staging: exfat: add exfat filesystem code to staging

The exfat code needs a lot of work to get it into "real" shape for
the fs/ part of the kernel, so put it into drivers/staging/ for now so
that it can be worked on by everyone in the community.

The full specification of the filesystem can be found at:
  https://docs.microsoft.com/en-us/windows/win32/fileio/exfat-specification

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20190828160817.6250-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

12 files changed, 10880 insertions, 0 deletions

diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index d972ec8e71fb..fbdc33874780 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -118,4 +118,6 @@ source "drivers/staging/kpc2000/Kconfig"
 
 source "drivers/staging/isdn/Kconfig"
 
+source "drivers/staging/exfat/Kconfig"
+
 endif # STAGING
diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
index 6018b9a4a077..ca13f87b1e1b 100644
--- a/drivers/staging/Makefile
+++ b/drivers/staging/Makefile
@@ -49,3 +49,4 @@ obj-$(CONFIG_XIL_AXIS_FIFO)	+= axis-fifo/
 obj-$(CONFIG_FIELDBUS_DEV)     += fieldbus/
 obj-$(CONFIG_KPC2000)		+= kpc2000/
 obj-$(CONFIG_ISDN_CAPI)		+= isdn/
+obj-$(CONFIG_EXFAT_FS)		+= exfat/
diff --git a/drivers/staging/exfat/Kconfig b/drivers/staging/exfat/Kconfig
new file mode 100644
index 000000000000..78b32aa2ca19
--- /dev/null
+++ b/drivers/staging/exfat/Kconfig
@@ -0,0 +1,39 @@
+config EXFAT_FS
+	tristate "exFAT fs support"
+	select NLS
+	help
+	  This adds support for the exFAT file system.
+
+config EXFAT_DISCARD
+	bool "enable discard support"
+	depends on EXFAT_FS
+	default y
+
+config EXFAT_DELAYED_SYNC
+	bool "enable delayed sync"
+	depends on EXFAT_FS
+	default n
+
+config EXFAT_KERNEL_DEBUG
+	bool "enable kernel debug features via ioctl"
+	depends on EXFAT_FS
+	default n
+
+config EXFAT_DEBUG_MSG
+	bool "print debug messages"
+	depends on EXFAT_FS
+	default n
+
+config EXFAT_DEFAULT_CODEPAGE
+	int "Default codepage for exFAT"
+	default 437
+	depends on EXFAT_FS
+	help
+	  This option should be set to the codepage of your exFAT filesystems.
+
+config EXFAT_DEFAULT_IOCHARSET
+	string "Default iocharset for exFAT"
+	default "utf8"
+	depends on EXFAT_FS
+	help
+	  Set this to the default input/output character set you'd like exFAT to use.
diff --git a/drivers/staging/exfat/Makefile b/drivers/staging/exfat/Makefile
new file mode 100644
index 000000000000..84944dfbae28
--- /dev/null
+++ b/drivers/staging/exfat/Makefile
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_EXFAT_FS) += exfat.o
+
+exfat-y :=	exfat_core.o	\
+		exfat_super.o	\
+		exfat_blkdev.o	\
+		exfat_cache.o	\
+		exfat_nls.o	\
+		exfat_upcase.o
diff --git a/drivers/staging/exfat/TODO b/drivers/staging/exfat/TODO
new file mode 100644
index 000000000000..a3eb282f9efc
--- /dev/null
+++ b/drivers/staging/exfat/TODO
@@ -0,0 +1,12 @@
+exfat_core.c - ffsReadFile - the goto err_out seem to leak a brelse().
+same for ffsWriteFile.
+
+exfat_core.c - fs_sync(sb,0) all over the place looks fishy as hell.
+There's only one place that calls it with a non-zero argument.
+
+ffsTruncateFile -  if (old_size <= new_size) {
+That doesn't look right. How did it ever work? Are they relying on lazy
+block allocation when actual writes happen? If nothing else, it never
+does the 'fid->size = new_size' and do the inode update....
+
+ffsSetAttr() is just dangling in the breeze, not wired up at all...
diff --git a/drivers/staging/exfat/exfat.h b/drivers/staging/exfat/exfat.h
new file mode 100644
index 000000000000..bae180e10609
--- /dev/null
+++ b/drivers/staging/exfat/exfat.h
@@ -0,0 +1,973 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  Copyright (C) 2012-2013 Samsung Electronics Co., Ltd.
