	sector_t sector;
#ifdef CONFIG_EXFAT_DISCARD
	struct exfat_sb_info *sbi = EXFAT_SB(sb);
	struct exfat_mount_options *opts = &sbi->options;
	int ret;
#endif /* CONFIG_EXFAT_DISCARD */
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	i = clu >> (p_bd->sector_size_bits + 3);
	b = clu & ((p_bd->sector_size << 3) - 1);

	sector = START_SECTOR(p_fs->map_clu) + i;

	exfat_bitmap_clear((u8 *)p_fs->vol_amap[i]->b_data, b);

	return sector_write(sb, sector, p_fs->vol_amap[i], 0);

#ifdef CONFIG_EXFAT_DISCARD
	if (opts->discard) {
		ret = sb_issue_discard(sb, START_SECTOR(clu),
				       (1 << p_fs->sectors_per_clu_bits),
				       GFP_NOFS, 0);
		if (ret == -EOPNOTSUPP) {
			pr_warn("discard not supported by device, disabling");
			opts->discard = 0;
		}
	}
#endif /* CONFIG_EXFAT_DISCARD */
}

u32 test_alloc_bitmap(struct super_block *sb, u32 clu)
{
	int i, map_i, map_b;
	u32 clu_base, clu_free;
	u8 k, clu_mask;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	clu_base = (clu & ~(0x7)) + 2;
	clu_mask = (1 << (clu - clu_base + 2)) - 1;

	map_i = clu >> (p_bd->sector_size_bits + 3);
	map_b = (clu >> 3) & p_bd->sector_size_mask;

	for (i = 2; i < p_fs->num_clusters; i += 8) {
		k = *(((u8 *)p_fs->vol_amap[map_i]->b_data) + map_b);
		if (clu_mask > 0) {
			k |= clu_mask;
			clu_mask = 0;
		}
		if (k < 0xFF) {
			clu_free = clu_base + free_bit[k];
			if (clu_free < p_fs->num_clusters)
				return clu_free;
		}
		clu_base += 8;

		if (((++map_b) >= p_bd->sector_size) ||
		    (clu_base >= p_fs->num_clusters)) {
			if ((++map_i) >= p_fs->map_sectors) {
				clu_base = 2;
				map_i = 0;
			}
			map_b = 0;
		}
	}

	return CLUSTER_32(~0);
}

void sync_alloc_bitmap(struct super_block *sb)
{
	int i;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (!p_fs->vol_amap)
		return;

	for (i = 0; i < p_fs->map_sectors; i++)
		sync_dirty_buffer(p_fs->vol_amap[i]);
}

/*
 *  Upcase table Management Functions
 */
static s32 __load_upcase_table(struct super_block *sb, sector_t sector,
			       u32 num_sectors, u32 utbl_checksum)
{
	int i, ret = FFS_ERROR;
	u32 j;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);
	struct buffer_head *tmp_bh = NULL;
	sector_t end_sector = num_sectors + sector;

	bool	skip = false;
	u32	index = 0;
	u16	uni = 0;
	u16 **upcase_table;

	u32 checksum = 0;

	upcase_table = p_fs->vol_utbl = kmalloc(UTBL_COL_COUNT * sizeof(u16 *),
						GFP_KERNEL);
	if (!upcase_table)
		return FFS_MEMORYERR;
	memset(upcase_table, 0, UTBL_COL_COUNT * sizeof(u16 *));

	while (sector < end_sector) {
		ret = sector_read(sb, sector, &tmp_bh, 1);
		if (ret != FFS_SUCCESS) {
			pr_debug("sector read (0x%llX)fail\n",
				 (unsigned long long)sector);
			goto error;
		}
		sector++;

		for (i = 0; i < p_bd->sector_size && index <= 0xFFFF; i += 2) {
			uni = GET16(((u8 *)tmp_bh->b_data) + i);

			checksum = ((checksum & 1) ? 0x80000000 : 0) +
				   (checksum >> 1) + *(((u8 *)tmp_bh->b_data) +
						       i);
			checksum = ((checksum & 1) ? 0x80000000 : 0) +
				   (checksum >> 1) + *(((u8 *)tmp_bh->b_data) +
						       (i + 1));

			if (skip) {
				pr_debug("skip from 0x%X ", index);
				index += uni;
				pr_debug("to 0x%X (amount of 0x%X)\n",
					 index, uni);
				skip = false;
			} else if (uni == index) {
				index++;
			} else if (uni == 0xFFFF) {
				skip = true;
			} else { /* uni != index , uni != 0xFFFF */
				u16 col_index = get_col_index(index);

				if (!upcase_table[col_index]) {
					pr_debug("alloc = 0x%X\n", col_index);
					upcase_table[col_index] = kmalloc_array(UTBL_ROW_COUNT,
						sizeof(u16), GFP_KERNEL);
					if (!upcase_table[col_index]) {
						ret = FFS_MEMORYERR;
						goto error;
					}

					for (j = 0; j < UTBL_ROW_COUNT; j++)
						upcase_table[col_index][j] = (col_index << LOW_INDEX_BIT) | j;
				}

				upcase_table[col_index][get_row_index(index)] = uni;
				index++;
			}
		}
	}
	if (index >= 0xFFFF && utbl_checksum == checksum) {
		if (tmp_bh)
			brelse(tmp_bh);
		return FFS_SUCCESS;
	}
	ret = FFS_ERROR;
error:
	if (tmp_bh)
		brelse(tmp_bh);
	free_upcase_table(sb);
	return ret;
}

static s32 __load_default_upcase_table(struct super_block *sb)
{
	int i, ret = FFS_ERROR;
	u32 j;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	bool	skip = false;
	u32	index = 0;
	u16	uni = 0;
	u16 **upcase_table;

	upcase_table = p_fs->vol_utbl = kmalloc(UTBL_COL_COUNT * sizeof(u16 *),
						GFP_KERNEL);
	if (!upcase_table)
		return FFS_MEMORYERR;
	memset(upcase_table, 0, UTBL_COL_COUNT * sizeof(u16 *));

	for (i = 0; index <= 0xFFFF && i < NUM_UPCASE * 2; i += 2) {
		uni = GET16(uni_upcase + i);
		if (skip) {
			pr_debug("skip from 0x%X ", index);
			index += uni;
			pr_debug("to 0x%X (amount of 0x%X)\n", index, uni);
			skip = false;
		} else if (uni == index) {
			index++;
		} else if (uni == 0xFFFF) {
			skip = true;
		} else { /* uni != index , uni != 0xFFFF */
			u16 col_index = get_col_index(index);

			if (!upcase_table[col_index]) {
				pr_debug("alloc = 0x%X\n", col_index);
				upcase_table[col_index] = kmalloc_array(UTBL_ROW_COUNT,
									sizeof(u16),
									GFP_KERNEL);
				if (!upcase_table[col_index]) {
					ret = FFS_MEMORYERR;
					goto error;
				}

				for (j = 0; j < UTBL_ROW_COUNT; j++)
					upcase_table[col_index][j] = (col_index << LOW_INDEX_BIT) | j;
			}

			upcase_table[col_index][get_row_index(index)] = uni;
			index++;
		}
	}

	if (index >= 0xFFFF)
		return FFS_SUCCESS;

error:
	/* FATAL error: default upcase table has error */
	free_upcase_table(sb);
	return ret;
}

s32 load_upcase_table(struct super_block *sb)
{
	int i;
	u32 tbl_clu, tbl_size;
	sector_t sector;
	u32 type, num_sectors;
	struct chain_t clu;
	struct case_dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	clu.dir = p_fs->root_dir;
	clu.flags = 0x01;

	if (p_fs->dev_ejected)
		return FFS_MEDIAERR;

	while (clu.dir != CLUSTER_32(~0)) {
		for (i = 0; i < p_fs->dentries_per_clu; i++) {
			ep = (struct case_dentry_t *)get_entry_in_dir(sb, &clu,
								      i, NULL);
			if (!ep)
				return FFS_MEDIAERR;

			type = p_fs->fs_func->get_entry_type((struct dentry_t *)ep);

			if (type == TYPE_UNUSED)
				break;
			if (type != TYPE_UPCASE)
				continue;

			tbl_clu  = GET32_A(ep->start_clu);
			tbl_size = (u32)GET64_A(ep->size);

			sector = START_SECTOR(tbl_clu);
			num_sectors = ((tbl_size - 1) >> p_bd->sector_size_bits) + 1;
			if (__load_upcase_table(sb, sector, num_sectors,
						GET32_A(ep->checksum)) != FFS_SUCCESS)
				break;
			return FFS_SUCCESS;
		}
		if (FAT_read(sb, clu.dir, &clu.dir) != 0)
			return FFS_MEDIAERR;
	}
	/* load default upcase table */
	return __load_default_upcase_table(sb);
}

void free_upcase_table(struct super_block *sb)
{
	u32 i;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	u16 **upcase_table;

	upcase_table = p_fs->vol_utbl;
	for (i = 0; i < UTBL_COL_COUNT; i++)
		kfree(upcase_table[i]);

	kfree(p_fs->vol_utbl);
	p_fs->vol_utbl = NULL;
}

/*
 *  Directory Entry Management Functions
 */

u32 fat_get_entry_type(struct dentry_t *p_entry)
{
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	if (*(ep->name) == 0x0)
		return TYPE_UNUSED;

	else if (*(ep->name) == 0xE5)
		return TYPE_DELETED;

	else if (ep->attr == ATTR_EXTEND)
		return TYPE_EXTEND;

	else if ((ep->attr & (ATTR_SUBDIR | ATTR_VOLUME)) == ATTR_VOLUME)
		return TYPE_VOLUME;

	else if ((ep->attr & (ATTR_SUBDIR | ATTR_VOLUME)) == ATTR_SUBDIR)
		return TYPE_DIR;

	return TYPE_FILE;
}

u32 exfat_get_entry_type(struct dentry_t *p_entry)
{
	struct file_dentry_t *ep = (struct file_dentry_t *)p_entry;

	if (ep->type == 0x0) {
		return TYPE_UNUSED;
	} else if (ep->type < 0x80) {
		return TYPE_DELETED;
	} else if (ep->type == 0x80) {
		return TYPE_INVALID;
	} else if (ep->type < 0xA0) {
		if (ep->type == 0x81) {
			return TYPE_BITMAP;
		} else if (ep->type == 0x82) {
			return TYPE_UPCASE;
		} else if (ep->type == 0x83) {
			return TYPE_VOLUME;
		} else if (ep->type == 0x85) {
			if (GET16_A(ep->attr) & ATTR_SUBDIR)
				return TYPE_DIR;
			else
				return TYPE_FILE;
		}
		return TYPE_CRITICAL_PRI;
	} else if (ep->type < 0xC0) {
		if (ep->type == 0xA0)
			return TYPE_GUID;
		else if (ep->type == 0xA1)
			return TYPE_PADDING;
		else if (ep->type == 0xA2)
			return TYPE_ACLTAB;
		return TYPE_BENIGN_PRI;
	} else if (ep->type < 0xE0) {
		if (ep->type == 0xC0)
			return TYPE_STREAM;
		else if (ep->type == 0xC1)
			return TYPE_EXTEND;
		else if (ep->type == 0xC2)
			return TYPE_ACL;
		return TYPE_CRITICAL_SEC;
	}

	return TYPE_BENIGN_SEC;
}

void fat_set_entry_type(struct dentry_t *p_entry, u32 type)
{
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	if (type == TYPE_UNUSED)
		*(ep->name) = 0x0;

	else if (type == TYPE_DELETED)
		*(ep->name) = 0xE5;

	else if (type == TYPE_EXTEND)
		ep->attr = ATTR_EXTEND;

	else if (type == TYPE_DIR)
		ep->attr = ATTR_SUBDIR;

	else if (type == TYPE_FILE)
		ep->attr = ATTR_ARCHIVE;

	else if (type == TYPE_SYMLINK)
		ep->attr = ATTR_ARCHIVE | ATTR_SYMLINK;
}

void exfat_set_entry_type(struct dentry_t *p_entry, u32 type)
{
	struct file_dentry_t *ep = (struct file_dentry_t *)p_entry;

	if (type == TYPE_UNUSED) {
		ep->type = 0x0;
	} else if (type == TYPE_DELETED) {
		ep->type &= ~0x80;
	} else if (type == TYPE_STREAM) {
		ep->type = 0xC0;
	} else if (type == TYPE_EXTEND) {
		ep->type = 0xC1;
	} else if (type == TYPE_BITMAP) {
		ep->type = 0x81;
	} else if (type == TYPE_UPCASE) {
		ep->type = 0x82;
	} else if (type == TYPE_VOLUME) {
		ep->type = 0x83;
	} else if (type == TYPE_DIR) {
		ep->type = 0x85;
		SET16_A(ep->attr, ATTR_SUBDIR);
	} else if (type == TYPE_FILE) {
		ep->type = 0x85;
		SET16_A(ep->attr, ATTR_ARCHIVE);
	} else if (type == TYPE_SYMLINK) {
		ep->type = 0x85;
		SET16_A(ep->attr, ATTR_ARCHIVE | ATTR_SYMLINK);
	}
}

u32 fat_get_entry_attr(struct dentry_t *p_entry)
{
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	return (u32)ep->attr;
}

u32 exfat_get_entry_attr(struct dentry_t *p_entry)
{
	struct file_dentry_t *ep = (struct file_dentry_t *)p_entry;

	return (u32)GET16_A(ep->attr);
}

void fat_set_entry_attr(struct dentry_t *p_entry, u32 attr)
{
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	ep->attr = (u8)attr;
}

void exfat_set_entry_attr(struct dentry_t *p_entry, u32 attr)
{
	struct file_dentry_t *ep = (struct file_dentry_t *)p_entry;

