On Wed, Oct 31, 2018 at 12:17 PM Amir Goldstein <amir73il@xxxxxxxxx> wrote:
>
> On Wed, Oct 31, 2018 at 11:55 AM Miklos Szeredi <mszeredi@xxxxxxxxxx> wrote:
> >
> > There's a bug in the overlayfs implementation starting from the very first
> > merged version that may cause an Oops of various forms if a directory is created
> > over a whiteout dentry, but the actual whiteout on the upper layer was removed
> > to the directory creation.
> >
> > Reported by: kaixuxia <xiakaixu1987@xxxxxxxxx>
> > Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
> > ---
>
> Looks good. A bit of commentary could be useful...
Eryu,
I see you have not included this test in today's update.
Maybe you though that this discussion did not conclude.
On my part, besides adding the 2 comment lines, there
are no further concerns.
FYI, the fix for this bug is now in master:
5e1275808630 ovl: check whiteout in ovl_create_over_whiteout()
Thanks,
Amir.
>
> > tests/overlay/062 | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++
> > tests/overlay/062.out | 2 ++
> > tests/overlay/group | 1 +
> > 3 files changed, 63 insertions(+)
> > create mode 100644 tests/overlay/062
> > create mode 100644 tests/overlay/062.out
> >
> > diff --git a/tests/overlay/062 b/tests/overlay/062
> > new file mode 100644
> > index 000000000000..b2cc350afefb
> > --- /dev/null
> > +++ b/tests/overlay/062
> > @@ -0,0 +1,60 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (c) 2018 Red Hat Inc. All Rights Reserved.
> > +#
> > +# FS QA Test 062
> > +#
> > +# Create dir over cached negative dentry, but whiteout removed from upper
> > +#
> > +# The following kernel commit fixed the kernel crash: ???
> > +#
> > +seq=`basename $0`
> > +seqres=$RESULT_DIR/$seq
> > +echo "QA output created by $seq"
> > +
> > +here=`pwd`
> > +tmp=/tmp/$$
> > +status=1 # failure is the default!
> > +trap "_cleanup; exit \$status" 0 1 2 3 15
> > +
> > +_cleanup()
> > +{
> > + cd /
> > + rm -f $tmp.*
> > +}
> > +
> > +# get standard environment, filters and checks
> > +. ./common/rc
> > +. ./common/filter
> > +
> > +# remove previous $seqres.full before test
> > +rm -f $seqres.full
> > +
> > +# real QA test starts here
> > +_supported_fs overlay
> > +_supported_os Linux
> > +_require_scratch
> > +
> > +# Remove all files from previous tests
> > +_scratch_mkfs
> > +
> > +# Create test file
> > +lowerdir=${OVL_BASE_SCRATCH_MNT}/${OVL_LOWER}
> > +upperdir=${OVL_BASE_SCRATCH_MNT}/${OVL_UPPER}
> > +mkdir -p $lowerdir
> > +touch ${lowerdir}/file
> > +
> > +_scratch_mount
> > +
>
> # Create whiteout and populate dcache with negative dentry
>
> > +rm ${SCRATCH_MNT}/file
> > +ls -l ${SCRATCH_MNT}/file > /dev/null 2>&1
>
> # Remove whiteout and try to create dir over negative dentry
>
> > +rm ${upperdir}/file
> > +mkdir ${SCRATCH_MNT}/file > /dev/null 2>&1
> > +
> > +# unmount overlayfs
> > +$UMOUNT_PROG $SCRATCH_MNT
>
> Umount of scratch is not needed at the end of the test.
>
> Thanks,
> Amir.
