Re: [PATCH 3/4] dmflakey: don't run dmflakey tests with an external log device

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Jul 20, 2022 at 12:43:55PM -0400, Theodore Ts'o wrote:
> dmflakey works by dropping all writes before unmounting to simulate a
> crash/power loss.  This doesn't work if there is an external log
> device, since we only drop writes to the primary block device, and not
> the external log device.  Fixing this for real would require somehow
> arranging to atomically loading a new dmflakey table for two block
> devices at the same time, so for now, just skip tests using dmflakey
> if the external log device is enabled.
> 
> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
> ---
>  common/dmflakey | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/common/dmflakey b/common/dmflakey
> index 52da3b10..c2be78e9 100644
> --- a/common/dmflakey
> +++ b/common/dmflakey
> @@ -12,6 +12,10 @@ _init_flakey()
>  {
>  	# Scratch device
>  	local BLK_DEV_SIZE=`blockdev --getsz $SCRATCH_DEV`
> +
> +	if test "$USE_EXTERNAL" = yes -a ! -z "$SCRATCH_LOGDEV" ; then
> +		_notrun "dmflakey tests don't work with an external log device"
> +	fi

I'm kinda surprised this still doesn't work -- last year Eryu merged a
patch[1] from me that's supposed to make common/dmflakey work with
external log devices.  What kind of failures do you see?

--D

[1] 9c1f3149 ("dmflakey: support external log and realtime devices")

>  	FLAKEY_DEV=/dev/mapper/flakey-test
>  	FLAKEY_TABLE="0 $BLK_DEV_SIZE flakey $SCRATCH_DEV 0 180 0"
>  	FLAKEY_TABLE_DROP="0 $BLK_DEV_SIZE flakey $SCRATCH_DEV 0 0 180 1 drop_writes"
> -- 
> 2.31.0
>