On Tue, Mar 03, 2020 at 11:26:13AM +0100, Bo Branten wrote: > > now I have another question on how to test the ext4 driver we implement for > another os: At mount time the driver should check the journal and use jbd2 > to replay if there is anything left in it and I would like to ask if there > is any other methods to do an unclean umount in linux besides pressing > reset? I would like to leave a lot of records in the journal that our driver > can try to process? The standard way to do this in xfstests is using the dm-flakey device-mapper device. We set it up so that all reads and writes are passed through, and then we start some workload such as fsstress, and then we reconfigure dm-flakey to drop 100% of all write requests to the underlying block device. We then kill the workload, and unmount the file system, and then we reset the dm-flakey device to pass through 100% of all writes. This simulates quite accurately what the block device would look like after a sudden power failure, but it doesn't require a power-fail rack (without shortening the lives of the equipment; dropping power tends to put a lot stress on the hardware). Cheers, - Ted
