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

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Message-ID: <176169820388.1433624.12333256574549591904.stgit@frogsfrogsfrogs>
Date: Tue, 28 Oct 2025 18:26:09 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: djwong@...nel.org, zlang@...hat.com
Cc: neal@...pa.dev, fstests@...r.kernel.org, linux-ext4@...r.kernel.org,
 linux-fsdevel@...r.kernel.org, joannelkoong@...il.com, bernd@...ernd.com
Subject: [PATCH 22/33] generic/631: don't run test if we can't mount overlayfs

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