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ext2_fs.h
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ext2_fs.h
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/*
* linux/include/linux/ext2_fs.h
*
* The second extended filesystem constants/structures
*
* Copyright (C) 1992, 1993, 1994, 1995
* Remy Card ([email protected])
* 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 */
};