commit 2e17a262 upstream.

When bcache device is clean, dirty keys may still exist after
journal replay, so we need to count these dirty keys even
device in clean status, otherwise after writeback, the amount
of dirty data would be incorrect.
Signed-off-by: NTang Junhui <tang.junhui.linux@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: NColy Li <colyli@suse.de>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>