[linux-lvm] PV corruption: allocated PE > total PE

Toby Dickenson toby at tarind.com
Tue Oct 12 23:01:19 UTC 2004

On Tuesday 12 Oct 2004 14:10, Alasdair G Kergon wrote:
> On Tue, Oct 12, 2004 at 08:41:14AM +0100, Toby Dickenson wrote:
> > Ive just noticed that one of my PVs has more allocated PE's than the
> > total available, leading to a negative amount of free space:
> >
> > This is on a gentoo linux system, kernel 2.6.6. The latest LVM userland
> > in gentoo is 2.00.08, I havent tried anything more recent, but there
> > doesnt seem anything relevant in the change log.
> Definitely try the latest version: there've been a few related fixes.

OK, I'm on lvm .25 and device mapper .19. 

I removed the newest LV in that PV, then rebooted. Everything looked right, 
and the metadata backup was as I expected. However using lvcreate again to 
create a sufficiently large LV (large enough to fill this PV plus a bit more) 
recreated the original problem in pvdisplay's output.

> (With lvm1 on-disk format, may need to backup restore/metadata if it's
> wrong on disk.)

The following values all seem to be consistent:
* pvdisplay 'Total PE'
* pe_count in /etc/lvm/backup/
* the total of the relevant 'extent_count' fields in /etc/lvm/backup/

But the value reported by pvdisplay 'Allocated PE' is too large. Where does 
pvdisplay get that value from? Do I need to worry about data corruption, or 
could this be just a display formatting bug?

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