From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Bart Van Assche To: "hch@infradead.org" , "snitzer@redhat.com" CC: "linux-block@vger.kernel.org" , "agk@redhat.com" , "linux-raid@vger.kernel.org" , "hch@lst.de" , "martin.petersen@oracle.com" , "philipp.reisner@linbit.com" , "axboe@kernel.dk" , "linux-scsi@vger.kernel.org" , "drbd-dev@lists.linbit.com" , "shli@kernel.org" , "dm-devel@redhat.com" Subject: Re: [Drbd-dev] RFC: always use REQ_OP_WRITE_ZEROES for zeroing offload Date: Mon, 27 Mar 2017 15:08:16 +0000 Message-ID: <1490627281.2461.4.camel@sandisk.com> References: <20170323143341.31549-1-hch@lst.de> <20170323155410.GD1138@soda.linbit> <20170327091056.GB6879@infradead.org> <20170327140307.GA13020@redhat.com> In-Reply-To: <20170327140307.GA13020@redhat.com> Content-Type: text/plain; charset="iso-8859-1" MIME-Version: 1.0 Return-Path: Bart.VanAssche@sandisk.com List-ID: 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.=