From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211] helo=newverein.lst.de) by merlin.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gMx7n-000858-Ng for linux-um@lists.infradead.org; Wed, 14 Nov 2018 15:30:40 +0000 Date: Wed, 14 Nov 2018 16:30:28 +0100 From: Christoph Hellwig Subject: Re: [PATCH 4/4] um: Add support for DISCARD in the UBD Driver Message-ID: <20181114153028.GB28557@lst.de> References: <20181113115947.19290-1-anton.ivanov@cambridgegreys.com> <20181113115947.19290-5-anton.ivanov@cambridgegreys.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20181113115947.19290-5-anton.ivanov@cambridgegreys.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: anton.ivanov@cambridgegreys.com Cc: axboe@kernel.dk, richard@nod.at, linux-um@lists.infradead.org, hch@lst.de Discards are defined to be hints. So if your fileystems return -EOPTNOTSUPP you just stop passing them to the file system and complete them from ->queue_rq. Write Zeroes isn't. So if you really want to support it you should manually write zeroes to the file as a fallback. But do you have a real use case for Write Zeroes to start with? _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um