/*
 *  linux/include/linux/ext2_fs.h
 *
 * The second extended filesystem constants/structures
 *
 * 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
 *
 *  Simplified for OS project use by Mark Kampe
 */

/* types normally from linux/types.h	*/
typedef __uint32_t	__u32;
typedef __uint16_t	__u16;
typedef unsigned char	__u8;
typedef __int32_t	__s32;
typedef __int16_t	__s16;

/*
 * The second extended file system version
 */
#define EXT2FS_DATE		"95/08/09"
#define EXT2FS_VERSION		"0.5b"

/*
 * Special inodes numbers
 */
#define	EXT2_BAD_INO		 1	/* Bad blocks inode */
#define EXT2_ROOT_INO		 2	/* Root inode */

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

/*
 * The second extended file system magic number
 */
#define EXT2_SUPER_MAGIC	0xEF53

/*
 * 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
#define EXT2_MIN_FRAG_SIZE		1024
#define	EXT2_MAX_FRAG_SIZE		4096

/*
 * Structure of a blocks group descriptor
 */
struct ext2_group_desc
{
	__u32	bg_block_bitmap;		/* Blocks bitmap block */
	__u32	bg_inode_bitmap;		/* Inodes bitmap block */
	__u32	bg_inode_table;		/* Inodes table block */
	__u16	bg_free_blocks_count;	/* Free blocks count */
	__u16	bg_free_inodes_count;	/* Free inodes count */
	__u16	bg_used_dirs_count;	/* Directories count */
	__u16	bg_pad;
	__u32	bg_reserved[3];
};

/*
 * 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)

/*
 * Structure of an inode on the disk
 */
struct ext2_inode {

	__u16	i_mode;		/* File mode */
	__u16	i_uid;		/* Owner Uid */
	__u32	i_size;		/* Size in bytes */
	__u32	i_atime;	/* Access time */
	__u32	i_ctime;	/* Creation time */
	__u32	i_mtime;	/* Modification time */
	__u32	i_dtime;	/* Deletion Time */
	__u16	i_gid;		/* Group Id */
	__u16	i_links_count;	/* Links count */
	__u32	i_blocks;	/* Blocks count */
	__u32	i_flags;	/* File flags */
	__u32   i_reserved1;

	__u32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
	__u32	i_version;	/* File version (for NFS) */
	__u32	i_file_acl;	/* File ACL */
	__u32	i_dir_acl;	/* Directory ACL */
	__u32	i_faddr;	/* Fragment address */
	__u8	i_frag;		/* Fragment number */
	__u8	i_fsize;	/* Fragment size */
	__u16	i_pad1;
	__u32	i_reserved2[2];
};

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

/*
 * Structure of the super block
 */
struct ext2_super_block {
	__u32	s_inodes_count;		/* Inodes count */
	__u32	s_blocks_count;		/* Blocks count */
	__u32	s_r_blocks_count;	/* Reserved blocks count */
	__u32	s_free_blocks_count;	/* Free blocks count */
	__u32	s_free_inodes_count;	/* Free inodes count */
	__u32	s_first_data_block;	/* First Data Block */
	__u32	s_log_block_size;	/* log2(Block size) */
		/* bsize = EXT2_MIN_BLOCK_SIZE << s_log_block_size	*/
	__s32	s_log_frag_size;	/* log2(Fragment size) */
		/* fsize = EXT2_MIN_BLOCK_SIZE << s_log_frag_size	*/
	__u32	s_blocks_per_group;	/* # Blocks per group */
	__u32	s_frags_per_group;	/* # Fragments per group */
	__u32	s_inodes_per_group;	/* # Inodes per group */
		/* last group may have fewer blocks/inodes/frags	*/
	__u32	s_mtime;		/* Mount time */
	__u32	s_wtime;		/* Write time */
	__u16	s_mnt_count;		/* Mount count */
	__s16	s_max_mnt_count;	/* Maximal mount count */
	__u16	s_magic;		/* Magic signature */
	__u16	s_state;		/* File system state */
	__u16	s_errors;		/* Behaviour when detecting errors */
	__u16	s_minor_rev_level; 	/* minor revision level */
	__u32	s_lastcheck;		/* time of last check */
	__u32	s_checkinterval;	/* max. time between checks */
	__u32	s_creator_os;		/* OS */
	__u32	s_rev_level;		/* Revision level */
	__u16	s_def_resuid;		/* Default uid for reserved blocks */
	__u16	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...
	 */
	__u32	s_first_ino; 		/* First non-reserved inode */
	__u16   s_inode_size; 		/* size of inode structure */
	__u16	s_block_group_nr; 	/* block group # of this superblock */
	__u32	s_feature_compat; 	/* compatible feature set */
	__u32	s_feature_incompat; 	/* incompatible feature set */
	__u32	s_feature_ro_compat; 	/* readonly-compatible feature set */
	__u32	s_reserved[230];	/* Padding to the end of the block */
};

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

struct ext2_dir_entry {
	__u32	inode;			/* Inode number */
	__u16	rec_len;		/* Directory entry length */
	__u8	name_len;		/* name length	*/
	__u8	file_type;		/* file type */
	char	name[EXT2_NAME_LEN];	/* File name */
};