+ */
+
+#ifndef _EXFAT_H
+#define _EXFAT_H
+
+#include <linux/types.h>
+#include <linux/buffer_head.h>
+
+#ifdef CONFIG_EXFAT_KERNEL_DEBUG
+  /* For Debugging Purpose */
+	/* IOCTL code 'f' used by
+	 *   - file systems typically #0~0x1F
+	 *   - embedded terminal devices #128~
+	 *   - exts for debugging purpose #99
+	 * number 100 and 101 is available now but has possible conflicts
+	 */
+#define EXFAT_IOC_GET_DEBUGFLAGS	_IOR('f', 100, long)
+#define EXFAT_IOC_SET_DEBUGFLAGS	_IOW('f', 101, long)
+
+#define EXFAT_DEBUGFLAGS_INVALID_UMOUNT	0x01
+#define EXFAT_DEBUGFLAGS_ERROR_RW	0x02
+#endif /* CONFIG_EXFAT_KERNEL_DEBUG */
+
+#ifdef CONFIG_EXFAT_DEBUG_MSG
+#define DEBUG	1
+#else
+#undef DEBUG
+#endif
+
+#define DENTRY_SIZE		32	/* dir entry size */
+#define DENTRY_SIZE_BITS	5
+
+/* PBR entries */
+#define PBR_SIGNATURE	0xAA55
+#define EXT_SIGNATURE	0xAA550000
+#define VOL_LABEL	"NO NAME    "	/* size should be 11 */
+#define OEM_NAME	"MSWIN4.1"	/* size should be 8 */
+#define STR_FAT12	"FAT12   "	/* size should be 8 */
+#define STR_FAT16	"FAT16   "	/* size should be 8 */
+#define STR_FAT32	"FAT32   "	/* size should be 8 */
+#define STR_EXFAT	"EXFAT   "	/* size should be 8 */
+#define VOL_CLEAN	0x0000
+#define VOL_DIRTY	0x0002
+
+/* max number of clusters */
+#define FAT12_THRESHOLD		4087		/* 2^12 - 1 + 2 (clu 0 & 1) */
+#define FAT16_THRESHOLD		65527		/* 2^16 - 1 + 2 */
+#define FAT32_THRESHOLD		268435457	/* 2^28 - 1 + 2 */
+#define EXFAT_THRESHOLD		268435457	/* 2^28 - 1 + 2 */
+
+/* file types */
+#define TYPE_UNUSED		0x0000
+#define TYPE_DELETED		0x0001
+#define TYPE_INVALID		0x0002
+#define TYPE_CRITICAL_PRI	0x0100
+#define TYPE_BITMAP		0x0101
+#define TYPE_UPCASE		0x0102
+#define TYPE_VOLUME		0x0103
+#define TYPE_DIR		0x0104
+#define TYPE_FILE		0x011F
+#define TYPE_SYMLINK		0x015F
+#define TYPE_CRITICAL_SEC	0x0200
+#define TYPE_STREAM		0x0201
+#define TYPE_EXTEND		0x0202
+#define TYPE_ACL		0x0203
+#define TYPE_BENIGN_PRI		0x0400
+#define TYPE_GUID		0x0401
+#define TYPE_PADDING		0x0402
+#define TYPE_ACLTAB		0x0403
+#define TYPE_BENIGN_SEC		0x0800
+#define TYPE_ALL		0x0FFF
+
+/* time modes */
+#define TM_CREATE		0
+#define TM_MODIFY		1
+#define TM_ACCESS		2
+
+/* checksum types */
+#define CS_DIR_ENTRY		0
+#define CS_PBR_SECTOR		1
+#define CS_DEFAULT		2
+
+#define CLUSTER_16(x)		((u16)(x))
+#define CLUSTER_32(x)		((u32)(x))
+
+#define FALSE			0
+#define TRUE			1
+
+#define START_SECTOR(x)							\
+	((((sector_t)((x) - 2)) << p_fs->sectors_per_clu_bits) +	\
+	 p_fs->data_start_sector)
+
+#define IS_LAST_SECTOR_IN_CLUSTER(sec)				\
+	((((sec) - p_fs->data_start_sector + 1) &		\
+	  ((1 <<  p_fs->sectors_per_clu_bits) - 1)) == 0)
+
+#define GET_CLUSTER_FROM_SECTOR(sec)				\
+	((u32)((((sec) - p_fs->data_start_sector) >>		\
+		p_fs->sectors_per_clu_bits) + 2))
+
+#define GET16(p_src)						\
+	(((u16)(p_src)[0]) | (((u16)(p_src)[1]) << 8))
+#define GET32(p_src)						\
+	(((u32)(p_src)[0]) | (((u32)(p_src)[1]) << 8) |		\
+	(((u32)(p_src)[2]) << 16) | (((u32)(p_src)[3]) << 24))
+#define GET64(p_src) \
+	(((u64)(p_src)[0]) | (((u64)(p_src)[1]) << 8) |		\
+	(((u64)(p_src)[2]) << 16) | (((u64)(p_src)[3]) << 24) |	\
+	(((u64)(p_src)[4]) << 32) | (((u64)(p_src)[5]) << 40) |	\
+	(((u64)(p_src)[6]) << 48) | (((u64)(p_src)[7]) << 56))
+
+#define SET16(p_dst, src)					\
+	do {							\
+		(p_dst)[0] = (u8)(src);				\
+		(p_dst)[1] = (u8)(((u16)(src)) >> 8);		\
+	} while (0)
+#define SET32(p_dst, src)					\
+	do {							\
+		(p_dst)[0] = (u8)(src);				\
+		(p_dst)[1] = (u8)(((u32)(src)) >> 8);		\
+		(p_dst)[2] = (u8)(((u32)(src)) >> 16);		\
+		(p_dst)[3] = (u8)(((u32)(src)) >> 24);		\
+	} while (0)
+#define SET64(p_dst, src)					\
+	do {							\
