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

Amir Goldstein
2025-10-30T11:35:06Z

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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

Thanks,
Amir.

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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