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

[Amir Goldstein <amir73il@gmail.com>]

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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