diff --git a/fs/btrfs/volumes.h b/fs/btrfs/volumes.h
index 7c12d61..6d866db 100644
--- a/fs/btrfs/volumes.h
+++ b/fs/btrfs/volumes.h
@@ -48,6 +48,7 @@
 	int writeable;
 	int in_fs_metadata;
 	int missing;
+	int can_discard;
 
 	spinlock_t io_lock;
 
@@ -104,6 +105,7 @@
 	u64 rw_devices;
 	u64 missing_devices;
 	u64 total_rw_bytes;
+	u64 num_can_discard;
 	struct block_device *latest_bdev;
 
 	/* all of the devices in the FS, protected by a mutex