From owner-freebsd-fs@FreeBSD.ORG Mon Apr 27 11:23:59 2009 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id DF554106564A for ; Mon, 27 Apr 2009 11:23:59 +0000 (UTC) (envelope-from freebsd-fs@m.gmane.org) Received: from ciao.gmane.org (main.gmane.org [80.91.229.2]) by mx1.freebsd.org (Postfix) with ESMTP id 680408FC15 for ; Mon, 27 Apr 2009 11:23:59 +0000 (UTC) (envelope-from freebsd-fs@m.gmane.org) Received: from list by ciao.gmane.org with local (Exim 4.43) id 1LyOwE-0001K3-CJ for freebsd-fs@freebsd.org; Mon, 27 Apr 2009 11:23:54 +0000 Received: from lara.cc.fer.hr ([161.53.72.113]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 27 Apr 2009 11:23:54 +0000 Received: from ivoras by lara.cc.fer.hr with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 27 Apr 2009 11:23:54 +0000 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-fs@freebsd.org From: Ivan Voras Date: Mon, 27 Apr 2009 13:23:39 +0200 Lines: 48 Message-ID: References: <49F048FB.6000401@bqinternet.com> <20090423195335.521db0a7@kan.dnsalias.net> <49F16009.3080206@bqinternet.com> <49F42786.6070008@bqinternet.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig846BEF3A81E86FCB5A3D385C" X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: lara.cc.fer.hr User-Agent: Thunderbird 2.0.0.21 (X11/20090318) In-Reply-To: <49F42786.6070008@bqinternet.com> X-Enigmail-Version: 0.95.0 Sender: news Subject: Re: UFS2 metadata checksums X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Apr 2009 11:24:00 -0000 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig846BEF3A81E86FCB5A3D385C Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Scott Burns wrote: > Ivan Voras wrote: >> Scott Burns wrote: >> >>> As long as there is some interest in this kind of functionality, I wi= ll >>> continue working on it. The next step is to protect metadata structu= res >>> beyond inodes. I am hoping to have some results to post in the next = few >>> weeks. >> >> Btw. what checksum do you use? >=20 > I haven't settled on anything yet. Currently I'm just reading the > dinode structure 32 bits at a time and doing a bitwise XOR. It's just = a > proof of concept and I am open to suggestions. For 32 bits of hash, adler32 or crc32 should be ok - the code is already used in the system for various purposes. Adler32 is faster; for a sample implementation see sys/net/zlib.c at line 5357. ZFS defaults to "fletcher2" (I guess 16-bit Fletcher?) which should be faster but its implementation could be a bit problematic (see http://opensolaris.org/jive/thread.jspa?threadID=3D69655&tstart=3D0). --------------enig846BEF3A81E86FCB5A3D385C Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFJ9ZXCldnAQVacBcgRAsARAJ0RFwItqrsPcC5+jKVs4LnJeHV9PACeKMzy dvgDWFrhWQ7U8NWRjLMyEWo= =lFbm -----END PGP SIGNATURE----- --------------enig846BEF3A81E86FCB5A3D385C--