ext2_fs.h

linux 下的文件管理的程序

/*
 *  linux/include/linux/ext2_fs.h
 *
 * Copyright (C) 1992, 1993, 1994, 1995
 * Remy Card ([e-mail])
 * 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>

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

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

/*
 * Define EXT2_PREALLOCATE to preallocate data blocks for expanding files
 */
#define EXT2_PREALLOCATE
#define EXT2_DEFAULT_PREALLOC_BLOCKS	8

/*
 * 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__, __FUNCTION__); \
				  	printk (f, ## a); \
					}
#else
#	define ext2_debug(f, a...)	/**/
#endif

/*
 * Special inodes numbers
 */
#define	EXT2_BAD_INO		 1	/* Bad blocks inode */
#define EXT2_ROOT_INO		 2	/* Root inode */
#define EXT2_ACL_IDX_INO	 3	/* ACL inode */
#define EXT2_ACL_DATA_INO	 4	/* ACL 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

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

/*
 * 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_ACLE_PER_BLOCK(s)		(EXT2_BLOCK_SIZE(s) / sizeof (struct ext2_acl_entry))
#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)	((s)->u.ext2_sb.s_addr_per_block_bits)
#define EXT2_INODE_SIZE(s)		((s)->u.ext2_sb.s_inode_size)
#define EXT2_FIRST_INO(s)		((s)->u.ext2_sb.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)		((s)->u.ext2_sb.s_frag_size)
# define EXT2_FRAGS_PER_BLOCK(s)	((s)->u.ext2_sb.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

/*
 * ACL structures
 */
struct ext2_acl_header	/* Header of Access Control Lists */
{
	__u32	aclh_size;
	__u32	aclh_file_count;
	__u32	aclh_acle_count;
	__u32	aclh_first_acle;
};

struct ext2_acl_entry	/* Access Control List Entry */
{
	__u32	acle_size;
	__u16	acle_perms;	/* Access permissions */
	__u16	acle_type;	/* Type of entry */
	__u16	acle_tag;	/* User or group identity */
	__u16	acle_pad1;
	__u32	acle_next;	/* Pointer on next entry for the */
					/* same inode or on next free entry */
};

/*
 * 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];
};

/*
 * Macro-instructions used to manage group descriptors
 */
#ifdef __KERNEL__
# define EXT2_BLOCKS_PER_GROUP(s)	((s)->u.ext2_sb.s_blocks_per_group)
# define EXT2_DESC_PER_BLOCK(s)		((s)->u.ext2_sb.s_desc_per_block)
# define EXT2_INODES_PER_GROUP(s)	((s)->u.ext2_sb.s_inodes_per_group)
# define EXT2_DESC_PER_BLOCK_BITS(s)	((s)->u.ext2_sb.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
 */
#define	EXT2_SECRM_FL			0x00000001 /* Secure deletion */
#define	EXT2_UNRM_FL			0x00000002 /* Undelete */
#define	EXT2_COMPR_FL			0x00000004 /* Compress file */
#define EXT2_SYNC_FL			0x00000008 /* Synchronous updates */
#define EXT2_IMMUTABLE_FL		0x00000010 /* Immutable file */
#define EXT2_APPEND_FL			0x00000020 /* writes to file may only append */
#define EXT2_NODUMP_FL			0x00000040 /* do not dump file */
#define EXT2_NOATIME_FL			0x00000080 /* do not update atime */
/* Reserved for compression usage... */
#define EXT2_DIRTY_FL			0x00000100
#define EXT2_COMPRBLK_FL		0x00000200 /* One or more compressed clusters */
#define EXT2_NOCOMP_FL			0x00000400 /* Don't compress */
#define EXT2_ECOMPR_FL			0x00000800 /* Compression error */
/* End compression flags --- maybe not all used */	
#define EXT2_BTREE_FL			0x00001000 /* btree format dir */
#define EXT2_RESERVED_FL		0x80000000 /* reserved for ext2 lib */

#define EXT2_FL_USER_VISIBLE		0x00001FFF /* User visible flags */
#define EXT2_FL_USER_MODIFIABLE		0x000000FF /* User modifiable flags */

/*
 * ioctl commands
 */
#define	EXT2_IOC_GETFLAGS		_IOR('f', 1, long)
#define	EXT2_IOC_SETFLAGS		_IOW('f', 2, long)
#define	EXT2_IOC_GETVERSION		_IOR('v', 1, long)
#define	EXT2_IOC_SETVERSION		_IOW('v', 2, long)

/*
 * Structure of an inode on the disk
 */
struct ext2_inode {
	__u16	i_mode;		/* File mode */
	__u16	i_uid;		/* Low 16 bits of 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;		/* Low 16 bits of Group Id */
	__u16	i_links_count;	/* Links count */
	__u32	i_blocks;	/* Blocks count */
	__u32	i_flags;	/* File flags */
	union {
		struct {
			__u32  l_i_reserved1;
		} linux1;
		struct {
			__u32  h_i_translator;
		} hurd1;
		struct {
			__u32  m_i_reserved1;
		} masix1;
	} osd1;				/* OS dependent 1 */
	__u32	i_block[EXT2_N_BLOCKS];/* Pointers to blocks */
	__u32	i_generation;	/* File version (for NFS) */
	__u32	i_file_acl;	/* File ACL */
	__u32	i_dir_acl;	/* Directory ACL */
	__u32	i_faddr;	/* Fragment address */
	union {
		struct {
			__u8	l_i_frag;	/* Fragment number */
			__u8	l_i_fsize;	/* Fragment size */
			__u16	i_pad1;
			__u16	l_i_uid_high;	/* these 2 fields    */
			__u16	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 */
			__u16	h_i_mode_high;
			__u16	h_i_uid_high;
			__u16	h_i_gid_high;
			__u32	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		0x0001	/* Do mount-time checks */
#define EXT2_MOUNT_GRPID		0x0004	/* Create files with directory's group */
#define EXT2_MOUNT_DEBUG		0x0008	/* Some debugging messages */
#define EXT2_MOUNT_ERRORS_CONT		0x0010	/* Continue on errors */
#define EXT2_MOUNT_ERRORS_RO		0x0020	/* Remount fs ro on errors */
#define EXT2_MOUNT_ERRORS_PANIC		0x0040	/* Panic on errors */
#define EXT2_MOUNT_MINIX_DF		0x0080	/* Mimics the Minix statfs */