diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index 61447a51f645..5802b1473c3d 100644
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -2251,6 +2251,7 @@ u64 btrfs_alloc_from_cluster(struct btrfs_block_group_cache *block_group,
 						 offset_index);
 				continue;
 			}
+			cluster->window_start += bytes;
 		} else {
 			ret = entry->offset;