Re: btrfsck: checksum verify failed

[Chris Mason <chris.mason@oracle.com>]

On Thu, Nov 12, 2009 at 05:16:34PM +0300, Alexander Beregalov wrote:
> 2009/11/12 Chris Mason <chris.mason@oracle.com>:
> > On Thu, Nov 12, 2009 at 05:08:53AM +0300, Alexander Beregalov wrote=
:
> >> # for i in `seq 1 20`; do btrfsck /dev/sde|grep "checksum verify
> >> failed";echo; done
> >> checksum verify failed on 31945617408 wanted 6607632D found 9CC3ED=
0
> >> checksum verify failed on 31945617408 wanted 6607632D found AFBBF4=
1
> >
> > Was your filesystem mounted at the time? =A0It's strange that the c=
hecksum
> > keeps changing, that points to the data in the block changing.
>=20
> It was not.
> Any tips how I can try to find a root cause?
> It is raid0 of two disks.

Well, I'd start by looking for anything else that could be touching the
=46S or the devices.  You shouldn't see more than two different csums i=
n this
configuration (one from each disk).

Somehow the disk is giving us different answers each time, which points
to a problem in the storage stack.

Otherwise it is possible that block 31945617408 is multiply linked and
is actually in use somehow else.  btrfsck is a readonly operation
though, it doesn't change the FS while it is running.

-chris

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