Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Tim Harvey <tharvey@gateworks.com> [fixes]

These patches were queued for 4.10. For possible use cases see added:
[PATCH] ubifs: Use dirty_writeback_interval value for wbuf timer

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>