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/init.h>
  10 #include <linux/xattr.h>
  11
  12 /* Magic value in attribute blocks */
  13 #define EXT2_XATTR_MAGIC                0xEA020000
  14
  15 /* Maximum number of references to one attribute block */
  16 #define EXT2_XATTR_REFCOUNT_MAX         1024
  17
  18 /* Name indexes */
  19 #define EXT2_XATTR_INDEX_USER                   1
  20 #define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS       2
  21 #define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT      3
  22 #define EXT2_XATTR_INDEX_TRUSTED                4
  23 #define EXT2_XATTR_INDEX_LUSTRE                 5
  24 #define EXT2_XATTR_INDEX_SECURITY               6
  25
  26 struct ext2_xattr_header {
  27         __le32  h_magic;        /* magic number for identification */
  28         __le32  h_refcount;     /* reference count */
  29         __le32  h_blocks;       /* number of disk blocks used */
  30         __le32  h_hash;         /* hash value of all attributes */
  31         __u32   h_reserved[4];  /* zero right now */
  32 };
  33
  34 struct ext2_xattr_entry {
  35         __u8    e_name_len;     /* length of name */
  36         __u8    e_name_index;   /* attribute name index */
  37         __le16  e_value_offs;   /* offset in disk block of value */
  38         __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
  39         __le32  e_value_size;   /* size of attribute value */
  40         __le32  e_hash;         /* hash value of name and value */
  41         char    e_name[0];      /* attribute name */
  42 };
  43
  44 #define EXT2_XATTR_PAD_BITS             2
  45 #define EXT2_XATTR_PAD          (1<<EXT2_XATTR_PAD_BITS)
  46 #define EXT2_XATTR_ROUND                (EXT2_XATTR_PAD-1)
  47 #define EXT2_XATTR_LEN(name_len) \
  48         (((name_len) + EXT2_XATTR_ROUND + \
  49         sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
  50 #define EXT2_XATTR_NEXT(entry) \
  51         ( (struct ext2_xattr_entry *)( \
  52           (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
  53 #define EXT2_XATTR_SIZE(size) \
  54         (((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
  55
  56 # ifdef CONFIG_EXT2_FS_XATTR
  57
  58 extern const struct xattr_handler ext2_xattr_user_handler;
  59 extern const struct xattr_handler ext2_xattr_trusted_handler;
  60 extern const struct xattr_handler ext2_xattr_acl_access_handler;
  61 extern const struct xattr_handler ext2_xattr_acl_default_handler;
  62 extern const struct xattr_handler ext2_xattr_security_handler;
  63
  64 extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
  65
  66 extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
  67 extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
  68
  69 extern void ext2_xattr_delete_inode(struct inode *);
  70 extern void ext2_xattr_put_super(struct super_block *);
  71
  72 extern int init_ext2_xattr(void);
  73 extern void exit_ext2_xattr(void);
  74
  75 extern const struct xattr_handler *ext2_xattr_handlers[];
  76
  77 # else  /* CONFIG_EXT2_FS_XATTR */
  78
  79 static inline int
  80 ext2_xattr_get(struct inode *inode, int name_index,
  81                const char *name, void *buffer, size_t size)
  82 {
  83         return -EOPNOTSUPP;
  84 }
  85
  86 static inline int
  87 ext2_xattr_set(struct inode *inode, int name_index, const char *name,
  88                const void *value, size_t size, int flags)
  89 {
  90         return -EOPNOTSUPP;
  91 }
  92
  93 static inline void
  94 ext2_xattr_delete_inode(struct inode *inode)
  95 {
  96 }
  97
  98 static inline void
  99 ext2_xattr_put_super(struct super_block *sb)
 100 {
 101 }
 102
 103 static inline int
 104 init_ext2_xattr(void)
 105 {
 106         return 0;
 107 }
 108
 109 static inline void
 110 exit_ext2_xattr(void)
 111 {
 112 }
 113
 114 #define ext2_xattr_handlers NULL
 115
 116 # endif  /* CONFIG_EXT2_FS_XATTR */
 117
 118 #ifdef CONFIG_EXT2_FS_SECURITY
 119 extern int ext2_init_security(struct inode *inode, struct inode *dir);
 120 #else
 121 static inline int ext2_init_security(struct inode *inode, struct inode *dir)
 122 {
 123         return 0;
 124 }
 125 #endif