diff --git a/fs/btrfs/direct-io.c b/fs/btrfs/direct-io.c
index b80dc45c3ff9..27d227f5bdc0 100644
--- a/fs/btrfs/direct-io.c
+++ b/fs/btrfs/direct-io.c
@@ -280,17 +280,24 @@ static int btrfs_get_blocks_direct_write(struct extent_map **map,
 		em2 = btrfs_create_dio_extent(BTRFS_I(inode), dio_data, start,
 					      &file_extent, type);
 		btrfs_dec_nocow_writers(bg);
-		if (type == BTRFS_ORDERED_PREALLOC) {
+		if (IS_ERR(em2)) {
+			ret = PTR_ERR(em2);
+			btrfs_free_extent_map(em);
+			*map = NULL;
+			goto out;
+		}
+
+		/*
+		 * True NOCOW writes don't need to create a new extent map,
+		 * while PREALLOC writes must replace the existing one.
+		 */
+		if (em2) {
+			ASSERT(type == BTRFS_ORDERED_PREALLOC);
 			btrfs_free_extent_map(em);
 			*map = em2;
 			em = em2;
 		}
 
-		if (IS_ERR(em2)) {
-			ret = PTR_ERR(em2);
-			goto out;
-		}
-
 		dio_data->nocow_done = true;
 	} else {
 		/* Our caller expects us to free the input extent map. */