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