+		(p_dst)[0] = (u8)(src);				\
+		(p_dst)[1] = (u8)(((u64)(src)) >> 8);		\
+		(p_dst)[2] = (u8)(((u64)(src)) >> 16);		\
+		(p_dst)[3] = (u8)(((u64)(src)) >> 24);		\
+		(p_dst)[4] = (u8)(((u64)(src)) >> 32);		\
+		(p_dst)[5] = (u8)(((u64)(src)) >> 40);		\
+		(p_dst)[6] = (u8)(((u64)(src)) >> 48);		\
+		(p_dst)[7] = (u8)(((u64)(src)) >> 56);		\
+	} while (0)
+
+#ifdef __LITTLE_ENDIAN
+#define GET16_A(p_src)		(*((u16 *)(p_src)))
+#define GET32_A(p_src)		(*((u32 *)(p_src)))
+#define GET64_A(p_src)		(*((u64 *)(p_src)))
+#define SET16_A(p_dst, src)	(*((u16 *)(p_dst)) = (u16)(src))
+#define SET32_A(p_dst, src)	(*((u32 *)(p_dst)) = (u32)(src))
+#define SET64_A(p_dst, src)	(*((u64 *)(p_dst)) = (u64)(src))
+#else /* BIG_ENDIAN */
+#define GET16_A(p_src)		GET16(p_src)
+#define GET32_A(p_src)		GET32(p_src)
+#define GET64_A(p_src)		GET64(p_src)
+#define SET16_A(p_dst, src)	SET16(p_dst, src)
+#define SET32_A(p_dst, src)	SET32(p_dst, src)
+#define SET64_A(p_dst, src)	SET64(p_dst, src)
+#endif
+
+/* cache size (in number of sectors) */
+/* (should be an exponential value of 2) */
+#define FAT_CACHE_SIZE		128
+#define FAT_CACHE_HASH_SIZE	64
+#define BUF_CACHE_SIZE		256
+#define BUF_CACHE_HASH_SIZE	64
+
+/* Upcase table macro */
+#define HIGH_INDEX_BIT	(8)
+#define HIGH_INDEX_MASK	(0xFF00)
+#define LOW_INDEX_BIT	(16-HIGH_INDEX_BIT)
+#define UTBL_ROW_COUNT	(1<<LOW_INDEX_BIT)
+#define UTBL_COL_COUNT	(1<<HIGH_INDEX_BIT)
+
+static inline u16 get_col_index(u16 i)
+{
+	return i >> LOW_INDEX_BIT;
+}
+static inline u16 get_row_index(u16 i)
+{
+	return i & ~HIGH_INDEX_MASK;
+}
+
+#define EXFAT_SUPER_MAGIC       (0x2011BAB0L)
+#define EXFAT_ROOT_INO          1
+
+/* FAT types */
+#define FAT12			0x01	/* FAT12 */
+#define FAT16			0x0E	/* Win95 FAT16 (LBA) */
+#define FAT32			0x0C	/* Win95 FAT32 (LBA) */
+#define EXFAT			0x07	/* exFAT */
+
+/* file name lengths */
+#define MAX_CHARSET_SIZE	3	/* max size of multi-byte character */
+#define MAX_PATH_DEPTH		15	/* max depth of path name */
+#define MAX_NAME_LENGTH		256	/* max len of filename including NULL */
+#define MAX_PATH_LENGTH		260	/* max len of pathname including NULL */
+#define DOS_NAME_LENGTH		11	/* DOS filename length excluding NULL */
+#define DOS_PATH_LENGTH		80	/* DOS pathname length excluding NULL */
+
+/* file attributes */
+#define ATTR_NORMAL		0x0000
+#define ATTR_READONLY		0x0001
+#define ATTR_HIDDEN		0x0002
+#define ATTR_SYSTEM		0x0004
+#define ATTR_VOLUME		0x0008
+#define ATTR_SUBDIR		0x0010
+#define ATTR_ARCHIVE		0x0020
+#define ATTR_SYMLINK		0x0040
+#define ATTR_EXTEND		0x000F
+#define ATTR_RWMASK		0x007E
+
+/* file creation modes */
+#define FM_REGULAR              0x00
+#define FM_SYMLINK              0x40
+
+/* return values */
+#define FFS_SUCCESS             0
+#define FFS_MEDIAERR            1
+#define FFS_FORMATERR           2
+#define FFS_MOUNTED             3
+#define FFS_NOTMOUNTED          4
+#define FFS_ALIGNMENTERR        5
+#define FFS_SEMAPHOREERR        6
+#define FFS_INVALIDPATH         7
+#define FFS_INVALIDFID          8
+#define FFS_NOTFOUND            9
+#define FFS_FILEEXIST           10
+#define FFS_PERMISSIONERR       11
+#define FFS_NOTOPENED           12
+#define FFS_MAXOPENED           13
+#define FFS_FULL                14
+#define FFS_EOF                 15
+#define FFS_DIRBUSY             16
+#define FFS_MEMORYERR           17
+#define FFS_NAMETOOLONG		18
+#define FFS_ERROR               19
+
+#define NUM_UPCASE              2918
+
+#define DOS_CUR_DIR_NAME        ".          "
+#define DOS_PAR_DIR_NAME        "..         "
+
+#ifdef __LITTLE_ENDIAN
+#define UNI_CUR_DIR_NAME        ".\0"
+#define UNI_PAR_DIR_NAME        ".\0.\0"
+#else
+#define UNI_CUR_DIR_NAME        "\0."
