Function foreach

src/slave/containerizer/docker.cpp:470–500

Unmount all persistent volumes that are no longer present.

#ifdef __linux__
  // Unmount all persistent volumes that are no longer present.
  foreach (const Resource& resource, current.persistentVolumes()) {
    // This is enforced by the master.
    CHECK(resource.disk().has_volume());

    // Ignore absolute and nested paths.
    const string& containerPath = resource.disk().volume().container_path();
    if (strings::contains(containerPath, "/")) {
      LOG(WARNING) << "Skipping updating mount for persistent volume "
                   << resource << " of container " << containerId
                   << " because the container path '" << containerPath
                   << "' contains slash";
      continue;
    }

    if (updated.contains(resource)) {
      continue;
    }

    const string target = path::join(
        directory, resource.disk().volume().container_path());

    Try<Nothing> unmount = fs::unmount(target);
    if (unmount.isError()) {
      return Error("Failed to unmount persistent volume at '" + target +
                   "': " + unmount.error());
    }

    // TODO(tnachen): Remove mount point after unmounting. This requires
    // making sure the work directory is marked as a shared mount. For
    // more details please refer to MESOS-3483.
  }

  // Get user and group info for this task based on the sandbox directory.
  struct stat s;