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         __le32  h_checksum;     /* crc32c(uuid+id+xattrblock) */
  31                                 /* id = inum if refcount=1, blknum otherwise */
  32         __u32   h_reserved[3];  /* zero right now */
  33 };
  34
  35 struct ext4_xattr_ibody_header {
  36         __le32  h_magic;        /* magic number for identification */
  37 };
  38
  39 struct ext4_xattr_entry {
  40         __u8    e_name_len;     /* length of name */
  41         __u8    e_name_index;   /* attribute name index */
  42         __le16  e_value_offs;   /* offset in disk block of value */
  43         __le32  e_value_block;  /* disk block attribute is stored on (n/i) */
  44         __le32  e_value_size;   /* size of attribute value */
  45         __le32  e_hash;         /* hash value of name and value */
  46         char    e_name[0];      /* attribute name */
  47 };
  48
  49 #define EXT4_XATTR_PAD_BITS             2
  50 #define EXT4_XATTR_PAD          (1<<EXT4_XATTR_PAD_BITS)
  51 #define EXT4_XATTR_ROUND                (EXT4_XATTR_PAD-1)
  52 #define EXT4_XATTR_LEN(name_len) \
  53         (((name_len) + EXT4_XATTR_ROUND + \
  54         sizeof(struct ext4_xattr_entry)) & ~EXT4_XATTR_ROUND)
  55 #define EXT4_XATTR_NEXT(entry) \
  56         ((struct ext4_xattr_entry *)( \
  57          (char *)(entry) + EXT4_XATTR_LEN((entry)->e_name_len)))
  58 #define EXT4_XATTR_SIZE(size) \
  59         (((size) + EXT4_XATTR_ROUND) & ~EXT4_XATTR_ROUND)
  60
  61 #define IHDR(inode, raw_inode) \
  62         ((struct ext4_xattr_ibody_header *) \
  63                 ((void *)raw_inode + \
  64                 EXT4_GOOD_OLD_INODE_SIZE + \
  65                 EXT4_I(inode)->i_extra_isize))
  66 #define IFIRST(hdr) ((struct ext4_xattr_entry *)((hdr)+1))
  67
  68 # ifdef CONFIG_EXT4_FS_XATTR
  69
  70 extern const struct xattr_handler ext4_xattr_user_handler;
  71 extern const struct xattr_handler ext4_xattr_trusted_handler;
  72 extern const struct xattr_handler ext4_xattr_acl_access_handler;
  73 extern const struct xattr_handler ext4_xattr_acl_default_handler;
  74 extern const struct xattr_handler ext4_xattr_security_handler;
  75
  76 extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);
  77
  78 extern int ext4_xattr_get(struct inode *, int, const char *, void *, size_t);
  79 extern int ext4_xattr_set(struct inode *, int, const char *, const void *, size_t, int);
  80 extern int ext4_xattr_set_handle(handle_t *, struct inode *, int, const char *, const void *, size_t, int);
  81
  82 extern void ext4_xattr_delete_inode(handle_t *, struct inode *);
  83 extern void ext4_xattr_put_super(struct super_block *);
  84
  85 extern int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
  86                             struct ext4_inode *raw_inode, handle_t *handle);
  87
  88 extern int __init ext4_init_xattr(void);
  89 extern void ext4_exit_xattr(void);
  90
  91 extern const struct xattr_handler *ext4_xattr_handlers[];
  92
  93 # else  /* CONFIG_EXT4_FS_XATTR */
  94
  95 static inline int
  96 ext4_xattr_get(struct inode *inode, int name_index, const char *name,
  97                void *buffer, size_t size, int flags)
  98 {
  99         return -EOPNOTSUPP;
 100 }
 101
 102 static inline int
 103 ext4_xattr_set(struct inode *inode, int name_index, const char *name,
 104                const void *value, size_t size, int flags)
 105 {
 106         return -EOPNOTSUPP;
 107 }
 108
 109 static inline int
 110 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index,
 111                const char *name, const void *value, size_t size, int flags)
 112 {
 113         return -EOPNOTSUPP;
 114 }
 115
 116 static inline void
 117 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode)
 118 {
 119 }
 120
 121 static inline void
 122 ext4_xattr_put_super(struct super_block *sb)
 123 {
 124 }
 125
 126 static __init inline int
 127 ext4_init_xattr(void)
 128 {
 129         return 0;
 130 }
 131
 132 static inline void
 133 ext4_exit_xattr(void)
 134 {
 135 }
 136
 137 static inline int
 138 ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize,
 139                             struct ext4_inode *raw_inode, handle_t *handle)
 140 {
 141         return -EOPNOTSUPP;
 142 }
 143
 144 #define ext4_xattr_handlers     NULL
 145
 146 # endif  /* CONFIG_EXT4_FS_XATTR */
 147
 148 #ifdef CONFIG_EXT4_FS_SECURITY
 149 extern int ext4_init_security(handle_t *handle, struct inode *inode,
 150                               struct inode *dir, const struct qstr *qstr);
 151 #else
 152 static inline int ext4_init_security(handle_t *handle, struct inode *inode,
 153                                      struct inode *dir, const struct qstr *qstr)
 154 {
 155         return 0;
 156 }
 157 #endif