From owner-freebsd-current@FreeBSD.ORG  Mon Mar  4 17:27:03 2013
Return-Path: <owner-freebsd-current@FreeBSD.ORG>
Delivered-To: current@freebsd.org
Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115])
 by hub.freebsd.org (Postfix) with ESMTP id E892E400;
 Mon,  4 Mar 2013 17:27:03 +0000 (UTC)
 (envelope-from shonnur@chelsio.com)
Received: from stargate.chelsio.com (stargate.chelsio.com [67.207.112.58])
 by mx1.freebsd.org (Postfix) with ESMTP id AE873999;
 Mon,  4 Mar 2013 17:27:03 +0000 (UTC)
Received: from maui.asicdesigners.com (maui.asicdesigners.com [10.192.180.15])
 by stargate.chelsio.com (8.13.1/8.13.1) with SMTP id r24GlJwK023643; 
 Mon, 4 Mar 2013 08:47:19 -0800
Received: from corona.asicdesigners.com ([10.192.160.6]) by
 maui.asicdesigners.com with Microsoft SMTPSVC(6.0.3790.4675); 
 Mon, 4 Mar 2013 08:47:18 -0800
Received: from NICE.asicdesigners.com (10.192.160.7) by
 corona.asicdesigners.com (10.192.160.6) with Microsoft SMTP Server (TLS) id
 8.3.83.0; Mon, 4 Mar 2013 08:47:18 -0800
Received: from NICE.asicdesigners.com ([fe80::51b2:ba95:9d72:babc]) by
 nice.asicdesigners.com ([fe80::51b2:ba95:9d72:babc%15]) with mapi id
 14.02.0247.003; Mon, 4 Mar 2013 08:47:18 -0800
From: Sreenivasa Honnur <shonnur@chelsio.com>
To: FreeBSD Tinderbox <tinderbox@freebsd.org>, "current@freebsd.org"
 <current@freebsd.org>, "i386@freebsd.org" <i386@freebsd.org>
Subject: cache sync on block device.
Thread-Topic: cache sync on block device.
Thread-Index: AQHOGPfuvltrNqjvQkecFV91fFvm4w==
Date: Mon, 4 Mar 2013 16:47:18 +0000
Message-ID: <F2BBBB6E0068844991318A316F34795C344106@nice.asicdesigners.com>
References: <201303041621.r24GL1Dn022279@freebsd-current.sentex.ca>
In-Reply-To: <201303041621.r24GL1Dn022279@freebsd-current.sentex.ca>
Accept-Language: en-US
Content-Language: en-US
X-MS-Has-Attach: 
X-MS-TNEF-Correlator: 
x-originating-ip: [10.193.190.128]
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-OriginalArrivalTime: 04 Mar 2013 16:47:18.0725 (UTC)
 FILETIME=[EF120F50:01CE18F7]
X-Mailman-Approved-At: Mon, 04 Mar 2013 17:30:06 +0000
X-BeenThere: freebsd-current@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Discussions about the use of FreeBSD-current
 <freebsd-current.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-current>, 
 <mailto:freebsd-current-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current>
List-Post: <mailto:freebsd-current@freebsd.org>
List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>,
 <mailto:freebsd-current-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 04 Mar 2013 17:27:04 -0000

Hi,
I want to  implementing cache sync functionality for a block device. I refe=
rred to CTL code, below link says
http://freebsd.1045724.n5.nabble.com/CAM-Target-Layer-and-dev-isp-td5727548=
.html

" If you use a block device (like a zvol) as the backing store, you'll want=
=20
to disable sending cache syncs to the disk, since that will trigger a GEOM=
=20
assertion.=20

ctladm realsync off"

How is cache sync (flush) implemented for a block device ? bio_cmd=3DBIO_FL=
USH results in ASSERT.

Thanks
Sreenivas