Milan Broz wrote:

Hi Paul,

Paul Clements wrote:

quoted

I've run into this bug on a 2.6.18 kernel, but I think the fix is still 
applicable to the latest kernels (even though the symptoms would be 
slightly different).

Perhaps someone who knows the block and/or SCSI layers well can comment 
on the legality of attaching new pages to a bio without fixing up the 
internal bio counters (details below)?

quoted

LVM over raid1 over SCSI/nbd

Please can you try that backporting of this patch helps?

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=5d84070ee0a433620c57e85dac7f82faaec5fbb3

(If so, see https://bugzilla.redhat.com/show_bug.cgi?id=512387)

Thanks Milan. I tested the patch and it does fix the issue. I replied to 
the bugzilla report with this information.

--
Paul