Description of problem: Unlike the linear and crypt targets, the thin target does not take an offset. Version-Release number of selected component (if applicable): 6.0.7 How reproducible: 100% Steps to Reproduce: Try to overwrite the first part of a device (a partition table, say) with the following table > 0 1 linear somedevice 0 > 1 100 thin 0 somepool / 1 Actual results: There is no way to do this without a separate linear layer, which hurts performance. Expected results: It is possible. Additional info: “/” is used as a placeholder to indicate “no external origin device”.
Related to proposed patch: https://listman.redhat.com/archives/dm-devel/2023-February/053187.html and developer's NACK: https://listman.redhat.com/archives/dm-devel/2023-February/053197.html we really can't be adding 'linear' capabilities to every target. Focus should go to optimize performance drop introduced by using 'extra' dm-layer on top of thin device. Passing to Mikulas to consider what we can the to improve dm core logic here.