include/linux/ext2_fs.h - linux-mtk - Git at Google


            
            /*

            
             *  linux/include/linux/ext2_fs.h

            
             *

            
             * Copyright (C) 1992, 1993, 1994, 1995

            
             * Remy Card (card@masi.ibp.fr)

            
             * Laboratoire MASI - Institut Blaise Pascal

            
             * Universite Pierre et Marie Curie (Paris VI)

            
             *

            
             *  from

            
             *

            
             *  linux/include/linux/minix_fs.h

            
             *

            
             *  Copyright (C) 1991, 1992  Linus Torvalds

            
             */


            #ifndef _LINUX_EXT2_FS_H

            
            #define _LINUX_EXT2_FS_H


            #include <linux/types.h>

            
            #include <linux/magic.h>


            /*

            
             * The second extended filesystem constants/structures

            
             */


            /*

            
             * Define EXT2FS_DEBUG to produce debug messages

            
             */

            
            #undef EXT2FS_DEBUG


            /*

            
             * Define EXT2_RESERVATION to reserve data blocks for expanding files

            
             */

            
            #define EXT2_DEFAULT_RESERVE_BLOCKS     8

            
            /*max window size: 1024(direct blocks) + 3([t,d]indirect blocks) */

            
            #define EXT2_MAX_RESERVE_BLOCKS         1027

            
            #define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0

            
            /*

            
             * The second extended file system version

            
             */

            
            #define EXT2FS_DATE		"95/08/09"

            
            #define EXT2FS_VERSION		"0.5b"


            /*

            
             * Debug code

            
             */

            
            #ifdef EXT2FS_DEBUG

            
            #	define ext2_debug(f, a...)	{ \

            
            					printk ("EXT2-fs DEBUG (%s, %d): %s:", \

            
            						__FILE__, __LINE__, __func__); \

            
            				  	printk (f, ## a); \

            
            					}

            
            #else

            
            #	define ext2_debug(f, a...)	/**/

            
            #endif


            /*

            
             * Special inode numbers

            
             */

            
            #define	EXT2_BAD_INO		 1	/* Bad blocks inode */

            
            #define EXT2_ROOT_INO		 2	/* Root inode */

            
            #define EXT2_BOOT_LOADER_INO	 5	/* Boot loader inode */

            
            #define EXT2_UNDEL_DIR_INO	 6	/* Undelete directory inode */


            /* First non-reserved inode for old ext2 filesystems */

            
            #define EXT2_GOOD_OLD_FIRST_INO	11


            #ifdef __KERNEL__

            
            #include <linux/ext2_fs_sb.h>

            
            static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb)

            
            {

            
            	return sb->s_fs_info;

            
            }

            
            #else

            
            /* Assume that user mode programs are passing in an ext2fs superblock, not

            
             * a kernel struct super_block.  This will allow us to call the feature-test

            
             * macros from user land. */

            
            #define EXT2_SB(sb)	(sb)

            
            #endif


            /*

            
             * Maximal count of links to a file

            
             */

            
            #define EXT2_LINK_MAX		32000


            /*

            
             * Macro-instructions used to manage several block sizes

            
             */

            
            #define EXT2_MIN_BLOCK_SIZE		1024

            
            #define	EXT2_MAX_BLOCK_SIZE		4096

            
            #define EXT2_MIN_BLOCK_LOG_SIZE		  10

            
            #ifdef __KERNEL__

            
            # define EXT2_BLOCK_SIZE(s)		((s)->s_blocksize)

            
            #else

            
            # define EXT2_BLOCK_SIZE(s)		(EXT2_MIN_BLOCK_SIZE << (s)->s_log_block_size)

            
            #endif

            
            #define	EXT2_ADDR_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (__u32))

            
            #ifdef __KERNEL__

            
            # define EXT2_BLOCK_SIZE_BITS(s)	((s)->s_blocksize_bits)

            
            #else

            
            # define EXT2_BLOCK_SIZE_BITS(s)	((s)->s_log_block_size + 10)

            
            #endif

            
            #ifdef __KERNEL__

            
            #define	EXT2_ADDR_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_addr_per_block_bits)

            
            #define EXT2_INODE_SIZE(s)		(EXT2_SB(s)->s_inode_size)

            
            #define EXT2_FIRST_INO(s)		(EXT2_SB(s)->s_first_ino)

            
            #else

            
            #define EXT2_INODE_SIZE(s)	(((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \

            
            				 EXT2_GOOD_OLD_INODE_SIZE : \

            
            				 (s)->s_inode_size)

            
            #define EXT2_FIRST_INO(s)	(((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \

            
            				 EXT2_GOOD_OLD_FIRST_INO : \

            
            				 (s)->s_first_ino)

            
            #endif


            /*

            
             * Macro-instructions used to manage fragments

            
             */

            
            #define EXT2_MIN_FRAG_SIZE		1024

            
            #define	EXT2_MAX_FRAG_SIZE		4096

            
            #define EXT2_MIN_FRAG_LOG_SIZE		  10

            
            #ifdef __KERNEL__

            
            # define EXT2_FRAG_SIZE(s)		(EXT2_SB(s)->s_frag_size)

            
            # define EXT2_FRAGS_PER_BLOCK(s)	(EXT2_SB(s)->s_frags_per_block)

            
            #else

            
            # define EXT2_FRAG_SIZE(s)		(EXT2_MIN_FRAG_SIZE << (s)->s_log_frag_size)

            
            # define EXT2_FRAGS_PER_BLOCK(s)	(EXT2_BLOCK_SIZE(s) / EXT2_FRAG_SIZE(s))

            
            #endif


            /*

            
             * Structure of a blocks group descriptor

            
             */

            
            struct ext2_group_desc

            
            {

            
            	__le32	bg_block_bitmap;		/* Blocks bitmap block */

            
            	__le32	bg_inode_bitmap;		/* Inodes bitmap block */

            
            	__le32	bg_inode_table;		/* Inodes table block */

            
            	__le16	bg_free_blocks_count;	/* Free blocks count */

            
            	__le16	bg_free_inodes_count;	/* Free inodes count */

            
            	__le16	bg_used_dirs_count;	/* Directories count */

            
            	__le16	bg_pad;

            
            	__le32	bg_reserved[3];

            
            };


            /*

            
             * Macro-instructions used to manage group descriptors

            
             */

            
            #ifdef __KERNEL__

            
            # define EXT2_BLOCKS_PER_GROUP(s)	(EXT2_SB(s)->s_blocks_per_group)

            
            # define EXT2_DESC_PER_BLOCK(s)		(EXT2_SB(s)->s_desc_per_block)

            
            # define EXT2_INODES_PER_GROUP(s)	(EXT2_SB(s)->s_inodes_per_group)

            
            # define EXT2_DESC_PER_BLOCK_BITS(s)	(EXT2_SB(s)->s_desc_per_block_bits)

            
            #else

            
            # define EXT2_BLOCKS_PER_GROUP(s)	((s)->s_blocks_per_group)

            
            # define EXT2_DESC_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))

            
            # define EXT2_INODES_PER_GROUP(s)	((s)->s_inodes_per_group)

            
            #endif


            /*

            
             * Constants relative to the data blocks

            
             */

            
            #define	EXT2_NDIR_BLOCKS		12

            
            #define	EXT2_IND_BLOCK			EXT2_NDIR_BLOCKS

            
            #define	EXT2_DIND_BLOCK			(EXT2_IND_BLOCK + 1)

