dlm: ignore cancel on granted lock

Return immediately from dlm_unlock(CANCEL) if the lock is
granted and not being converted; there's nothing to cancel.

Signed-off-by: David Teigland <teigland@redhat.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 8cb92046a584..205ec95b347e 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -2186,6 +2186,13 @@ static int validate_unlock_args(struct dlm_lkb *lkb, struct dlm_args *args)
                         goto out;
                 }
 
+                /* there's nothing to cancel */
+                if (lkb->lkb_status == DLM_LKSTS_GRANTED &&
+                    !lkb->lkb_wait_type) {
+                        rv = -EBUSY;
+                        goto out;
+                }
+
                 switch (lkb->lkb_wait_type) {
                 case DLM_MSG_LOOKUP:
                 case DLM_MSG_REQUEST: