>From reading the series and the discussions with Darrick and Dave I'm coming more and more back to my initial position that tying this user visible feature to hardware limits is wrong and will just keep on creating ever more painpoints in the future. Based on that I suspect that doing proper software only atomic writes using the swapext log item and selective always COW mode and making that work should be the first step. We can then avoid that overhead for properly aligned writs if the hardware supports it. For your Oracle DB loads you'll set the alignment hints and maybe even check with fiemap that everything is fine and will get the offload, but we also provide a nice and useful API for less performance critical applications that don't have to care about all these details.