            
            #define	EXT2_TIND_BLOCK			(EXT2_DIND_BLOCK + 1)

            
            #define	EXT2_N_BLOCKS			(EXT2_TIND_BLOCK + 1)


            /*

            
             * Inode flags (GETFLAGS/SETFLAGS)

            
             */

            
            #define	EXT2_SECRM_FL			FS_SECRM_FL	/* Secure deletion */

            
            #define	EXT2_UNRM_FL			FS_UNRM_FL	/* Undelete */

            
            #define	EXT2_COMPR_FL			FS_COMPR_FL	/* Compress file */

            
            #define EXT2_SYNC_FL			FS_SYNC_FL	/* Synchronous updates */

            
            #define EXT2_IMMUTABLE_FL		FS_IMMUTABLE_FL	/* Immutable file */

            
            #define EXT2_APPEND_FL			FS_APPEND_FL	/* writes to file may only append */

            
            #define EXT2_NODUMP_FL			FS_NODUMP_FL	/* do not dump file */

            
            #define EXT2_NOATIME_FL			FS_NOATIME_FL	/* do not update atime */

            
            /* Reserved for compression usage... */

            
            #define EXT2_DIRTY_FL			FS_DIRTY_FL

            
            #define EXT2_COMPRBLK_FL		FS_COMPRBLK_FL	/* One or more compressed clusters */

            
            #define EXT2_NOCOMP_FL			FS_NOCOMP_FL	/* Don't compress */

            
            #define EXT2_ECOMPR_FL			FS_ECOMPR_FL	/* Compression error */

            
            /* End compression flags --- maybe not all used */

            
            #define EXT2_BTREE_FL			FS_BTREE_FL	/* btree format dir */

            
            #define EXT2_INDEX_FL			FS_INDEX_FL	/* hash-indexed directory */

            
            #define EXT2_IMAGIC_FL			FS_IMAGIC_FL	/* AFS directory */

            
            #define EXT2_JOURNAL_DATA_FL		FS_JOURNAL_DATA_FL /* Reserved for ext3 */

            
            #define EXT2_NOTAIL_FL			FS_NOTAIL_FL	/* file tail should not be merged */

            
            #define EXT2_DIRSYNC_FL			FS_DIRSYNC_FL	/* dirsync behaviour (directories only) */

            
            #define EXT2_TOPDIR_FL			FS_TOPDIR_FL	/* Top of directory hierarchies*/

            
            #define EXT2_RESERVED_FL		FS_RESERVED_FL	/* reserved for ext2 lib */


            #define EXT2_FL_USER_VISIBLE		FS_FL_USER_VISIBLE	/* User visible flags */

            
            #define EXT2_FL_USER_MODIFIABLE		FS_FL_USER_MODIFIABLE	/* User modifiable flags */


            /*

            
             * ioctl commands

            
             */

            
            #define	EXT2_IOC_GETFLAGS		FS_IOC_GETFLAGS

            
            #define	EXT2_IOC_SETFLAGS		FS_IOC_SETFLAGS

            
            #define	EXT2_IOC_GETVERSION		FS_IOC_GETVERSION

            
            #define	EXT2_IOC_SETVERSION		FS_IOC_SETVERSION

            
            #define	EXT2_IOC_GETRSVSZ		_IOR('f', 5, long)

            
            #define	EXT2_IOC_SETRSVSZ		_IOW('f', 6, long)


            /*

            
             * ioctl commands in 32 bit emulation

            
             */

            
            #define EXT2_IOC32_GETFLAGS		FS_IOC32_GETFLAGS

            
            #define EXT2_IOC32_SETFLAGS		FS_IOC32_SETFLAGS

            
            #define EXT2_IOC32_GETVERSION		FS_IOC32_GETVERSION

            
            #define EXT2_IOC32_SETVERSION		FS_IOC32_SETVERSION


            /*

            
             * Structure of an inode on the disk

            
             */

            
            struct ext2_inode {

            
            	__le16	i_mode;		/* File mode */

            
            	__le16	i_uid;		/* Low 16 bits of Owner Uid */

            
            	__le32	i_size;		/* Size in bytes */

            
            	__le32	i_atime;	/* Access time */

            
            	__le32	i_ctime;	/* Creation time */

            
            	__le32	i_mtime;	/* Modification time */

            
            	__le32	i_dtime;	/* Deletion Time */

            
            	__le16	i_gid;		/* Low 16 bits of Group Id */

            
            	__le16	i_links_count;	/* Links count */

            
            	__le32	i_blocks;	/* Blocks count */

            
            	__le32	i_flags;	/* File flags */

            
            	union {

            
            		struct {

            
            			__le32  l_i_reserved1;

            
            		} linux1;

            
            		struct {

            
            			__le32  h_i_translator;

            
            		} hurd1;

            
            		struct {

            
            			__le32  m_i_reserved1;

            
            		} masix1;

            
            	} osd1;				/* OS dependent 1 */

            
            	__le32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */

            
            	__le32	i_generation;	/* File version (for NFS) */

            
            	__le32	i_file_acl;	/* File ACL */

            
            	__le32	i_dir_acl;	/* Directory ACL */

            
            	__le32	i_faddr;	/* Fragment address */

            
            	union {

            
            		struct {

            
            			__u8	l_i_frag;	/* Fragment number */

            
            			__u8	l_i_fsize;	/* Fragment size */

            
            			__u16	i_pad1;

            
            			__le16	l_i_uid_high;	/* these 2 fields    */

            
            			__le16	l_i_gid_high;	/* were reserved2[0] */

            
            			__u32	l_i_reserved2;

            
            		} linux2;

            
            		struct {

            
            			__u8	h_i_frag;	/* Fragment number */

            
            			__u8	h_i_fsize;	/* Fragment size */

            
            			__le16	h_i_mode_high;

            
            			__le16	h_i_uid_high;

            
            			__le16	h_i_gid_high;

            
            			__le32	h_i_author;

            
            		} hurd2;

            
            		struct {

            
            			__u8	m_i_frag;	/* Fragment number */

            
            			__u8	m_i_fsize;	/* Fragment size */

            
            			__u16	m_pad1;

            
            			__u32	m_i_reserved2[2];

            
            		} masix2;

            
            	} osd2;				/* OS dependent 2 */

            
            };


            #define i_size_high	i_dir_acl


            #if defined(__KERNEL__) || defined(__linux__)

