add a custom response for full storage

src/multipart.rs

@@ -173,10 +173,20 @@ async fn write_to_file(
                 )));
             }
         }
-        file.write_all(&chunk).await.map_err(|write_err| {
-            log::error!("could not write file {:?}", write_err);
-            error::ErrorInternalServerError("could not write file")
-        })?;
+        file.write_all(&chunk)
+            .await
+            .map_err(|write_err| match write_err.kind() {
+                std::io::ErrorKind::StorageFull => {
+                    log::warn!("storage is full {:?}", write_err);
+                    error::ErrorServiceUnavailable(
+                        "storage is full, you will need to wait for some files to expire",
+                    )
+                }
+                _ => {
+                    log::error!("could not write file {:?}", write_err);
+                    error::ErrorInternalServerError("could not write file")
+                }
+            })?;
     }
     Ok(written_bytes)
 }