Add format header updates for xattrs

The kernel now has items and structs for xattrs.

Signed-off-by: Zach Brown <zab@versity.com>

utils/src/format.h

@@ -51,8 +51,9 @@ struct scoutfs_key {
  * have to stress about cleverly allocating the types.
  */
 #define SCOUTFS_INODE_KEY	1
-#define SCOUTFS_DIRENT_KEY	2
-#define SCOUTFS_DATA_KEY	3
+#define SCOUTFS_XATTR_KEY	2
+#define SCOUTFS_DIRENT_KEY	3
+#define SCOUTFS_DATA_KEY	4
 
 #define SCOUTFS_MAX_ITEM_LEN 2048
 
@@ -237,4 +238,14 @@ enum {
 	SCOUTFS_DT_WHT,
 };
 
+#define SCOUTFS_MAX_XATTR_NAME_LEN 255
+#define SCOUTFS_MAX_XATTR_VALUE_LEN 255
+#define SCOUTFS_XATTR_HASH_MASK 7ULL
+
+struct scoutfs_xattr {
+	__u8 name_len;
+	__u8 value_len;
+	__u8 name[0];
+} __packed;
+
 #endif