+#define UNI_PAR_DIR_NAME        "\0.\0."
+#endif
+
+struct date_time_t {
+	u16      Year;
+	u16      Month;
+	u16      Day;
+	u16      Hour;
+	u16      Minute;
+	u16      Second;
+	u16      MilliSecond;
+};
+
+struct part_info_t {
+	u32      Offset;    /* start sector number of the partition */
+	u32      Size;      /* in sectors */
+};
+
+struct dev_info_t {
+	u32      SecSize;    /* sector size in bytes */
+	u32      DevSize;    /* block device size in sectors */
+};
+
+struct vol_info_t {
+	u32      FatType;
+	u32      ClusterSize;
+	u32      NumClusters;
+	u32      FreeClusters;
+	u32      UsedClusters;
+};
+
+/* directory structure */
+struct chain_t {
+	u32      dir;
+	s32       size;
+	u8       flags;
+};
+
+struct file_id_t {
+	struct chain_t     dir;
+	s32       entry;
+	u32      type;
+	u32      attr;
+	u32      start_clu;
+	u64      size;
+	u8       flags;
+	s64       rwoffset;
+	s32       hint_last_off;
+	u32      hint_last_clu;
+};
+
+struct dir_entry_t {
+	char Name[MAX_NAME_LENGTH * MAX_CHARSET_SIZE];
+
+	/* used only for FAT12/16/32, not used for exFAT */
+	char ShortName[DOS_NAME_LENGTH + 2];
+
+	u32 Attr;
+	u64 Size;
+	u32 NumSubdirs;
+	struct date_time_t CreateTimestamp;
+	struct date_time_t ModifyTimestamp;
+	struct date_time_t AccessTimestamp;
+};
+
+struct timestamp_t {
+	u16      sec;        /* 0 ~ 59               */
+	u16      min;        /* 0 ~ 59               */
+	u16      hour;       /* 0 ~ 23               */
+	u16      day;        /* 1 ~ 31               */
+	u16      mon;        /* 1 ~ 12               */
+	u16      year;       /* 0 ~ 127 (since 1980) */
+};
+
+/* MS_DOS FAT partition boot record (512 bytes) */
+struct pbr_sector_t {
+	u8       jmp_boot[3];
+	u8       oem_name[8];
+	u8       bpb[109];
+	u8       boot_code[390];
+	u8       signature[2];
+};
+
+/* MS-DOS FAT12/16 BIOS parameter block (51 bytes) */
+struct bpb16_t {
+	u8       sector_size[2];
+	u8       sectors_per_clu;
+	u8       num_reserved[2];
+	u8       num_fats;
+	u8       num_root_entries[2];
+	u8       num_sectors[2];
+	u8       media_type;
+	u8       num_fat_sectors[2];
+	u8       sectors_in_track[2];
+	u8       num_heads[2];
+	u8       num_hid_sectors[4];
+	u8       num_huge_sectors[4];
+
+	u8       phy_drv_no;
+	u8       reserved;
+	u8       ext_signature;
+	u8       vol_serial[4];
+	u8       vol_label[11];
+	u8       vol_type[8];
+};
+
+/* MS-DOS FAT32 BIOS parameter block (79 bytes) */
+struct bpb32_t {
+	u8       sector_size[2];
+	u8       sectors_per_clu;
+	u8       num_reserved[2];
+	u8       num_fats;
+	u8       num_root_entries[2];
+	u8       num_sectors[2];
+	u8       media_type;
+	u8       num_fat_sectors[2];
+	u8       sectors_in_track[2];
+	u8       num_heads[2];
+	u8       num_hid_sectors[4];
+	u8       num_huge_sectors[4];
+	u8       num_fat32_sectors[4];
+	u8       ext_flags[2];
+	u8       fs_version[2];
+	u8       root_cluster[4];
+	u8       fsinfo_sector[2];
+	u8       backup_sector[2];
+	u8       reserved[12];
+
+	u8       phy_drv_no;
+	u8       ext_reserved;
+	u8       ext_signature;
+	u8       vol_serial[4];
+	u8       vol_label[11];
+	u8       vol_type[8];
+};
+
+/* MS-DOS EXFAT BIOS parameter block (109 bytes) */
+struct bpbex_t {
+	u8       reserved1[53];
+	u8       vol_offset[8];
+	u8       vol_length[8];
+	u8       fat_offset[4];
+	u8       fat_length[4];
+	u8       clu_offset[4];
+	u8       clu_count[4];
+	u8       root_cluster[4];
+	u8       vol_serial[4];
+	u8       fs_version[2];
+	u8       vol_flags[2];
+	u8       sector_size_bits;
+	u8       sectors_per_clu_bits;
+	u8       num_fats;
+	u8       phy_drv_no;
+	u8       perc_in_use;
