Re: [PATCH 2/3] common/rc: pass -V 1 when probing pwrite and pread -U

[Brian Foster <bfoster@redhat.com>]

On Thu, Oct 15, 2026 at 04:54:03PM -0400, Tal Zussman wrote:
> xfs_io refuses pwritev2() and preadv2() flags unless -V is given, so
> probing -U without it always fails. Pass -V 1 for -U in both the pwrite
> and pread cases.
> 
> Signed-off-by: Tal Zussman <tz2294@columbia.edu>
> ---
>  common/rc | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/common/rc b/common/rc
> index 945c9e42..a0239034 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -3105,6 +3105,10 @@ _require_xfs_io_command()
>  			opts+=" -d"
>  			pwrite_opts+="-V 1 -b $write_size"
>  		fi
> +		# -U (RWF_DONTCACHE) only works with vectored I/O writes
> +		if [ "$param" == "-U" ]; then
> +			pwrite_opts+="-V 1 -b $write_size"
> +		fi
>  		if [ "$param" == "-A" ]; then
>  			opts+=" -d"
>  			# try to write the minimum supported atomic write size
> @@ -3121,9 +3125,14 @@ _require_xfs_io_command()
>  		param_checked="$pwrite_opts $param"
>  		;;
>  	"pread")
> +		# -U (RWF_DONTCACHE) only works with vectored I/O reads
> +		local pread_opts=" "
> +		if [ "$param" == "-U" ]; then
> +			pread_opts+="-V 1 -b 4k"
> +		fi
>  		testio=`$XFS_IO_PROG -f -c "pwrite 0 4k" \
> -			-c "pread $param 0 4k" $testfile 2>&1`
> -		param_checked="$param"
> +			-c "pread $pread_opts $param 0 4k" $testfile 2>&1`
> +		param_checked="$pread_opts $param"
>  		;;

I find it a little odd that we auto add command related options here
even though the test still needs to know to use those options for the
commands to work correctly. But I guess there's precedent for it, so oh
well:

Reviewed-by: Brian Foster <bfoster@redhat.com>

>  	"scrub"|"repair")
>  		test -z "$param" && param="probe"
> 
> -- 
> 2.39.5
> 
>