Re: [PATCH 1/2] xfs/270: only check new_ro_compat value when mkfs.xfs supports nrext64 feature

["xuyang2018.jy@fujitsu.com" <xuyang2018.jy@fujitsu.com>]

Hi Zorro

What do you think this patch or should I just add a 'x' string when
comparing get_value/new_value, then just remind user they may hit a old
xfsprogs bug

f4afdcb0a ("xfs_db: clean up the salvage read callsites in set_cur()").

Best Regards
Yang Xu

> Currently, this case fails on old xfsprogs as below:
> +/var/lib/xfstests/tests/xfs/270: line 51: [: !=: unary operator expected
> 
> Getting ro_compat value will report the following error after setting new ro_compat
> value:
> +cache_purge: shake on cache 0x56033fde4920 left 1 nodes!?
> +cache_purge: shake on cache 0x56033fde4920 left 1 nodes!?
> +cache_zero_check: refcount is 1, not zero (node=0x56033fdf9110
> 
> Old xfsprogs miss a bugfix
> f4afdcb0ad ("xfs_db: clean up the salvage read callsites in set_cur()").
> 
> Here we skip the get step of new ro_comap value when nrext64 feature is supported.
> Also will add a new test to cover this xfsprog bug.
> 
> Signed-off-by: Yang Xu<xuyang2018.jy@fujitsu.com>
> ---
>   tests/xfs/270 | 23 ++++++++++++++++-------
>   1 file changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/tests/xfs/270 b/tests/xfs/270
> index b740c379..5ff83ead 100755
> --- a/tests/xfs/270
> +++ b/tests/xfs/270
> @@ -22,6 +22,10 @@ _require_scratch_nocheck
>   # Only V5 XFS disallow rw mount/remount with unknown ro-compat features
>   _require_scratch_xfs_crc
> 
> +nrext64_supported=0
> +_scratch_mkfs_xfs_supported -m crc=1 -i nrext64>  /dev/null 2>&1&&  \
> +	nrext64_supported=1
> +
>   _scratch_mkfs_xfs>>$seqres.full 2>&1
> 
>   # set the highest bit of features_ro_compat, use it as an unknown
> @@ -43,13 +47,18 @@ ro_compat=$(echo $ro_compat | \
>   _scratch_xfs_set_metadata_field "features_ro_compat" "$ro_compat" "sb 0" \
>   				>  $seqres.full 2>&1
> 
> -# read the newly set ro compat filed for verification
> -new_ro_compat=$(_scratch_xfs_get_metadata_field "features_ro_compat" "sb 0" \
> -						2>/dev/null)
> -
> -# verify the new ro_compat field is correct.
> -if [ $new_ro_compat != $ro_compat ]; then
> -	echo "Unable to set new features_ro_compat. Wanted $ro_compat, got $new_ro_compat"
> +# Indeed, xfsprogs has a bug here and fixed by commit f4afdcb
> +# ("xfs_db: clean up the salvage read callsites in set_cur()")
> +# Here, we use nrext64 feature as a proxy.
> +if [ $nrext64_supported -eq 1 ]; then
> +	# read the newly set ro compat filed for verification
> +	new_ro_compat=$(_scratch_xfs_get_metadata_field "features_ro_compat" \
> +					"sb 0" 2>/dev/null)
> +	# verify the new ro_compat field is correct.
> +	if [ $new_ro_compat != $ro_compat ]; then
> +		echo "Unable to set new features_ro_compat. Wanted $ro_compat, \
> +			got $new_ro_compat"
> +	fi
>   fi
> 
>   # rw mount with unknown ro-compat feature should fail