	SET16_A(ep->attr, (u16)attr);
}

u8 fat_get_entry_flag(struct dentry_t *p_entry)
{
	return 0x01;
}

u8 exfat_get_entry_flag(struct dentry_t *p_entry)
{
	struct strm_dentry_t *ep = (struct strm_dentry_t *)p_entry;

	return ep->flags;
}

void fat_set_entry_flag(struct dentry_t *p_entry, u8 flags)
{
}

void exfat_set_entry_flag(struct dentry_t *p_entry, u8 flags)
{
	struct strm_dentry_t *ep = (struct strm_dentry_t *)p_entry;

	ep->flags = flags;
}

u32 fat_get_entry_clu0(struct dentry_t *p_entry)
{
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	return ((u32)GET16_A(ep->start_clu_hi) << 16) |
		GET16_A(ep->start_clu_lo);
}

u32 exfat_get_entry_clu0(struct dentry_t *p_entry)
{
	struct strm_dentry_t *ep = (struct strm_dentry_t *)p_entry;

	return GET32_A(ep->start_clu);
}

void fat_set_entry_clu0(struct dentry_t *p_entry, u32 start_clu)
{
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	SET16_A(ep->start_clu_lo, CLUSTER_16(start_clu));
	SET16_A(ep->start_clu_hi, CLUSTER_16(start_clu >> 16));
}

void exfat_set_entry_clu0(struct dentry_t *p_entry, u32 start_clu)
{
	struct strm_dentry_t *ep = (struct strm_dentry_t *)p_entry;

	SET32_A(ep->start_clu, start_clu);
}

u64 fat_get_entry_size(struct dentry_t *p_entry)
{
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	return (u64)GET32_A(ep->size);
}

u64 exfat_get_entry_size(struct dentry_t *p_entry)
{
	struct strm_dentry_t *ep = (struct strm_dentry_t *)p_entry;

	return GET64_A(ep->valid_size);
}

void fat_set_entry_size(struct dentry_t *p_entry, u64 size)
{
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	SET32_A(ep->size, (u32)size);
}

void exfat_set_entry_size(struct dentry_t *p_entry, u64 size)
{
	struct strm_dentry_t *ep = (struct strm_dentry_t *)p_entry;

	SET64_A(ep->valid_size, size);
	SET64_A(ep->size, size);
}

void fat_get_entry_time(struct dentry_t *p_entry, struct timestamp_t *tp,
			u8 mode)
{
	u16 t = 0x00, d = 0x21;
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	switch (mode) {
	case TM_CREATE:
		t = GET16_A(ep->create_time);
		d = GET16_A(ep->create_date);
		break;
	case TM_MODIFY:
		t = GET16_A(ep->modify_time);
		d = GET16_A(ep->modify_date);
		break;
	}

	tp->sec  = (t & 0x001F) << 1;
	tp->min  = (t >> 5) & 0x003F;
	tp->hour = (t >> 11);
	tp->day  = (d & 0x001F);
	tp->mon  = (d >> 5) & 0x000F;
	tp->year = (d >> 9);
}

void exfat_get_entry_time(struct dentry_t *p_entry, struct timestamp_t *tp,
			  u8 mode)
{
	u16 t = 0x00, d = 0x21;
	struct file_dentry_t *ep = (struct file_dentry_t *)p_entry;

	switch (mode) {
	case TM_CREATE:
		t = GET16_A(ep->create_time);
		d = GET16_A(ep->create_date);
		break;
	case TM_MODIFY:
		t = GET16_A(ep->modify_time);
		d = GET16_A(ep->modify_date);
		break;
	case TM_ACCESS:
		t = GET16_A(ep->access_time);
		d = GET16_A(ep->access_date);
		break;
	}

	tp->sec  = (t & 0x001F) << 1;
	tp->min  = (t >> 5) & 0x003F;
	tp->hour = (t >> 11);
	tp->day  = (d & 0x001F);
	tp->mon  = (d >> 5) & 0x000F;
	tp->year = (d >> 9);
}

void fat_set_entry_time(struct dentry_t *p_entry, struct timestamp_t *tp,
			u8 mode)
{
	u16 t, d;
	struct dos_dentry_t *ep = (struct dos_dentry_t *)p_entry;

	t = (tp->hour << 11) | (tp->min << 5) | (tp->sec >> 1);
	d = (tp->year <<  9) | (tp->mon << 5) |  tp->day;

	switch (mode) {
	case TM_CREATE:
		SET16_A(ep->create_time, t);
		SET16_A(ep->create_date, d);
		break;
	case TM_MODIFY:
		SET16_A(ep->modify_time, t);
		SET16_A(ep->modify_date, d);
		break;
	}
}

void exfat_set_entry_time(struct dentry_t *p_entry, struct timestamp_t *tp,
			  u8 mode)
{
	u16 t, d;
	struct file_dentry_t *ep = (struct file_dentry_t *)p_entry;

	t = (tp->hour << 11) | (tp->min << 5) | (tp->sec >> 1);
	d = (tp->year <<  9) | (tp->mon << 5) |  tp->day;

	switch (mode) {
	case TM_CREATE:
		SET16_A(ep->create_time, t);
		SET16_A(ep->create_date, d);
		break;
	case TM_MODIFY:
		SET16_A(ep->modify_time, t);
		SET16_A(ep->modify_date, d);
		break;
	case TM_ACCESS:
		SET16_A(ep->access_time, t);
		SET16_A(ep->access_date, d);
		break;
	}
}

s32 fat_init_dir_entry(struct super_block *sb, struct chain_t *p_dir, s32 entry,
		       u32 type, u32 start_clu, u64 size)
{
	sector_t sector;
	struct dos_dentry_t *dos_ep;

	dos_ep = (struct dos_dentry_t *)get_entry_in_dir(sb, p_dir, entry,
							 &sector);
	if (!dos_ep)
		return FFS_MEDIAERR;

	init_dos_entry(dos_ep, type, start_clu);
	buf_modify(sb, sector);

	return FFS_SUCCESS;
}

s32 exfat_init_dir_entry(struct super_block *sb, struct chain_t *p_dir,
			 s32 entry, u32 type, u32 start_clu, u64 size)
{
	sector_t sector;
	u8 flags;
	struct file_dentry_t *file_ep;
	struct strm_dentry_t *strm_ep;

	flags = (type == TYPE_FILE) ? 0x01 : 0x03;

	/* we cannot use get_entry_set_in_dir here because file ep is not initialized yet */
	file_ep = (struct file_dentry_t *)get_entry_in_dir(sb, p_dir, entry,
							   &sector);
	if (!file_ep)
		return FFS_MEDIAERR;

	strm_ep = (struct strm_dentry_t *)get_entry_in_dir(sb, p_dir, entry + 1,
							   &sector);
	if (!strm_ep)
		return FFS_MEDIAERR;

	init_file_entry(file_ep, type);
	buf_modify(sb, sector);

	init_strm_entry(strm_ep, flags, start_clu, size);
	buf_modify(sb, sector);

	return FFS_SUCCESS;
}

static s32 fat_init_ext_entry(struct super_block *sb, struct chain_t *p_dir,
			      s32 entry, s32 num_entries,
			      struct uni_name_t *p_uniname,
			      struct dos_name_t *p_dosname)
{
	int i;
	sector_t sector;
	u8 chksum;
	u16 *uniname = p_uniname->name;
	struct dos_dentry_t *dos_ep;
	struct ext_dentry_t *ext_ep;

	dos_ep = (struct dos_dentry_t *)get_entry_in_dir(sb, p_dir, entry,
							 &sector);
	if (!dos_ep)
		return FFS_MEDIAERR;

	dos_ep->lcase = p_dosname->name_case;
	memcpy(dos_ep->name, p_dosname->name, DOS_NAME_LENGTH);
	buf_modify(sb, sector);

	if ((--num_entries) > 0) {
		chksum = calc_checksum_1byte((void *)dos_ep->name,
					     DOS_NAME_LENGTH, 0);

		for (i = 1; i < num_entries; i++) {
			ext_ep = (struct ext_dentry_t *)get_entry_in_dir(sb,
									 p_dir,
									 entry - i,
									 &sector);
			if (!ext_ep)
				return FFS_MEDIAERR;

			init_ext_entry(ext_ep, i, chksum, uniname);
			buf_modify(sb, sector);
			uniname += 13;
		}

		ext_ep = (struct ext_dentry_t *)get_entry_in_dir(sb, p_dir,
								 entry - i,
								 &sector);
		if (!ext_ep)
			return FFS_MEDIAERR;

		init_ext_entry(ext_ep, i + 0x40, chksum, uniname);
		buf_modify(sb, sector);
	}

	return FFS_SUCCESS;
}

static s32 exfat_init_ext_entry(struct super_block *sb, struct chain_t *p_dir,
				s32 entry, s32 num_entries,
				struct uni_name_t *p_uniname,
				struct dos_name_t *p_dosname)
{
	int i;
	sector_t sector;
	u16 *uniname = p_uniname->name;
	struct file_dentry_t *file_ep;
	struct strm_dentry_t *strm_ep;
	struct name_dentry_t *name_ep;

	file_ep = (struct file_dentry_t *)get_entry_in_dir(sb, p_dir, entry,
							   &sector);
	if (!file_ep)
		return FFS_MEDIAERR;

	file_ep->num_ext = (u8)(num_entries - 1);
	buf_modify(sb, sector);

	strm_ep = (struct strm_dentry_t *)get_entry_in_dir(sb, p_dir, entry + 1,
							   &sector);
	if (!strm_ep)
		return FFS_MEDIAERR;

	strm_ep->name_len = p_uniname->name_len;
	SET16_A(strm_ep->name_hash, p_uniname->name_hash);
	buf_modify(sb, sector);

	for (i = 2; i < num_entries; i++) {
		name_ep = (struct name_dentry_t *)get_entry_in_dir(sb, p_dir,
								   entry + i,
								   &sector);
		if (!name_ep)
			return FFS_MEDIAERR;

		init_name_entry(name_ep, uniname);
		buf_modify(sb, sector);
		uniname += 15;
	}

	update_dir_checksum(sb, p_dir, entry);

	return FFS_SUCCESS;
}

void init_dos_entry(struct dos_dentry_t *ep, u32 type, u32 start_clu)
{
	struct timestamp_t tm, *tp;

	fat_set_entry_type((struct dentry_t *)ep, type);
	SET16_A(ep->start_clu_lo, CLUSTER_16(start_clu));
	SET16_A(ep->start_clu_hi, CLUSTER_16(start_clu >> 16));
	SET32_A(ep->size, 0);

	tp = tm_current(&tm);
	fat_set_entry_time((struct dentry_t *)ep, tp, TM_CREATE);
	fat_set_entry_time((struct dentry_t *)ep, tp, TM_MODIFY);
	SET16_A(ep->access_date, 0);
	ep->create_time_ms = 0;
}

