From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Freemyer Subject: Re: [RFC PATCH] dm-csum: A new device mapper target that checks data integrity Date: Thu, 21 May 2009 14:17:58 -0400 Message-ID: <87f94c370905211117y13758f72i2ea113c9c6771061@mail.gmail.com> References: <20090521161317.GU1376@blitiri.com.ar> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20090521161317.GU1376@blitiri.com.ar> Sender: linux-raid-owner@vger.kernel.org To: Alberto Bertogli Cc: linux-kernel@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, agk@redhat.com, neilb@suse.de List-Id: linux-raid.ids On Thu, May 21, 2009 at 12:13 PM, Alberto Bertogli wrote: > > Hi! > > I'm writing this device mapper target that stores checksums on writes= and > verifies them on reads. > > It's not widely tested, but you can run mke2fs on it and do basic fil= e > operations. The to-do list is still large, and most of it can be foun= d within > the code. > > To test it, you will need to format the device using the (very rough)= attached > tool, and then create the dm device with something like: > > =A0 =A0 =A0 =A0echo 0 $SIZE csum $REALDEVICE 0 | dmsetup create $NAME > > > I think it can be useful for people who want to detect data corruptio= n and are > either using the block layer directly or a filesystem that doesn't ch= eck data > integrity (which are most, if not all, of the popular ones today). Ma= ybe it > could also be used for testing the bio-integrity extensions, although= at the > moment it's completely independent and I haven't looked much, but it'= s on my > to-do list. > > It does NOT pretend to be useful for consistency checks for security = purposes. > Use something else if you do not want someone evil tampering with you= r data. > > > Comments are obviously welcome. There are also some questions embedde= d in the > code, if anyone cares to answer any of them, I'd really appreciate it= =2E > > Thanks a lot, > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0Alberto I have not looked at your patch, but does this tie into the integrity logic that was added to mainline a few months ago? I'm not sure if it should or not, but I am curious how it ties in. Greg --=20 Greg Freemyer Head of EDD Tape Extraction and Processing team Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer =46irst 99 Days Litigation White Paper - http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.p= df The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html