From https://review.whamcloud.com/#/c/30836/

{save,restore}_layout() are "probably more reliable than the mechanism used in e.g. sanity-pfl.sh test_10, which tries to parse the layout parameters and restore them, but that will only work for simple layouts. It would be good to update that test to use save_layout() and restore_layout() as well.
Looking a bit more I see sanity.sh test_27A(), test_65[ij], test_65m (in case of success), test_406 would also benefit from proper layout restore. The test_65[ij] tests look like they should be combined into a single test so that the layout is always restored, and not/skipped or deleted.
That should be a separate patch so that this one can land more quickly."