fs/ext2/xattr.h

   1 /*
   2   File: linux/ext2_xattr.h
   3
   4   On-disk format of extended attributes for the ext2 filesystem.
   5
   6   (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
   7 */
   8
   9 #include <linux/config.h>
  10 #include <linux/init.h>
  11 #include <linux/xattr.h>
  12
  13 /* Magic value in attribute blocks */
  14 #define EXT2_XATTR_MAGIC                0xEA020000
  15
  16 /* Maximum number of references to one attribute block */
  17 #define EXT2_XATTR_REFCOUNT_MAX         1024
  18
  19 /* Name indexes */
  20 #define EXT2_XATTR_INDEX_USER                   1
  21 #define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS       2
  22 #define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT      3
  23 #define EXT2_XATTR_INDEX_TRUSTED                4
  24 #define EXT2_XATTR_INDEX_LUSTRE                 5
  25 #define EXT2_XATTR_INDEX_SECURITY               6
  26
  27 struct ext2_xattr_header {
  28         __le32  h_magic;        /* magic number for identification */
  29         __le32  h_refcount;     /* reference count */
  30         __le32  h_blocks;       /* number of disk blocks used */
  31         __le32  h_hash;         /* hash value of all attributes */
  32         __u32   h_reserved[4];  /* zero right now */
  33 };
  34
  35 struct ext2_xattr_entry {
  36         __u8    e_name_len;     /* length of name */
  37         __u8    e_name_index;   /* attribute name index */
  38         __le16  e_value_offs;   /* offset in disk block of value */
  39         __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
  40         __le32  e_value_size;   /* size of attribute value */
  41         __le32  e_hash;         /* hash value of name and value */
  42         char    e_name[0];      /* attribute name */
  43 };
  44
  45 #define EXT2_XATTR_PAD_BITS             2
  46 #define EXT2_XATTR_PAD          (1<<EXT2_XATTR_PAD_BITS)
  47 #define EXT2_XATTR_ROUND                (EXT2_XATTR_PAD-1)
  48 #define EXT2_XATTR_LEN(name_len) \
  49         (((name_len) + EXT2_XATTR_ROUND + \
  50         sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
  51 #define EXT2_XATTR_NEXT(entry) \
  52         ( (struct ext2_xattr_entry *)( \
  53           (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
  54 #define EXT2_XATTR_SIZE(size) \
  55         (((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
  56
  57 # ifdef CONFIG_EXT2_FS_XATTR
  58
  59 extern struct xattr_handler ext2_xattr_user_handler;
  60 extern struct xattr_handler ext2_xattr_trusted_handler;
  61 extern struct xattr_handler ext2_xattr_acl_access_handler;
  62 extern struct xattr_handler ext2_xattr_acl_default_handler;
  63 extern struct xattr_handler ext2_xattr_security_handler;
  64
  65 extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
  66
  67 extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
  68 extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
  69
  70 extern void ext2_xattr_delete_inode(struct inode *);
  71 extern void ext2_xattr_put_super(struct super_block *);
  72
  73 extern int init_ext2_xattr(void);
  74 extern void exit_ext2_xattr(void);
  75
  76 extern struct xattr_handler *ext2_xattr_handlers[];
  77
  78 # else  /* CONFIG_EXT2_FS_XATTR */
  79
  80 static inline int
  81 ext2_xattr_get(struct inode *inode, int name_index,
  82                const char *name, void *buffer, size_t size)
  83 {
  84         return -EOPNOTSUPP;
  85 }
  86
  87 static inline int
  88 ext2_xattr_set(struct inode *inode, int name_index, const char *name,
  89                const void *value, size_t size, int flags)
  90 {
  91         return -EOPNOTSUPP;
  92 }
  93
  94 static inline void
  95 ext2_xattr_delete_inode(struct inode *inode)
  96 {
  97 }
  98
  99 static inline void
 100 ext2_xattr_put_super(struct super_block *sb)
 101 {
 102 }
 103
 104 static inline int
 105 init_ext2_xattr(void)
 106 {
 107         return 0;
 108 }
 109
 110 static inline void
 111 exit_ext2_xattr(void)
 112 {
 113 }
 114
 115 #define ext2_xattr_handlers NULL
 116
 117 # endif  /* CONFIG_EXT2_FS_XATTR */
 118