[Drbd-dev] RFC: always use REQ_OP_WRITE_ZEROES for zeroing offload

[Bart Van Assche]

On Mon, 2017-03-27 at 10:03 -0400, Mike Snitzer wrote:
> 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 ;)

Some time ago I posted a patch series for the block layer that zeroes
start and tail for nonaligned discard requests if dzd has been set. See
also "[PATCH v3 0/5] Make blkdev_issue_discard() submit aligned discard
requests" (https://www.spinics.net/lists/linux-block/msg02360.html).

Bart.