+	u8       reserved2[7];
+};
+
+/* MS-DOS FAT file system information sector (512 bytes) */
+struct fsi_sector_t {
+	u8       signature1[4];
+	u8       reserved1[480];
+	u8       signature2[4];
+	u8       free_cluster[4];
+	u8       next_cluster[4];
+	u8       reserved2[14];
+	u8       signature3[2];
+};
+
+/* MS-DOS FAT directory entry (32 bytes) */
+struct dentry_t {
+	u8       dummy[32];
+};
+
+struct dos_dentry_t {
+	u8       name[DOS_NAME_LENGTH];
+	u8       attr;
+	u8       lcase;
+	u8       create_time_ms;
+	u8       create_time[2];
+	u8       create_date[2];
+	u8       access_date[2];
+	u8       start_clu_hi[2];
+	u8       modify_time[2];
+	u8       modify_date[2];
+	u8       start_clu_lo[2];
+	u8       size[4];
+};
+
+/* MS-DOS FAT extended directory entry (32 bytes) */
+struct ext_dentry_t {
+	u8       order;
+	u8       unicode_0_4[10];
+	u8       attr;
+	u8       sysid;
+	u8       checksum;
+	u8       unicode_5_10[12];
+	u8       start_clu[2];
+	u8       unicode_11_12[4];
+};
+
+/* MS-DOS EXFAT file directory entry (32 bytes) */
+struct file_dentry_t {
+	u8       type;
+	u8       num_ext;
+	u8       checksum[2];
+	u8       attr[2];
+	u8       reserved1[2];
+	u8       create_time[2];
+	u8       create_date[2];
+	u8       modify_time[2];
+	u8       modify_date[2];
+	u8       access_time[2];
+	u8       access_date[2];
+	u8       create_time_ms;
+	u8       modify_time_ms;
+	u8       access_time_ms;
+	u8       reserved2[9];
+};
+
+/* MS-DOS EXFAT stream extension directory entry (32 bytes) */
+struct strm_dentry_t {
+	u8       type;
+	u8       flags;
+	u8       reserved1;
+	u8       name_len;
+	u8       name_hash[2];
+	u8       reserved2[2];
+	u8       valid_size[8];
+	u8       reserved3[4];
+	u8       start_clu[4];
+	u8       size[8];
+};
+
+/* MS-DOS EXFAT file name directory entry (32 bytes) */
+struct name_dentry_t {
+	u8       type;
+	u8       flags;
+	u8       unicode_0_14[30];
+};
+
+/* MS-DOS EXFAT allocation bitmap directory entry (32 bytes) */
+struct bmap_dentry_t {
+	u8       type;
+	u8       flags;
+	u8       reserved[18];
+	u8       start_clu[4];
+	u8       size[8];
+};
+
+/* MS-DOS EXFAT up-case table directory entry (32 bytes) */
+struct case_dentry_t {
+	u8       type;
+	u8       reserved1[3];
+	u8       checksum[4];
+	u8       reserved2[12];
+	u8       start_clu[4];
+	u8       size[8];
+};
+
+/* MS-DOS EXFAT volume label directory entry (32 bytes) */
+struct volm_dentry_t {
+	u8       type;
+	u8       label_len;
+	u8       unicode_0_10[22];
+	u8       reserved[8];
+};
+
+/* unused entry hint information */
+struct uentry_t {
+	u32      dir;
+	s32       entry;
+	struct chain_t     clu;
+};
+
+/* DOS name structure */
+struct dos_name_t {
+	u8       name[DOS_NAME_LENGTH];
+	u8       name_case;
+};
+
+/* unicode name structure */
+struct uni_name_t {
+	u16      name[MAX_NAME_LENGTH];
+	u16      name_hash;
+	u8       name_len;
+};
+
+struct buf_cache_t {
+	struct buf_cache_t *next;
+	struct buf_cache_t *prev;
+	struct buf_cache_t *hash_next;
+	struct buf_cache_t *hash_prev;
+	s32                drv;
+	sector_t          sec;
+	u32               flag;
+	struct buffer_head   *buf_bh;
+};
+
+struct fs_func {
+	s32	(*alloc_cluster)(struct super_block *sb, s32 num_alloc,
+				 struct chain_t *p_chain);
+	void	(*free_cluster)(struct super_block *sb, struct chain_t *p_chain,
+				s32 do_relse);
+	s32	(*count_used_clusters)(struct super_block *sb);
+
+	s32	(*init_dir_entry)(struct super_block *sb, struct chain_t *p_dir,
+				  s32 entry, u32 type, u32 start_clu, u64 size);
+	s32	(*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);
+	s32	(*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);
