On Mon, May 26, 2025 at 10:18:52AM +0200, Amir Goldstein wrote: > libmount v1.41 calls several unneeded fsconfig() calls to reconfigure > lowerdir/upperdir when user requests only -o remount,ro. > > Those calls fail because overlayfs does not allow making any config > changes with new mount api, besides MS_RDONLY. > > force mount(8) to use mount(2) to remount ro/rw to workaround > this issue, by setting LIBMOUNT_FORCE_MOUNT2=always. > > Reported-by: André Almeida <andrealmeid@xxxxxxxxxx> > Cc: Karel Zak <kzak@xxxxxxxxxx> > Link: https://lore.kernel.org/linux-fsdevel/20250521-ovl_ro-v1-1-2350b1493d94@xxxxxxxxxx/ Is my bug report (a year ago) gotten fixed? https://lore.kernel.org/linux-fsdevel/20241026180741.cfqm6oqp3frvasfm@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ If this kernel fix works, do we still need this workaround? Thanks, Zorro > Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx> > --- > common/overlay | 4 +++- > tests/overlay/035 | 2 +- > 2 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/common/overlay b/common/overlay > index a6d37a93..5ee9f561 100644 > --- a/common/overlay > +++ b/common/overlay > @@ -127,7 +127,9 @@ _overlay_base_scratch_mount() > _overlay_scratch_mount() > { > if echo "$*" | grep -q remount; then > - $MOUNT_PROG $SCRATCH_MNT $* > + # force mount(8) to use mount(2), to workaround libmount v1.41 > + # failed fsconfig() calls to reconfigure lowerdir/upperdir > + LIBMOUNT_FORCE_MOUNT2=always $MOUNT_PROG $SCRATCH_MNT $* > return > fi > > diff --git a/tests/overlay/035 b/tests/overlay/035 > index 0b3257c4..2a4df99a 100755 > --- a/tests/overlay/035 > +++ b/tests/overlay/035 > @@ -42,7 +42,7 @@ mkdir -p $lowerdir1 $lowerdir2 $upperdir $workdir > # Verify that overlay is mounted read-only and that it cannot be remounted rw. > _overlay_scratch_mount_opts -o"lowerdir=$lowerdir2:$lowerdir1" > touch $SCRATCH_MNT/foo 2>&1 | _filter_scratch > -$MOUNT_PROG -o remount,rw $SCRATCH_MNT 2>&1 | _filter_ro_mount > +_scratch_remount rw 2>&1 | _filter_ro_mount > $UMOUNT_PROG $SCRATCH_MNT > > # Make workdir immutable to prevent workdir re-create on mount > -- > 2.34.1 >