void init_ext_entry(struct ext_dentry_t *ep, s32 order, u8 chksum, u16 *uniname)
{
	int i;
	bool end = false;

	fat_set_entry_type((struct dentry_t *)ep, TYPE_EXTEND);
	ep->order = (u8)order;
	ep->sysid = 0;
	ep->checksum = chksum;
	SET16_A(ep->start_clu, 0);

	for (i = 0; i < 10; i += 2) {
		if (!end) {
			SET16(ep->unicode_0_4 + i, *uniname);
			if (*uniname == 0x0)
				end = true;
			else
				uniname++;
		} else {
			SET16(ep->unicode_0_4 + i, 0xFFFF);
		}
	}

	for (i = 0; i < 12; i += 2) {
		if (!end) {
			SET16_A(ep->unicode_5_10 + i, *uniname);
			if (*uniname == 0x0)
				end = true;
			else
				uniname++;
		} else {
			SET16_A(ep->unicode_5_10 + i, 0xFFFF);
		}
	}

	for (i = 0; i < 4; i += 2) {
		if (!end) {
			SET16_A(ep->unicode_11_12 + i, *uniname);
			if (*uniname == 0x0)
				end = true;
			else
				uniname++;
		} else {
			SET16_A(ep->unicode_11_12 + i, 0xFFFF);
		}
	}
}

void init_file_entry(struct file_dentry_t *ep, u32 type)
{
	struct timestamp_t tm, *tp;

	exfat_set_entry_type((struct dentry_t *)ep, type);

	tp = tm_current(&tm);
	exfat_set_entry_time((struct dentry_t *)ep, tp, TM_CREATE);
	exfat_set_entry_time((struct dentry_t *)ep, tp, TM_MODIFY);
	exfat_set_entry_time((struct dentry_t *)ep, tp, TM_ACCESS);
	ep->create_time_ms = 0;
	ep->modify_time_ms = 0;
	ep->access_time_ms = 0;
}

void init_strm_entry(struct strm_dentry_t *ep, u8 flags, u32 start_clu, u64 size)
{
	exfat_set_entry_type((struct dentry_t *)ep, TYPE_STREAM);
	ep->flags = flags;
	SET32_A(ep->start_clu, start_clu);
	SET64_A(ep->valid_size, size);
	SET64_A(ep->size, size);
}

void init_name_entry(struct name_dentry_t *ep, u16 *uniname)
{
	int i;

	exfat_set_entry_type((struct dentry_t *)ep, TYPE_EXTEND);
	ep->flags = 0x0;

	for (i = 0; i < 30; i++, i++) {
		SET16_A(ep->unicode_0_14 + i, *uniname);
		if (*uniname == 0x0)
			break;
		uniname++;
	}
}

void fat_delete_dir_entry(struct super_block *sb, struct chain_t *p_dir,
		s32 entry, s32 order, s32 num_entries)
{
	int i;
	sector_t sector;
	struct dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	for (i = num_entries - 1; i >= order; i--) {
		ep = get_entry_in_dir(sb, p_dir, entry - i, &sector);
		if (!ep)
			return;

		p_fs->fs_func->set_entry_type(ep, TYPE_DELETED);
		buf_modify(sb, sector);
	}
}

void exfat_delete_dir_entry(struct super_block *sb, struct chain_t *p_dir,
		s32 entry, s32 order, s32 num_entries)
{
	int i;
	sector_t sector;
	struct dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	for (i = order; i < num_entries; i++) {
		ep = get_entry_in_dir(sb, p_dir, entry + i, &sector);
		if (!ep)
			return;

		p_fs->fs_func->set_entry_type(ep, TYPE_DELETED);
		buf_modify(sb, sector);
	}
}

void update_dir_checksum(struct super_block *sb, struct chain_t *p_dir,
			 s32 entry)
{
	int i, num_entries;
	sector_t sector;
	u16 chksum;
	struct file_dentry_t *file_ep;
	struct dentry_t *ep;

	file_ep = (struct file_dentry_t *)get_entry_in_dir(sb, p_dir, entry,
							   &sector);
	if (!file_ep)
		return;

	buf_lock(sb, sector);

	num_entries = (s32)file_ep->num_ext + 1;
	chksum = calc_checksum_2byte((void *)file_ep, DENTRY_SIZE, 0,
				     CS_DIR_ENTRY);

	for (i = 1; i < num_entries; i++) {
		ep = get_entry_in_dir(sb, p_dir, entry + i, NULL);
		if (!ep) {
			buf_unlock(sb, sector);
			return;
		}

		chksum = calc_checksum_2byte((void *)ep, DENTRY_SIZE, chksum,
					     CS_DEFAULT);
	}

	SET16_A(file_ep->checksum, chksum);
	buf_modify(sb, sector);
	buf_unlock(sb, sector);
}

void update_dir_checksum_with_entry_set(struct super_block *sb,
					struct entry_set_cache_t *es)
{
	struct dentry_t *ep;
	u16 chksum = 0;
	s32 chksum_type = CS_DIR_ENTRY, i;

	ep = (struct dentry_t *)&(es->__buf);
	for (i = 0; i < es->num_entries; i++) {
		pr_debug("%s ep %p\n", __func__, ep);
		chksum = calc_checksum_2byte((void *)ep, DENTRY_SIZE, chksum,
					     chksum_type);
		ep++;
		chksum_type = CS_DEFAULT;
	}

	ep = (struct dentry_t *)&(es->__buf);
	SET16_A(((struct file_dentry_t *)ep)->checksum, chksum);
	write_whole_entry_set(sb, es);
}

static s32 _walk_fat_chain(struct super_block *sb, struct chain_t *p_dir,
			   s32 byte_offset, u32 *clu)
{
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	s32 clu_offset;
	u32 cur_clu;

	clu_offset = byte_offset >> p_fs->cluster_size_bits;
	cur_clu = p_dir->dir;

	if (p_dir->flags == 0x03) {
		cur_clu += clu_offset;
	} else {
		while (clu_offset > 0) {
			if (FAT_read(sb, cur_clu, &cur_clu) == -1)
				return FFS_MEDIAERR;
			clu_offset--;
		}
	}

	if (clu)
		*clu = cur_clu;
	return FFS_SUCCESS;
}

s32 find_location(struct super_block *sb, struct chain_t *p_dir, s32 entry,
		  sector_t *sector, s32 *offset)
{
	s32 off, ret;
	u32 clu = 0;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	off = entry << DENTRY_SIZE_BITS;

	if (p_dir->dir == CLUSTER_32(0)) { /* FAT16 root_dir */
		*offset = off & p_bd->sector_size_mask;
		*sector = off >> p_bd->sector_size_bits;
		*sector += p_fs->root_start_sector;
	} else {
		ret = _walk_fat_chain(sb, p_dir, off, &clu);
		if (ret != FFS_SUCCESS)
			return ret;

		/* byte offset in cluster */
		off &= p_fs->cluster_size - 1;

		/* byte offset in sector    */
		*offset = off & p_bd->sector_size_mask;

		/* sector offset in cluster */
		*sector = off >> p_bd->sector_size_bits;
		*sector += START_SECTOR(clu);
	}
	return FFS_SUCCESS;
}

struct dentry_t *get_entry_with_sector(struct super_block *sb, sector_t sector,
				       s32 offset)
{
	u8 *buf;

	buf = buf_getblk(sb, sector);

	if (!buf)
		return NULL;

	return (struct dentry_t *)(buf + offset);
}

struct dentry_t *get_entry_in_dir(struct super_block *sb, struct chain_t *p_dir,
				  s32 entry, sector_t *sector)
{
	s32 off;
	sector_t sec;
	u8 *buf;

	if (find_location(sb, p_dir, entry, &sec, &off) != FFS_SUCCESS)
		return NULL;

	buf = buf_getblk(sb, sec);

	if (!buf)
		return NULL;

	if (sector)
		*sector = sec;
	return (struct dentry_t *)(buf + off);
}

/* returns a set of dentries for a file or dir.
 * Note that this is a copy (dump) of dentries so that user should call write_entry_set()
 * to apply changes made in this entry set to the real device.
 * in:
 *   sb+p_dir+entry: indicates a file/dir
 *   type:  specifies how many dentries should be included.
 * out:
 *   file_ep: will point the first dentry(= file dentry) on success
 * return:
 *   pointer of entry set on success,
 *   NULL on failure.
 */

#define ES_MODE_STARTED				0
#define ES_MODE_GET_FILE_ENTRY			1
#define ES_MODE_GET_STRM_ENTRY			2
#define ES_MODE_GET_NAME_ENTRY			3
#define ES_MODE_GET_CRITICAL_SEC_ENTRY		4
struct entry_set_cache_t *get_entry_set_in_dir(struct super_block *sb,
					       struct chain_t *p_dir, s32 entry,
					       u32 type,
					       struct dentry_t **file_ep)
{
	s32 off, ret, byte_offset;
	u32 clu = 0;
	sector_t sec;
	u32 entry_type;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);
	struct entry_set_cache_t *es = NULL;
	struct dentry_t *ep, *pos;
	u8 *buf;
	u8 num_entries;
	s32 mode = ES_MODE_STARTED;
	size_t bufsize;

	pr_debug("%s entered p_dir dir %u flags %x size %d\n",
		__func__, p_dir->dir, p_dir->flags, p_dir->size);

	byte_offset = entry << DENTRY_SIZE_BITS;
	ret = _walk_fat_chain(sb, p_dir, byte_offset, &clu);
	if (ret != FFS_SUCCESS)
		return NULL;

	/* byte offset in cluster */
	byte_offset &= p_fs->cluster_size - 1;

	/* byte offset in sector    */
	off = byte_offset & p_bd->sector_size_mask;

	/* sector offset in cluster */
	sec = byte_offset >> p_bd->sector_size_bits;
	sec += START_SECTOR(clu);

	buf = buf_getblk(sb, sec);
	if (!buf)
		goto err_out;

	ep = (struct dentry_t *)(buf + off);
	entry_type = p_fs->fs_func->get_entry_type(ep);

	if ((entry_type != TYPE_FILE)
		&& (entry_type != TYPE_DIR))
		goto err_out;

	if (type == ES_ALL_ENTRIES)
		num_entries = ((struct file_dentry_t *)ep)->num_ext + 1;
	else
		num_entries = type;

	bufsize = offsetof(struct entry_set_cache_t, __buf) + (num_entries) *
		  sizeof(struct dentry_t);
	pr_debug("%s: trying to kmalloc %zx bytes for %d entries\n", __func__,
		 bufsize, num_entries);
	es = kmalloc(bufsize, GFP_KERNEL);
	if (!es)
		goto err_out;

	es->num_entries = num_entries;
	es->sector = sec;
	es->offset = off;
	es->alloc_flag = p_dir->flags;

	pos = (struct dentry_t *)&es->__buf;

	while (num_entries) {
		/*
		 * instead of copying whole sector, we will check every entry.
		 * this will provide minimum stablity and consistency.
		 */
		entry_type = p_fs->fs_func->get_entry_type(ep);

		if ((entry_type == TYPE_UNUSED) || (entry_type == TYPE_DELETED))
			goto err_out;

		switch (mode) {
		case ES_MODE_STARTED:
			if ((entry_type == TYPE_FILE) || (entry_type == TYPE_DIR))
				mode = ES_MODE_GET_FILE_ENTRY;
			else
				goto err_out;
			break;
		case ES_MODE_GET_FILE_ENTRY:
			if (entry_type == TYPE_STREAM)
				mode = ES_MODE_GET_STRM_ENTRY;
			else
				goto err_out;
			break;
		case ES_MODE_GET_STRM_ENTRY:
			if (entry_type == TYPE_EXTEND)
				mode = ES_MODE_GET_NAME_ENTRY;
			else
				goto err_out;
			break;
		case ES_MODE_GET_NAME_ENTRY:
			if (entry_type == TYPE_EXTEND)
				break;
			else if (entry_type == TYPE_STREAM)
				goto err_out;
			else if (entry_type & TYPE_CRITICAL_SEC)
				mode = ES_MODE_GET_CRITICAL_SEC_ENTRY;
			else
				goto err_out;
			break;
		case ES_MODE_GET_CRITICAL_SEC_ENTRY:
			if ((entry_type == TYPE_EXTEND) ||
			    (entry_type == TYPE_STREAM))
				goto err_out;
			else if ((entry_type & TYPE_CRITICAL_SEC) !=
				 TYPE_CRITICAL_SEC)
				goto err_out;
			break;
		}

