linux-ext4 - Re: [PATCH 22/33] generic/631: don't run test if we can't mount overlayfs

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Message-ID: <CAOQ4uxhQt6LNo7QaN3rWy3eCeAS9r0xNcMW4ZvdrY5YgMbq66g@mail.gmail.com>
Date: Thu, 6 Nov 2025 10:23:04 +0100
From: Amir Goldstein <amir73il@...il.com>
To: "Darrick J. Wong" <djwong@...nel.org>
Cc: zlang@...hat.com, neal@...pa.dev, fstests@...r.kernel.org, 
	linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	joannelkoong@...il.com, bernd@...ernd.com
Subject: Re: [PATCH 22/33] generic/631: don't run test if we can't mount overlayfs

On Thu, Nov 6, 2025 at 12:12 AM Darrick J. Wong <djwong@...nel.org> wrote:
>
> 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@...nel.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@...nel.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?
>

Attached.
Now it's even tested.

I put you down as Suggested-by.
Feel free to choose your own roles...

Thanks,
Amir.

View attachment "0001-generic-631-don-t-run-test-if-we-can-t-mount-overlay.patch" of type "text/x-patch" (3285 bytes)