fs/ext4/xattr.h

   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_EXT4DEV_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_list(struct inode *, char *, size_t);
  78 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
  79 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
  80
  81 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
  82 extern void ext4_xattr_put_super(struct super_block *);
  83
  84 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
  85                             struct ext4_inode *raw_inode, handle_t *handle);
  86
  87 extern int init_ext4_xattr(void);
  88 extern void exit_ext4_xattr(void);
  89
  90 extern struct xattr_handler *ext4_xattr_handlers[];
  91
  92 # else  /* CONFIG_EXT4DEV_FS_XATTR */
  93
  94 static inline int
  95 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
  96                void *buffer, size_t size, int flags)
  97 {
  98         return -EOPNOTSUPP;
  99 }
 100
 101 static inline int
 102 ext4_xattr_list(struct inode *inode, void *buffer, size_t size)
 103 {
 104         return -EOPNOTSUPP;
 105 }
 106
 107 static inline int
 108 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 109                const void *value, size_t size, int flags)
 110 {
 111         return -EOPNOTSUPP;
 112 }
 113
 114 static inline int
 115 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 116                const char *name, const void *value, size_t size, int flags)
 117 {
 118         return -EOPNOTSUPP;
 119 }
 120
 121 static inline void
 122 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
 123 {
 124 }
 125
 126 static inline void
 127 ext4_xattr_put_super(struct super_block *sb)
 128 {
 129 }
 130
 131 static inline int
 132 init_ext4_xattr(void)
 133 {
 134         return 0;
 135 }
 136
 137 static inline void
 138 exit_ext4_xattr(void)
 139 {
 140 }
 141
 142 static inline int
 143 ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 144                             struct ext4_inode *raw_inode, handle_t *handle)
 145 {
 146         return -EOPNOTSUPP;
 147 }
 148
 149 #define ext4_xattr_handlers     NULL
 150
 151 # endif  /* CONFIG_EXT4DEV_FS_XATTR */
 152
 153 #ifdef CONFIG_EXT4DEV_FS_SECURITY
 154 extern int ext4_init_security(handle_t *handle, struct inode *inode,
 155                                 struct inode *dir);
 156 #else
 157 static inline int ext4_init_security(handle_t *handle, struct inode *inode,
 158                                 struct inode *dir)
 159 {
 160         return 0;
 161 }
 162 #endif