Re: [RFC] common: skip data write EIO tests on fatal configs

[Christoph Hellwig <hch@lst.de>]

On Thu, Jun 18, 2026 at 11:47:56AM +0800, Yao Sang wrote:
> The auto detection is intentionally XFS-specific for now. It checks the XFS
> per-mount sysfs attribute zoned/max_open_zones, not the block layer
> /sys/block/.../queue/zoned attribute. A zoned block device alone does not
> prove that the mounted XFS instance is using zoned filesystem semantics.

Yeah, make sense.

> One test-number detail is worth calling out. The maintainer report first
> mentions generic/441 and xfs/665, but the following fserror/healthmon
> description refers to xfs/656. I checked both tests: xfs/656 is the dmerror
> plus healthmon data I/O error test and matches the reported failure; xfs/665 is

Sorry, I fat-fingered the number.

> +_scratch_data_write_eio_is_fatal()
> +{
> +	local dev="${1:-$SCRATCH_DEV}"

I'll defer to Zorro, but normally either requiring an argument
always or neve seems nice.  And my preference here would be to
always pass the device, and not have _scratch in the name.

> +
> +	case "${FS_DATA_WRITE_EIO_SHUTDOWN:-auto}" in
> +	yes|true|1)
> +		return 0
> +		;;
> +	no|false|0)
> +		return 1
> +		;;
> +	auto|"")
> +		;;
> +	*)
> +		_fail "invalid FS_DATA_WRITE_EIO_SHUTDOWN=$FS_DATA_WRITE_EIO_SHUTDOWN"
> +		;;
> +	esac

I don't understand what this part is about at all.

> +
> +	case "$FSTYP" in
> +	xfs)
> +		# This is an XFS per-mount sysfs attribute, not a block queue
> +		# attribute.  Its existence means XFS mounted this instance with
> +		# zoned filesystem semantics.
> +		_has_fs_sysfs_attr "$dev" "zoned/max_open_zones" && return 0
> +		;;
> +	esac
> +
> +	return 1

This part looks fine.

> +}
> +
> +# Require that data write errors are reported through the regular error
> +# reporting path instead of shutting down the filesystem.
> +_require_scratch_survives_data_write_errors()
> +{
> +	local dev="${1:-$SCRATCH_DEV}"
> +
> +	_scratch_data_write_eio_is_fatal "$dev" || return
> +
> +	_notrun "$FSTYP treats data write errors as fatal"
> +}

Do we need both survives and fatal versions of this?  Or decide
on one polarity and be done with it?