+	void	(*delete_dir_entry)(struct super_block *sb,
+				    struct chain_t *p_dir, s32 entry,
+				    s32 offset, s32 num_entries);
+	void	(*get_uni_name_from_ext_entry)(struct super_block *sb,
+					       struct chain_t *p_dir, s32 entry,
+					       u16 *uniname);
+	s32	(*count_ext_entries)(struct super_block *sb,
+				     struct chain_t *p_dir, s32 entry,
+				     struct dentry_t *p_entry);
+	s32	(*calc_num_entries)(struct uni_name_t *p_uniname);
+
+	u32	(*get_entry_type)(struct dentry_t *p_entry);
+	void	(*set_entry_type)(struct dentry_t *p_entry, u32 type);
+	u32	(*get_entry_attr)(struct dentry_t *p_entry);
+	void	(*set_entry_attr)(struct dentry_t *p_entry, u32 attr);
+	u8	(*get_entry_flag)(struct dentry_t *p_entry);
+	void	(*set_entry_flag)(struct dentry_t *p_entry, u8 flag);
+	u32	(*get_entry_clu0)(struct dentry_t *p_entry);
+	void	(*set_entry_clu0)(struct dentry_t *p_entry, u32 clu0);
+	u64	(*get_entry_size)(struct dentry_t *p_entry);
+	void	(*set_entry_size)(struct dentry_t *p_entry, u64 size);
+	void	(*get_entry_time)(struct dentry_t *p_entry,
+				  struct timestamp_t *tp, u8 mode);
+	void	(*set_entry_time)(struct dentry_t *p_entry,
+				  struct timestamp_t *tp, u8 mode);
+};
+
+struct fs_info_t {
+	u32      drv;                    /* drive ID */
+	u32      vol_type;               /* volume FAT type */
+	u32      vol_id;                 /* volume serial number */
+
+	u64      num_sectors;            /* num of sectors in volume */
+	u32      num_clusters;           /* num of clusters in volume */
+	u32      cluster_size;           /* cluster size in bytes */
+	u32      cluster_size_bits;
+	u32      sectors_per_clu;        /* cluster size in sectors */
+	u32      sectors_per_clu_bits;
+
+	u32      PBR_sector;             /* PBR sector */
+	u32      FAT1_start_sector;      /* FAT1 start sector */
+	u32      FAT2_start_sector;      /* FAT2 start sector */
+	u32      root_start_sector;      /* root dir start sector */
+	u32      data_start_sector;      /* data area start sector */
+	u32      num_FAT_sectors;        /* num of FAT sectors */
+
+	u32      root_dir;               /* root dir cluster */
+	u32      dentries_in_root;       /* num of dentries in root dir */
+	u32      dentries_per_clu;       /* num of dentries per cluster */
+
+	u32      vol_flag;               /* volume dirty flag */
+	struct buffer_head *pbr_bh;         /* PBR sector */
+
+	u32      map_clu;                /* allocation bitmap start cluster */
+	u32      map_sectors;            /* num of allocation bitmap sectors */
+	struct buffer_head **vol_amap;      /* allocation bitmap */
+
+	u16 **vol_utbl;			/* upcase table */
+
+	u32 clu_srch_ptr;		/* cluster search pointer */
+	u32 used_clusters;		/* number of used clusters */
+	struct uentry_t hint_uentry;	/* unused entry hint information */
+
+	u32 dev_ejected;	/* block device operation error flag */
+
+	struct fs_func *fs_func;
+	struct semaphore v_sem;
+
+	/* FAT cache */
+	struct buf_cache_t FAT_cache_array[FAT_CACHE_SIZE];
+	struct buf_cache_t FAT_cache_lru_list;
+	struct buf_cache_t FAT_cache_hash_list[FAT_CACHE_HASH_SIZE];
+
+	/* buf cache */
+	struct buf_cache_t buf_cache_array[BUF_CACHE_SIZE];
+	struct buf_cache_t buf_cache_lru_list;
+	struct buf_cache_t buf_cache_hash_list[BUF_CACHE_HASH_SIZE];
+};
+
+#define ES_2_ENTRIES		2
+#define ES_3_ENTRIES		3
+#define ES_ALL_ENTRIES		0
+
+struct entry_set_cache_t {
+	/* sector number that contains file_entry */
+	sector_t sector;
+
+	/* byte offset in the sector */
+	s32 offset;
+
+	/*
+	 * flag in stream entry.
+	 * 01 for cluster chain,
+	 * 03 for contig. clusteres.
