Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 11 Mar 2002 06:13:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 11 Mar 2002 06:13:22 -0500 Received: from etpmod.phys.tue.nl ([131.155.111.35]:51531 "EHLO etpmod.phys.tue.nl") by vger.kernel.org with ESMTP id ; Mon, 11 Mar 2002 06:13:08 -0500 Date: Mon, 11 Mar 2002 12:13:00 +0100 From: Kurt Garloff To: Douglas Gilbert Cc: "Stephen C. Tweedie" , Jeremy Higdon , Daniel Phillips , James Bottomley , Chris Mason , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: [PATCH] 2.4.x write barriers (updated for ext3) Message-ID: <20020311121300.G2346@nbkurt.etpnet.phys.tue.nl> Mail-Followup-To: Kurt Garloff , Douglas Gilbert , "Stephen C. Tweedie" , Jeremy Higdon , Daniel Phillips , James Bottomley , Chris Mason , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org In-Reply-To: <200202281536.g1SFaqF02079@localhost.localdomain> <10203032021.ZM443706@classic.engr.sgi.com>

<10203032209.ZM424559@classic.engr.sgi.com> <20020304165216.A1444@redhat.com> <3C8AEDFC.502CAD04@torque.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="7IgncvKP0CVPV/ZZ" Content-Disposition: inline In-Reply-To: <3C8AEDFC.502CAD04@torque.net> User-Agent: Mutt/1.3.22.1i X-Operating-System: Linux 2.4.16-schedJ2 i686 X-PGP-Info: on http://www.garloff.de/kurt/mykeys.pgp X-PGP-Key: 1024D/1C98774E, 1024R/CEFC9215 Organization: TU/e(NL), SuSE(DE) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --7IgncvKP0CVPV/ZZ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Doug, On Sun, Mar 10, 2002 at 12:24:12AM -0500, Douglas Gilbert wrote: > "Stephen C. Tweedie" wrote: > > Even if WCE is enabled in the caching mode page, we can still set FUA > > (Force Unit Access) in individual write commands to force platter > > completion before commands complete. > >=20 > > Of course, it's a good question whether this is honoured properly on > > all drives. > >=20 > > FUA is not available on WRITE6, only WRITE10 or WRITE12 commands. >=20 > Stephen, [...] >=20 > Also SYNCHRONIZE CACHE(10) allows a range of blocks to be sent > to the platter but the size of the range is limited to 2**16 - 1 > blocks which is probably too small to be useful. If the > "number of blocks" field is set to 0 then the whole disk cache > is flushed to the platter. Which I think we should send before shutdown (and possible poweroff) for disks (DASDs), Write-Once and Optical Memory devices. (Funny enough, the SCSI spec also lists SYNCHRONIZE_CACHE for CD-Rom devices Unfortunately, SYNCHRONIZE CACHE is optional, so we would need to ignore any errors returned by this command. Regards, --=20 Kurt Garloff Eindhoven, NL GPG key: See mail header, key servers Linux kernel development SuSE Linux AG, Nuernberg, DE SCSI, Security --7IgncvKP0CVPV/ZZ Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE8jJE8xmLh6hyYd04RArF2AJ9jQ0iQdKVTyth28OZaFtqeWr3zBgCg1pzc KkAub5YVSAyAsHU58JIiBRc= =L3yN -----END PGP SIGNATURE----- --7IgncvKP0CVPV/ZZ-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/