		memcpy(pos, ep, sizeof(struct dentry_t));

		if (--num_entries == 0)
			break;

		if (((off + DENTRY_SIZE) & p_bd->sector_size_mask) <
		    (off &  p_bd->sector_size_mask)) {
			/* get the next sector */
			if (IS_LAST_SECTOR_IN_CLUSTER(sec)) {
				if (es->alloc_flag == 0x03) {
					clu++;
				} else {
					if (FAT_read(sb, clu, &clu) == -1)
						goto err_out;
				}
				sec = START_SECTOR(clu);
			} else {
				sec++;
			}
			buf = buf_getblk(sb, sec);
			if (!buf)
				goto err_out;
			off = 0;
			ep = (struct dentry_t *)(buf);
		} else {
			ep++;
			off += DENTRY_SIZE;
		}
		pos++;
	}

	if (file_ep)
		*file_ep = (struct dentry_t *)&(es->__buf);

	pr_debug("%s exiting es %p sec %llu offset %d flags %d, num_entries %u buf ptr %p\n",
		   __func__, es, (unsigned long long)es->sector, es->offset,
		   es->alloc_flag, es->num_entries, &es->__buf);
	return es;
err_out:
	pr_debug("%s exited NULL (es %p)\n", __func__, es);
	kfree(es);
	return NULL;
}

void release_entry_set(struct entry_set_cache_t *es)
{
	pr_debug("%s es=%p\n", __func__, es);
	kfree(es);
}

static s32 __write_partial_entries_in_entry_set(struct super_block *sb,
						struct entry_set_cache_t *es,
						sector_t sec, s32 off, u32 count)
{
	s32 num_entries, buf_off = (off - es->offset);
	u32 remaining_byte_in_sector, copy_entries;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);
	u32 clu;
	u8 *buf, *esbuf = (u8 *)&(es->__buf);

	pr_debug("%s entered es %p sec %llu off %d count %d\n",
		__func__, es, (unsigned long long)sec, off, count);
	num_entries = count;

	while (num_entries) {
		/* white per sector base */
		remaining_byte_in_sector = (1 << p_bd->sector_size_bits) - off;
		copy_entries = min_t(s32,
				     remaining_byte_in_sector >> DENTRY_SIZE_BITS,
				     num_entries);
		buf = buf_getblk(sb, sec);
		if (!buf)
			goto err_out;
		pr_debug("es->buf %p buf_off %u\n", esbuf, buf_off);
		pr_debug("copying %d entries from %p to sector %llu\n",
			copy_entries, (esbuf + buf_off),
			(unsigned long long)sec);
		memcpy(buf + off, esbuf + buf_off,
		       copy_entries << DENTRY_SIZE_BITS);
		buf_modify(sb, sec);
		num_entries -= copy_entries;

		if (num_entries) {
			/* get next sector */
			if (IS_LAST_SECTOR_IN_CLUSTER(sec)) {
				clu = GET_CLUSTER_FROM_SECTOR(sec);
				if (es->alloc_flag == 0x03) {
					clu++;
				} else {
					if (FAT_read(sb, clu, &clu) == -1)
						goto err_out;
				}
				sec = START_SECTOR(clu);
			} else {
				sec++;
			}
			off = 0;
			buf_off += copy_entries << DENTRY_SIZE_BITS;
		}
	}

	pr_debug("%s exited successfully\n", __func__);
	return FFS_SUCCESS;
err_out:
	pr_debug("%s failed\n", __func__);
	return FFS_ERROR;
}

/* write back all entries in entry set */
s32 write_whole_entry_set(struct super_block *sb, struct entry_set_cache_t *es)
{
	return __write_partial_entries_in_entry_set(sb, es, es->sector,
						    es->offset,
						    es->num_entries);
}

/* write back some entries in entry set */
s32 write_partial_entries_in_entry_set(struct super_block *sb,
	struct entry_set_cache_t *es, struct dentry_t *ep, u32 count)
{
	s32 ret, byte_offset, off;
	u32 clu = 0;
	sector_t sec;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);
	struct chain_t dir;

	/* vaidity check */
	if (ep + count  > ((struct dentry_t *)&(es->__buf)) + es->num_entries)
		return FFS_ERROR;

	dir.dir = GET_CLUSTER_FROM_SECTOR(es->sector);
	dir.flags = es->alloc_flag;
	dir.size = 0xffffffff;		/* XXX */

	byte_offset = (es->sector - START_SECTOR(dir.dir)) <<
			p_bd->sector_size_bits;
	byte_offset += ((void **)ep - &(es->__buf)) + es->offset;

	ret = _walk_fat_chain(sb, &dir, byte_offset, &clu);
	if (ret != FFS_SUCCESS)
		return ret;

	/* byte offset in cluster */
	byte_offset &= p_fs->cluster_size - 1;

	/* byte offset in sector    */
	off = byte_offset & p_bd->sector_size_mask;

	/* sector offset in cluster */
	sec = byte_offset >> p_bd->sector_size_bits;
	sec += START_SECTOR(clu);
	return __write_partial_entries_in_entry_set(sb, es, sec, off, count);
}

/* search EMPTY CONTINUOUS "num_entries" entries */
s32 search_deleted_or_unused_entry(struct super_block *sb,
				   struct chain_t *p_dir, s32 num_entries)
{
	int i, dentry, num_empty = 0;
	s32 dentries_per_clu;
	u32 type;
	struct chain_t clu;
	struct dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
		dentries_per_clu = p_fs->dentries_in_root;
	else
		dentries_per_clu = p_fs->dentries_per_clu;

	if (p_fs->hint_uentry.dir == p_dir->dir) {
		if (p_fs->hint_uentry.entry == -1)
			return -1;

		clu.dir = p_fs->hint_uentry.clu.dir;
		clu.size = p_fs->hint_uentry.clu.size;
		clu.flags = p_fs->hint_uentry.clu.flags;

		dentry = p_fs->hint_uentry.entry;
	} else {
		p_fs->hint_uentry.entry = -1;

		clu.dir = p_dir->dir;
		clu.size = p_dir->size;
		clu.flags = p_dir->flags;

		dentry = 0;
	}

	while (clu.dir != CLUSTER_32(~0)) {
		if (p_fs->dev_ejected)
			break;

		if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
			i = dentry % dentries_per_clu;
		else
			i = dentry & (dentries_per_clu - 1);

		for (; i < dentries_per_clu; i++, dentry++) {
			ep = get_entry_in_dir(sb, &clu, i, NULL);
			if (!ep)
				return -1;

			type = p_fs->fs_func->get_entry_type(ep);

			if (type == TYPE_UNUSED) {
				num_empty++;
				if (p_fs->hint_uentry.entry == -1) {
					p_fs->hint_uentry.dir = p_dir->dir;
					p_fs->hint_uentry.entry = dentry;

					p_fs->hint_uentry.clu.dir = clu.dir;
					p_fs->hint_uentry.clu.size = clu.size;
					p_fs->hint_uentry.clu.flags = clu.flags;
				}
			} else if (type == TYPE_DELETED) {
				num_empty++;
			} else {
				num_empty = 0;
			}

			if (num_empty >= num_entries) {
				p_fs->hint_uentry.dir = CLUSTER_32(~0);
				p_fs->hint_uentry.entry = -1;

				if (p_fs->vol_type == EXFAT)
					return dentry - (num_entries - 1);
				else
					return dentry;
			}
		}

		if (p_dir->dir == CLUSTER_32(0))
			break; /* FAT16 root_dir */

		if (clu.flags == 0x03) {
			if ((--clu.size) > 0)
				clu.dir++;
			else
				clu.dir = CLUSTER_32(~0);
		} else {
			if (FAT_read(sb, clu.dir, &clu.dir) != 0)
				return -1;
		}
	}

	return -1;
}

s32 find_empty_entry(struct inode *inode, struct chain_t *p_dir, s32 num_entries)
{
	s32 ret, dentry;
	u32 last_clu;
	sector_t sector;
	u64 size = 0;
	struct chain_t clu;
	struct dentry_t *ep = NULL;
	struct super_block *sb = inode->i_sb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct file_id_t *fid = &(EXFAT_I(inode)->fid);

	if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
		return search_deleted_or_unused_entry(sb, p_dir, num_entries);

	while ((dentry = search_deleted_or_unused_entry(sb, p_dir, num_entries)) < 0) {
		if (p_fs->dev_ejected)
			break;

		if (p_fs->vol_type == EXFAT) {
			if (p_dir->dir != p_fs->root_dir)
				size = i_size_read(inode);
		}

		last_clu = find_last_cluster(sb, p_dir);
		clu.dir = last_clu + 1;
		clu.size = 0;
		clu.flags = p_dir->flags;

		/* (1) allocate a cluster */
		ret = p_fs->fs_func->alloc_cluster(sb, 1, &clu);
		if (ret < 1)
			return -1;

		if (clear_cluster(sb, clu.dir) != FFS_SUCCESS)
			return -1;

		/* (2) append to the FAT chain */
		if (clu.flags != p_dir->flags) {
			exfat_chain_cont_cluster(sb, p_dir->dir, p_dir->size);
			p_dir->flags = 0x01;
			p_fs->hint_uentry.clu.flags = 0x01;
		}
		if (clu.flags == 0x01)
			if (FAT_write(sb, last_clu, clu.dir) < 0)
				return -1;

		if (p_fs->hint_uentry.entry == -1) {
			p_fs->hint_uentry.dir = p_dir->dir;
			p_fs->hint_uentry.entry = p_dir->size << (p_fs->cluster_size_bits - DENTRY_SIZE_BITS);

			p_fs->hint_uentry.clu.dir = clu.dir;
			p_fs->hint_uentry.clu.size = 0;
			p_fs->hint_uentry.clu.flags = clu.flags;
		}
		p_fs->hint_uentry.clu.size++;
		p_dir->size++;

		/* (3) update the directory entry */
		if (p_fs->vol_type == EXFAT) {
			if (p_dir->dir != p_fs->root_dir) {
				size += p_fs->cluster_size;

				ep = get_entry_in_dir(sb, &fid->dir,
						      fid->entry + 1, &sector);
				if (!ep)
					return -1;
				p_fs->fs_func->set_entry_size(ep, size);
				p_fs->fs_func->set_entry_flag(ep, p_dir->flags);
				buf_modify(sb, sector);

				update_dir_checksum(sb, &(fid->dir),
						    fid->entry);
			}
		}

		i_size_write(inode, i_size_read(inode) + p_fs->cluster_size);
		EXFAT_I(inode)->mmu_private += p_fs->cluster_size;
		EXFAT_I(inode)->fid.size += p_fs->cluster_size;
		EXFAT_I(inode)->fid.flags = p_dir->flags;
		inode->i_blocks += 1 << (p_fs->cluster_size_bits - 9);
	}

	return dentry;
}

/* return values of fat_find_dir_entry()
 * >= 0 : return dir entiry position with the name in dir
 * -1 : (root dir, ".") it is the root dir itself
 * -2 : entry with the name does not exist
 */
s32 fat_find_dir_entry(struct super_block *sb, struct chain_t *p_dir,
		       struct uni_name_t *p_uniname, s32 num_entries,
		       struct dos_name_t *p_dosname, u32 type)
{
	int i, dentry = 0, len;
	s32 order = 0;
	bool is_feasible_entry = true, has_ext_entry = false;
	s32 dentries_per_clu;
	u32 entry_type;
	u16 entry_uniname[14], *uniname = NULL, unichar;
	struct chain_t clu;
	struct dentry_t *ep;
	struct dos_dentry_t *dos_ep;
	struct ext_dentry_t *ext_ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (p_dir->dir == p_fs->root_dir) {
		if ((!nls_uniname_cmp(sb, p_uniname->name,
				      (u16 *)UNI_CUR_DIR_NAME)) ||
			(!nls_uniname_cmp(sb, p_uniname->name,
					  (u16 *)UNI_PAR_DIR_NAME)))
			return -1; // special case, root directory itself
	}

	if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
		dentries_per_clu = p_fs->dentries_in_root;
	else
		dentries_per_clu = p_fs->dentries_per_clu;

	clu.dir = p_dir->dir;
	clu.flags = p_dir->flags;

	while (clu.dir != CLUSTER_32(~0)) {
		if (p_fs->dev_ejected)
			break;

		for (i = 0; i < dentries_per_clu; i++, dentry++) {
			ep = get_entry_in_dir(sb, &clu, i, NULL);
			if (!ep)
				return -2;

			entry_type = p_fs->fs_func->get_entry_type(ep);

			if ((entry_type == TYPE_FILE) || (entry_type == TYPE_DIR)) {
				if ((type == TYPE_ALL) || (type == entry_type)) {
					if (is_feasible_entry && has_ext_entry)
						return dentry;

					dos_ep = (struct dos_dentry_t *)ep;
					if (!nls_dosname_cmp(sb, p_dosname->name, dos_ep->name))
						return dentry;
				}
				is_feasible_entry = true;
				has_ext_entry = false;
			} else if (entry_type == TYPE_EXTEND) {
				if (is_feasible_entry) {
					ext_ep = (struct ext_dentry_t *)ep;
					if (ext_ep->order > 0x40) {
						order = (s32)(ext_ep->order - 0x40);
						uniname = p_uniname->name + 13 * (order - 1);
					} else {
						order = (s32)ext_ep->order;
						uniname -= 13;
					}

					len = extract_uni_name_from_ext_entry(ext_ep, entry_uniname, order);

					unichar = *(uniname + len);
					*(uniname + len) = 0x0;

					if (nls_uniname_cmp(sb, uniname, entry_uniname))
						is_feasible_entry = false;