+	 */
+	s32 alloc_flag;
+
+	u32 num_entries;
+
+	/* __buf should be the last member */
+	void *__buf;
+};
+
+#define EXFAT_ERRORS_CONT	1	/* ignore error and continue */
+#define EXFAT_ERRORS_PANIC	2	/* panic on error */
+#define EXFAT_ERRORS_RO		3	/* remount r/o on error */
+
+/* ioctl command */
+#define EXFAT_IOCTL_GET_VOLUME_ID _IOR('r', 0x12, __u32)
+
+struct exfat_mount_options {
+	kuid_t fs_uid;
+	kgid_t fs_gid;
+	unsigned short fs_fmask;
+	unsigned short fs_dmask;
+
+	/* permission for setting the [am]time */
+	unsigned short allow_utime;
+
+	/* codepage for shortname conversions */
+	unsigned short codepage;
+
+	/* charset for filename input/display */
+	char *iocharset;
+
+	unsigned char casesensitive;
+
+	/* on error: continue, panic, remount-ro */
+	unsigned char errors;
+#ifdef CONFIG_EXFAT_DISCARD
+	/* flag on if -o dicard specified and device support discard() */
+	unsigned char discard;
+#endif /* CONFIG_EXFAT_DISCARD */
+};
+
+#define EXFAT_HASH_BITS		8
+#define EXFAT_HASH_SIZE		(1UL << EXFAT_HASH_BITS)
+
+/*
+ * EXFAT file system in-core superblock data
+ */
+struct bd_info_t {
+	s32 sector_size;	/* in bytes */
+	s32 sector_size_bits;
+	s32 sector_size_mask;
+
+	/* total number of sectors in this block device */
+	s32 num_sectors;
+
+	/* opened or not */
+	bool opened;
+};
+
+struct exfat_sb_info {
+	struct fs_info_t fs_info;
+	struct bd_info_t bd_info;
+
+	struct exfat_mount_options options;
+
+	int s_dirt;
+	struct mutex s_lock;
+	struct nls_table *nls_disk; /* Codepage used on disk */
+	struct nls_table *nls_io;   /* Charset used for input and display */
+
+	struct inode *fat_inode;
+
+	spinlock_t inode_hash_lock;
+	struct hlist_head inode_hashtable[EXFAT_HASH_SIZE];
+#ifdef CONFIG_EXFAT_KERNEL_DEBUG
+	long debug_flags;
+#endif /* CONFIG_EXFAT_KERNEL_DEBUG */
+};
+
+/*
+ * EXFAT file system inode data in memory
+ */
+struct exfat_inode_info {
+	struct file_id_t fid;
+	char  *target;
+	/* NOTE: mmu_private is 64bits, so must hold ->i_mutex to access */
+	loff_t mmu_private;	/* physically allocated size */
+	loff_t i_pos;		/* on-disk position of directory entry or 0 */
+	struct hlist_node i_hash_fat;	/* hash by i_location */
+	struct rw_semaphore truncate_lock;
+	struct inode vfs_inode;
+	struct rw_semaphore i_alloc_sem; /* protect bmap against truncate */
+};
+
+#define EXFAT_SB(sb)		((struct exfat_sb_info *)((sb)->s_fs_info))
+
+static inline struct exfat_inode_info *EXFAT_I(struct inode *inode)
+{
+	return container_of(inode, struct exfat_inode_info, vfs_inode);
+}
+
+/* NLS management function */
+u16 nls_upper(struct super_block *sb, u16 a);
+int nls_dosname_cmp(struct super_block *sb, u8 *a, u8 *b);
+int nls_uniname_cmp(struct super_block *sb, u16 *a, u16 *b);
+void nls_uniname_to_dosname(struct super_block *sb,
+			    struct dos_name_t *p_dosname,
+			    struct uni_name_t *p_uniname, bool *p_lossy);
+void nls_dosname_to_uniname(struct super_block *sb,
+			    struct uni_name_t *p_uniname,
+			    struct dos_name_t *p_dosname);
+void nls_uniname_to_cstring(struct super_block *sb, u8 *p_cstring,
+			    struct uni_name_t *p_uniname);
+void nls_cstring_to_uniname(struct super_block *sb,
+			    struct uni_name_t *p_uniname, u8 *p_cstring,
+			    bool *p_lossy);
+
+/* buffer cache management */
+void buf_init(struct super_block *sb);
+void buf_shutdown(struct super_block *sb);
+int FAT_read(struct super_block *sb, u32 loc, u32 *content);
+s32 FAT_write(struct super_block *sb, u32 loc, u32 content);
+u8 *FAT_getblk(struct super_block *sb, sector_t sec);
+void FAT_modify(struct super_block *sb, sector_t sec);
+void FAT_release_all(struct super_block *sb);
+void FAT_sync(struct super_block *sb);
+u8 *buf_getblk(struct super_block *sb, sector_t sec);
+void buf_modify(struct super_block *sb, sector_t sec);
+void buf_lock(struct super_block *sb, sector_t sec);
+void buf_unlock(struct super_block *sb, sector_t sec);
+void buf_release(struct super_block *sb, sector_t sec);
+void buf_release_all(struct super_block *sb);
+void buf_sync(struct super_block *sb);
+
+/* fs management functions */
+void fs_set_vol_flags(struct super_block *sb, u32 new_flag);
+void fs_error(struct super_block *sb);
+
+/* cluster management functions */
+s32 clear_cluster(struct super_block *sb, u32 clu);
+s32 fat_alloc_cluster(struct super_block *sb, s32 num_alloc,
+		      struct chain_t *p_chain);
+s32 exfat_alloc_cluster(struct super_block *sb, s32 num_alloc,
+			struct chain_t *p_chain);
+void fat_free_cluster(struct super_block *sb, struct chain_t *p_chain,
+		      s32 do_relse);
