 - Grab a mnt ref in vfs_busy() before dropping the interlock.  This will    prevent the mount point from going away while we're waiting on the lock.    The ref does not need to persist once we have the lock because the    lock prevents the mount point from being unmounted.
 - Grab a mnt ref in vfs_busy() before dropping the interlock.  This will
   prevent the mount point from going away while we're waiting on the lock.
   The ref does not need to persist once we have the lock because the
   lock prevents the mount point from being unmounted.

MFC After:	1 week

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase