Re: [PATCH] overlay/065: adjust test to expect EBUSY only with index=on

[Eryu Guan <guaneryu@gmail.com>]

On Mon, Jul 22, 2019 at 08:02:27AM +0300, Amir Goldstein wrote:
> This is needed to support the kernel regression fix commit 0be0bfd2de9d
> ("ovl: fix regression caused by overlapping layers detection").
> 
> Overlayfs mount is not supposed to fail due to upper/work dir in-use
> by other mount unless option index=on is enabled.

Sorry for the late review.. Looks like this patch only mount overlay
with "index=on" explicitly, but doesn't check that mount succeeds when
"index=off", which is really regressed. Do we need to add more
"index=off" tests to ensure we allow re-use upperdir?

Thanks,
Eryu

> 
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>
> ---
> 
> Eryu,
> 
> With this applied, test is expected to fail on upstream kernel,
> because upstream kernel has a regression.
> 
> The kernel fix commit is on Miklos' overlayfs-next branch.
> 
> Thanks,
> Amir.
> 
>  tests/overlay/065     | 26 ++++++++++++++++----------
>  tests/overlay/065.out |  4 ++--
>  2 files changed, 18 insertions(+), 12 deletions(-)
> 
> diff --git a/tests/overlay/065 b/tests/overlay/065
> index abfc6737..a75a9a10 100755
> --- a/tests/overlay/065
> +++ b/tests/overlay/065
> @@ -13,9 +13,14 @@
>  #
>  # Overlapping layers on mount or lookup results in ELOOP.
>  # Overlapping lowerdir with other mount upperdir/workdir
> -# result in EBUSY.
> +# result in EBUSY (if index=on is used).
>  #
> -# Kernel patch "ovl: detect overlapping layers" is needed to pass the test.
> +# This is a regression test for kernel commit:
> +#
> +#    146d62e5a586 "ovl: detect overlapping layers"
> +#
> +# and its followup fix commit:
> +#    0be0bfd2de9d "ovl: fix regression caused by overlapping layers detection"
>  #
>  seq=`basename $0`
>  seqres=$RESULT_DIR/$seq
> @@ -46,6 +51,7 @@ _supported_os Linux
>  # Use non-default scratch underlying overlay dirs, we need to check
>  # them explicity after test.
>  _require_scratch_nocheck
> +_require_scratch_feature index
>  
>  # Remove all files from previous tests
>  _scratch_mkfs
> @@ -61,10 +67,10 @@ mnt2=$basedir/mnt.2
>  
>  mkdir -p $lowerdir/lower $upperdir $workdir
>  
> -# Try to mount an overlay with the same upperdir/lowerdir - expect EBUSY
> +# Try to mount an overlay with the same upperdir/lowerdir - expect ELOOP
>  echo Conflicting upperdir/lowerdir
>  _overlay_scratch_mount_dirs $upperdir $upperdir $workdir \
> -	2>&1 | _filter_busy_mount
> +	2>&1 | _filter_error_mount
>  $UMOUNT_PROG $SCRATCH_MNT 2>/dev/null
>  
>  # Use new upper/work dirs for each test to avoid ESTALE errors
> @@ -72,11 +78,11 @@ $UMOUNT_PROG $SCRATCH_MNT 2>/dev/null
>  rm -rf $upperdir $workdir
>  mkdir $upperdir $workdir
>  
> -# Try to mount an overlay with the same workdir/lowerdir - expect EBUSY
> +# Try to mount an overlay with the same workdir/lowerdir - expect ELOOP
>  # because $workdir/work overlaps with lowerdir
>  echo Conflicting workdir/lowerdir
>  _overlay_scratch_mount_dirs $workdir $upperdir $workdir \
> -	2>&1 | _filter_busy_mount
> +	-oindex=off 2>&1 | _filter_error_mount
>  $UMOUNT_PROG $SCRATCH_MNT 2>/dev/null
>  
>  rm -rf $upperdir $workdir
> @@ -126,20 +132,20 @@ rm -rf $upperdir2 $workdir2
>  mkdir -p $upperdir2 $workdir2 $mnt2
>  
>  # Try to mount an overlay with layers overlapping with another overlayfs
> -# upperdir - expect EBUSY
> +# upperdir - expect EBUSY with index=on
>  echo Overlapping with upperdir of another instance
>  _overlay_scratch_mount_dirs $upperdir/upper $upperdir2 $workdir2 \
> -	2>&1 | _filter_busy_mount
> +	-oindex=on 2>&1 | _filter_busy_mount
>  $UMOUNT_PROG $SCRATCH_MNT 2>/dev/null
>  
>  rm -rf $upperdir2 $workdir2
>  mkdir -p $upperdir2 $workdir2
>  
>  # Try to mount an overlay with layers overlapping with another overlayfs
> -# workdir - expect EBUSY
> +# workdir - expect EBUSY with index=on
>  echo Overlapping with workdir of another instance
>  _overlay_scratch_mount_dirs $workdir/work $upperdir2 $workdir2 \
> -	2>&1 | _filter_busy_mount
> +	-oindex=on 2>&1 | _filter_busy_mount
>  $UMOUNT_PROG $SCRATCH_MNT 2>/dev/null
>  
>  # Move upper layer root into lower layer after mount
> diff --git a/tests/overlay/065.out b/tests/overlay/065.out
> index 0260327c..c63d4df8 100644
> --- a/tests/overlay/065.out
> +++ b/tests/overlay/065.out
> @@ -1,8 +1,8 @@
>  QA output created by 065
>  Conflicting upperdir/lowerdir
> -mount: device already mounted or mount point busy
> +mount: Too many levels of symbolic links
>  Conflicting workdir/lowerdir
> -mount: device already mounted or mount point busy
> +mount: Too many levels of symbolic links
>  Overlapping upperdir/lowerdir
>  mount: Too many levels of symbolic links
>  Conflicting lower layers
> -- 
> 2.17.1
>