+void exfat_free_cluster(struct super_block *sb, struct chain_t *p_chain,
+			s32 do_relse);
+u32 find_last_cluster(struct super_block *sb, struct chain_t *p_chain);
+s32 count_num_clusters(struct super_block *sb, struct chain_t *dir);
+s32 fat_count_used_clusters(struct super_block *sb);
+s32 exfat_count_used_clusters(struct super_block *sb);
+void exfat_chain_cont_cluster(struct super_block *sb, u32 chain, s32 len);
+
+/* allocation bitmap management functions */
+s32 load_alloc_bitmap(struct super_block *sb);
+void free_alloc_bitmap(struct super_block *sb);
+s32 set_alloc_bitmap(struct super_block *sb, u32 clu);
+s32 clr_alloc_bitmap(struct super_block *sb, u32 clu);
+u32 test_alloc_bitmap(struct super_block *sb, u32 clu);
+void sync_alloc_bitmap(struct super_block *sb);
+
+/* upcase table management functions */
+s32 load_upcase_table(struct super_block *sb);
+void free_upcase_table(struct super_block *sb);
+
+/* dir entry management functions */
+u32 fat_get_entry_type(struct dentry_t *p_entry);
+u32 exfat_get_entry_type(struct dentry_t *p_entry);
+void fat_set_entry_type(struct dentry_t *p_entry, u32 type);
+void exfat_set_entry_type(struct dentry_t *p_entry, u32 type);
+u32 fat_get_entry_attr(struct dentry_t *p_entry);
+u32 exfat_get_entry_attr(struct dentry_t *p_entry);
+void fat_set_entry_attr(struct dentry_t *p_entry, u32 attr);
+void exfat_set_entry_attr(struct dentry_t *p_entry, u32 attr);
+u8 fat_get_entry_flag(struct dentry_t *p_entry);
+u8 exfat_get_entry_flag(struct dentry_t *p_entry);
+void fat_set_entry_flag(struct dentry_t *p_entry, u8 flag);
+void exfat_set_entry_flag(struct dentry_t *p_entry, u8 flag);
+u32 fat_get_entry_clu0(struct dentry_t *p_entry);
+u32 exfat_get_entry_clu0(struct dentry_t *p_entry);
+void fat_set_entry_clu0(struct dentry_t *p_entry, u32 start_clu);
+void exfat_set_entry_clu0(struct dentry_t *p_entry, u32 start_clu);
+u64 fat_get_entry_size(struct dentry_t *p_entry);
+u64 exfat_get_entry_size(struct dentry_t *p_entry);
+void fat_set_entry_size(struct dentry_t *p_entry, u64 size);
+void exfat_set_entry_size(struct dentry_t *p_entry, u64 size);
+struct timestamp_t *tm_current(struct timestamp_t *tm);
+void fat_get_entry_time(struct dentry_t *p_entry, struct timestamp_t *tp,
+			u8 mode);
+void exfat_get_entry_time(struct dentry_t *p_entry, struct timestamp_t *tp,
+			  u8 mode);
+void fat_set_entry_time(struct dentry_t *p_entry, struct timestamp_t *tp,
+			u8 mode);
+void exfat_set_entry_time(struct dentry_t *p_entry, struct timestamp_t *tp,
+			  u8 mode);
+s32 fat_init_dir_entry(struct super_block *sb, struct chain_t *p_dir, s32 entry,
+		       u32 type, u32 start_clu, u64 size);
+s32 exfat_init_dir_entry(struct super_block *sb, struct chain_t *p_dir,
+			 s32 entry, u32 type, u32 start_clu, u64 size);
+s32 fat_init_ext_dir_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);
+s32 exfat_init_ext_dir_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);
+void init_dos_entry(struct dos_dentry_t *ep, u32 type, u32 start_clu);
+void init_ext_entry(struct ext_dentry_t *ep, s32 order, u8 chksum,
+		    u16 *uniname);
+void init_file_entry(struct file_dentry_t *ep, u32 type);
+void init_strm_entry(struct strm_dentry_t *ep, u8 flags, u32 start_clu,
+		     u64 size);
+void init_name_entry(struct name_dentry_t *ep, u16 *uniname);
+void fat_delete_dir_entry(struct super_block *sb, struct chain_t *p_dir,
+			  s32 entry, s32 order, s32 num_entries);
+void exfat_delete_dir_entry(struct super_block *sb, struct chain_t *p_dir,
+			    s32 entry, s32 order, s32 num_entries);
+
+s32 find_location(struct super_block *sb, struct chain_t *p_dir, s32 entry,
+		  sector_t *sector, s32 *offset);
+struct dentry_t *get_entry_with_sector(struct super_block *sb, sector_t sector,
+				       s32 offset);
+struct dentry_t *get_entry_in_dir(struct super_block *sb, struct chain_t *p_dir,
+				  s32 entry, sector_t *sector);
+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);
+void release_entry_set(struct entry_set_cache_t *es);
+s32 write_whole_entry_set(struct super_block *sb, struct entry_set_cache_t *es);
+s32 write_partial_entries_in_entry_set(struct super_block *sb,
+				       struct entry_set_cache_t *es,
+				       struct dentry_t *ep, u32 count);
+s32 search_deleted_or_unused_entry(struct super_block *sb,
+				   struct chain_t *p_dir, s32 num_entries);
+s32 find_empty_entry(struct inode *inode, struct chain_t *p_dir,
+		     s32 num_entries);
+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);
+s32 exfat_find_dir_entry(struct super_block *sb, struct chain_t *p_dir,
+			 struct uni_name_t