Re: [PATCH 2/4] generic/765: Fix sysfs path for nvme partitions

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, Apr 01, 2026 at 04:10:48PM +0530, Ojaswin Mujoo wrote:
> This tests checks atomic write limits reported by statx() are same as
> the ones reported by sysfs, however nvme partitions don't have the
> /sys/block/nvme0n1p1 style entry and also use the namespace's queue
> limits for atomic writes. This causes the test to fail because it
> expects /sys/block/nvme0n*p* to be present.
> 
> Hence, in this case, just check against the parent namespace.
> 
> Reported-by: Disha Goel <disgoel@linux.ibm.com>
> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
> ---
>  tests/generic/765 | 23 +++++++++++++++++++----
>  1 file changed, 19 insertions(+), 4 deletions(-)
> 
> diff --git a/tests/generic/765 b/tests/generic/765
> index 8c4e0bd0..4c768783 100755
> --- a/tests/generic/765
> +++ b/tests/generic/765
> @@ -94,16 +94,31 @@ test_atomic_writes()
>      _scratch_unmount
>  }
>  
> -sys_min_write=$(cat "/sys/block/$(_short_dev $SCRATCH_DEV)/queue/atomic_write_unit_min_bytes")
> -sys_max_write=$(cat "/sys/block/$(_short_dev $SCRATCH_DEV)/queue/atomic_write_unit_max_bytes")

I see this show up in a few other places:

$ git grep /sys/block
common/dmlogwrites:64:  local sysfs="/sys/block/$(_short_dev $1)"
common/rc:2567: local sysfs="/sys/block/$(_short_dev $SCRATCH_DEV)"
common/rc:2631: if [ -e /sys/block/${sdev}/queue/zoned ]; then
common/rc:2632:         cat /sys/block/${sdev}/queue/zoned
common/scsi_debug:67:   device=`grep -wl scsi_debug /sys/block/sd*/device/model | awk -F / '{print $4}'`
tests/btrfs/076:31:     zone_append_max=$(cat "/sys/block/$(_short_dev $SCRATCH_DEV)/queue/zone_append_max_bytes")
tests/btrfs/237:48:zone_size=$(($(cat /sys/block/${sdev}/queue/chunk_sectors) << 9))
tests/btrfs/283:29:     zone_append_max=$(cat "/sys/block/$(_short_dev $SCRATCH_DEV)/queue/zone_append_max_bytes")
vests/generic/108:20:   echo running > /sys/block/`_short_dev $SCSI_DEBUG_DEV`/device/state
tests/generic/108:81:echo offline > /sys/block/`_short_dev $SCSI_DEBUG_DEV`/device/state
tests/generic/730:56:echo 1 > /sys/block/$(_short_dev $SCSI_DEBUG_DEV)/device/delete
tests/generic/731:49:echo 1 > /sys/block/`_short_dev $SCSI_DEBUG_DEV`/device/delete
tests/generic/765:97:sys_min_write=$(cat "/sys/block/$(_short_dev $SCRATCH_DEV)/queue/atomic_write_unit_min_bytes")
tests/generic/765:98:sys_max_write=$(cat "/sys/block/$(_short_dev $SCRATCH_DEV)/queue/atomic_write_unit_max_bytes")

So I wonder if the same problem exists there as well?

(Well, maybe not the scsi-debug users)

> +# Get the right sysfs dev for the atomic write device
> +get_aw_dev() {
> +    local dev
> +    dev=$(_short_dev "$1")
> +
> +    # Special case: nvme partitions don't have the /sys/block/nvme0n1p1 style
> +    # entry and also use the namespace's queue limits for atomic writes, hence
> +    # just return the parent namespace.
> +    if [[ $dev == nvme* ]]; then
> +        echo "${dev%%p[0-9]*}"
> +    else
> +        echo "$dev"
> +    fi
> +}

Perhaps this ought to turn into a common helper to fix them all?

_sys_block_path() {
	local dev=$(_short_dev "$1")

	# Special case: nvme partitions don't have the /sys/block/nvme0n1p1 style
	# entry and also use the namespace's queue limits for atomic writes, hence
	# just return the parent namespace.
	if [[ $dev == nvme* ]]; then
		echo "/sys/block/${dev%%p[0-9]*}"
	else
		echo "/sys/block/$dev"
	fi
}

sys_min_write=$(_sys_block_path $SCRATCH_DEV)/queue/<whatever>)

Also, don't some of the other block devices follow this "partition has
pXXX suffix" pattern as well?  Not that I have a clue why scsi doesn't
follow that pattern or even which part of sd.c triggers the sdaX
behavior. :/

--D

> +
> +sys_min_write=$(cat "/sys/block/$(get_aw_dev $SCRATCH_DEV)/queue/atomic_write_unit_min_bytes")
> +sys_max_write=$(cat "/sys/block/$(get_aw_dev $SCRATCH_DEV)/queue/atomic_write_unit_max_bytes")
>  
>  bdev_min_write=$(_get_atomic_write_unit_min $SCRATCH_DEV)
>  bdev_max_write=$(_get_atomic_write_unit_max $SCRATCH_DEV)
>  
>  echo "sysfs awu_min $sys_min_write" >> $seqres.full
> -echo "sysfs awu_min $sys_max_write" >> $seqres.full
> +echo "sysfs awu_max $sys_max_write" >> $seqres.full
>  echo "bdev awu_min $bdev_min_write" >> $seqres.full
> -echo "bdev awu_min $bdev_max_write" >> $seqres.full
> +echo "bdev awu_max $bdev_max_write" >> $seqres.full
>  
>  # Test that statx atomic values are the same as sysfs values
>  if [ "$sys_min_write" -ne "$bdev_min_write" ]; then
> -- 
> 2.53.0
> 
>