From owner-freebsd-current@FreeBSD.ORG Wed Aug 31 13:25:51 2005 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8988516A420 for ; Wed, 31 Aug 2005 13:25:51 +0000 (GMT) (envelope-from doconnor@gsoft.com.au) Received: from cain.gsoft.com.au (cain.gsoft.com.au [203.31.81.10]) by mx1.FreeBSD.org (Postfix) with ESMTP id 35B8C43D48 for ; Wed, 31 Aug 2005 13:25:47 +0000 (GMT) (envelope-from doconnor@gsoft.com.au) Received: from inchoate.gsoft.com.au (ppp215-145.lns1.adl2.internode.on.net [203.122.215.145]) (authenticated bits=0) by cain.gsoft.com.au (8.13.4/8.13.4) with ESMTP id j7VDPZTA002372 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NO); Wed, 31 Aug 2005 22:55:42 +0930 (CST) (envelope-from doconnor@gsoft.com.au) From: "Daniel O'Connor" To: Eric Anderson Date: Wed, 31 Aug 2005 22:55:25 +0930 User-Agent: KMail/1.8.1 References: <1125452228.740.3.camel@arbitor.homelinux.com> <200508312230.20301.doconnor@gsoft.com.au> <4315AD00.70809@centtech.com> In-Reply-To: <4315AD00.70809@centtech.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart1804758.TfUzCiH1id"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200508312255.26347.doconnor@gsoft.com.au> X-Spam-Score: 0.05 () FORGED_RCVD_HELO X-Scanned-By: MIMEDefang 2.51 on 203.31.81.10 Cc: freebsd-current@freebsd.org Subject: Re: panic after removing usb flash drive X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 31 Aug 2005 13:25:51 -0000 --nextPart1804758.TfUzCiH1id Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Wednesday 31 August 2005 22:43, Eric Anderson wrote: > This is where I think it would be great to have a sort of 'flashfs' - > something like a UFS2 filesystem, but read only until a write happens, > and all writes would be synchronous, and after the write occurs, the fs > goes back to a 'read only' state. Maybe this could be done with > gjournal or even unionfs - mount the usb flash read only, do all writes > to a memory backed disk, and then flush the writes out to the usb flash > periodically. Not perfect, but maybe this will stir some ideas up. I think if you can differentiate behaviour for normal file systems based on= =20 some information about the device then it would be good. ie if it is a removable type device the default behaviour would be to disab= le=20 write caching and mount it synchronously. Coupled with a kernel that is=20 willing to throw away pages dirtied on such a volume you would be able to=20 readily hot plug a device without too much worry about data loss. =2D-=20 Daniel O'Connor software and network engineer for Genesis Software - http://www.gsoft.com.au "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C --nextPart1804758.TfUzCiH1id Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1 (FreeBSD) iD8DBQBDFa/G5ZPcIHs/zowRAtmmAJ96qePIPxCmvHLnZnwbwiwtx/DhQwCePKxx xXuxitNE+QkniUwVFhwI9m8= =tpzq -----END PGP SIGNATURE----- --nextPart1804758.TfUzCiH1id--