drbd: drbd_md_sync before calling user space helpers

Just in case we have some pending meta data changes to sync, do it
before we call our userland helper, as that may take some time,
or even cause a hard reboot.

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c
index e0061a906ba80fc4108f850f526e863ae5bc4461..5b30f90cab3e33fc40869d16610f53ee4e2a794a 100644 (file)
--- a/drivers/block/drbd/drbd_nl.c
+++ b/drivers/block/drbd/drbd_nl.c
@@ -172,6 +172,10 @@ int drbd_khelper(struct drbd_conf *mdev, char *cmd)
                put_net_conf(mdev);
        }
 
+       /* The helper may take some time.
+        * write out any unsynced meta data changes now */
+       drbd_md_sync(mdev);
+
        dev_info(DEV, "helper command: %s %s %s\n", usermode_helper, cmd, mb);
 
        drbd_bcast_ev_helper(mdev, cmd);