            
            #define i_reserved1	osd1.linux1.l_i_reserved1

            
            #define i_frag		osd2.linux2.l_i_frag

            
            #define i_fsize		osd2.linux2.l_i_fsize

            
            #define i_uid_low	i_uid

            
            #define i_gid_low	i_gid

            
            #define i_uid_high	osd2.linux2.l_i_uid_high

            
            #define i_gid_high	osd2.linux2.l_i_gid_high

            
            #define i_reserved2	osd2.linux2.l_i_reserved2

            
            #endif


            #ifdef	__hurd__

            
            #define i_translator	osd1.hurd1.h_i_translator

            
            #define i_frag		osd2.hurd2.h_i_frag

            
            #define i_fsize		osd2.hurd2.h_i_fsize

            
            #define i_uid_high	osd2.hurd2.h_i_uid_high

            
            #define i_gid_high	osd2.hurd2.h_i_gid_high

            
            #define i_author	osd2.hurd2.h_i_author

            
            #endif


            #ifdef	__masix__

            
            #define i_reserved1	osd1.masix1.m_i_reserved1

            
            #define i_frag		osd2.masix2.m_i_frag

            
            #define i_fsize		osd2.masix2.m_i_fsize

            
            #define i_reserved2	osd2.masix2.m_i_reserved2

            
            #endif


            /*

            
             * File system states

            
             */

            
            #define	EXT2_VALID_FS			0x0001	/* Unmounted cleanly */

            
            #define	EXT2_ERROR_FS			0x0002	/* Errors detected */


            /*

            
             * Mount flags

            
             */

            
            #define EXT2_MOUNT_CHECK		0x000001  /* Do mount-time checks */

            
            #define EXT2_MOUNT_OLDALLOC		0x000002  /* Don't use the new Orlov allocator */

            
            #define EXT2_MOUNT_GRPID		0x000004  /* Create files with directory's group */

            
            #define EXT2_MOUNT_DEBUG		0x000008  /* Some debugging messages */

            
            #define EXT2_MOUNT_ERRORS_CONT		0x000010  /* Continue on errors */

            
            #define EXT2_MOUNT_ERRORS_RO		0x000020  /* Remount fs ro on errors */

            
            #define EXT2_MOUNT_ERRORS_PANIC		0x000040  /* Panic on errors */

            
            #define EXT2_MOUNT_MINIX_DF		0x000080  /* Mimics the Minix statfs */

            
            #define EXT2_MOUNT_NOBH			0x000100  /* No buffer_heads */

            
            #define EXT2_MOUNT_NO_UID32		0x000200  /* Disable 32-bit UIDs */

            
            #define EXT2_MOUNT_XATTR_USER		0x004000  /* Extended user attributes */

            
            #define EXT2_MOUNT_POSIX_ACL		0x008000  /* POSIX Access Control Lists */

            
            #define EXT2_MOUNT_XIP			0x010000  /* Execute in place */

            
            #define EXT2_MOUNT_USRQUOTA		0x020000  /* user quota */

            
            #define EXT2_MOUNT_GRPQUOTA		0x040000  /* group quota */

            
            #define EXT2_MOUNT_RESERVATION		0x080000  /* Preallocation */


            #define clear_opt(o, opt)		o &= ~EXT2_MOUNT_##opt

            
            #define set_opt(o, opt)			o |= EXT2_MOUNT_##opt

            
            #define test_opt(sb, opt)		(EXT2_SB(sb)->s_mount_opt & \

            
            					 EXT2_MOUNT_##opt)

            
            /*

            
             * Maximal mount counts between two filesystem checks

            
             */

            
            #define EXT2_DFL_MAX_MNT_COUNT		20	/* Allow 20 mounts */

            
            #define EXT2_DFL_CHECKINTERVAL		0	/* Don't use interval check */


            /*

            
             * Behaviour when detecting errors

            
             */

            
            #define EXT2_ERRORS_CONTINUE		1	/* Continue execution */

            
            #define EXT2_ERRORS_RO			2	/* Remount fs read-only */

            
            #define EXT2_ERRORS_PANIC		3	/* Panic */

            
            #define EXT2_ERRORS_DEFAULT		EXT2_ERRORS_CONTINUE


            /*

            
             * Structure of the super block

            
             */

            
            struct ext2_super_block {

            
            	__le32	s_inodes_count;		/* Inodes count */

            
            	__le32	s_blocks_count;		/* Blocks count */

            
            	__le32	s_r_blocks_count;	/* Reserved blocks count */

            
            	__le32	s_free_blocks_count;	/* Free blocks count */

            
            	__le32	s_free_inodes_count;	/* Free inodes count */

            
            	__le32	s_first_data_block;	/* First Data Block */

            
            	__le32	s_log_block_size;	/* Block size */

            
            	__le32	s_log_frag_size;	/* Fragment size */

            
            	__le32	s_blocks_per_group;	/* # Blocks per group */

            
            	__le32	s_frags_per_group;	/* # Fragments per group */

            
            	__le32	s_inodes_per_group;	/* # Inodes per group */

            
            	__le32	s_mtime;		/* Mount time */

            
            	__le32	s_wtime;		/* Write time */

            
            	__le16	s_mnt_count;		/* Mount count */

            
            	__le16	s_max_mnt_count;	/* Maximal mount count */

            
            	__le16	s_magic;		/* Magic signature */

            
            	__le16	s_state;		/* File system state */

            
            	__le16	s_errors;		/* Behaviour when detecting errors */

            
            	__le16	s_minor_rev_level; 	/* minor revision level */

            
            	__le32	s_lastcheck;		/* time of last check */

            
            	__le32	s_checkinterval;	/* max. time between checks */

            
            	__le32	s_creator_os;		/* OS */

            
            	__le32	s_rev_level;		/* Revision level */

            
            	__le16	s_def_resuid;		/* Default uid for reserved blocks */

            
            	__le16	s_def_resgid;		/* Default gid for reserved blocks */

            
            	/*

            
            	 * These fields are for EXT2_DYNAMIC_REV superblocks only.

            
            	 *

            
            	 * Note: the difference between the compatible feature set and

            
            	 * the incompatible feature set is that if there is a bit set

            
            	 * in the incompatible feature set that the kernel doesn't

            
            	 * know about, it should refuse to mount the filesystem.

            
            	 *

            
            	 * e2fsck's requirements are more strict; if it doesn't know

            
            	 * about a feature in either the compatible or incompatible

            
            	 * feature set, it must abort and not try to meddle with

            
            	 * things it doesn't understand...

            
            	 */

            
            	__le32	s_first_ino; 		/* First non-reserved inode */

            
            	__le16   s_inode_size; 		/* size of inode structure */

            
            	__le16	s_block_group_nr; 	/* block group # of this superblock */

            
            	__le32	s_feature_compat; 	/* compatible feature set */

            
            	__le32	s_feature_incompat; 	/* incompatible feature set */

            
            	__le32	s_feature_ro_compat; 	/* readonly-compatible feature set */

            
            	__u8	s_uuid[16];		/* 128-bit uuid for volume */

            
            	char	s_volume_name[16]; 	/* volume name */

            
            	char	s_last_mounted[64]; 	/* directory where last mounted */

            
            	__le32	s_algorithm_usage_bitmap; /* For compression */

            
            	/*

            
            	 * Performance hints.  Directory preallocation should only

            
            	 * happen if the EXT2_COMPAT_PREALLOC flag is on.

