Comment 9 for bug 1209199

一、I create a volume-01,and then create a snapshotfor it.
volume-01-->volume-01-snapshot
二、use volume-01-snapshot create a volume，named volume-02，and then create a snapshotfor it：volume-02-snapshot
volume-02-->volume-02-snapshot
三、use volume-02-snapshot create a volume，named volume-03，and then create a snapshotfor it：volume-03-snapshot
volume-03-->volume-03-snapshot
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volume-08-->volume-08-snapshot

i find that ,there hava chains between volume-01~volume-08,and the chains don't flatten ,is there hava special reason?