From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner+w=401wt.eu-S1757727AbZCZBeT@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1757727AbZCZBeT (ORCPT <rfc822;w@1wt.eu>);
	Wed, 25 Mar 2009 21:34:19 -0400
Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752838AbZCZBeG
	(ORCPT <rfc822;linux-kernel-outgoing>);
	Wed, 25 Mar 2009 21:34:06 -0400
Received: from srv5.dvmed.net ([207.36.208.214]:48063 "EHLO mail.dvmed.net"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752799AbZCZBeD (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Wed, 25 Mar 2009 21:34:03 -0400
Message-ID: <49CADB55.8050400@garzik.org>
Date: Wed, 25 Mar 2009 21:33:09 -0400
From: Jeff Garzik <jeff@garzik.org>
User-Agent: Thunderbird 2.0.0.21 (X11/20090320)
MIME-Version: 1.0
To: Ric Wheeler <rwheeler@redhat.com>
CC: Eric Sandeen <sandeen@sandeen.net>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Theodore Tso <tytso@mit.edu>, Ingo Molnar <mingo@elte.hu>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>,
       Arjan van de Ven <arjan@infradead.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>, Nick Piggin <npiggin@suse.de>,
       David Rees <drees76@gmail.com>, Jesper Krogh <jesper@krogh.cc>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] issue storage device flush via sync_blockdev() (was Re:
 Linux 2.6.29)
References: <20090324132032.GK5814@mit.edu> <alpine.LFD.2.00.0903241053200.3032@localhost.localdomain> <20090324184549.GE32307@mit.edu> <alpine.LFD.2.00.0903241218130.3032@localhost.localdomain> <49C93AB0.6070300@garzik.org> <20090325093913.GJ27476@kernel.dk> <49CA86BD.6060205@garzik.org> <20090325194341.GB27476@kernel.dk> <49CA9346.6040108@garzik.org> <alpine.LFD.2.00.0903251337410.3032@localhost.localdomain> <20090325212923.GA5620@havoc.gtf.org> <49CAA88B.1080102@sandeen.net> <49CAD343.5070009@redhat.com> <49CAD9B3.1010208@garzik.org>
In-Reply-To: <49CAD9B3.1010208@garzik.org>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
X-Spam-Score: -4.4 (----)
X-Spam-Report: SpamAssassin version 3.2.5 on srv5.dvmed.net summary:
	Content analysis details:   (-4.4 points, 5.0 required)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Jeff Garzik wrote:
> Ric Wheeler wrote:
> What do you think sync_blockdev() does?  What is its purpose?

> Twofold:
> (1) guarantee all user data is flushed out before a major event 
> (unmount, journal close, unplug, poweroff, explosion, ...)

> (2) As a sledgehammer hack for simple or legacy filesystems that do not 
> wish or need the complexity of transactional protection. sync_blockdev() 
> is intentionally used in lieu of complexity for the following 
> filesystems: HFS, HFS+, ADFS, AFFS, FAT, bfs, UFS, NTFS, qnx4.

> My patch adds needed guarantees, only for the above filesystems, where 
> none were present before.

To be specific, I was referring to fsync(2) guarantees being added to 
HFS, HFS+, ADFS, AFFS, FAT, bfs, UFS, NTFS, and qnx4.

Other filesystems, besides those in the list, gain the flush-on-unmount 
action (a rare but useful addition) with my patch.

	Jeff