ceph/ceph — pull request #2968 by wonzhq (2014-11-19 08:45:27+00:00)
Title: osd: tiering: do not block proxy read on background promotion

Allow proxy read when there is no op blocked on the promotion
(background promotion). Also, when the promotion is done, kick off the
blocked proxy reads to preserve op ordering.

Signed-off-by: Zhiqiang Wang