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/*
File: linux/ext2_ext_attr.h
On-disk format of extended attributes for the ext2 filesystem.
(C) 2000 Andreas Gruenbacher, <a.gruenbacher@computer.org>
*/
#ifndef _EXT2_EXT_ATTR_H
#define _EXT2_EXT_ATTR_H
/* Magic value in attribute blocks */
#define EXT2_EXT_ATTR_MAGIC_v1 0xEA010000
#define EXT2_EXT_ATTR_MAGIC 0xEA020000
/* Maximum number of references to one attribute block */
#define EXT2_EXT_ATTR_REFCOUNT_MAX 1024
struct ext2_ext_attr_header {
__u32 h_magic; /* magic number for identification */
__u32 h_refcount; /* reference count */
__u32 h_blocks; /* number of disk blocks used */
__u32 h_hash; /* hash value of all attributes */
__u32 h_checksum; /* crc32c(uuid+id+xattrs) */
/* id = inum if refcount = 1, else blknum */
__u32 h_reserved[3]; /* zero right now */
};
struct ext2_ext_attr_entry {
__u8 e_name_len; /* length of name */
__u8 e_name_index; /* attribute name index */
__u16 e_value_offs; /* offset in disk block of value */
__u32 e_value_inum; /* inode in which the value is stored */
__u32 e_value_size; /* size of attribute value */
__u32 e_hash; /* hash value of name and value */
#if 0
char e_name[0]; /* attribute name */
#endif
};
#define EXT2_EXT_ATTR_PAD_BITS 2
#define EXT2_EXT_ATTR_PAD ((unsigned) 1<<EXT2_EXT_ATTR_PAD_BITS)
#define EXT2_EXT_ATTR_ROUND (EXT2_EXT_ATTR_PAD-1)
#define EXT2_EXT_ATTR_LEN(name_len) \
(((name_len) + EXT2_EXT_ATTR_ROUND + \
sizeof(struct ext2_ext_attr_entry)) & ~EXT2_EXT_ATTR_ROUND)
#define EXT2_EXT_ATTR_NEXT(entry) \
( (struct ext2_ext_attr_entry *)( \
(char *)(entry) + EXT2_EXT_ATTR_LEN((entry)->e_name_len)) )
#define EXT2_EXT_ATTR_SIZE(size) \
(((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND)
#define EXT2_EXT_IS_LAST_ENTRY(entry) (*((__u32 *)(entry)) == 0UL)
#define EXT2_EXT_ATTR_NAME(entry) \
(((char *) (entry)) + sizeof(struct ext2_ext_attr_entry))
#define EXT2_XATTR_LEN(name_len) \
(((name_len) + EXT2_EXT_ATTR_ROUND + \
sizeof(struct ext2_xattr_entry)) & ~EXT2_EXT_ATTR_ROUND)
#define EXT2_XATTR_SIZE(size) \
(((size) + EXT2_EXT_ATTR_ROUND) & ~EXT2_EXT_ATTR_ROUND)
/*
* XATTR_SIZE_MAX is currently 64k, but for the purposes of checking
* for file system consistency errors, we use a somewhat bigger value.
* This allows XATTR_SIZE_MAX to grow in the future, but by using this
* instead of INT_MAX for certain consistency checks, we don't need to
* worry about arithmetic overflows. (Actually XATTR_SIZE_MAX is
* defined in include/uapi/linux/limits.h, so changing it is going
* not going to be trivial....)
*/
#define EXT2_XATTR_SIZE_MAX (1 << 24)
#ifdef __KERNEL__
# ifdef CONFIG_EXT2_FS_EXT_ATTR
extern int ext2_get_ext_attr(struct inode *, const char *, char *, size_t, int);
extern int ext2_set_ext_attr(struct inode *, const char *, char *, size_t, int);
extern void ext2_ext_attr_free_inode(struct inode *inode);
extern void ext2_ext_attr_put_super(struct super_block *sb);
extern int ext2_ext_attr_init(void);
extern void ext2_ext_attr_done(void);
# else
# define ext2_get_ext_attr NULL
# define ext2_set_ext_attr NULL
# endif
#endif /* __KERNEL__ */
#endif /* _EXT2_EXT_ATTR_H */
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