diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 654ed3de0054..4ebabd237153 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -595,9 +595,14 @@ int clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end,
 		clear = 1;
 again:
 	if (!prealloc && (mask & __GFP_WAIT)) {
+		/*
+		 * Don't care for allocation failure here because we might end
+		 * up not needing the pre-allocated extent state at all, which
+		 * is the case if we only have in the tree extent states that
+		 * cover our input range and don't cover too any other range.
+		 * If we end up needing a new extent state we allocate it later.
+		 */
 		prealloc = alloc_extent_state(mask);
-		if (!prealloc)
-			return -ENOMEM;
 	}
 
 	spin_lock(&tree->lock);