            
            	 */

            
            	__u8	s_prealloc_blocks;	/* Nr of blocks to try to preallocate*/

            
            	__u8	s_prealloc_dir_blocks;	/* Nr to preallocate for dirs */

            
            	__u16	s_padding1;

            
            	/*

            
            	 * Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.

            
            	 */

            
            	__u8	s_journal_uuid[16];	/* uuid of journal superblock */

            
            	__u32	s_journal_inum;		/* inode number of journal file */

            
            	__u32	s_journal_dev;		/* device number of journal file */

            
            	__u32	s_last_orphan;		/* start of list of inodes to delete */

            
            	__u32	s_hash_seed[4];		/* HTREE hash seed */

            
            	__u8	s_def_hash_version;	/* Default hash version to use */

            
            	__u8	s_reserved_char_pad;

            
            	__u16	s_reserved_word_pad;

            
            	__le32	s_default_mount_opts;

            
             	__le32	s_first_meta_bg; 	/* First metablock block group */

            
            	__u32	s_reserved[190];	/* Padding to the end of the block */

            
            };


            /*

            
             * Codes for operating systems

            
             */

            
            #define EXT2_OS_LINUX		0

            
            #define EXT2_OS_HURD		1

            
            #define EXT2_OS_MASIX		2

            
            #define EXT2_OS_FREEBSD		3

            
            #define EXT2_OS_LITES		4


            /*

            
             * Revision levels

            
             */

            
            #define EXT2_GOOD_OLD_REV	0	/* The good old (original) format */

            
            #define EXT2_DYNAMIC_REV	1 	/* V2 format w/ dynamic inode sizes */


            #define EXT2_CURRENT_REV	EXT2_GOOD_OLD_REV

            
            #define EXT2_MAX_SUPP_REV	EXT2_DYNAMIC_REV


            #define EXT2_GOOD_OLD_INODE_SIZE 128


            /*

            
             * Feature set definitions

            
             */


            #define EXT2_HAS_COMPAT_FEATURE(sb,mask)			\

            
            	( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )

            
            #define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask)			\

            
            	( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )

            
            #define EXT2_HAS_INCOMPAT_FEATURE(sb,mask)			\

            
            	( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )

            
            #define EXT2_SET_COMPAT_FEATURE(sb,mask)			\

            
            	EXT2_SB(sb)->s_es->s_feature_compat |= cpu_to_le32(mask)

            
            #define EXT2_SET_RO_COMPAT_FEATURE(sb,mask)			\

            
            	EXT2_SB(sb)->s_es->s_feature_ro_compat |= cpu_to_le32(mask)

            
            #define EXT2_SET_INCOMPAT_FEATURE(sb,mask)			\

            
            	EXT2_SB(sb)->s_es->s_feature_incompat |= cpu_to_le32(mask)

            
            #define EXT2_CLEAR_COMPAT_FEATURE(sb,mask)			\

            
            	EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)

            
            #define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask)			\

            
            	EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)

            
            #define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask)			\

            
            	EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)


            #define EXT2_FEATURE_COMPAT_DIR_PREALLOC	0x0001

            
            #define EXT2_FEATURE_COMPAT_IMAGIC_INODES	0x0002

            
            #define EXT3_FEATURE_COMPAT_HAS_JOURNAL		0x0004

            
            #define EXT2_FEATURE_COMPAT_EXT_ATTR		0x0008

            
            #define EXT2_FEATURE_COMPAT_RESIZE_INO		0x0010

            
            #define EXT2_FEATURE_COMPAT_DIR_INDEX		0x0020

            
            #define EXT2_FEATURE_COMPAT_ANY			0xffffffff


            #define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER	0x0001

            
            #define EXT2_FEATURE_RO_COMPAT_LARGE_FILE	0x0002

            
            #define EXT2_FEATURE_RO_COMPAT_BTREE_DIR	0x0004

            
            #define EXT2_FEATURE_RO_COMPAT_ANY		0xffffffff


            #define EXT2_FEATURE_INCOMPAT_COMPRESSION	0x0001

            
            #define EXT2_FEATURE_INCOMPAT_FILETYPE		0x0002

            
            #define EXT3_FEATURE_INCOMPAT_RECOVER		0x0004

            
            #define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV	0x0008

            
            #define EXT2_FEATURE_INCOMPAT_META_BG		0x0010

            
            #define EXT2_FEATURE_INCOMPAT_ANY		0xffffffff


            #define EXT2_FEATURE_COMPAT_SUPP	EXT2_FEATURE_COMPAT_EXT_ATTR

            
            #define EXT2_FEATURE_INCOMPAT_SUPP	(EXT2_FEATURE_INCOMPAT_FILETYPE| \

            
            					 EXT2_FEATURE_INCOMPAT_META_BG)

            
            #define EXT2_FEATURE_RO_COMPAT_SUPP	(EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \

            
            					 EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \

            
            					 EXT2_FEATURE_RO_COMPAT_BTREE_DIR)

            
            #define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED	~EXT2_FEATURE_RO_COMPAT_SUPP

            
            #define EXT2_FEATURE_INCOMPAT_UNSUPPORTED	~EXT2_FEATURE_INCOMPAT_SUPP


            /*

            
             * Default values for user and/or group using reserved blocks

            
             */

            
            #define	EXT2_DEF_RESUID		0

            
            #define	EXT2_DEF_RESGID		0


            /*

            
             * Default mount options

            
             */

            
            #define EXT2_DEFM_DEBUG		0x0001

            
            #define EXT2_DEFM_BSDGROUPS	0x0002

            
            #define EXT2_DEFM_XATTR_USER	0x0004

            
            #define EXT2_DEFM_ACL		0x0008

            
            #define EXT2_DEFM_UID16		0x0010

            
                /* Not used by ext2, but reserved for use by ext3 */

            
            #define EXT3_DEFM_JMODE		0x0060

            
            #define EXT3_DEFM_JMODE_DATA	0x0020

            
            #define EXT3_DEFM_JMODE_ORDERED	0x0040

            
            #define EXT3_DEFM_JMODE_WBACK	0x0060


            /*

            
             * Structure of a directory entry

            
             */

            
            #define EXT2_NAME_LEN 255


            struct ext2_dir_entry {

            
            	__le32	inode;			/* Inode number */

            
            	__le16	rec_len;		/* Directory entry length */

            
            	__le16	name_len;		/* Name length */

            
            	char	name[EXT2_NAME_LEN];	/* File name */

            
            };


            /*

            
             * The new version of the directory entry.  Since EXT2 structures are

            
             * stored in intel byte order, and the name_len field could never be

            
             * bigger than 255 chars, it's safe to reclaim the extra byte for the

            
             * file_type field.

            
             */

            
            struct ext2_dir_entry_2 {

            
            	__le32	inode;			/* Inode number */

            
            	__le16	rec_len;		/* Directory entry length */

            
            	__u8	name_len;		/* Name length */

            
            	__u8	file_type;

            
            	char	name[EXT2_NAME_LEN];	/* File name */

            
            };


            /*

            
             * Ext2 directory file types.  Only the low 3 bits are used.  The

            
             * other bits are reserved for now.

