Introduce a new dlm lock resource, which will be used to communicate
during fstrimming of an ocfs2 device from cluster nodes.

Link: http://lkml.kernel.org/r/1513228484-2084-1-git-send-email-ghe@suse.comSigned-off-by: NGang He <ghe@suse.com>
Reviewed-by: NChangwei Ge <ge.changwei@h3c.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>