					*(uniname + len) = unichar;
				}
				has_ext_entry = true;
			} else if (entry_type == TYPE_UNUSED) {
				return -2;
			}
			is_feasible_entry = true;
			has_ext_entry = false;
		}

		if (p_dir->dir == CLUSTER_32(0))
			break; /* FAT16 root_dir */

		if (FAT_read(sb, clu.dir, &clu.dir) != 0)
			return -2;
	}

	return -2;
}

/* return values of exfat_find_dir_entry()
 * >= 0 : return dir entiry position with the name in dir
 * -1 : (root dir, ".") it is the root dir itself
 * -2 : entry with the name does not exist
 */
s32 exfat_find_dir_entry(struct super_block *sb, struct chain_t *p_dir,
			 struct uni_name_t *p_uniname, s32 num_entries,
			 struct dos_name_t *p_dosname, u32 type)
{
	int i = 0, dentry = 0, num_ext_entries = 0, len, step;
	s32 order = 0;
	bool is_feasible_entry = false;
	s32 dentries_per_clu, num_empty = 0;
	u32 entry_type;
	u16 entry_uniname[16], *uniname = NULL, unichar;
	struct chain_t clu;
	struct dentry_t *ep;
	struct file_dentry_t *file_ep;
	struct strm_dentry_t *strm_ep;
	struct name_dentry_t *name_ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (p_dir->dir == p_fs->root_dir) {
		if ((!nls_uniname_cmp(sb, p_uniname->name,
				      (u16 *)UNI_CUR_DIR_NAME)) ||
			(!nls_uniname_cmp(sb, p_uniname->name,
					  (u16 *)UNI_PAR_DIR_NAME)))
			return -1; // special case, root directory itself
	}

	if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
		dentries_per_clu = p_fs->dentries_in_root;
	else
		dentries_per_clu = p_fs->dentries_per_clu;

	clu.dir = p_dir->dir;
	clu.size = p_dir->size;
	clu.flags = p_dir->flags;

	p_fs->hint_uentry.dir = p_dir->dir;
	p_fs->hint_uentry.entry = -1;

	while (clu.dir != CLUSTER_32(~0)) {
		if (p_fs->dev_ejected)
			break;

		while (i < dentries_per_clu) {
			ep = get_entry_in_dir(sb, &clu, i, NULL);
			if (!ep)
				return -2;

			entry_type = p_fs->fs_func->get_entry_type(ep);
			step = 1;

			if ((entry_type == TYPE_UNUSED) || (entry_type == TYPE_DELETED)) {
				is_feasible_entry = false;

				if (p_fs->hint_uentry.entry == -1) {
					num_empty++;

					if (num_empty == 1) {
						p_fs->hint_uentry.clu.dir = clu.dir;
						p_fs->hint_uentry.clu.size = clu.size;
						p_fs->hint_uentry.clu.flags = clu.flags;
					}
					if ((num_empty >= num_entries) || (entry_type == TYPE_UNUSED))
						p_fs->hint_uentry.entry = dentry - (num_empty - 1);
				}

				if (entry_type == TYPE_UNUSED)
					return -2;
			} else {
				num_empty = 0;

				if ((entry_type == TYPE_FILE) || (entry_type == TYPE_DIR)) {
					file_ep = (struct file_dentry_t *)ep;
					if ((type == TYPE_ALL) || (type == entry_type)) {
						num_ext_entries = file_ep->num_ext;
						is_feasible_entry = true;
					} else {
						is_feasible_entry = false;
						step = file_ep->num_ext + 1;
					}
				} else if (entry_type == TYPE_STREAM) {
					if (is_feasible_entry) {
						strm_ep = (struct strm_dentry_t *)ep;
						if (p_uniname->name_hash == GET16_A(strm_ep->name_hash) &&
						    p_uniname->name_len == strm_ep->name_len) {
							order = 1;
						} else {
							is_feasible_entry = false;
							step = num_ext_entries;
						}
					}
				} else if (entry_type == TYPE_EXTEND) {
					if (is_feasible_entry) {
						name_ep = (struct name_dentry_t *)ep;

						if ((++order) == 2)
							uniname = p_uniname->name;
						else
							uniname += 15;

						len = extract_uni_name_from_name_entry(name_ep,
								entry_uniname, order);

						unichar = *(uniname + len);
						*(uniname + len) = 0x0;

						if (nls_uniname_cmp(sb, uniname, entry_uniname)) {
							is_feasible_entry = false;
							step = num_ext_entries - order + 1;
						} else if (order == num_ext_entries) {
							p_fs->hint_uentry.dir = CLUSTER_32(~0);
							p_fs->hint_uentry.entry = -1;
							return dentry - (num_ext_entries);
						}

						*(uniname + len) = unichar;
					}
				} else {
					is_feasible_entry = false;
				}
			}

			i += step;
			dentry += step;
		}

		i -= dentries_per_clu;

		if (p_dir->dir == CLUSTER_32(0))
			break; /* FAT16 root_dir */

		if (clu.flags == 0x03) {
			if ((--clu.size) > 0)
				clu.dir++;
			else
				clu.dir = CLUSTER_32(~0);
		} else {
			if (FAT_read(sb, clu.dir, &clu.dir) != 0)
				return -2;
		}
	}

	return -2;
}

s32 fat_count_ext_entries(struct super_block *sb, struct chain_t *p_dir,
			  s32 entry, struct dentry_t *p_entry)
{
	s32 count = 0;
	u8 chksum;
	struct dos_dentry_t *dos_ep = (struct dos_dentry_t *)p_entry;
	struct ext_dentry_t *ext_ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	chksum = calc_checksum_1byte((void *)dos_ep->name, DOS_NAME_LENGTH, 0);

	for (entry--; entry >= 0; entry--) {
		ext_ep = (struct ext_dentry_t *)get_entry_in_dir(sb, p_dir,
								 entry, NULL);
		if (!ext_ep)
			return -1;

		if ((p_fs->fs_func->get_entry_type((struct dentry_t *)ext_ep) ==
		     TYPE_EXTEND) && (ext_ep->checksum == chksum)) {
			count++;
			if (ext_ep->order > 0x40)
				return count;
		} else {
			return count;
		}
	}

	return count;
}

s32 exfat_count_ext_entries(struct super_block *sb, struct chain_t *p_dir,
			    s32 entry, struct dentry_t *p_entry)
{
	int i, count = 0;
	u32 type;
	struct file_dentry_t *file_ep = (struct file_dentry_t *)p_entry;
	struct dentry_t *ext_ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	for (i = 0, entry++; i < file_ep->num_ext; i++, entry++) {
		ext_ep = get_entry_in_dir(sb, p_dir, entry, NULL);
		if (!ext_ep)
			return -1;

		type = p_fs->fs_func->get_entry_type(ext_ep);
		if ((type == TYPE_EXTEND) || (type == TYPE_STREAM))
			count++;
		else
			return count;
	}

	return count;
}

s32 count_dos_name_entries(struct super_block *sb, struct chain_t *p_dir,
			   u32 type)
{
	int i, count = 0;
	s32 dentries_per_clu;
	u32 entry_type;
	struct chain_t clu;
	struct dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
		dentries_per_clu = p_fs->dentries_in_root;
	else
		dentries_per_clu = p_fs->dentries_per_clu;

	clu.dir = p_dir->dir;
	clu.size = p_dir->size;
	clu.flags = p_dir->flags;

	while (clu.dir != CLUSTER_32(~0)) {
		if (p_fs->dev_ejected)
			break;

		for (i = 0; i < dentries_per_clu; i++) {
			ep = get_entry_in_dir(sb, &clu, i, NULL);
			if (!ep)
				return -1;

			entry_type = p_fs->fs_func->get_entry_type(ep);

			if (entry_type == TYPE_UNUSED)
				return count;
			if (!(type & TYPE_CRITICAL_PRI) &&
			    !(type & TYPE_BENIGN_PRI))
				continue;

			if ((type == TYPE_ALL) || (type == entry_type))
				count++;
		}

		if (p_dir->dir == CLUSTER_32(0))
			break; /* FAT16 root_dir */

		if (clu.flags == 0x03) {
			if ((--clu.size) > 0)
				clu.dir++;
			else
				clu.dir = CLUSTER_32(~0);
		} else {
			if (FAT_read(sb, clu.dir, &clu.dir) != 0)
				return -1;
		}
	}

	return count;
}

bool is_dir_empty(struct super_block *sb, struct chain_t *p_dir)
{
	int i, count = 0;
	s32 dentries_per_clu;
	u32 type;
	struct chain_t clu;
	struct dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
		dentries_per_clu = p_fs->dentries_in_root;
	else
		dentries_per_clu = p_fs->dentries_per_clu;

	clu.dir = p_dir->dir;
	clu.size = p_dir->size;
	clu.flags = p_dir->flags;

	while (clu.dir != CLUSTER_32(~0)) {
		if (p_fs->dev_ejected)
			break;

		for (i = 0; i < dentries_per_clu; i++) {
			ep = get_entry_in_dir(sb, &clu, i, NULL);
			if (!ep)
				break;

			type = p_fs->fs_func->get_entry_type(ep);

			if (type == TYPE_UNUSED)
				return true;
			if ((type != TYPE_FILE) && (type != TYPE_DIR))
				continue;

			if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
				return false;

			if (p_fs->vol_type == EXFAT)
				return false;
			if ((p_dir->dir == p_fs->root_dir) || ((++count) > 2))
				return false;
		}

		if (p_dir->dir == CLUSTER_32(0))
			break; /* FAT16 root_dir */

		if (clu.flags == 0x03) {
			if ((--clu.size) > 0)
				clu.dir++;
			else
				clu.dir = CLUSTER_32(~0);
		}
		if (FAT_read(sb, clu.dir, &clu.dir) != 0)
			break;
	}

	return true;
}

/*
 *  Name Conversion Functions
 */

/* input  : dir, uni_name
 * output : num_of_entry, dos_name(format : aaaaaa~1.bbb)
 */
s32 get_num_entries_and_dos_name(struct super_block *sb, struct chain_t *p_dir,
				 struct uni_name_t *p_uniname, s32 *entries,
				 struct dos_name_t *p_dosname)
{
	s32 ret, num_entries;
	bool lossy = false;
	char **r;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	num_entries = p_fs->fs_func->calc_num_entries(p_uniname);
	if (num_entries == 0)
		return FFS_INVALIDPATH;

	if (p_fs->vol_type != EXFAT) {
		nls_uniname_to_dosname(sb, p_dosname, p_uniname, &lossy);

		if (lossy) {
			ret = fat_generate_dos_name(sb, p_dir, p_dosname);
			if (ret)
				return ret;
		} else {
			for (r = reserved_names; *r; r++) {
				if (!strncmp((void *)p_dosname->name, *r, 8))
					return FFS_INVALIDPATH;
			}

