From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: [PATCH 4/4] ext4: call blkdev_issue_flush on fsync Date: Tue, 20 May 2008 21:54:37 +0200 Message-ID: <20080520195437.GZ22369@kernel.dk> References: <482DDA56.6000301@redhat.com> <482DDC04.7020706@redhat.com> <20080520023454.GM15035@mit.edu> <20080520154313.GI16676@shareable.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii To: Theodore Tso , Eric Sandeen , ext4 development , linux-kernel Mailing List , linux-fsdevel Return-path: Received: from brick.kernel.dk ([87.55.233.238]:20505 "EHLO kernel.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756896AbYETTyp (ORCPT ); Tue, 20 May 2008 15:54:45 -0400 Content-Disposition: inline In-Reply-To: <20080520154313.GI16676@shareable.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, May 20 2008, Jamie Lokier wrote: > Does WRITE_BARRIER always cause a flush? It does not have to > according to Documentation/block/barrier.txt. There are caveats about > tagged queuing "not yet implemented" in the text, but can we rely on > that? The documentation is older than the current implementation; > those caveats might no longer apply. It does, if you use ordered tags then that assumes write through caching (or ordered tag + drain + flush after completion). -- Jens Axboe