From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: [PATCH v7 0/6] block: Introduce REQ_ALLOCATE flag for REQ_OP_WRITE_ZEROES Date: Wed, 25 Mar 2020 13:23:33 -0400 Message-ID: References: <158157930219.111879.12072477040351921368.stgit@localhost.localdomain> <69c0b8a4-656f-98c4-eb55-2fd1184f5fc9@virtuozzo.com> <67d63190-c16f-cd26-6b67-641c8943dc3d@virtuozzo.com> <20200319102819.GA26418@infradead.org> <20200325162656.GJ29351@magnolia> <20200325163223.GA27156@infradead.org> Mime-Version: 1.0 Content-Type: text/plain Return-path: In-Reply-To: <20200325163223.GA27156@infradead.org> (Christoph Hellwig's message of "Wed, 25 Mar 2020 09:32:23 -0700") Sender: linux-block-owner@vger.kernel.org To: Christoph Hellwig Cc: "Darrick J. Wong" , "Martin K. Petersen" , Kirill Tkhai , axboe@kernel.dk, bob.liu@oracle.com, agk@redhat.com, snitzer@redhat.com, dm-devel@redhat.com, song@kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, Chaitanya.Kulkarni@wdc.com, ming.lei@redhat.com, osandov@fb.com, jthumshirn@suse.de, minwoo.im.dev@gmail.com, damien.lemoal@wdc.com, andrea.parri@amarulasolutions.com, hare@suse.com, tj@kernel.org, ajay.joshi@wdc.com, sagi@grimberg.me, dsterba@suse.com, bvanassche@acm.org, dhowells@redhat.com, asml.silence@gmail.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: dm-devel.ids Christoph, > I am very much against that for the following reason: > > - the current REQ_OP_DISCARD is purely a hint, and implementations can > (and do) choose to ignore it > > - REQ_OP_WRITE_ZEROES is an actual data integrity operation with > everything that entails If you want to keep emphasis on the "integrity operation" instead of the provisioning aspect, would you expect REQ_ALLOCATE (which may or may not zero blocks) to be considered a deterministic operation or a non-deterministic one? Should this depend on whether the device guarantees zeroing when provisioning blocks or not? -- Martin K. Petersen Oracle Linux Engineering