ceph/ceph — pull request #3074 by ukernel (2014-12-04 04:35:39+00:00)
Title: osdc/Filer: use finisher to execute C_Probe and C_PurgeRange

Currently contexts C_Probe/C_PurgeRange are executed while holding
OSDSession::completion_lock. C_Probe and C_PurgeRange may call
Objecter::stat() and Objecter::remove() respectively, which acquire
Objecter::rwlock. This can cause deadlock because there is intermediate
dependency between Objecter::rwlock and OSDSession::completion_lock:

Objecter::rwlock -> OSDSession::lock -> OSDSession::completion_lock

The fix is exexcute C_Probe/C_PurgeRange in finisher thread.

Fixes: #10229
Signed-off-by: Yan, Zheng