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1  /*
2    File: fs/ext4/xattr.h
3  
4    On-disk format of extended attributes for the ext4 filesystem.
5  
6    (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
7  */
8  
9  #include <linux/xattr.h>
10  
11  /* Magic value in attribute blocks */
12  #define EXT4_XATTR_MAGIC		0xEA020000
13  
14  /* Maximum number of references to one attribute block */
15  #define EXT4_XATTR_REFCOUNT_MAX		1024
16  
17  /* Name indexes */
18  #define EXT4_XATTR_INDEX_USER			1
19  #define EXT4_XATTR_INDEX_POSIX_ACL_ACCESS	2
20  #define EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT	3
21  #define EXT4_XATTR_INDEX_TRUSTED		4
22  #define	EXT4_XATTR_INDEX_LUSTRE			5
23  #define EXT4_XATTR_INDEX_SECURITY	        6
24  
25  struct ext4_xattr_header {
26  	__le32	h_magic;	/* magic number for identification */
27  	__le32	h_refcount;	/* reference count */
28  	__le32	h_blocks;	/* number of disk blocks used */
29  	__le32	h_hash;		/* hash value of all attributes */
30  	__u32	h_reserved[4];	/* zero right now */
31  };
32  
33  struct ext4_xattr_ibody_header {
34  	__le32	h_magic;	/* magic number for identification */
35  };
36  
37  struct ext4_xattr_entry {
38  	__u8	e_name_len;	/* length of name */
39  	__u8	e_name_index;	/* attribute name index */
40  	__le16	e_value_offs;	/* offset in disk block of value */
41  	__le32	e_value_block;	/* disk block attribute is stored on (n/i) */
42  	__le32	e_value_size;	/* size of attribute value */
43  	__le32	e_hash;		/* hash value of name and value */
44  	char	e_name[0];	/* attribute name */
45  };
46  
47  #define EXT4_XATTR_PAD_BITS		2
48  #define EXT4_XATTR_PAD		(1<<EXT4_XATTR_PAD_BITS)
49  #define EXT4_XATTR_ROUND		(EXT4_XATTR_PAD-1)
50  #define EXT4_XATTR_LEN(name_len) \
51  	(((name_len) + EXT4_XATTR_ROUND + \
52  	sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
53  #define EXT4_XATTR_NEXT(entry) \
54  	((struct ext4_xattr_entry *)( \
55  	 (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
56  #define EXT4_XATTR_SIZE(size) \
57  	(((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
58  
59  #define IHDR(inode, raw_inode) \
60  	((struct ext4_xattr_ibody_header *) \
61  		((void *)raw_inode + \
62  		EXT4_GOOD_OLD_INODE_SIZE + \
63  		EXT4_I(inode)->i_extra_isize))
64  #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
65  
66  # ifdef CONFIG_EXT4_FS_XATTR
67  
68  extern struct xattr_handler ext4_xattr_user_handler;
69  extern struct xattr_handler ext4_xattr_trusted_handler;
70  extern struct xattr_handler ext4_xattr_acl_access_handler;
71  extern struct xattr_handler ext4_xattr_acl_default_handler;
72  extern struct xattr_handler ext4_xattr_security_handler;
73  
74  extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
75  
76  extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
77  extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
78  extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
79  
80  extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
81  extern void ext4_xattr_put_super(struct super_block *);
82  
83  extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
84  			    struct ext4_inode *raw_inode, handle_t *handle);
85  
86  extern int init_ext4_xattr(void);
87  extern void exit_ext4_xattr(void);
88  
89  extern struct xattr_handler *ext4_xattr_handlers[];
90  
91  # else  /* CONFIG_EXT4_FS_XATTR */
92  
93  static inline int
ext4_xattr_get(struct inode * inode,int name_index,const char * name,void * buffer,size_t size,int flags)94  ext4_xattr_get(struct inode *inode, int name_index, const char *name,
95  	       void *buffer, size_t size, int flags)
96  {
97  	return -EOPNOTSUPP;
98  }
99  
100  static inline int
ext4_xattr_set(struct inode * inode,int name_index,const char * name,const void * value,size_t size,int flags)101  ext4_xattr_set(struct inode *inode, int name_index, const char *name,
102  	       const void *value, size_t size, int flags)
103  {
104  	return -EOPNOTSUPP;
105  }
106  
107  static inline int
ext4_xattr_set_handle(handle_t * handle,struct inode * inode,int name_index,const char * name,const void * value,size_t size,int flags)108  ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
109  	       const char *name, const void *value, size_t size, int flags)
110  {
111  	return -EOPNOTSUPP;
112  }
113  
114  static inline void
ext4_xattr_delete_inode(handle_t * handle,struct inode * inode)115  ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
116  {
117  }
118  
119  static inline void
ext4_xattr_put_super(struct super_block * sb)120  ext4_xattr_put_super(struct super_block *sb)
121  {
122  }
123  
124  static inline int
init_ext4_xattr(void)125  init_ext4_xattr(void)
126  {
127  	return 0;
128  }
129  
130  static inline void
exit_ext4_xattr(void)131  exit_ext4_xattr(void)
132  {
133  }
134  
135  static inline int
ext4_expand_extra_isize_ea(struct inode * inode,int new_extra_isize,struct ext4_inode * raw_inode,handle_t * handle)136  ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
137  			    struct ext4_inode *raw_inode, handle_t *handle)
138  {
139  	return -EOPNOTSUPP;
140  }
141  
142  #define ext4_xattr_handlers	NULL
143  
144  # endif  /* CONFIG_EXT4_FS_XATTR */
145  
146  #ifdef CONFIG_EXT4_FS_SECURITY
147  extern int ext4_init_security(handle_t *handle, struct inode *inode,
148  				struct inode *dir);
149  #else
ext4_init_security(handle_t * handle,struct inode * inode,struct inode * dir)150  static inline int ext4_init_security(handle_t *handle, struct inode *inode,
151  				struct inode *dir)
152  {
153  	return 0;
154  }
155  #endif
156