Re: [PATCH v2] generic/108: fix test hand upon failure to create LV

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

On Wed, Jan 07, 2026 at 04:07:44PM +0530, Ojaswin Mujoo wrote:
> In case the lvcreate operation fails, we don't catch the error and
> proceed as usual. The test then tries to wait for the LV to come up
> but it never does, causing a hang.
> 
> To fix this:
> 1. Add a check to ensure SCSI_DEBUG dev is of required size
> 2. Additionally, fail if there are errors while creating the LV.
> 
> Context for completeness:
> 
> This was noticed when we accidentally used CONFIG_SCSI_DEBUG=y instead
> of =m, causing it to create an 8MB SCSI debug device. This led to the
> lvcreate operation to fail with:
> 
>   Insufficient suitable allocatable extents for logical volume lv_108: 68 more required
> 
> However the test never caught this resulting in a hang.
> 
> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
> Reported-by: Disha Goel <disgoel@linux.ibm.com>

Ooops.  Yeah, I think it's a good idea to check the scsi_debug size and
to bail out if lvcreate fails.

Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>

--D

> ---
>  tests/generic/108 | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/tests/generic/108 b/tests/generic/108
> index 4f86ec94..05d743a9 100755
> --- a/tests/generic/108
> +++ b/tests/generic/108
> @@ -50,6 +50,11 @@ SCSI_DEBUG_DEV=`_get_scsi_debug_dev ${physical:-512} ${logical:-512} 0 $size`
>  test -b "$SCSI_DEBUG_DEV" || _notrun "Failed to initialize scsi debug device"
>  echo "SCSI debug device $SCSI_DEBUG_DEV" >>$seqres.full
>  
> +got_size_kb=$(_get_device_size $SCSI_DEBUG_DEV)
> +
> +[[ $got_size_kb -lt $((size * 1024)) ]] &&
> +	_notrun "Need SCSI debug device of size $(( size * 1024 )) KB. Got $got_size_kb KB"
> +
>  # create striped volume with 4MB stripe size
>  #
>  # lvm has a hardcoded list of valid devices and fails with
> @@ -60,7 +65,7 @@ $LVM_PROG vgcreate -f $vgname $SCSI_DEBUG_DEV $SCRATCH_DEV >>$seqres.full 2>&1
>  # We use yes pipe instead of 'lvcreate --yes' because old version of lvm
>  # (like 2.02.95 in RHEL6) don't support --yes option
>  yes | $LVM_PROG lvcreate -i 2 -I 4m -L ${lvsize}m -n $lvname $vgname \
> -	>>$seqres.full 2>&1
> +	>>$seqres.full 2>&1 || _fail "Failed to create LVM lv"
>  _udev_wait /dev/mapper/$vgname-$lvname
>  
>  # _mkfs_dev exits the test on failure, this makes sure test lv is created by
> -- 
> 2.51.0
> 
>