xattr.h:
/*
File: linux/ext2_xattr.h
On-disk format of extended attributes for the ext2 filesystem.
(C) 2001 Andreas Gruenbacher, <a .gruenbacher@computer.org>
*/
#include <linux /init.h>
#include </linux><linux /xattr.h>
/* Magic value in attribute blocks */
#define EXT2_XATTR_MAGIC 0xEA020000
//定义属性block中使用的魔数(一个标记，唯一的值)
/* Maximum number of references to one attribute block */
#define EXT2_XATTR_REFCOUNT_MAX 1024
//定义一个属性block
/* Name indexes */
#define EXT2_XATTR_INDEX_USER 1
#define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS 2
#define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT 3
#define EXT2_XATTR_INDEX_TRUSTED 4
#define EXT2_XATTR_INDEX_LUSTRE 5
#define EXT2_XATTR_INDEX_SECURITY 6
struct ext2_xattr_header {
__le32 h_magic; /* magic number for identification */
__le32 h_refcount; /* reference count */
__le32 h_blocks; /* number of disk blocks used */
__le32 h_hash; /* hash value of all attributes */
__u32 h_reserved[4]; /* zero right now */
};
//__le32 h_magic; 标识码，为0xEA020000
//__le32 h_refcount; 属性块被链接的数目
//__le32 h_blocks; 用于扩展属性的块数
//__le32 h_hash; 所有属性的哈希值
//__u32 h_reserved[4]; 保留变量，目前为0
struct ext2_xattr_entry {
__u8 e_name_len; /* length of name */
__u8 e_name_index; /* attribute name index */
__le16 e_value_offs; /* offset in disk block of value */
__le32 e_value_block; /* disk block attribute is stored on (n/i) */
__le32 e_value_size; /* size of attribute value */
__le32 e_hash; /* hash value of name and value */
char e_name[0]; /* attribute name */
};
//__u8 e_name_len; 属性名长度
//__u8 e_name_index; 属性名索引
//__le16 e_value_offs; 属性值在值块中的偏移量
//__le32 e_value_block; 保存属性值的块的块号
//__le32 e_value_size; 属性值长度
//__le32 e_hash; 属性名和值的哈希值
//char e_name[0]; 属性名
#define EXT2_XATTR_PAD_BITS 2
#define EXT2_XATTR_PAD (1< <EXT2_XATTR_PAD_BITS)
#define EXT2_XATTR_ROUND (EXT2_XATTR_PAD-1)
#define EXT2_XATTR_LEN(name_len) \
(((name_len) + EXT2_XATTR_ROUND + \
sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
#define EXT2_XATTR_NEXT(entry) \
( (struct ext2_xattr_entry *)( \
(char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
#define EXT2_XATTR_SIZE(size) \
(((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
# ifdef CONFIG_EXT2_FS_XATTR
//当内核编译时指定使用xattr扩展属性时，xattr相关函数的申明
extern struct xattr_handler ext2_xattr_user_handler;
extern struct xattr_handler ext2_xattr_trusted_handler;
extern struct xattr_handler ext2_xattr_acl_access_handler;
extern struct xattr_handler ext2_xattr_acl_default_handler;
extern struct xattr_handler ext2_xattr_security_handler;
extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
extern void ext2_xattr_delete_inode(struct inode *);
extern void ext2_xattr_put_super(struct super_block *);
extern int init_ext2_xattr(void);
extern void exit_ext2_xattr(void);
extern struct xattr_handler *ext2_xattr_handlers[];
# else /* CONFIG_EXT2_FS_XATTR */
//当内核编译时未使用xattr扩展属性，xattr相关函数被置为空
static inline int
ext2_xattr_get(struct inode *inode, int name_index,
const char *name, void *buffer, size_t size)
{
return -EOPNOTSUPP;
}
static inline int
ext2_xattr_set(struct inode *inode, int name_index, const char *name,
const void *value, size_t size, int flags)
{
return -EOPNOTSUPP;
}
static inline void
ext2_xattr_delete_inode(struct inode *inode)
{
}
static inline void
ext2_xattr_put_super(struct super_block *sb)
{
}
static inline int
init_ext2_xattr(void)
{
return 0;
}
static inline void
exit_ext2_xattr(void)
{
}
#define ext2_xattr_handlers NULL
# endif /* CONFIG_EXT2_FS_XATTR */
#ifdef CONFIG_EXT2_FS_SECURITY
extern int ext2_init_security(struct inode *inode, struct inode *dir);
#else
static inline int ext2_init_security(struct inode *inode, struct inode *dir)
{
return 0;
}
#endif
[/c]
**xip.h**:
[c]
/*
* linux/fs/ext2/xip.h
*
* Copyright (C) 2005 IBM Corporation
* Author: Carsten Otte (cotte@de.ibm.com)
*/
#ifdef CONFIG_EXT2_FS_XIP
//当内核编译时指定使用xip扩展属性时，xip相关操作的函数申明
extern void ext2_xip_verify_sb (struct super_block *);
extern int ext2_clear_xip_target (struct inode *, int);
static inline int ext2_use_xip (struct super_block *sb)
{
struct ext2_sb_info *sbi = EXT2_SB(sb);
return (sbi->s_mount_opt & EXT2_MOUNT_XIP);
}
struct page* ext2_get_xip_page (struct address_space *, sector_t, int);
#define mapping_is_xip(map) unlikely(map->a_ops->get_xip_page)
#else
//当内核编译时未指定使用xattr扩展属性时，置这些函数操作为空
#define mapping_is_xip(map) 0
#define ext2_xip_verify_sb(sb) do { } while (0)
#define ext2_use_xip(sb) 0
#define ext2_clear_xip_target(inode, chain) 0
#define ext2_get_xip_page NULL
#endif
Comments
cocobear: 你也找一个好做得呗……
luguo: 哎，dp同学的毕设好做啊，写写注释就完～！ ;-)
