Re: btrfsck: checksum verify failed

[Alexander Beregalov <a.beregalov@gmail.com>]

2009/11/12 Chris Mason <chris.mason@oracle.com>:
> On Thu, Nov 12, 2009 at 06:43:00PM +0300, Alexander Beregalov wrote:
>> 2009/11/12 Chris Mason <chris.mason@oracle.com>:
>> > On Thu, Nov 12, 2009 at 05:16:34PM +0300, Alexander Beregalov wrot=
e:
>> >> 2009/11/12 Chris Mason <chris.mason@oracle.com>:
>> >> > On Thu, Nov 12, 2009 at 05:08:53AM +0300, Alexander Beregalov w=
rote:
>> >> >> # for i in `seq 1 20`; do btrfsck /dev/sde|grep "checksum veri=
fy
>> >> >> failed";echo; done
>> >> >> checksum verify failed on 31945617408 wanted 6607632D found 9C=
C3ED0
>> >> >> checksum verify failed on 31945617408 wanted 6607632D found AF=
BBF41
>> >> >
>> >> > Was your filesystem mounted at the time? =C2=A0It's strange tha=
t the checksum
>> >> > keeps changing, that points to the data in the block changing.
>> >>
>> >> 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 touchin=
g the
>> > FS or the devices. =C2=A0You shouldn't see more than two different=
 csums in this
>> > configuration (one from each disk).
>> I always see only these two blocks in output.
>
> The wanted is always the same but the found is always different?

Yes, exactly. The bits marked as X look as random.

>
>> >
>> > Somehow the disk is giving us different answers each time, which p=
oints
>> > to a problem in the storage stack.
>> Hm, I will try to check discs by "badblocks" with few cycles of writ=
e-read.
>> >
>> > Otherwise it is possible that block 31945617408 is multiply linked=
 and
>> > is actually in use somehow else. =C2=A0btrfsck is a readonly opera=
tion
>> > though, it doesn't change the FS while it is running.
>>
>> Can it be a bug in the filesystem itself - in checksum calculation
>> code, wrong pointer to data or something else?
>
> We can check, =C2=A0I'll make a program to map a logical block number=
 to the
> physical sector.

Ok, thanks, I will not reboot it.
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" =
in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html