This bug exists on RHEL6 as well. I already have a patch to fix it.
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux major release. Product Management has requested further
review of this request by Red Hat Engineering, for potential inclusion in a Red
Hat Enterprise Linux Major release. This request is not yet committed for
multipath now uses the resize code that doesn't set noflush for reloads because of changed size.
You can pick up packages with this fix at http://people.redhat.com/bmarzins/device-mapper-multipath/rpms/RHEL6/
Verified on snap-13 on storageqe-04. Upgraded a LUN from 30GB to 40GB.
Red Hat Enterprise Linux 6.0 is now available and should resolve
the problem described in this bug report. This report is therefore being closed
with a resolution of CURRENTRELEASE. You may reopen this bug report if the
solution does not work for you.