Make bdrv_child_cb_detach() call bdrv_backing_detach() for children with
a COW role (and drop the reverse call from bdrv_backing_detach()), so it
can be used for any child (with a proper role set).
Because so far no child has a proper role set, we need a temporary new
callback for child_backing.detach that ensures bdrv_backing_detach() is
called for all COW children that do not have their role set yet.
Signed-off-by: Max Reitz <address@hidden>
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block.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)