Seems like discussion on this patch series has died down. There's been a concern raised that we could generalize infrastructure across loop, md, etc. This may be possible, in the future, but it isn't clear to me how this would look like. I'm inclined to fix the existing issue with loop devices now (this is a problem we hit at FB) and address consolidation with other cases if and when those are addressed. Jens, you've expressed interest in seeing this series go through the block tree so I'm interested in your perspective here. Barring any concrete implementation bugs, would you be okay merging this version?