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 # ifdef CONFIG_EXT4DEV_FS_XATTR
  60
  61 extern struct xattr_handler ext4_xattr_user_handler;
  62 extern struct xattr_handler ext4_xattr_trusted_handler;
  63 extern struct xattr_handler ext4_xattr_acl_access_handler;
  64 extern struct xattr_handler ext4_xattr_acl_default_handler;
  65 extern struct xattr_handler ext4_xattr_security_handler;
  66
  67 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
  68
  69 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
  70 extern int ext4_xattr_list(struct inode *, char *, size_t);
  71 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
  72 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
  73
  74 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
  75 extern void ext4_xattr_put_super(struct super_block *);
  76
  77 extern int init_ext4_xattr(void);
  78 extern void exit_ext4_xattr(void);
  79
  80 extern struct xattr_handler *ext4_xattr_handlers[];
  81
  82 # else  /* CONFIG_EXT4DEV_FS_XATTR */
  83
  84 static inline int
  85 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
  86                void *buffer, size_t size, int flags)
  87 {
  88         return -EOPNOTSUPP;
  89 }
  90
  91 static inline int
  92 ext4_xattr_list(struct inode *inode, void *buffer, size_t size)
  93 {
  94         return -EOPNOTSUPP;
  95 }
  96
  97 static inline int
  98 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
  99                const void *value, size_t size, int flags)
 100 {
 101         return -EOPNOTSUPP;
 102 }
 103
 104 static inline int
 105 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 106                const char *name, const void *value, size_t size, int flags)
 107 {
 108         return -EOPNOTSUPP;
 109 }
 110
 111 static inline void
 112 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
 113 {
 114 }
 115
 116 static inline void
 117 ext4_xattr_put_super(struct super_block *sb)
 118 {
 119 }
 120
 121 static inline int
 122 init_ext4_xattr(void)
 123 {
 124         return 0;
 125 }
 126
 127 static inline void
 128 exit_ext4_xattr(void)
 129 {
 130 }
 131
 132 #define ext4_xattr_handlers     NULL
 133
 134 # endif  /* CONFIG_EXT4DEV_FS_XATTR */
 135
 136 #ifdef CONFIG_EXT4DEV_FS_SECURITY
 137 extern int ext4_init_security(handle_t *handle, struct inode *inode,
 138                                 struct inode *dir);
 139 #else
 140 static inline int ext4_init_security(handle_t *handle, struct inode *inode,
 141                                 struct inode *dir)
 142 {
 143         return 0;
 144 }
 145 #endif