From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <53031967.3060009@redhat.com> Date: Tue, 18 Feb 2014 09:27:19 +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> <52F8C3FC.6000302@redhat.com> <20140210144821.65cf1a19@leda.localdomain> <20140218091500.324235de@leda.localdomain> In-Reply-To: <20140218091500.324235de@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: Christian Hesse , LVM general discussion and development Dne 18.2.2014 09:15, Christian Hesse napsal(a): > Christian Hesse on Mon, 2014/02/10 14:48: >> Zdenek Kabelac on Mon, 2014/02/10 13:20: >>> 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; >>> } >> >> This looks good to me. I've made some backups now without any corruption. > > I have not seen anything show up in git master. Or did I miss the final > solution? No yet committed upstream - there are more ongoing fixes in this area - I'll commit them all together. There will also fix for lvcreate -an Zdenek