            
             */

            
            enum {

            
            	EXT2_FT_UNKNOWN,

            
            	EXT2_FT_REG_FILE,

            
            	EXT2_FT_DIR,

            
            	EXT2_FT_CHRDEV,

            
            	EXT2_FT_BLKDEV,

            
            	EXT2_FT_FIFO,

            
            	EXT2_FT_SOCK,

            
            	EXT2_FT_SYMLINK,

            
            	EXT2_FT_MAX

            
            };


            /*

            
             * EXT2_DIR_PAD defines the directory entries boundaries

            
             *

            
             * NOTE: It must be a multiple of 4

            
             */

            
            #define EXT2_DIR_PAD		 	4

            
            #define EXT2_DIR_ROUND 			(EXT2_DIR_PAD - 1)

            
            #define EXT2_DIR_REC_LEN(name_len)	(((name_len) + 8 + EXT2_DIR_ROUND) & \

            
            					 ~EXT2_DIR_ROUND)

            
            #define EXT2_MAX_REC_LEN		((1<<16)-1)


            #endif	/* _LINUX_EXT2_FS_H */
	/*
	* linux/include/linux/ext2_fs.h
	*
	* Copyright (C) 1992, 1993, 1994, 1995
	* Remy Card (card@masi.ibp.fr)
	* Laboratoire MASI - Institut Blaise Pascal
	* Universite Pierre et Marie Curie (Paris VI)
	*
	* from
	*
	* linux/include/linux/minix_fs.h
	*
	* Copyright (C) 1991, 1992 Linus Torvalds
	*/

	#ifndef _LINUX_EXT2_FS_H
	#define _LINUX_EXT2_FS_H

	#include <linux/types.h>
	#include <linux/magic.h>

	/*
	* The second extended filesystem constants/structures
	*/

	/*
	* Define EXT2FS_DEBUG to produce debug messages
	*/
	#undef EXT2FS_DEBUG

	/*
	* Define EXT2_RESERVATION to reserve data blocks for expanding files
	*/
	#define EXT2_DEFAULT_RESERVE_BLOCKS 8
	/max window size: 1024(direct blocks) + 3([t,d]indirect blocks) /
	#define EXT2_MAX_RESERVE_BLOCKS 1027
	#define EXT2_RESERVE_WINDOW_NOT_ALLOCATED 0
	/*
	* The second extended file system version
	*/
	#define EXT2FS_DATE "95/08/09"
	#define EXT2FS_VERSION "0.5b"

	/*
	* Debug code
	*/
	#ifdef EXT2FS_DEBUG
	# define ext2_debug(f, a...) { \
	printk ("EXT2-fs DEBUG (%s, %d): %s:", \
	__FILE__, __LINE__, __func__); \
	printk (f, ## a); \
	}
	#else
	# define ext2_debug(f, a...) /**/
	#endif

	/*
	* Special inode numbers
	*/
	#define EXT2_BAD_INO 1 /* Bad blocks inode */
	#define EXT2_ROOT_INO 2 /* Root inode */
	#define EXT2_BOOT_LOADER_INO 5 /* Boot loader inode */
	#define EXT2_UNDEL_DIR_INO 6 /* Undelete directory inode */

	/* First non-reserved inode for old ext2 filesystems */
	#define EXT2_GOOD_OLD_FIRST_INO 11

	#ifdef __KERNEL__
	#include <linux/ext2_fs_sb.h>
	static inline struct ext2_sb_info EXT2_SB(struct super_block sb)
	{
	return sb->s_fs_info;
	}
	#else
	/* Assume that user mode programs are passing in an ext2fs superblock, not
	* a kernel struct super_block. This will allow us to call the feature-test
	* macros from user land. */
	#define EXT2_SB(sb) (sb)
	#endif

	/*
	* Maximal count of links to a file
	*/
	#define EXT2_LINK_MAX 32000

	/*
	* Macro-instructions used to manage several block sizes
	*/
	#define EXT2_MIN_BLOCK_SIZE 1024
	#define EXT2_MAX_BLOCK_SIZE 4096
	#define EXT2_MIN_BLOCK_LOG_SIZE 10
	#ifdef __KERNEL__
	# define EXT2_BLOCK_SIZE(s) ((s)->s_blocksize)
	#else
	# define EXT2_BLOCK_SIZE(s) (EXT2_MIN_BLOCK_SIZE << (s)->s_log_block_size)
	#endif
	#define EXT2_ADDR_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / sizeof (__u32))
	#ifdef __KERNEL__
	# define EXT2_BLOCK_SIZE_BITS(s) ((s)->s_blocksize_bits)
	#else
	# define EXT2_BLOCK_SIZE_BITS(s) ((s)->s_log_block_size + 10)
	#endif
	#ifdef __KERNEL__
	#define EXT2_ADDR_PER_BLOCK_BITS(s) (EXT2_SB(s)->s_addr_per_block_bits)
	#define EXT2_INODE_SIZE(s) (EXT2_SB(s)->s_inode_size)
	#define EXT2_FIRST_INO(s) (EXT2_SB(s)->s_first_ino)
	#else
	#define EXT2_INODE_SIZE(s) (((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \
	EXT2_GOOD_OLD_INODE_SIZE : \
	(s)->s_inode_size)
	#define EXT2_FIRST_INO(s) (((s)->s_rev_level == EXT2_GOOD_OLD_REV) ? \
	EXT2_GOOD_OLD_FIRST_INO : \
	(s)->s_first_ino)
	#endif

	/*
	* Macro-instructions used to manage fragments
	*/
	#define EXT2_MIN_FRAG_SIZE 1024
	#define EXT2_MAX_FRAG_SIZE 4096
	#define EXT2_MIN_FRAG_LOG_SIZE 10
	#ifdef __KERNEL__
	# define EXT2_FRAG_SIZE(s) (EXT2_SB(s)->s_frag_size)
	# define EXT2_FRAGS_PER_BLOCK(s) (EXT2_SB(s)->s_frags_per_block)
	#else
	# define EXT2_FRAG_SIZE(s) (EXT2_MIN_FRAG_SIZE << (s)->s_log_frag_size)
	# define EXT2_FRAGS_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / EXT2_FRAG_SIZE(s))
	#endif

	/*
	* Structure of a blocks group descriptor
	*/
	struct ext2_group_desc
	{
	__le32 bg_block_bitmap; /* Blocks bitmap block */
	__le32 bg_inode_bitmap; /* Inodes bitmap block */
	__le32 bg_inode_table; /* Inodes table block */
	__le16 bg_free_blocks_count; /* Free blocks count */
	__le16 bg_free_inodes_count; /* Free inodes count */
	__le16 bg_used_dirs_count; /* Directories count */
	__le16 bg_pad;
	__le32 bg_reserved[3];
	};

