LU-8480 ofd: hold obd_dev_lock across grant comparison

LU-8480 ofd: hold obd_dev_lock across grant comparison

Hold obd_dev_lock until the global ofd_tot_* grant values are saved,
so that their comparison is not racy.  Otherwise it is possible to
report grant inconsistencies when multiple clients are unmounted.

Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Change-Id: I19ffd102b657df2df539d01d182a782aa17ad924
Reviewed-on: http://review.whamcloud.com/21813
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Niu Yawei <yawei.niu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>