On Mon, Mar 27, 2017 at 10:03:07AM -0400, Mike Snitzer wrote: > By "you" I assume you're referring to Lars? Yes. > Lars' approach for discard, > when drbd is layered on dm-thinp, feels over-engineered. Not his fault, > the way discard and zeroing got conflated certainly lends itself to > these ugly hacks. SO I do appreciate that for anything to leverage > discard_zeroes_data it needs to be reliable. Which runs counter to how > discard was implemented (discard may get silently dropped!) But that is > why dm-thinp doesn't advertise dzd. Anyway... That's exactly what this series does - remove discard_zeroes_data and use the new REQ_OP_WRITE_ZEROES for anything that wants zeroing offload. > As for the blkdev_issue_zeroout() resorting to manually zeroing the > range, if the discard fails or dzd not supported, that certainly > requires DM thinp to implement manual zeroing of the head and tail of > the range if partial blocks are being zeroed. So I welcome any advances > there. It is probably something that is best left to Joe or myself to > tackle. But I'll gladly accept patches ;) Ok, I'll happily leave this to the two of you..