	/*
	* Macro-instructions used to manage group descriptors
	*/
	#ifdef __KERNEL__
	# define EXT2_BLOCKS_PER_GROUP(s) (EXT2_SB(s)->s_blocks_per_group)
	# define EXT2_DESC_PER_BLOCK(s) (EXT2_SB(s)->s_desc_per_block)
	# define EXT2_INODES_PER_GROUP(s) (EXT2_SB(s)->s_inodes_per_group)
	# define EXT2_DESC_PER_BLOCK_BITS(s) (EXT2_SB(s)->s_desc_per_block_bits)
	#else
	# define EXT2_BLOCKS_PER_GROUP(s) ((s)->s_blocks_per_group)
	# define EXT2_DESC_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_group_desc))
	# define EXT2_INODES_PER_GROUP(s) ((s)->s_inodes_per_group)
	#endif

	/*
	* Constants relative to the data blocks
	*/
	#define EXT2_NDIR_BLOCKS 12
	#define EXT2_IND_BLOCK EXT2_NDIR_BLOCKS
	#define EXT2_DIND_BLOCK (EXT2_IND_BLOCK + 1)
	#define EXT2_TIND_BLOCK (EXT2_DIND_BLOCK + 1)
	#define EXT2_N_BLOCKS (EXT2_TIND_BLOCK + 1)

	/*
	* Inode flags (GETFLAGS/SETFLAGS)
	*/
	#define EXT2_SECRM_FL FS_SECRM_FL /* Secure deletion */
	#define EXT2_UNRM_FL FS_UNRM_FL /* Undelete */
	#define EXT2_COMPR_FL FS_COMPR_FL /* Compress file */
	#define EXT2_SYNC_FL FS_SYNC_FL /* Synchronous updates */
	#define EXT2_IMMUTABLE_FL FS_IMMUTABLE_FL /* Immutable file */
	#define EXT2_APPEND_FL FS_APPEND_FL /* writes to file may only append */
	#define EXT2_NODUMP_FL FS_NODUMP_FL /* do not dump file */
	#define EXT2_NOATIME_FL FS_NOATIME_FL /* do not update atime */
	/* Reserved for compression usage... */
	#define EXT2_DIRTY_FL FS_DIRTY_FL
	#define EXT2_COMPRBLK_FL FS_COMPRBLK_FL /* One or more compressed clusters */
	#define EXT2_NOCOMP_FL FS_NOCOMP_FL /* Don't compress */
	#define EXT2_ECOMPR_FL FS_ECOMPR_FL /* Compression error */
	/* End compression flags --- maybe not all used */
	#define EXT2_BTREE_FL FS_BTREE_FL /* btree format dir */
	#define EXT2_INDEX_FL FS_INDEX_FL /* hash-indexed directory */
	#define EXT2_IMAGIC_FL FS_IMAGIC_FL /* AFS directory */
	#define EXT2_JOURNAL_DATA_FL FS_JOURNAL_DATA_FL /* Reserved for ext3 */
	#define EXT2_NOTAIL_FL FS_NOTAIL_FL /* file tail should not be merged */
	#define EXT2_DIRSYNC_FL FS_DIRSYNC_FL /* dirsync behaviour (directories only) */
	#define EXT2_TOPDIR_FL FS_TOPDIR_FL /* Top of directory hierarchies*/
	#define EXT2_RESERVED_FL FS_RESERVED_FL /* reserved for ext2 lib */

	#define EXT2_FL_USER_VISIBLE FS_FL_USER_VISIBLE /* User visible flags */
	#define EXT2_FL_USER_MODIFIABLE FS_FL_USER_MODIFIABLE /* User modifiable flags */

	/*
	* ioctl commands
	*/
	#define EXT2_IOC_GETFLAGS FS_IOC_GETFLAGS
	#define EXT2_IOC_SETFLAGS FS_IOC_SETFLAGS
	#define EXT2_IOC_GETVERSION FS_IOC_GETVERSION
	#define EXT2_IOC_SETVERSION FS_IOC_SETVERSION
	#define EXT2_IOC_GETRSVSZ _IOR('f', 5, long)
	#define EXT2_IOC_SETRSVSZ _IOW('f', 6, long)

	/*
	* ioctl commands in 32 bit emulation
	*/
	#define EXT2_IOC32_GETFLAGS FS_IOC32_GETFLAGS
	#define EXT2_IOC32_SETFLAGS FS_IOC32_SETFLAGS
	#define EXT2_IOC32_GETVERSION FS_IOC32_GETVERSION
	#define EXT2_IOC32_SETVERSION FS_IOC32_SETVERSION

	/*
	* Structure of an inode on the disk
	*/
	struct ext2_inode {
	__le16 i_mode; /* File mode */
	__le16 i_uid; /* Low 16 bits of Owner Uid */
	__le32 i_size; /* Size in bytes */
	__le32 i_atime; /* Access time */
	__le32 i_ctime; /* Creation time */
	__le32 i_mtime; /* Modification time */
	__le32 i_dtime; /* Deletion Time */
	__le16 i_gid; /* Low 16 bits of Group Id */
	__le16 i_links_count; /* Links count */
	__le32 i_blocks; /* Blocks count */
	__le32 i_flags; /* File flags */
	union {
	struct {
	__le32 l_i_reserved1;
	} linux1;
	struct {
	__le32 h_i_translator;
	} hurd1;
	struct {
	__le32 m_i_reserved1;
	} masix1;
	} osd1; /* OS dependent 1 */
	__le32 i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
	__le32 i_generation; /* File version (for NFS) */
	__le32 i_file_acl; /* File ACL */
	__le32 i_dir_acl; /* Directory ACL */
	__le32 i_faddr; /* Fragment address */
	union {
	struct {
	__u8 l_i_frag; /* Fragment number */
	__u8 l_i_fsize; /* Fragment size */
	__u16 i_pad1;
	__le16 l_i_uid_high; /* these 2 fields */
	__le16 l_i_gid_high; /* were reserved2[0] */
	__u32 l_i_reserved2;
	} linux2;
	struct {
	__u8 h_i_frag; /* Fragment number */
	__u8 h_i_fsize; /* Fragment size */
	__le16 h_i_mode_high;
	__le16 h_i_uid_high;
	__le16 h_i_gid_high;
	__le32 h_i_author;
	} hurd2;
	struct {
	__u8 m_i_frag; /* Fragment number */
	__u8 m_i_fsize; /* Fragment size */
	__u16 m_pad1;
	__u32 m_i_reserved2[2];
	} masix2;
	} osd2; /* OS dependent 2 */
	};

	#define i_size_high i_dir_acl

	#if defined(__KERNEL__) \|\| defined(__linux__)
	#define i_reserved1 osd1.linux1.l_i_reserved1
	#define i_frag osd2.linux2.l_i_frag
	#define i_fsize osd2.linux2.l_i_fsize
	#define i_uid_low i_uid
	#define i_gid_low i_gid
	#define i_uid_high osd2.linux2.l_i_uid_high
	#define i_gid_high osd2.linux2.l_i_gid_high
	#define i_reserved2 osd2.linux2.l_i_reserved2
	#endif

	#ifdef __hurd__
	#define i_translator osd1.hurd1.h_i_translator
	#define i_frag osd2.hurd2.h_i_frag
	#define i_fsize osd2.hurd2.h_i_fsize
	#define i_uid_high osd2.hurd2.h_i_uid_high
	#define i_gid_high osd2.hurd2.h_i_gid_high
	#define i_author osd2.hurd2.h_i_author
	#endif