			if (p_dosname->name_case != 0xFF)
				num_entries = 1;
		}

		if (num_entries > 1)
			p_dosname->name_case = 0x0;
	}

	*entries = num_entries;

	return FFS_SUCCESS;
}

void get_uni_name_from_dos_entry(struct super_block *sb,
				 struct dos_dentry_t *ep,
				 struct uni_name_t *p_uniname, u8 mode)
{
	struct dos_name_t dos_name;

	if (mode == 0x0)
		dos_name.name_case = 0x0;
	else
		dos_name.name_case = ep->lcase;

	memcpy(dos_name.name, ep->name, DOS_NAME_LENGTH);
	nls_dosname_to_uniname(sb, p_uniname, &dos_name);
}

void fat_get_uni_name_from_ext_entry(struct super_block *sb,
				     struct chain_t *p_dir, s32 entry,
				     u16 *uniname)
{
	int i;
	struct ext_dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	for (entry--, i = 1; entry >= 0; entry--, i++) {
		ep = (struct ext_dentry_t *)get_entry_in_dir(sb, p_dir, entry,
							     NULL);
		if (!ep)
			return;

		if (p_fs->fs_func->get_entry_type((struct dentry_t *)ep) ==
		    TYPE_EXTEND) {
			extract_uni_name_from_ext_entry(ep, uniname, i);
			if (ep->order > 0x40)
				return;
		} else {
			return;
		}

		uniname += 13;
	}
}

void exfat_get_uni_name_from_ext_entry(struct super_block *sb,
				       struct chain_t *p_dir, s32 entry,
				       u16 *uniname)
{
	int i;
	struct dentry_t *ep;
	struct entry_set_cache_t *es;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	es = get_entry_set_in_dir(sb, p_dir, entry, ES_ALL_ENTRIES, &ep);
	if (!es || es->num_entries < 3) {
		if (es)
			release_entry_set(es);
		return;
	}

	ep += 2;

	/*
	 * First entry  : file entry
	 * Second entry : stream-extension entry
	 * Third entry  : first file-name entry
	 * So, the index of first file-name dentry should start from 2.
	 */
	for (i = 2; i < es->num_entries; i++, ep++) {
		if (p_fs->fs_func->get_entry_type(ep) == TYPE_EXTEND)
			extract_uni_name_from_name_entry((struct name_dentry_t *)
							 ep, uniname, i);
		else
			goto out;
		uniname += 15;
	}

out:
	release_entry_set(es);
}

s32 extract_uni_name_from_ext_entry(struct ext_dentry_t *ep, u16 *uniname,
				    s32 order)
{
	int i, len = 0;

	for (i = 0; i < 10; i += 2) {
		*uniname = GET16(ep->unicode_0_4 + i);
		if (*uniname == 0x0)
			return len;
		uniname++;
		len++;
	}

	if (order < 20) {
		for (i = 0; i < 12; i += 2) {
			*uniname = GET16_A(ep->unicode_5_10 + i);
			if (*uniname == 0x0)
				return len;
			uniname++;
			len++;
		}
	} else {
		for (i = 0; i < 8; i += 2) {
			*uniname = GET16_A(ep->unicode_5_10 + i);
			if (*uniname == 0x0)
				return len;
			uniname++;
			len++;
		}
		*uniname = 0x0; /* uniname[MAX_NAME_LENGTH-1] */
		return len;
	}

	for (i = 0; i < 4; i += 2) {
		*uniname = GET16_A(ep->unicode_11_12 + i);
		if (*uniname == 0x0)
			return len;
		uniname++;
		len++;
	}

	*uniname = 0x0;
	return len;
}

s32 extract_uni_name_from_name_entry(struct name_dentry_t *ep, u16 *uniname,
				     s32 order)
{
	int i, len = 0;

	for (i = 0; i < 30; i += 2) {
		*uniname = GET16_A(ep->unicode_0_14 + i);
		if (*uniname == 0x0)
			return len;
		uniname++;
		len++;
	}

	*uniname = 0x0;
	return len;
}

s32 fat_generate_dos_name(struct super_block *sb, struct chain_t *p_dir,
			  struct dos_name_t *p_dosname)
{
	int i, j, count = 0;
	bool count_begin = false;
	s32 dentries_per_clu;
	u32 type;
	u8 bmap[128/* 1 ~ 1023 */];
	struct chain_t clu;
	struct dos_dentry_t *ep;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	memset(bmap, 0, sizeof(bmap));
	exfat_bitmap_set(bmap, 0);

	if (p_dir->dir == CLUSTER_32(0)) /* FAT16 root_dir */
		dentries_per_clu = p_fs->dentries_in_root;
	else
		dentries_per_clu = p_fs->dentries_per_clu;

	clu.dir = p_dir->dir;
	clu.flags = p_dir->flags;

	while (clu.dir != CLUSTER_32(~0)) {
		if (p_fs->dev_ejected)
			break;

		for (i = 0; i < dentries_per_clu; i++) {
			ep = (struct dos_dentry_t *)get_entry_in_dir(sb, &clu,
								     i, NULL);
			if (!ep)
				return FFS_MEDIAERR;

			type = p_fs->fs_func->get_entry_type((struct dentry_t *)
							     ep);

			if (type == TYPE_UNUSED)
				break;
			if ((type != TYPE_FILE) && (type != TYPE_DIR))
				continue;

			count = 0;
			count_begin = false;

			for (j = 0; j < 8; j++) {
				if (ep->name[j] == ' ')
					break;

				if (ep->name[j] == '~') {
					count_begin = true;
				} else if (count_begin) {
					if ((ep->name[j] >= '0') &&
					    (ep->name[j] <= '9')) {
						count = count * 10 +
							(ep->name[j] - '0');
					} else {
						count = 0;
						count_begin = false;
					}
				}
			}

			if ((count > 0) && (count < 1024))
				exfat_bitmap_set(bmap, count);
		}

		if (p_dir->dir == CLUSTER_32(0))
			break; /* FAT16 root_dir */

		if (FAT_read(sb, clu.dir, &clu.dir) != 0)
			return FFS_MEDIAERR;
	}

	count = 0;
	for (i = 0; i < 128; i++) {
		if (bmap[i] != 0xFF) {
			for (j = 0; j < 8; j++) {
				if (exfat_bitmap_test(&bmap[i], j) == 0) {
					count = (i << 3) + j;
					break;
				}
			}
			if (count != 0)
				break;
		}
	}

	if ((count == 0) || (count >= 1024))
		return FFS_FILEEXIST;
	fat_attach_count_to_dos_name(p_dosname->name, count);

	/* Now dos_name has DOS~????.EXT */
	return FFS_SUCCESS;
}

void fat_attach_count_to_dos_name(u8 *dosname, s32 count)
{
	int i, j, length;
	char str_count[6];

	snprintf(str_count, sizeof(str_count), "~%d", count);
	length = strlen(str_count);

	i = 0;
	j = 0;
	while (j <= (8 - length)) {
		i = j;
		if (dosname[j] == ' ')
			break;
		if (dosname[j] & 0x80)
			j += 2;
		else
			j++;
	}

	for (j = 0; j < length; i++, j++)
		dosname[i] = (u8)str_count[j];

	if (i == 7)
		dosname[7] = ' ';
}

s32 fat_calc_num_entries(struct uni_name_t *p_uniname)
{
	s32 len;

	len = p_uniname->name_len;
	if (len == 0)
		return 0;

	/* 1 dos name entry + extended entries */
	return (len - 1) / 13 + 2;
}

s32 exfat_calc_num_entries(struct uni_name_t *p_uniname)
{
	s32 len;

	len = p_uniname->name_len;
	if (len == 0)
		return 0;

	/* 1 file entry + 1 stream entry + name entries */
	return (len - 1) / 15 + 3;
}

u8 calc_checksum_1byte(void *data, s32 len, u8 chksum)
{
	int i;
	u8 *c = (u8 *)data;

	for (i = 0; i < len; i++, c++)
		chksum = (((chksum & 1) << 7) | ((chksum & 0xFE) >> 1)) + *c;

	return chksum;
}

u16 calc_checksum_2byte(void *data, s32 len, u16 chksum, s32 type)
{
	int i;
	u8 *c = (u8 *)data;

	switch (type) {
	case CS_DIR_ENTRY:
		for (i = 0; i < len; i++, c++) {
			if ((i == 2) || (i == 3))
				continue;
			chksum = (((chksum & 1) << 15) |
				  ((chksum & 0xFFFE) >> 1)) + (u16)*c;
		}
		break;
	default
			:
		for (i = 0; i < len; i++, c++)
			chksum = (((chksum & 1) << 15) |
				  ((chksum & 0xFFFE) >> 1)) + (u16)*c;
	}

	return chksum;
}

u32 calc_checksum_4byte(void *data, s32 len, u32 chksum, s32 type)
{
	int i;
	u8 *c = (u8 *)data;

	switch (type) {
	case CS_PBR_SECTOR:
		for (i = 0; i < len; i++, c++) {
			if ((i == 106) || (i == 107) || (i == 112))
				continue;
			chksum = (((chksum & 1) << 31) |
				  ((chksum & 0xFFFFFFFE) >> 1)) + (u32)*c;
		}
		break;
	default
			:
		for (i = 0; i < len; i++, c++)
			chksum = (((chksum & 1) << 31) |
				  ((chksum & 0xFFFFFFFE) >> 1)) + (u32)*c;
	}

	return chksum;
}

/*
 *  Name Resolution Functions
 */

/* return values of resolve_path()
 * > 0 : return the length of the path
 * < 0 : return error
 */
s32 resolve_path(struct inode *inode, char *path, struct chain_t *p_dir,
		 struct uni_name_t *p_uniname)
{
	bool lossy = false;
	struct super_block *sb = inode->i_sb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct file_id_t *fid = &(EXFAT_I(inode)->fid);

	if (strscpy(name_buf, path, sizeof(name_buf)) < 0)
		return FFS_INVALIDPATH;

	nls_cstring_to_uniname(sb, p_uniname, name_buf, &lossy);
	if (lossy)
		return FFS_INVALIDPATH;

	fid->size = i_size_read(inode);

	p_dir->dir = fid->start_clu;
	p_dir->size = (s32)(fid->size >> p_fs->cluster_size_bits);
	p_dir->flags = fid->flags;

	return FFS_SUCCESS;
}

/*
 *  File Operation Functions
 */
static struct fs_func fat_fs_func = {
	.alloc_cluster = fat_alloc_cluster,
	.free_cluster = fat_free_cluster,
	.count_used_clusters = fat_count_used_clusters,

	.init_dir_entry = fat_init_dir_entry,
	.init_ext_entry = fat_init_ext_entry,
	.find_dir_entry = fat_find_dir_entry,
	.delete_dir_entry = fat_delete_dir_entry,
	.get_uni_name_from_ext_entry = fat_get_uni_name_from_ext_entry,
	.count_ext_entries = fat_count_ext_entries,
	.calc_num_entries = fat_calc_num_entries,

