Only forget client inodes on cache drop. This is cheaper in case we

happen to know a lot of inodes.

unionfs/unionfs.go

@@ -917,10 +917,10 @@ func (me *UnionFs) Open(name string, flags uint32, context *fuse.Context) (fuseF
 	if name == _DROP_CACHE {
 		if flags&fuse.O_ANYWRITE != 0 {
 			log.Println("Forced cache drop on", me.Name())
-			me.nodeFs.RereadClientInodes()
 			me.DropBranchCache(nil)
 			me.DropDeletionCache()
 			me.DropSubFsCaches()
+			me.nodeFs.ForgetClientInodes()
 		}
 		return fuse.NewDevNullFile(), fuse.OK
 	}