	#ifdef __masix__
	#define i_reserved1 osd1.masix1.m_i_reserved1
	#define i_frag osd2.masix2.m_i_frag
	#define i_fsize osd2.masix2.m_i_fsize
	#define i_reserved2 osd2.masix2.m_i_reserved2
	#endif

	/*
	* File system states
	*/
	#define EXT2_VALID_FS 0x0001 /* Unmounted cleanly */
	#define EXT2_ERROR_FS 0x0002 /* Errors detected */

	/*
	* Mount flags
	*/
	#define EXT2_MOUNT_CHECK 0x000001 /* Do mount-time checks */
	#define EXT2_MOUNT_OLDALLOC 0x000002 /* Don't use the new Orlov allocator */
	#define EXT2_MOUNT_GRPID 0x000004 /* Create files with directory's group */
	#define EXT2_MOUNT_DEBUG 0x000008 /* Some debugging messages */
	#define EXT2_MOUNT_ERRORS_CONT 0x000010 /* Continue on errors */
	#define EXT2_MOUNT_ERRORS_RO 0x000020 /* Remount fs ro on errors */
	#define EXT2_MOUNT_ERRORS_PANIC 0x000040 /* Panic on errors */
	#define EXT2_MOUNT_MINIX_DF 0x000080 /* Mimics the Minix statfs */
	#define EXT2_MOUNT_NOBH 0x000100 /* No buffer_heads */
	#define EXT2_MOUNT_NO_UID32 0x000200 /* Disable 32-bit UIDs */
	#define EXT2_MOUNT_XATTR_USER 0x004000 /* Extended user attributes */
	#define EXT2_MOUNT_POSIX_ACL 0x008000 /* POSIX Access Control Lists */
	#define EXT2_MOUNT_XIP 0x010000 /* Execute in place */
	#define EXT2_MOUNT_USRQUOTA 0x020000 /* user quota */
	#define EXT2_MOUNT_GRPQUOTA 0x040000 /* group quota */
	#define EXT2_MOUNT_RESERVATION 0x080000 /* Preallocation */


	#define clear_opt(o, opt) o &= ~EXT2_MOUNT_##opt
	#define set_opt(o, opt) o \|= EXT2_MOUNT_##opt
	#define test_opt(sb, opt) (EXT2_SB(sb)->s_mount_opt & \
	EXT2_MOUNT_##opt)
	/*
	* Maximal mount counts between two filesystem checks
	*/
	#define EXT2_DFL_MAX_MNT_COUNT 20 /* Allow 20 mounts */
	#define EXT2_DFL_CHECKINTERVAL 0 /* Don't use interval check */

	/*
	* Behaviour when detecting errors
	*/
	#define EXT2_ERRORS_CONTINUE 1 /* Continue execution */
	#define EXT2_ERRORS_RO 2 /* Remount fs read-only */
	#define EXT2_ERRORS_PANIC 3 /* Panic */
	#define EXT2_ERRORS_DEFAULT EXT2_ERRORS_CONTINUE

	/*
	* Structure of the super block
	*/
	struct ext2_super_block {
	__le32 s_inodes_count; /* Inodes count */
	__le32 s_blocks_count; /* Blocks count */
	__le32 s_r_blocks_count; /* Reserved blocks count */
	__le32 s_free_blocks_count; /* Free blocks count */
	__le32 s_free_inodes_count; /* Free inodes count */
	__le32 s_first_data_block; /* First Data Block */
	__le32 s_log_block_size; /* Block size */
	__le32 s_log_frag_size; /* Fragment size */
	__le32 s_blocks_per_group; /* # Blocks per group */
	__le32 s_frags_per_group; /* # Fragments per group */
	__le32 s_inodes_per_group; /* # Inodes per group */
	__le32 s_mtime; /* Mount time */
	__le32 s_wtime; /* Write time */
	__le16 s_mnt_count; /* Mount count */
	__le16 s_max_mnt_count; /* Maximal mount count */
	__le16 s_magic; /* Magic signature */
	__le16 s_state; /* File system state */
	__le16 s_errors; /* Behaviour when detecting errors */
	__le16 s_minor_rev_level; /* minor revision level */
	__le32 s_lastcheck; /* time of last check */
	__le32 s_checkinterval; /* max. time between checks */
	__le32 s_creator_os; /* OS */
	__le32 s_rev_level; /* Revision level */
	__le16 s_def_resuid; /* Default uid for reserved blocks */
	__le16 s_def_resgid; /* Default gid for reserved blocks */
	/*
	* These fields are for EXT2_DYNAMIC_REV superblocks only.
	*
	* Note: the difference between the compatible feature set and
	* the incompatible feature set is that if there is a bit set
	* in the incompatible feature set that the kernel doesn't
	* know about, it should refuse to mount the filesystem.
	*
	* e2fsck's requirements are more strict; if it doesn't know
	* about a feature in either the compatible or incompatible
	* feature set, it must abort and not try to meddle with
	* things it doesn't understand...
	*/
	__le32 s_first_ino; /* First non-reserved inode */
	__le16 s_inode_size; /* size of inode structure */
	__le16 s_block_group_nr; /* block group # of this superblock */
	__le32 s_feature_compat; /* compatible feature set */
	__le32 s_feature_incompat; /* incompatible feature set */
	__le32 s_feature_ro_compat; /* readonly-compatible feature set */
	__u8 s_uuid[16]; /* 128-bit uuid for volume */
	char s_volume_name[16]; /* volume name */
	char s_last_mounted[64]; /* directory where last mounted */
	__le32 s_algorithm_usage_bitmap; /* For compression */
	/*
	* Performance hints. Directory preallocation should only
	* happen if the EXT2_COMPAT_PREALLOC flag is on.
	*/
	__u8 s_prealloc_blocks; /* Nr of blocks to try to preallocate*/
	__u8 s_prealloc_dir_blocks; /* Nr to preallocate for dirs */
	__u16 s_padding1;
	/*
	* Journaling support valid if EXT3_FEATURE_COMPAT_HAS_JOURNAL set.
	*/
	__u8 s_journal_uuid[16]; /* uuid of journal superblock */
	__u32 s_journal_inum; /* inode number of journal file */
	__u32 s_journal_dev; /* device number of journal file */
	__u32 s_last_orphan; /* start of list of inodes to delete */
	__u32 s_hash_seed[4]; /* HTREE hash seed */
	__u8 s_def_hash_version; /* Default hash version to use */
	__u8 s_reserved_char_pad;
	__u16 s_reserved_word_pad;
	__le32 s_default_mount_opts;
	__le32 s_first_meta_bg; /* First metablock block group */
	__u32 s_reserved[190]; /* Padding to the end of the block */
	};

	/*
	* Codes for operating systems
	*/
	#define EXT2_OS_LINUX 0
	#define EXT2_OS_HURD 1
	#define EXT2_OS_MASIX 2
	#define EXT2_OS_FREEBSD 3
	#define EXT2_OS_LITES 4

