staging/lustre: conflicting PW & PR extent locks on a client

staging/lustre: conflicting PW & PR extent locks on a client

PW lock isn't replayed once a lock is marked
LDLM_FL_CANCELING and glimpse lock doesn't wait for
conflicting locks on the client. So the server will
grant a PR lock in response to the glimpse lock request,
which conflicts with the PW lock in LDLM_FL_CANCELING
state on the client.

Lock in LDLM_FL_CANCELING state may still have pending IO,
so it should be replayed until LDLM_FL_BL_DONE is set to
avoid granted conflicting lock by a server.

Seagate-bug-id: MRP-3311
Signed-off-by: Andriy Skulysh <andriy.skulysh@seagate.com>
Reviewed-on: http://review.whamcloud.com/20345
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-8175
Reviewed-by: Jinshan Xiong <jinshan.xiong@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>