The device-mapper mirror target is putting out a status string that has trailing
white-space.  This is causing target tables to be loaded multiple times for the
same device during LVM operations like lvconvert and lvrename, because LVM is
doing a simple string comparison.  Loading multiple identical tables causes
serious problems with cluster mirroring especially.

This issue is not severe, as the work-around in user-space is trivial.  However,
it should be fixed in the kernel.  The attached patch is being push upstream.