From owner-freebsd-stable@FreeBSD.ORG Sun Jul 17 00:32:04 2005 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 6907316A41C for ; Sun, 17 Jul 2005 00:32:04 +0000 (GMT) (envelope-from jd@ugcs.caltech.edu) Received: from vomit.ugcs.caltech.edu (vomit.ugcs.caltech.edu [131.215.176.103]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2B43943D46 for ; Sun, 17 Jul 2005 00:32:03 +0000 (GMT) (envelope-from jd@ugcs.caltech.edu) Received: by vomit.ugcs.caltech.edu (Postfix, from userid 3640) id 8B59AE816; Sat, 16 Jul 2005 17:32:03 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by vomit.ugcs.caltech.edu (Postfix) with ESMTP id 6B4CEE815; Sat, 16 Jul 2005 17:32:03 -0700 (PDT) Date: Sat, 16 Jul 2005 17:32:03 -0700 (PDT) From: Jon Dama To: Matthias Buelow In-Reply-To: <20050716172632.GG752@drjekyll.mkbuelow.net> Message-ID: References: <20050715224650.GA48516@outcold.yadt.co.uk> <200507152342.j6FNg5Tx015427@drjekyll.mkbuelow.net> <20050716133710.GA71580@outcold.yadt.co.uk> <20050716141630.GB752@drjekyll.mkbuelow.net> <1121530912.17757.32.camel@zappa.Chelsea-Ct.Org> <44k6jqof72.fsf@be-well.ilk.org> <20050716172632.GG752@drjekyll.mkbuelow.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: freebsd-stable@freebsd.org, Lowell Gilbert Subject: Re: dangerous situation with shutdown process X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 17 Jul 2005 00:32:04 -0000 No, it's at a level below softupdates that this must be done. Softupdates only understands when things have been marked completed with biodone()--the underlying scsi/ata/sata driver must make the determination as to when biodone should be called. The flush has to be done there. _IF_ the flush is being done there, then request barriers represent a performance enhancement, not an integrity enhancement. -Jon On Sat, 16 Jul 2005, Matthias Buelow wrote: > Lowell Gilbert wrote: > > >Well, break it down a little bit. If an ATA drive properly implements > >the cache flush command, then none of the ongoing discussion is > > Are you sure this is the case? Are there sequence points in softupdates > where it issues a flush request and by this guarantees fs integrity? > I've read thru McKusick's paper in search for an answer but haven't > found any. All I've read so far on mailing lists and from googling > was that softupdates doesn't work if the wb-cache is enabled. > > mkb. > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >