Commit f3f854648d ("ocfs2_dlm: Ensure correct ordering of set/clear
refmap bit on lockres") still exists a race which can't ensure the
ordering is exactly correct.
Node1 Node2 Node3
umount, migrate
lockres to Node2
migrate finished,
send migrate request
to Node3
received migrate request,
create a migration_mle,
respond to Node2.
set DLM_LOCK_RES_SETREF_INPROG
and send assert master to
Node3
delete migration_mle in
assert_master_handler,
Node3 umount without response
dlm_thread purge
this lockres, send drop
deref message to Node2
found the flag of
DLM_LOCK_RES_SETREF_INPROG
is set, dispatch
dlm_deref_lockres_worker to
clear refmap, but in function of
dlm_deref_lockres_worker,
only if node in refmap it wait
DLM_LOCK_RES_SETREF_INPROG
to be cleared. So worker is
done successfully
purge lockres, send
assert master response
to Node1, and finish umount
set Node3 in refmap, and it
won't be cleared forever, thus
lead to umount hung
so wait until DLM_LOCK_RES_SETREF_INPROG is cleared in
dlm_deref_lockres_worker.
Signed-off-by: Yiwen Jiang <jiangyiwen@huawei.com>
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>
Reviewed-by: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
b556014338