*/
#define BTRFS_METADATA_ITEM_KEY 169
+/*
+ * Special inline ref key which stores the id of the subvolume which originally
+ * created the extent. This subvolume owns the extent permanently from the
+ * perspective of simple quotas. Needed to know which subvolume to free quota
+ * usage from when the extent is deleted.
+ *
+ * Stored as an inline ref rather to avoid wasting space on a separate item on
+ * top of the existing extent item. However, unlike the other inline refs,
+ * there is one one owner ref per extent rather than one per extent.
+ *
+ * Because of this, it goes at the front of the list of inline refs, and thus
+ * must have a lower type value than any other inline ref type (to satisfy the
+ * disk format rule that inline refs have non-decreasing type).
+ */
+#define BTRFS_EXTENT_OWNER_REF_KEY 172
+
#define BTRFS_TREE_BLOCK_REF_KEY 176
#define BTRFS_EXTENT_DATA_REF_KEY 178
#define BTRFS_SHARED_DATA_REF_KEY 184
-/*
- * Special inline ref key which stores the id of the subvolume which originally
- * created the extent. This subvolume owns the extent permanently from the
- * perspective of simple quotas. Needed to know which subvolume to free quota
- * usage from when the extent is deleted.
- */
-#define BTRFS_EXTENT_OWNER_REF_KEY 188
-
/*
* block groups give us hints into the extent allocation trees. Which
* blocks are free etc etc