xfs_getfsmap_device
fm->fmr_device == xfs_getfsmap_device(mp, XFS_DEV_DATA) ||
fm->fmr_device == xfs_getfsmap_device(mp, XFS_DEV_LOG) ||
fm->fmr_device == xfs_getfsmap_device(mp, XFS_DEV_RT));
handlers[0].dev = xfs_getfsmap_device(mp, XFS_DEV_DATA);
handlers[1].dev = xfs_getfsmap_device(mp, XFS_DEV_LOG);
handlers[2].dev = xfs_getfsmap_device(mp, XFS_DEV_RT);