	.get_entry_type = fat_get_entry_type,
	.set_entry_type = fat_set_entry_type,
	.get_entry_attr = fat_get_entry_attr,
	.set_entry_attr = fat_set_entry_attr,
	.get_entry_flag = fat_get_entry_flag,
	.set_entry_flag = fat_set_entry_flag,
	.get_entry_clu0 = fat_get_entry_clu0,
	.set_entry_clu0 = fat_set_entry_clu0,
	.get_entry_size = fat_get_entry_size,
	.set_entry_size = fat_set_entry_size,
	.get_entry_time = fat_get_entry_time,
	.set_entry_time = fat_set_entry_time,
};

s32 fat16_mount(struct super_block *sb, struct pbr_sector_t *p_pbr)
{
	s32 num_reserved, num_root_sectors;
	struct bpb16_t *p_bpb = (struct bpb16_t *)p_pbr->bpb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	if (p_bpb->num_fats == 0)
		return FFS_FORMATERR;

	num_root_sectors = GET16(p_bpb->num_root_entries) << DENTRY_SIZE_BITS;
	num_root_sectors = ((num_root_sectors - 1) >>
			    p_bd->sector_size_bits) + 1;

	p_fs->sectors_per_clu = p_bpb->sectors_per_clu;
	p_fs->sectors_per_clu_bits = ilog2(p_bpb->sectors_per_clu);
	p_fs->cluster_size_bits = p_fs->sectors_per_clu_bits +
				  p_bd->sector_size_bits;
	p_fs->cluster_size = 1 << p_fs->cluster_size_bits;

	p_fs->num_FAT_sectors = GET16(p_bpb->num_fat_sectors);

	p_fs->FAT1_start_sector = p_fs->PBR_sector + GET16(p_bpb->num_reserved);
	if (p_bpb->num_fats == 1)
		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector;
	else
		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector +
					  p_fs->num_FAT_sectors;

	p_fs->root_start_sector = p_fs->FAT2_start_sector +
				  p_fs->num_FAT_sectors;
	p_fs->data_start_sector = p_fs->root_start_sector + num_root_sectors;

	p_fs->num_sectors = GET16(p_bpb->num_sectors);
	if (p_fs->num_sectors == 0)
		p_fs->num_sectors = GET32(p_bpb->num_huge_sectors);

	num_reserved = p_fs->data_start_sector - p_fs->PBR_sector;
	p_fs->num_clusters = ((p_fs->num_sectors - num_reserved) >>
			      p_fs->sectors_per_clu_bits) + 2;
	/* because the cluster index starts with 2 */

	if (p_fs->num_clusters < FAT12_THRESHOLD)
		p_fs->vol_type = FAT12;
	else
		p_fs->vol_type = FAT16;
	p_fs->vol_id = GET32(p_bpb->vol_serial);

	p_fs->root_dir = 0;
	p_fs->dentries_in_root = GET16(p_bpb->num_root_entries);
	p_fs->dentries_per_clu = 1 << (p_fs->cluster_size_bits -
				       DENTRY_SIZE_BITS);

	p_fs->vol_flag = VOL_CLEAN;
	p_fs->clu_srch_ptr = 2;
	p_fs->used_clusters = UINT_MAX;

	p_fs->fs_func = &fat_fs_func;

	return FFS_SUCCESS;
}

s32 fat32_mount(struct super_block *sb, struct pbr_sector_t *p_pbr)
{
	s32 num_reserved;
	struct bpb32_t *p_bpb = (struct bpb32_t *)p_pbr->bpb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	if (p_bpb->num_fats == 0)
		return FFS_FORMATERR;

	p_fs->sectors_per_clu = p_bpb->sectors_per_clu;
	p_fs->sectors_per_clu_bits = ilog2(p_bpb->sectors_per_clu);
	p_fs->cluster_size_bits = p_fs->sectors_per_clu_bits +
				  p_bd->sector_size_bits;
	p_fs->cluster_size = 1 << p_fs->cluster_size_bits;

	p_fs->num_FAT_sectors = GET32(p_bpb->num_fat32_sectors);

	p_fs->FAT1_start_sector = p_fs->PBR_sector + GET16(p_bpb->num_reserved);
	if (p_bpb->num_fats == 1)
		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector;
	else
		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector +
					  p_fs->num_FAT_sectors;

	p_fs->root_start_sector = p_fs->FAT2_start_sector +
				  p_fs->num_FAT_sectors;
	p_fs->data_start_sector = p_fs->root_start_sector;

	p_fs->num_sectors = GET32(p_bpb->num_huge_sectors);
	num_reserved = p_fs->data_start_sector - p_fs->PBR_sector;

	p_fs->num_clusters = ((p_fs->num_sectors - num_reserved) >>
			      p_fs->sectors_per_clu_bits) + 2;
	/* because the cluster index starts with 2 */

	p_fs->vol_type = FAT32;
	p_fs->vol_id = GET32(p_bpb->vol_serial);

	p_fs->root_dir = GET32(p_bpb->root_cluster);
	p_fs->dentries_in_root = 0;
	p_fs->dentries_per_clu = 1 << (p_fs->cluster_size_bits -
				       DENTRY_SIZE_BITS);

	p_fs->vol_flag = VOL_CLEAN;
	p_fs->clu_srch_ptr = 2;
	p_fs->used_clusters = UINT_MAX;

	p_fs->fs_func = &fat_fs_func;

	return FFS_SUCCESS;
}

static struct fs_func exfat_fs_func = {
	.alloc_cluster = exfat_alloc_cluster,
	.free_cluster = exfat_free_cluster,
	.count_used_clusters = exfat_count_used_clusters,

	.init_dir_entry = exfat_init_dir_entry,
	.init_ext_entry = exfat_init_ext_entry,
	.find_dir_entry = exfat_find_dir_entry,
	.delete_dir_entry = exfat_delete_dir_entry,
	.get_uni_name_from_ext_entry = exfat_get_uni_name_from_ext_entry,
	.count_ext_entries = exfat_count_ext_entries,
	.calc_num_entries = exfat_calc_num_entries,

	.get_entry_type = exfat_get_entry_type,
	.set_entry_type = exfat_set_entry_type,
	.get_entry_attr = exfat_get_entry_attr,
	.set_entry_attr = exfat_set_entry_attr,
	.get_entry_flag = exfat_get_entry_flag,
	.set_entry_flag = exfat_set_entry_flag,
	.get_entry_clu0 = exfat_get_entry_clu0,
	.set_entry_clu0 = exfat_set_entry_clu0,
	.get_entry_size = exfat_get_entry_size,
	.set_entry_size = exfat_set_entry_size,
	.get_entry_time = exfat_get_entry_time,
	.set_entry_time = exfat_set_entry_time,
};

s32 exfat_mount(struct super_block *sb, struct pbr_sector_t *p_pbr)
{
	struct bpbex_t *p_bpb = (struct bpbex_t *)p_pbr->bpb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct bd_info_t *p_bd = &(EXFAT_SB(sb)->bd_info);

	if (p_bpb->num_fats == 0)
		return FFS_FORMATERR;

	p_fs->sectors_per_clu = 1 << p_bpb->sectors_per_clu_bits;
	p_fs->sectors_per_clu_bits = p_bpb->sectors_per_clu_bits;
	p_fs->cluster_size_bits = p_fs->sectors_per_clu_bits +
				  p_bd->sector_size_bits;
	p_fs->cluster_size = 1 << p_fs->cluster_size_bits;

	p_fs->num_FAT_sectors = GET32(p_bpb->fat_length);

	p_fs->FAT1_start_sector = p_fs->PBR_sector + GET32(p_bpb->fat_offset);
	if (p_bpb->num_fats == 1)
		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector;
	else
		p_fs->FAT2_start_sector = p_fs->FAT1_start_sector +
					  p_fs->num_FAT_sectors;

	p_fs->root_start_sector = p_fs->PBR_sector + GET32(p_bpb->clu_offset);
	p_fs->data_start_sector = p_fs->root_start_sector;

	p_fs->num_sectors = GET64(p_bpb->vol_length);
	p_fs->num_clusters = GET32(p_bpb->clu_count) + 2;
	/* because the cluster index starts with 2 */

	p_fs->vol_type = EXFAT;
	p_fs->vol_id = GET32(p_bpb->vol_serial);

	p_fs->root_dir = GET32(p_bpb->root_cluster);
	p_fs->dentries_in_root = 0;
	p_fs->dentries_per_clu = 1 << (p_fs->cluster_size_bits -
				       DENTRY_SIZE_BITS);

	p_fs->vol_flag = (u32)GET16(p_bpb->vol_flags);
	p_fs->clu_srch_ptr = 2;
	p_fs->used_clusters = UINT_MAX;

	p_fs->fs_func = &exfat_fs_func;

	return FFS_SUCCESS;
}

s32 create_dir(struct inode *inode, struct chain_t *p_dir,
	       struct uni_name_t *p_uniname, struct file_id_t *fid)
{
	s32 ret, dentry, num_entries;
	u64 size;
	struct chain_t clu;
	struct dos_name_t dos_name, dot_name;
	struct super_block *sb = inode->i_sb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct fs_func *fs_func = p_fs->fs_func;

	ret = get_num_entries_and_dos_name(sb, p_dir, p_uniname, &num_entries,
					   &dos_name);
	if (ret)
		return ret;

	/* find_empty_entry must be called before alloc_cluster */
	dentry = find_empty_entry(inode, p_dir, num_entries);
	if (dentry < 0)
		return FFS_FULL;

	clu.dir = CLUSTER_32(~0);
	clu.size = 0;
	clu.flags = (p_fs->vol_type == EXFAT) ? 0x03 : 0x01;

	/* (1) allocate a cluster */
	ret = fs_func->alloc_cluster(sb, 1, &clu);
	if (ret < 0)
		return FFS_MEDIAERR;
	else if (ret == 0)
		return FFS_FULL;

	ret = clear_cluster(sb, clu.dir);
	if (ret != FFS_SUCCESS)
		return ret;

	if (p_fs->vol_type == EXFAT) {
		size = p_fs->cluster_size;
	} else {
		size = 0;

		/* initialize the . and .. entry
		 * Information for . points to itself
		 * Information for .. points to parent dir
		 */

		dot_name.name_case = 0x0;
		memcpy(dot_name.name, DOS_CUR_DIR_NAME, DOS_NAME_LENGTH);

		ret = fs_func->init_dir_entry(sb, &clu, 0, TYPE_DIR, clu.dir,
					      0);
		if (ret != FFS_SUCCESS)
			return ret;

		ret = fs_func->init_ext_entry(sb, &clu, 0, 1, NULL, &dot_name);
		if (ret != FFS_SUCCESS)
			return ret;

		memcpy(dot_name.name, DOS_PAR_DIR_NAME, DOS_NAME_LENGTH);

		if (p_dir->dir == p_fs->root_dir)
			ret = fs_func->init_dir_entry(sb, &clu, 1, TYPE_DIR,
						      CLUSTER_32(0), 0);
		else
			ret = fs_func->init_dir_entry(sb, &clu, 1, TYPE_DIR,
						      p_dir->dir, 0);

		if (ret != FFS_SUCCESS)
			return ret;

		ret = p_fs->fs_func->init_ext_entry(sb, &clu, 1, 1, NULL,
						    &dot_name);
		if (ret != FFS_SUCCESS)
			return ret;
	}

	/* (2) update the directory entry */
	/* make sub-dir entry in parent directory */
	ret = fs_func->init_dir_entry(sb, p_dir, dentry, TYPE_DIR, clu.dir,
				      size);
	if (ret != FFS_SUCCESS)
		return ret;

	ret = fs_func->init_ext_entry(sb, p_dir, dentry, num_entries, p_uniname,
				      &dos_name);
	if (ret != FFS_SUCCESS)
		return ret;

	fid->dir.dir = p_dir->dir;
	fid->dir.size = p_dir->size;
	fid->dir.flags = p_dir->flags;
	fid->entry = dentry;

	fid->attr = ATTR_SUBDIR;
	fid->flags = (p_fs->vol_type == EXFAT) ? 0x03 : 0x01;
	fid->size = size;
	fid->start_clu = clu.dir;

	fid->type = TYPE_DIR;
	fid->rwoffset = 0;
	fid->hint_last_off = -1;

	return FFS_SUCCESS;
}

s32 create_file(struct inode *inode, struct chain_t *p_dir,
		struct uni_name_t *p_uniname, u8 mode, struct file_id_t *fid)
{
	s32 ret, dentry, num_entries;
	struct dos_name_t dos_name;
	struct super_block *sb = inode->i_sb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct fs_func *fs_func = p_fs->fs_func;

	ret = get_num_entries_and_dos_name(sb, p_dir, p_uniname, &num_entries,
					   &dos_name);
	if (ret)
		return ret;

	/* find_empty_entry must be called before alloc_cluster() */
	dentry = find_empty_entry(inode, p_dir, num_entries);
	if (dentry < 0)
		return FFS_FULL;

	/* (1) update the directory entry */
	/* fill the dos name directory entry information of the created file.
	 * the first cluster is not determined yet. (0)
	 */
	ret = fs_func->init_dir_entry(sb, p_dir, dentry, TYPE_FILE | mode,
				      CLUSTER_32(0), 0);
	if (ret != FFS_SUCCESS)
		return ret;

	ret = fs_func->init_ext_entry(sb, p_dir, dentry, num_entries, p_uniname,
				      &dos_name);
	if (ret != FFS_SUCCESS)
		return ret;

	fid->dir.dir = p_dir->dir;
	fid->dir.size = p_dir->size;
	fid->dir.flags = p_dir->flags;
	fid->entry = dentry;

	fid->attr = ATTR_ARCHIVE | mode;
	fid->flags = (p_fs->vol_type == EXFAT) ? 0x03 : 0x01;
	fid->size = 0;
	fid->start_clu = CLUSTER_32(~0);

	fid->type = TYPE_FILE;
	fid->rwoffset = 0;
	fid->hint_last_off = -1;

	return FFS_SUCCESS;
}

void remove_file(struct inode *inode, struct chain_t *p_dir, s32 entry)
{
	s32 num_entries;
	sector_t sector;
	struct dentry_t *ep;
	struct super_block *sb = inode->i_sb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct fs_func *fs_func = p_fs->fs_func;

	ep = get_entry_in_dir(sb, p_dir, entry, &sector);
	if (!ep)
		return;

	buf_lock(sb, sector);

	/* buf_lock() before call count_ext_entries() */
	num_entries = fs_func->count_ext_entries(sb, p_dir, entry, ep);
	if (num_entries < 0) {
		buf_unlock(sb, sector);
		return;
	}
	num_entries++;

	buf_unlock(sb, sector);

	/* (1) update the directory entry */
	fs_func->delete_dir_entry(sb, p_dir, entry, 0, num_entries);
}

s32 rename_file(struct inode *inode, struct chain_t *p_dir, s32 oldentry,
		struct uni_name_t *p_uniname, struct file_id_t *fid)
{
	s32 ret, newentry = -1, num_old_entries, num_new_entries;
	sector_t sector_old, sector_new;
	struct dos_name_t dos_name;
	struct dentry_t *epold, *epnew;
	struct super_block *sb = inode->i_sb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct fs_func *fs_func = p_fs->fs_func;

	epold = get_entry_in_dir(sb, p_dir, oldentry, &sector_old);
	if (!epold)
		return FFS_MEDIAERR;

	buf_lock(sb, sector_old);

	/* buf_lock() before call count_ext_entries() */
	num_old_entries = fs_func->count_ext_entries(sb, p_dir, oldentry,
						     epold);
	if (num_old_entries < 0) {
		buf_unlock(sb, sector_old);
		return FFS_MEDIAERR;
	}
	num_old_entries++;

	ret = get_num_entries_and_dos_name(sb, p_dir, p_uniname,
					   &num_new_entries, &dos_name);
	if (ret) {
		buf_unlock(sb, sector_old);
		return ret;
	}

	if (num_old_entries < num_new_entries) {
		newentry = find_empty_entry(inode, p_dir, num_new_entries);
		if (newentry < 0) {
			buf_unlock(sb, sector_old);
			return FFS_FULL;
		}

		epnew = get_entry_in_dir(sb, p_dir, newentry, &sector_new);
		if (!epnew) {
			buf_unlock(sb, sector_old);
			return FFS_MEDIAERR;
		}

		memcpy((void *)epnew, (void *)epold, DENTRY_SIZE);
		if (fs_func->get_entry_type(epnew) == TYPE_FILE) {
			fs_func->set_entry_attr(epnew,
						fs_func->get_entry_attr(epnew) |
						ATTR_ARCHIVE);
			fid->attr |= ATTR_ARCHIVE;
		}
		buf_modify(sb, sector_new);
		buf_unlock(sb, sector_old);

		if (p_fs->vol_type == EXFAT) {
			epold = get_entry_in_dir(sb, p_dir, oldentry + 1,
						 &sector_old);
			buf_lock(sb, sector_old);
			epnew = get_entry_in_dir(sb, p_dir, newentry + 1,
						 &sector_new);

			if (!epold || !epnew) {
				buf_unlock(sb, sector_old);
				return FFS_MEDIAERR;
			}

			memcpy((void *)epnew, (void *)epold, DENTRY_SIZE);
			buf_modify(sb, sector_new);
			buf_unlock(sb, sector_old);
		}

		ret = fs_func->init_ext_entry(sb, p_dir, newentry,
					      num_new_entries, p_uniname,
					      &dos_name);
		if (ret != FFS_SUCCESS)
			return ret;

		fs_func->delete_dir_entry(sb, p_dir, oldentry, 0,
					  num_old_entries);
		fid->entry = newentry;
	} else {
		if (fs_func->get_entry_type(epold) == TYPE_FILE) {
			fs_func->set_entry_attr(epold,
						fs_func->get_entry_attr(epold) |
						ATTR_ARCHIVE);
			fid->attr |= ATTR_ARCHIVE;
		}
		buf_modify(sb, sector_old);
		buf_unlock(sb, sector_old);

		ret = fs_func->init_ext_entry(sb, p_dir, oldentry,
					      num_new_entries, p_uniname,
					      &dos_name);
		if (ret != FFS_SUCCESS)
			return ret;

		fs_func->delete_dir_entry(sb, p_dir, oldentry, num_new_entries,
					  num_old_entries);
	}

	return FFS_SUCCESS;
}

s32 move_file(struct inode *inode, struct chain_t *p_olddir, s32 oldentry,
	      struct chain_t *p_newdir, struct uni_name_t *p_uniname,
	      struct file_id_t *fid)
{
	s32 ret, newentry, num_new_entries, num_old_entries;
	sector_t sector_mov, sector_new;
	struct chain_t clu;
	struct dos_name_t dos_name;
	struct dentry_t *epmov, *epnew;
	struct super_block *sb = inode->i_sb;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);
	struct fs_func *fs_func = p_fs->fs_func;

	epmov = get_entry_in_dir(sb, p_olddir, oldentry, &sector_mov);
	if (!epmov)
		return FFS_MEDIAERR;

	/* check if the source and target directory is the same */
	if (fs_func->get_entry_type(epmov) == TYPE_DIR &&
	    fs_func->get_entry_clu0(epmov) == p_newdir->dir)
		return FFS_INVALIDPATH;

	buf_lock(sb, sector_mov);

	/* buf_lock() before call count_ext_entries() */
	num_old_entries = fs_func->count_ext_entries(sb, p_olddir, oldentry,
						     epmov);
	if (num_old_entries < 0) {
		buf_unlock(sb, sector_mov);
		return FFS_MEDIAERR;
	}
	num_old_entries++;

	ret = get_num_entries_and_dos_name(sb, p_newdir, p_uniname,
					   &num_new_entries, &dos_name);
	if (ret) {
		buf_unlock(sb, sector_mov);
		return ret;
	}

	newentry = find_empty_entry(inode, p_newdir, num_new_entries);
	if (newentry < 0) {
		buf_unlock(sb, sector_mov);
		return FFS_FULL;
	}

	epnew = get_entry_in_dir(sb, p_newdir, newentry, &sector_new);
	if (!epnew) {
		buf_unlock(sb, sector_mov);
		return FFS_MEDIAERR;
	}

	memcpy((void *)epnew, (void *)epmov, DENTRY_SIZE);
	if (fs_func->get_entry_type(epnew) == TYPE_FILE) {
		fs_func->set_entry_attr(epnew, fs_func->get_entry_attr(epnew) |
					ATTR_ARCHIVE);
		fid->attr |= ATTR_ARCHIVE;
	}
	buf_modify(sb, sector_new);
	buf_unlock(sb, sector_mov);

	if (p_fs->vol_type == EXFAT) {
		epmov = get_entry_in_dir(sb, p_olddir, oldentry + 1,
					 &sector_mov);
		buf_lock(sb, sector_mov);
		epnew = get_entry_in_dir(sb, p_newdir, newentry + 1,
					 &sector_new);
		if (!epmov || !epnew) {
			buf_unlock(sb, sector_mov);
			return FFS_MEDIAERR;
		}

		memcpy((void *)epnew, (void *)epmov, DENTRY_SIZE);
		buf_modify(sb, sector_new);
		buf_unlock(sb, sector_mov);
	} else if (fs_func->get_entry_type(epnew) == TYPE_DIR) {
		/* change ".." pointer to new parent dir */
		clu.dir = fs_func->get_entry_clu0(epnew);
		clu.flags = 0x01;

		epnew = get_entry_in_dir(sb, &clu, 1, &sector_new);
		if (!epnew)
			return FFS_MEDIAERR;

		if (p_newdir->dir == p_fs->root_dir)
			fs_func->set_entry_clu0(epnew, CLUSTER_32(0));
		else
			fs_func->set_entry_clu0(epnew, p_newdir->dir);
		buf_modify(sb, sector_new);
	}

	ret = fs_func->init_ext_entry(sb, p_newdir, newentry, num_new_entries,
				      p_uniname, &dos_name);
	if (ret != FFS_SUCCESS)
		return ret;

	fs_func->delete_dir_entry(sb, p_olddir, oldentry, 0, num_old_entries);

	fid->dir.dir = p_newdir->dir;
	fid->dir.size = p_newdir->size;
	fid->dir.flags = p_newdir->flags;

	fid->entry = newentry;

	return FFS_SUCCESS;
}

/*
 *  Sector Read/Write Functions
 */

int sector_read(struct super_block *sb, sector_t sec, struct buffer_head **bh,
		bool read)
{
	s32 ret = FFS_MEDIAERR;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if ((sec >= (p_fs->PBR_sector + p_fs->num_sectors)) &&
	    (p_fs->num_sectors > 0)) {
		pr_err("[EXFAT] %s: out of range error! (sec = %llu)\n",
		       __func__, (unsigned long long)sec);
		fs_error(sb);
		return ret;
	}

	if (!p_fs->dev_ejected) {
		ret = bdev_read(sb, sec, bh, 1, read);
		if (ret != FFS_SUCCESS)
			p_fs->dev_ejected = 1;
	}

	return ret;
}

int sector_write(struct super_block *sb, sector_t sec, struct buffer_head *bh,
		 bool sync)
{
	s32 ret = FFS_MEDIAERR;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (sec >= (p_fs->PBR_sector + p_fs->num_sectors) &&
	    (p_fs->num_sectors > 0)) {
		pr_err("[EXFAT] %s: out of range error! (sec = %llu)\n",
		       __func__, (unsigned long long)sec);
		fs_error(sb);
		return ret;
	}

	if (!bh) {
		pr_err("[EXFAT] %s: bh is NULL!\n", __func__);
		fs_error(sb);
		return ret;
	}

	if (!p_fs->dev_ejected) {
		ret = bdev_write(sb, sec, bh, 1, sync);
		if (ret != FFS_SUCCESS)
			p_fs->dev_ejected = 1;
	}

	return ret;
}

int multi_sector_read(struct super_block *sb, sector_t sec,
		      struct buffer_head **bh, s32 num_secs, bool read)
{
	s32 ret = FFS_MEDIAERR;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if (((sec + num_secs) > (p_fs->PBR_sector + p_fs->num_sectors)) &&
	    (p_fs->num_sectors > 0)) {
		pr_err("[EXFAT] %s: out of range error! (sec = %llu, num_secs = %d)\n",
		       __func__, (unsigned long long)sec, num_secs);
		fs_error(sb);
		return ret;
	}

	if (!p_fs->dev_ejected) {
		ret = bdev_read(sb, sec, bh, num_secs, read);
		if (ret != FFS_SUCCESS)
			p_fs->dev_ejected = 1;
	}

	return ret;
}

int multi_sector_write(struct super_block *sb, sector_t sec,
		       struct buffer_head *bh, s32 num_secs, bool sync)
{
	s32 ret = FFS_MEDIAERR;
	struct fs_info_t *p_fs = &(EXFAT_SB(sb)->fs_info);

	if ((sec + num_secs) > (p_fs->PBR_sector + p_fs->num_sectors) &&
	    (p_fs->num_sectors > 0)) {
		pr_err("[EXFAT] %s: out of range error! (sec = %llu, num_secs = %d)\n",
		       __func__, (unsigned long long)sec, num_secs);
		fs_error(sb);
		return ret;
	}
	if (!bh) {
		pr_err("[EXFAT] %s: bh is NULL!\n", __func__);
		fs_error(sb);
		return ret;
	}

	if (!p_fs->dev_ejected) {
		ret = bdev_write(sb, sec, bh, num_secs, sync);
		if (ret != FFS_SUCCESS)
			p_fs->dev_ejected = 1;
	}

	return ret;
}