diff --git a/block/blk-wbt.h b/block/blk-wbt.h
index 8038b4a..d6a125e 100644
--- a/block/blk-wbt.h
+++ b/block/blk-wbt.h
@@ -14,13 +14,15 @@ enum wbt_flags {
 	WBT_TRACKED		= 1,	/* write, tracked for throttling */
 	WBT_READ		= 2,	/* read */
 	WBT_KSWAPD		= 4,	/* write, from kswapd */
+	WBT_DISCARD		= 8,	/* discard */
 
-	WBT_NR_BITS		= 3,	/* number of bits */
+	WBT_NR_BITS		= 4,	/* number of bits */
 };
 
 enum {
 	WBT_RWQ_BG		= 0,
 	WBT_RWQ_KSWAPD,
+	WBT_RWQ_DISCARD,
 	WBT_NUM_RWQ,
 };