Re: [PATCH 22/33] generic/631: don't run test if we can't mount overlayfs

Darrick J. Wong
2025-11-05T23:12:29Z

On Thu, Oct 30, 2025 at 12:35:03PM +0100, Amir Goldstein wrote:
> On Tue, Oct 28, 2025 at 06:26:09PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> >
> > This test fails on fuse2fs with the following:
> >
> > +mount: /opt/merged0: wrong fs type, bad option, bad superblock on overlay, missing codepage or helper program, or other error.
> > + dmesg(1) may have more information after failed mount system call.
> >
> > dmesg logs the following:
> >
> > [ 764.775172] overlayfs: upper fs does not support tmpfile.
> > [ 764.777707] overlayfs: upper fs does not support RENAME_WHITEOUT.
> >
> > From this, it's pretty clear why the test fails -- overlayfs checks that
> > the upper filesystem (fuse2fs) supports RENAME_WHITEOUT and O_TMPFILE.
> > fuse2fs doesn't support either of these, so the mount fails and then the
> > test goes wild.
> >
> > Instead of doing that, let's do an initial test mount with the same
> > options as the workers, and _notrun if that first mount doesn't succeed.
> >
> > Fixes: 210089cfa00315 ("generic: test a deadlock in xfs_rename when whiteing out files")
> > Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
> > ---
> > tests/generic/631 | 22 ++++++++++++++++++++++
> > 1 file changed, 22 insertions(+)
> >
> >
> > diff --git a/tests/generic/631 b/tests/generic/631
> > index 72bf85e30bdd4b..64e2f911fdd10e 100755
> > --- a/tests/generic/631
> > +++ b/tests/generic/631
> > @@ -64,6 +64,26 @@ stop_workers() {
> > done
> > }
> >
> > +require_overlayfs() {
> > + local tag="check"
> > + local mergedir="$SCRATCH_MNT/merged$tag"
> > + local l="lowerdir=$SCRATCH_MNT/lowerdir:$SCRATCH_MNT/lowerdir1"
> > + local u="upperdir=$SCRATCH_MNT/upperdir$tag"
> > + local w="workdir=$SCRATCH_MNT/workdir$tag"
> > + local i="index=off"
> > +
> > + rm -rf $SCRATCH_MNT/merged$tag
> > + rm -rf $SCRATCH_MNT/upperdir$tag
> > + rm -rf $SCRATCH_MNT/workdir$tag
> > + mkdir $SCRATCH_MNT/merged$tag
> > + mkdir $SCRATCH_MNT/workdir$tag
> > + mkdir $SCRATCH_MNT/upperdir$tag
> > +
> > + _mount -t overlay overlay -o "$l,$u,$w,$i" $mergedir || \
> > + _notrun "cannot mount overlayfs"
> > + umount $mergedir
> > +}
> > +
> > worker() {
> > local tag="$1"
> > local mergedir="$SCRATCH_MNT/merged$tag"
> > @@ -91,6 +111,8 @@ worker() {
> > rm -f $SCRATCH_MNT/workers/$tag
> > }
> >
> > +require_overlayfs
> > +
> > for i in $(seq 0 $((4 + LOAD_FACTOR)) ); do
> > worker $i &
> > done
> >
>
> I agree in general, but please consider this (untested) cleaner patch

Yes, this works too. Since this is your code, could you send it to the
list with a proper commit message (or even just copy mine) and then I
can ack it?

--D

> Thanks,
> Amir.
>

> From 470e7e26dc962b58ee1aabd578e63fe7a0df8cdd Mon Sep 17 00:00:00 2001
> From: Amir Goldstein <amir73il@gmail.com>
> Date: Thu, 30 Oct 2025 12:24:21 +0100
> Subject: [PATCH] generic/631: don't run test if we can't mount overlayfs
>
> ---
> tests/generic/631 | 39 ++++++++++++++++++++++++++++-----------
> 1 file changed, 28 insertions(+), 11 deletions(-)
>
> diff --git a/tests/generic/631 b/tests/generic/631
> index c38ab771..7dc335aa 100755
> --- a/tests/generic/631
> +++ b/tests/generic/631
> @@ -46,7 +46,6 @@ _require_extra_fs overlay
>
> _scratch_mkfs >> $seqres.full
> _scratch_mount
> -_supports_filetype $SCRATCH_MNT || _notrun "overlayfs test requires d_type"
>
> mkdir $SCRATCH_MNT/lowerdir
> mkdir $SCRATCH_MNT/lowerdir1
> @@ -64,7 +63,7 @@ stop_workers() {
> done
> }
>
> -worker() {
> +mount_overlay() {
> local tag="$1"
> local mergedir="$SCRATCH_MNT/merged$tag"
> local l="lowerdir=$SCRATCH_MNT/lowerdir:$SCRATCH_MNT/lowerdir1"
> @@ -72,25 +71,43 @@ worker() {
> local w="workdir=$SCRATCH_MNT/workdir$tag"
> local i="index=off"
>
> + rm -rf $SCRATCH_MNT/merged$tag
> + rm -rf $SCRATCH_MNT/upperdir$tag
> + rm -rf $SCRATCH_MNT/workdir$tag
> + mkdir $SCRATCH_MNT/merged$tag
> + mkdir $SCRATCH_MNT/workdir$tag
> + mkdir $SCRATCH_MNT/upperdir$tag
> +
> + mount -t overlay overlay -o "$l,$u,$w,$i" "$mergedir"
> +}
> +
> +unmount_overlay() {
> + local tag="$1"
> + local mergedir="$SCRATCH_MNT/merged$tag"
> +
> + _unmount $mergedir
> +}
> +
> +worker() {
> + local tag="$1"
> + local mergedir="$SCRATCH_MNT/merged$tag"
> +
> touch $SCRATCH_MNT/workers/$tag
> while test -e $SCRATCH_MNT/running; do
> - rm -rf $SCRATCH_MNT/merged$tag
> - rm -rf $SCRATCH_MNT/upperdir$tag
> - rm -rf $SCRATCH_MNT/workdir$tag
> - mkdir $SCRATCH_MNT/merged$tag
> - mkdir $SCRATCH_MNT/workdir$tag
> - mkdir $SCRATCH_MNT/upperdir$tag
> -
> - mount -t overlay overlay -o "$l,$u,$w,$i" $mergedir
> + mount_overlay $tag
> mv $mergedir/etc/access.conf $mergedir/etc/access.conf.bak
> touch $mergedir/etc/access.conf
> mv $mergedir/etc/access.conf $mergedir/etc/access.conf.bak
> touch $mergedir/etc/access.conf
> - _unmount $mergedir
> + unmount_overlay $tag
> done
> rm -f $SCRATCH_MNT/workers/$tag
> }
>
> +mount_overlay check || \
> + _notrun "cannot mount overlayfs with underlying filesystem $FSTYP"
> +unmount_overlay check
> +
> for i in $(seq 0 $((4 + LOAD_FACTOR)) ); do
> worker $i &
> done
> --
> 2.51.1
>