People have repeatedly expected that you can do things like snapshotting
an image with qemu-img while a qemu instance is running. Maybe we need
to consider locking the files while they are in use, but having a
warning in the qemu-img manpage is doable for 1.2 and can't hurt anyway.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
(cherry picked from commit 48467328)
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>