Re: [PATCH v2] fstests: btrfs test if show_devname returns sprout device

[Eryu Guan <guan@eryu.me>]

On Mon, Jul 13, 2020 at 07:32:57PM +0800, Anand Jain wrote:
> 
> 
> 
> > > +# check if the show_devname() returns the sprout device instead of seed device.
> > > +cat /proc/self/mounts | grep $SCRATCH_MNT | awk '{print $1}' | \
> > > +							_filter_devs $sprout
> > 
> > Why does this have to be so complicated - 4 chained program executions,
> > 1 additional function...
> > 
> 
> For example:
>  /dev/sdb /btrfs btrfs ro,relatime,noacl,space_cache,subvolid=5,subvol=/ 0 0
> 
>  $1 to $3 remain constant, but $4 options might vary. So to avoid
>  unnecessary breakage of test case due to kernel updates or mount
>  options, I just used $1.
> 
> > dev=$(grep $SCRATCH_MOUNT /proc/mounts | awk '{printf $1}')

This looks simpler, just use $AWK_PROG instead of bare awk.

> > 
> > if [ $sprout != $dev ]; then
> >   _fail "Unexpected device"
> > fi
>  fstests prefers use of .out file to look for the expected string.
>  Will wait for Eryu comments.

Even $dev is not constant, we don't have to filter the device to
"SCRATCH_DEV" by _filter_devs. Just do

echo "Silence is golden"
if [ "$sprout" != "$dev" ]; then
	echo "Unexpected device: $dev"
fi

Thanks,
Eryu