[linux-lvm] blkid_wiping breaks snapshots

[Christian Hesse]

Zdenek Kabelac <zkabelac at redhat.com> on Mon, 2014/02/10 09:33:
> Dne 8.2.2014 00:55, Christian Hesse napsal(a):
> > Christian Hesse <list at eworm.de> 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?
-- 
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