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_MAX                    10
  21 #define EXT2_XATTR_INDEX_USER                   1
  22 #define EXT2_XATTR_INDEX_POSIX_ACL_ACCESS       2
  23 #define EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT      3
  24 #define EXT2_XATTR_INDEX_TRUSTED                4
  25 #define EXT2_XATTR_INDEX_LUSTRE                 5
  26 #define EXT2_XATTR_INDEX_SECURITY               6
  27
  28 struct ext2_xattr_header {
  29         __le32  h_magic;        /* magic number for identification */
  30         __le32  h_refcount;     /* reference count */
  31         __le32  h_blocks;       /* number of disk blocks used */
  32         __le32  h_hash;         /* hash value of all attributes */
  33         __u32   h_reserved[4];  /* zero right now */
  34 };
  35
  36 struct ext2_xattr_entry {
  37         __u8    e_name_len;     /* length of name */
  38         __u8    e_name_index;   /* attribute name index */
  39         __le16  e_value_offs;   /* offset in disk block of value */
  40         __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
  41         __le32  e_value_size;   /* size of attribute value */
  42         __le32  e_hash;         /* hash value of name and value */
  43         char    e_name[0];      /* attribute name */
  44 };
  45
  46 #define EXT2_XATTR_PAD_BITS             2
  47 #define EXT2_XATTR_PAD          (1<<EXT2_XATTR_PAD_BITS)
  48 #define EXT2_XATTR_ROUND                (EXT2_XATTR_PAD-1)
  49 #define EXT2_XATTR_LEN(name_len) \
  50         (((name_len) + EXT2_XATTR_ROUND + \
  51         sizeof(struct ext2_xattr_entry)) & ~EXT2_XATTR_ROUND)
  52 #define EXT2_XATTR_NEXT(entry) \
  53         ( (struct ext2_xattr_entry *)( \
  54           (char *)(entry) + EXT2_XATTR_LEN((entry)->e_name_len)) )
  55 #define EXT2_XATTR_SIZE(size) \
  56         (((size) + EXT2_XATTR_ROUND) & ~EXT2_XATTR_ROUND)
  57
  58 # ifdef CONFIG_EXT2_FS_XATTR
  59
  60 struct ext2_xattr_handler {
  61         char *prefix;
  62         size_t (*list)(char *list, struct inode *inode, const char *name,
  63                        int name_len);
  64         int (*get)(struct inode *inode, const char *name, void *buffer,
  65                    size_t size);
  66         int (*set)(struct inode *inode, const char *name, const void *buffer,
  67                    size_t size, int flags);
  68 };
  69
  70 extern int ext2_xattr_register(int, struct ext2_xattr_handler *);
  71 extern void ext2_xattr_unregister(int, struct ext2_xattr_handler *);
  72
  73 extern int ext2_setxattr(struct dentry *, const char *, const void *, size_t, int);
  74 extern ssize_t ext2_getxattr(struct dentry *, const char *, void *, size_t);
  75 extern ssize_t ext2_listxattr(struct dentry *, char *, size_t);
  76 extern int ext2_removexattr(struct dentry *, const char *);
  77
  78 extern int ext2_xattr_get(struct inode *, int, const char *, void *, size_t);
  79 extern int ext2_xattr_list(struct inode *, char *, size_t);
  80 extern int ext2_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
  81
  82 extern void ext2_xattr_delete_inode(struct inode *);
  83 extern void ext2_xattr_put_super(struct super_block *);
  84
  85 extern int init_ext2_xattr(void);
  86 extern void exit_ext2_xattr(void);
  87
  88 # else  /* CONFIG_EXT2_FS_XATTR */
  89 #  define ext2_setxattr         NULL
  90 #  define ext2_getxattr         NULL
  91 #  define ext2_listxattr        NULL
  92 #  define ext2_removexattr      NULL
  93
  94 static inline int
  95 ext2_xattr_get(struct inode *inode, int name_index,
  96                const char *name, void *buffer, size_t size)
  97 {
  98         return -EOPNOTSUPP;
  99 }
 100
 101 static inline int
 102 ext2_xattr_list(struct inode *inode, char *buffer, size_t size)
 103 {
 104         return -EOPNOTSUPP;
 105 }
 106
 107 static inline int
 108 ext2_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 void
 115 ext2_xattr_delete_inode(struct inode *inode)
 116 {
 117 }
 118
 119 static inline void
 120 ext2_xattr_put_super(struct super_block *sb)
 121 {
 122 }
 123
 124 static inline int
 125 init_ext2_xattr(void)
 126 {
 127         return 0;
 128 }
 129
 130 static inline void
 131 exit_ext2_xattr(void)
 132 {
 133 }
 134
 135 # endif  /* CONFIG_EXT2_FS_XATTR */
 136
 137 extern struct ext2_xattr_handler ext2_xattr_user_handler;
 138 extern struct ext2_xattr_handler ext2_xattr_trusted_handler;
 139 extern struct ext2_xattr_handler ext2_xattr_security_handler;
 140