Re: [PATCH 8/8] common: fix _require_xfs_io_command pwrite -A for various blocksizes

["Nirjhar Roy (IBM)" <nirjhar.roy.lists@gmail.com>]

On Wed, 2025-10-15 at 09:38 -0700, Darrick J. Wong wrote:
> From: Darrick J. Wong <djwong@kernel.org>
> 
> In this predicate, we should test an atomic write of the minimum
> supported size, not just 4k.  This fixes a problem where none of the
> atomic write tests actually run on a 32k-fsblock xfs because you can't
> do a sub-fsblock atomic write.
> 
> Cc: <fstests@vger.kernel.org> # v2025.04.13
> Fixes: d90ee3b6496346 ("generic: add a test for atomic writes")
> Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
> ---
>  common/rc |   14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> 
> diff --git a/common/rc b/common/rc
> index 1b78cd0c358bb9..dcae5bc33b19ce 100644
> --- a/common/rc
> +++ b/common/rc
> @@ -3030,16 +3030,24 @@ _require_xfs_io_command()
>  	"pwrite")
>  		# -N (RWF_NOWAIT) only works with direct vectored I/O writes
>  		local pwrite_opts=" "
> +		local write_size="4k"
>  		if [ "$param" == "-N" ]; then
>  			opts+=" -d"
> -			pwrite_opts+="-V 1 -b 4k"
> +			pwrite_opts+="-V 1 -b $write_size"
Nit: We can still keep this to 4k (or any random size and not necessarily a size = fsblocksize),
right?
>  		fi
>  		if [ "$param" == "-A" ]; then
>  			opts+=" -d"
> -			pwrite_opts+="-V 1 -b 4k"
> +			# try to write the minimum supported atomic write size
> +			write_size="$($XFS_IO_PROG -f -c "statx -r -m $STATX_WRITE_ATOMIC" $testfile 2>/dev/null | \
> +				grep atomic_write_unit_min | \
> +				grep -o '[0-9]\+')"
> +			if [ -z "$write_size" ] || [ "$write_size" = "0" ]; then
> +				write_size="0 --not-supported"
> +			fi
> +			pwrite_opts+="-V 1 -b $write_size"
>  		fi
>  		testio=`$XFS_IO_PROG -f $opts -c \
> -		        "pwrite $pwrite_opts $param 0 4k" $testfile 2>&1`
> +		        "pwrite $pwrite_opts $param 0 $write_size" $testfile 2>&1`
This looks good to me:

Reviewed-by: Nirjhar Roy (IBM) <nirjhar.roy.lists@gmail.com>
>  		param_checked="$pwrite_opts $param"
>  		;;
>  	"scrub"|"repair")
>