There is no documented methods to mark FAT as dirty. Unofficially MS started to use reserved Byte in boot sector for this purpose, at least since Win 2000. With Win 7 user is warned if fs is dirty and asked to clean it. Different versions of Win, handle it in different ways, but always have same meaning: - Win 2000 and XP, set it on write operations and remove it after operation was finnished - Win 7, set dirty flag on first write and remove it on umount. We will do it as follows: - set dirty flag on mount. If fs was initially dirty, warn user, remember it and do not do any changes to boot sector. - clean it on umount. If fs was initially dirty, leave it dirty. - do not do any thing if fs mounted read-only. - TODO: leave fs dirty if we found some error after mount. Signed-off-by: Oleksij Rempel <bug-track@fisher-privat.net> Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
		
			
				
	
	
		
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			189 lines
		
	
	
	
		
			6.3 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
#ifndef _UAPI_LINUX_MSDOS_FS_H
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#define _UAPI_LINUX_MSDOS_FS_H
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#include <linux/types.h>
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#include <linux/magic.h>
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#include <asm/byteorder.h>
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/*
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 * The MS-DOS filesystem constants/structures
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 */
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#define SECTOR_SIZE	512		/* sector size (bytes) */
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#define SECTOR_BITS	9		/* log2(SECTOR_SIZE) */
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#define MSDOS_DPB	(MSDOS_DPS)	/* dir entries per block */
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#define MSDOS_DPB_BITS	4		/* log2(MSDOS_DPB) */
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#define MSDOS_DPS	(SECTOR_SIZE / sizeof(struct msdos_dir_entry))
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#define MSDOS_DPS_BITS	4		/* log2(MSDOS_DPS) */
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#define MSDOS_LONGNAME	256		/* maximum name length */
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#define CF_LE_W(v)	le16_to_cpu(v)
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#define CF_LE_L(v)	le32_to_cpu(v)
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#define CT_LE_W(v)	cpu_to_le16(v)
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#define CT_LE_L(v)	cpu_to_le32(v)
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#define MSDOS_ROOT_INO	 1	/* The root inode number */
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#define MSDOS_FSINFO_INO 2	/* Used for managing the FSINFO block */
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#define MSDOS_DIR_BITS	5	/* log2(sizeof(struct msdos_dir_entry)) */
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/* directory limit */
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#define FAT_MAX_DIR_ENTRIES	(65536)
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#define FAT_MAX_DIR_SIZE	(FAT_MAX_DIR_ENTRIES << MSDOS_DIR_BITS)
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#define ATTR_NONE	0	/* no attribute bits */
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#define ATTR_RO		1	/* read-only */
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#define ATTR_HIDDEN	2	/* hidden */
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#define ATTR_SYS	4	/* system */
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#define ATTR_VOLUME	8	/* volume label */
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#define ATTR_DIR	16	/* directory */
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#define ATTR_ARCH	32	/* archived */
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/* attribute bits that are copied "as is" */
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#define ATTR_UNUSED	(ATTR_VOLUME | ATTR_ARCH | ATTR_SYS | ATTR_HIDDEN)
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/* bits that are used by the Windows 95/Windows NT extended FAT */
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#define ATTR_EXT	(ATTR_RO | ATTR_HIDDEN | ATTR_SYS | ATTR_VOLUME)
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#define CASE_LOWER_BASE	8	/* base is lower case */
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#define CASE_LOWER_EXT	16	/* extension is lower case */
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#define DELETED_FLAG	0xe5	/* marks file as deleted when in name[0] */
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#define IS_FREE(n)	(!*(n) || *(n) == DELETED_FLAG)
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#define FAT_LFN_LEN	255	/* maximum long name length */
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#define MSDOS_NAME	11	/* maximum name length */
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#define MSDOS_SLOTS	21	/* max # of slots for short and long names */
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#define MSDOS_DOT	".          "	/* ".", padded to MSDOS_NAME chars */
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#define MSDOS_DOTDOT	"..         "	/* "..", padded to MSDOS_NAME chars */
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#define FAT_FIRST_ENT(s, x)	((MSDOS_SB(s)->fat_bits == 32 ? 0x0FFFFF00 : \
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	MSDOS_SB(s)->fat_bits == 16 ? 0xFF00 : 0xF00) | (x))
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/* start of data cluster's entry (number of reserved clusters) */
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#define FAT_START_ENT	2
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/* maximum number of clusters */
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#define MAX_FAT12	0xFF4
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#define MAX_FAT16	0xFFF4
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#define MAX_FAT32	0x0FFFFFF6
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#define MAX_FAT(s)	(MSDOS_SB(s)->fat_bits == 32 ? MAX_FAT32 : \
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	MSDOS_SB(s)->fat_bits == 16 ? MAX_FAT16 : MAX_FAT12)
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/* bad cluster mark */
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#define BAD_FAT12	0xFF7
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#define BAD_FAT16	0xFFF7
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#define BAD_FAT32	0x0FFFFFF7
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/* standard EOF */
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#define EOF_FAT12	0xFFF
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#define EOF_FAT16	0xFFFF
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#define EOF_FAT32	0x0FFFFFFF
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#define FAT_ENT_FREE	(0)
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#define FAT_ENT_BAD	(BAD_FAT32)
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#define FAT_ENT_EOF	(EOF_FAT32)
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#define FAT_FSINFO_SIG1	0x41615252
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#define FAT_FSINFO_SIG2	0x61417272
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#define IS_FSINFO(x)	(le32_to_cpu((x)->signature1) == FAT_FSINFO_SIG1 \
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			 && le32_to_cpu((x)->signature2) == FAT_FSINFO_SIG2)
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#define FAT_STATE_DIRTY 0x01
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struct __fat_dirent {
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	long		d_ino;
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	__kernel_off_t	d_off;
