From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753723AbaCLLAW (ORCPT ); Wed, 12 Mar 2014 07:00:22 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:59878 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753224AbaCLLAV (ORCPT ); Wed, 12 Mar 2014 07:00:21 -0400 Date: Wed, 12 Mar 2014 04:00:15 -0700 From: Christoph Hellwig To: NeilBrown Cc: Jens Axboe , Alexander Viro , Linus Torvalds , linux-kernel@vger.kernel.org, linux-man@vger.kernel.org Subject: SuSE O_DIRECT|O_NONBLOCK overload Message-ID: <20140312110015.GA29907@infradead.org> References: <20140130132620.GA6031@infradead.org> <20140130132630.GB6031@infradead.org> <20140308155240.GA32297@infradead.org> <531B74B6.4070004@suse.de> <20140312102849.GA26509@infradead.org> <53203BE5.402@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <53203BE5.402@suse.de> User-Agent: Mutt/1.5.21 (2010-09-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The SLES12 tree has various patches to implement special O_DIRECT|O_NONBLOCK semantics for block devices: https://gitorious.org/opensuse/kernel-source/source/806eab3e4b02e798c1ae942440051f81c822ca35:patches.suse/block-nonblock-causes-failfast this seems genuinely useful and I'd be really happy if people would do this work upstream for two reasons: a) implementing different semantics only in a vendor kernel is a nightmare. No proper way to document it in the man pages for example, and silent breakage of applications that expect it to be present, or even more nasty not present. b) Which brings us to: we had various issues with adding O_NONBLOCK to files that didn't support it before. How well was this whole feature tested?