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If the clone is resized down to 0, it becomes standalone. If such resize is carried over while an image is mapped we would detect this and call rbd_dev_parent_put() which means "let go of all parent state, including the spec(s) of parent images(s)". This leads to a mismatch between "rbd info" and sysfs parent fields, so a fix is in order. # rbd create --image-format 2 --size 1 foo # rbd snap create foo@snap # rbd snap protect foo@snap # rbd clone foo@snap bar # DEV=$(rbd map bar) # rbd resize --allow-shrink --size 0 bar # rbd resize --size 1 bar # rbd info bar | grep parent parent: rbd/foo@snap Before: # cat /sys/bus/rbd/devices/0/parent (no parent image) After: # cat /sys/bus/rbd/devices/0/parent pool_id 0 pool_name rbd image_id 10056b8b4567 image_name foo snap_id 2 snap_name snap overlap 0 Signed-off-by: Ilya Dryomov <idryomov@redhat.com> Reviewed-by: Josh Durgin <jdurgin@redhat.com> Reviewed-by: Alex Elder <elder@linaro.org>