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	unsigned short	d_reclen;
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	char		d_name[256]; /* We must not include limits.h! */
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};
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/*
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 * ioctl commands
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 */
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#define VFAT_IOCTL_READDIR_BOTH		_IOR('r', 1, struct __fat_dirent[2])
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#define VFAT_IOCTL_READDIR_SHORT	_IOR('r', 2, struct __fat_dirent[2])
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/* <linux/videotext.h> has used 0x72 ('r') in collision, so skip a few */
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#define FAT_IOCTL_GET_ATTRIBUTES	_IOR('r', 0x10, __u32)
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#define FAT_IOCTL_SET_ATTRIBUTES	_IOW('r', 0x11, __u32)
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struct fat_boot_sector {
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	__u8	ignored[3];	/* Boot strap short or near jump */
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	__u8	system_id[8];	/* Name - can be used to special case
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				   partition manager volumes */
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	__u8	sector_size[2];	/* bytes per logical sector */
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	__u8	sec_per_clus;	/* sectors/cluster */
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	__le16	reserved;	/* reserved sectors */
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	__u8	fats;		/* number of FATs */
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	__u8	dir_entries[2];	/* root directory entries */
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	__u8	sectors[2];	/* number of sectors */
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	__u8	media;		/* media code */
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	__le16	fat_length;	/* sectors/FAT */
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	__le16	secs_track;	/* sectors per track */
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	__le16	heads;		/* number of heads */
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	__le32	hidden;		/* hidden sectors (unused) */
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	__le32	total_sect;	/* number of sectors (if sectors == 0) */
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	union {
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		struct {
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			/*  Extended BPB Fields for FAT16 */
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			__u8	drive_number;	/* Physical drive number */
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			__u8	state;		/* undocumented, but used
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						   for mount state. */
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			/* other fiealds are not added here */
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		} fat16;
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		struct {
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			/* only used by FAT32 */
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			__le32	length;		/* sectors/FAT */
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			__le16	flags;		/* bit 8: fat mirroring,
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						   low 4: active fat */
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			__u8	version[2];	/* major, minor filesystem
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						   version */
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			__le32	root_cluster;	/* first cluster in
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						   root directory */
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			__le16	info_sector;	/* filesystem info sector */
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			__le16	backup_boot;	/* backup boot sector */
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			__le16	reserved2[6];	/* Unused */
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			/* Extended BPB Fields for FAT32 */
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			__u8	drive_number;   /* Physical drive number */
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			__u8    state;       	/* undocumented, but used
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						   for mount state. */
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			/* other fiealds are not added here */
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		} fat32;
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	};
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};
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struct fat_boot_fsinfo {
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	__le32   signature1;	/* 0x41615252L */
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	__le32   reserved1[120];	/* Nothing as far as I can tell */
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	__le32   signature2;	/* 0x61417272L */
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	__le32   free_clusters;	/* Free cluster count.  -1 if unknown */
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	__le32   next_cluster;	/* Most recently allocated cluster */
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	__le32   reserved2[4];
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};
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struct msdos_dir_entry {
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	__u8	name[MSDOS_NAME];/* name and extension */
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	__u8	attr;		/* attribute bits */
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	__u8    lcase;		/* Case for base and extension */
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	__u8	ctime_cs;	/* Creation time, centiseconds (0-199) */
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	__le16	ctime;		/* Creation time */
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	__le16	cdate;		/* Creation date */
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	__le16	adate;		/* Last access date */
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	__le16	starthi;	/* High 16 bits of cluster in FAT32 */
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	__le16	time,date,start;/* time, date and first cluster */
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	__le32	size;		/* file size (in bytes) */
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};
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/* Up to 13 characters of the name */
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struct msdos_dir_slot {
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	__u8    id;		/* sequence number for slot */
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	__u8    name0_4[10];	/* first 5 characters in name */
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	__u8    attr;		/* attribute byte */
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	__u8    reserved;	/* always 0 */
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	__u8    alias_checksum;	/* checksum for 8.3 alias */
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	__u8    name5_10[12];	/* 6 more characters in name */
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	__le16   start;		/* starting cluster number, 0 in long slots */
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	__u8    name11_12[4];	/* last 2 characters in name */
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};
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#endif /* _UAPI_LINUX_MSDOS_FS_H */
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