From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [10.34.131.133] (dhcp131-133.brq.redhat.com [10.34.131.133]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id s1ACKDU8020498 for ; Mon, 10 Feb 2014 07:20:13 -0500 Message-ID: <52F8C3FC.6000302@redhat.com> Date: Mon, 10 Feb 2014 13:20:12 +0100 From: Zdenek Kabelac MIME-Version: 1.0 References: <20140123142700.315e2d3f@leda.localdomain> <20140204095544.65cad0f2@leda.localdomain> <52F1198B.8000706@redhat.com> <20140207141420.54239977@leda.localdomain> <20140208003607.503a44c9@leda.localdomain> <20140208005550.6b7e134d@leda.localdomain> <52F88ED0.8030201@redhat.com> <20140210103056.2f2a950f@leda.localdomain> In-Reply-To: <20140210103056.2f2a950f@leda.localdomain> Content-Transfer-Encoding: 7bit Subject: Re: [linux-lvm] blkid_wiping breaks snapshots Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-lvm@redhat.com Dne 10.2.2014 10:30, Christian Hesse napsal(a): > Zdenek Kabelac on Mon, 2014/02/10 09:33: >> Dne 8.2.2014 00:55, Christian Hesse napsal(a): >>> Christian Hesse on Sat, 2014/02/08 00:36: >>>> Hello everybody, >>>> >>>> I think I nailed it down with git bisect. My first bad commit is: >>>> >>>> 75628f341ad38b68aae33eae0b5700be2a6e5769 >>>> configure: enable blkid_wiping by default if the blkid library is present >>>> >>>> Looks like this wipes data that is still needed... Building a package >>>> with '--disable-blkid_wipe' now to verify on another system. >>> >>> Uh, this only helps part of... >>> >>> I changed my test setup and used writable snapshots. After that I got: >>> >>> WARNING: DM_snapshot_cow signature detected on /dev/cvg/snap-home at >>> offset 0. Wipe it? [y/n] >>> >>> (see https://bbs.archlinux.org/viewtopic.php?id=176504 for another report) >>> >>> Looks like disabling blkid_wiping fixes this. My snapshot corruption still >>> occurs though. :-/ >>> Bad thing about it is that the corruption does not occur reliable when >>> doing simple tests in 'git bisect'... Out of ideas for now - Will go to >>> bed now. >> >> Now this was helpful, I guess I think what is going on. > > Great! Waiting for patches then. :D > > I could provide some more information when needed: > > * This happens with read only snapshots only. > * I could reproduce with commit eaa23d32732c9bc3dd4f948781b5764cf21d84ba > (wiping: add support for blkid wiping), so it was introduced there or > before. > > Should I investigate further or wait for something to test from you? Is the patch bellow fixing your problem ? (It's still not final - but should help) Zdenek diff --git a/tools/lvcreate.c b/tools/lvcreate.c index 638a868..e8b1a7f 100644 --- a/tools/lvcreate.c +++ b/tools/lvcreate.c @@ -772,7 +772,7 @@ static int _read_activation_params(struct lvcreate_params *lp, LVM_READ | LVM_WRITE); /* Must not zero/wipe read only volume */ - if (!(lp->permission & LVM_WRITE)) { + if (!lp->snapshot && !(lp->permission & LVM_WRITE)) { lp->zero = 0; lp->wipe_signatures = 0; }