The House can have the sergeant at arms go to Barr’s house and bring him to the Capital jail. In addition they can impose daily fines.
However, Barr could argue with the court that he is being punished and forced to d something illegal without a signed order by a Judge to release the un-redacted report to all of Congress and their staff.
I honestly don’t know what protection or recourse Barr has other then a Judge or court releasing him to release what they request
Barr can also slam the door in their face.