	/*
	* Revision levels
	*/
	#define EXT2_GOOD_OLD_REV 0 /* The good old (original) format */
	#define EXT2_DYNAMIC_REV 1 /* V2 format w/ dynamic inode sizes */

	#define EXT2_CURRENT_REV EXT2_GOOD_OLD_REV
	#define EXT2_MAX_SUPP_REV EXT2_DYNAMIC_REV

	#define EXT2_GOOD_OLD_INODE_SIZE 128

	/*
	* Feature set definitions
	*/

	#define EXT2_HAS_COMPAT_FEATURE(sb,mask) \
	( EXT2_SB(sb)->s_es->s_feature_compat & cpu_to_le32(mask) )
	#define EXT2_HAS_RO_COMPAT_FEATURE(sb,mask) \
	( EXT2_SB(sb)->s_es->s_feature_ro_compat & cpu_to_le32(mask) )
	#define EXT2_HAS_INCOMPAT_FEATURE(sb,mask) \
	( EXT2_SB(sb)->s_es->s_feature_incompat & cpu_to_le32(mask) )
	#define EXT2_SET_COMPAT_FEATURE(sb,mask) \
	EXT2_SB(sb)->s_es->s_feature_compat \|= cpu_to_le32(mask)
	#define EXT2_SET_RO_COMPAT_FEATURE(sb,mask) \
	EXT2_SB(sb)->s_es->s_feature_ro_compat \|= cpu_to_le32(mask)
	#define EXT2_SET_INCOMPAT_FEATURE(sb,mask) \
	EXT2_SB(sb)->s_es->s_feature_incompat \|= cpu_to_le32(mask)
	#define EXT2_CLEAR_COMPAT_FEATURE(sb,mask) \
	EXT2_SB(sb)->s_es->s_feature_compat &= ~cpu_to_le32(mask)
	#define EXT2_CLEAR_RO_COMPAT_FEATURE(sb,mask) \
	EXT2_SB(sb)->s_es->s_feature_ro_compat &= ~cpu_to_le32(mask)
	#define EXT2_CLEAR_INCOMPAT_FEATURE(sb,mask) \
	EXT2_SB(sb)->s_es->s_feature_incompat &= ~cpu_to_le32(mask)

	#define EXT2_FEATURE_COMPAT_DIR_PREALLOC 0x0001
	#define EXT2_FEATURE_COMPAT_IMAGIC_INODES 0x0002
	#define EXT3_FEATURE_COMPAT_HAS_JOURNAL 0x0004
	#define EXT2_FEATURE_COMPAT_EXT_ATTR 0x0008
	#define EXT2_FEATURE_COMPAT_RESIZE_INO 0x0010
	#define EXT2_FEATURE_COMPAT_DIR_INDEX 0x0020
	#define EXT2_FEATURE_COMPAT_ANY 0xffffffff

	#define EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER 0x0001
	#define EXT2_FEATURE_RO_COMPAT_LARGE_FILE 0x0002
	#define EXT2_FEATURE_RO_COMPAT_BTREE_DIR 0x0004
	#define EXT2_FEATURE_RO_COMPAT_ANY 0xffffffff

	#define EXT2_FEATURE_INCOMPAT_COMPRESSION 0x0001
	#define EXT2_FEATURE_INCOMPAT_FILETYPE 0x0002
	#define EXT3_FEATURE_INCOMPAT_RECOVER 0x0004
	#define EXT3_FEATURE_INCOMPAT_JOURNAL_DEV 0x0008
	#define EXT2_FEATURE_INCOMPAT_META_BG 0x0010
	#define EXT2_FEATURE_INCOMPAT_ANY 0xffffffff

	#define EXT2_FEATURE_COMPAT_SUPP EXT2_FEATURE_COMPAT_EXT_ATTR
	#define EXT2_FEATURE_INCOMPAT_SUPP (EXT2_FEATURE_INCOMPAT_FILETYPE\| \
	EXT2_FEATURE_INCOMPAT_META_BG)
	#define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER\| \
	EXT2_FEATURE_RO_COMPAT_LARGE_FILE\| \
	EXT2_FEATURE_RO_COMPAT_BTREE_DIR)
	#define EXT2_FEATURE_RO_COMPAT_UNSUPPORTED ~EXT2_FEATURE_RO_COMPAT_SUPP
	#define EXT2_FEATURE_INCOMPAT_UNSUPPORTED ~EXT2_FEATURE_INCOMPAT_SUPP

	/*
	* Default values for user and/or group using reserved blocks
	*/
	#define EXT2_DEF_RESUID 0
	#define EXT2_DEF_RESGID 0

	/*
	* Default mount options
	*/
	#define EXT2_DEFM_DEBUG 0x0001
	#define EXT2_DEFM_BSDGROUPS 0x0002
	#define EXT2_DEFM_XATTR_USER 0x0004
	#define EXT2_DEFM_ACL 0x0008
	#define EXT2_DEFM_UID16 0x0010
	/* Not used by ext2, but reserved for use by ext3 */
	#define EXT3_DEFM_JMODE 0x0060
	#define EXT3_DEFM_JMODE_DATA 0x0020
	#define EXT3_DEFM_JMODE_ORDERED 0x0040
	#define EXT3_DEFM_JMODE_WBACK 0x0060

	/*
	* Structure of a directory entry
	*/
	#define EXT2_NAME_LEN 255

	struct ext2_dir_entry {
	__le32 inode; /* Inode number */
	__le16 rec_len; /* Directory entry length */
	__le16 name_len; /* Name length */
	char name[EXT2_NAME_LEN]; /* File name */
	};

	/*
	* The new version of the directory entry. Since EXT2 structures are
	* stored in intel byte order, and the name_len field could never be
	* bigger than 255 chars, it's safe to reclaim the extra byte for the
	* file_type field.
	*/
	struct ext2_dir_entry_2 {
	__le32 inode; /* Inode number */
	__le16 rec_len; /* Directory entry length */
	__u8 name_len; /* Name length */
	__u8 file_type;
	char name[EXT2_NAME_LEN]; /* File name */
	};

	/*
	* Ext2 directory file types. Only the low 3 bits are used. The
	* other bits are reserved for now.
	*/
	enum {
	EXT2_FT_UNKNOWN,
	EXT2_FT_REG_FILE,
	EXT2_FT_DIR,
	EXT2_FT_CHRDEV,
	EXT2_FT_BLKDEV,
	EXT2_FT_FIFO,
	EXT2_FT_SOCK,
	EXT2_FT_SYMLINK,
	EXT2_FT_MAX
	};

	/*
	* EXT2_DIR_PAD defines the directory entries boundaries
	*
	* NOTE: It must be a multiple of 4
	*/
	#define EXT2_DIR_PAD 4
	#define EXT2_DIR_ROUND (EXT2_DIR_PAD - 1)
	#define EXT2_DIR_REC_LEN(name_len) (((name_len) + 8 + EXT2_DIR_ROUND) & \
	~EXT2_DIR_ROUND)
	#define EXT2_MAX_REC_LEN ((1<<16)-1)

	#endif /* _LINUX_EXT2_FS_H */