Re: [PATCH 13/13] xfs/2308: test rebuilding of csum files in xfs_repair

[Christoph Hellwig <hch@lst.de>]

On Mon, Sep 28, 2026 at 07:03:57PM -0700, Darrick J. Wong wrote:
> On Thu, Sep 24, 2026 at 12:07:54PM +0200, Christoph Hellwig wrote:
> > Plus handling of corrupted csum files in the kernel as a side effect.
> > 
> > Signed-off-by: Christoph Hellwig <hch@lst.de>
> > ---
> >  tests/xfs/2308     | 47 ++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/xfs/2308.out |  4 ++++
> >  2 files changed, 51 insertions(+)
> >  create mode 100755 tests/xfs/2308
> >  create mode 100644 tests/xfs/2308.out
> > 
> > diff --git a/tests/xfs/2308 b/tests/xfs/2308
> > new file mode 100755
> > index 000000000000..5c4f647ced7a
> > --- /dev/null
> > +++ b/tests/xfs/2308
> > @@ -0,0 +1,47 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0-or-later
> > +# Copyright (c) 2026 Christoph Hellwig.
> > +#
> > +# FS QA Test No. 2308
> > +#
> > +# Corrupt rtcsum and check that scrub and different kinds of reads catch them.
> 
> Heh ok here's the real meat :D
> 
> > +#
> > +. ./common/preamble
> > +_begin_fstest auto quick zone datacsum scrub
> > +
> > +. ./common/filter
> > +. ./common/fuzzy
> > +
> > +_require_scratch_nocheck
> > +
> > +_scratch_mkfs >> $seqres.full 2>&1
> > +_scratch_mount
> > +_require_xfs_data_csum $TEST_DIR
> > +
> > +cat /bin/sh > $SCRATCH_MNT/sh
> > +sync $SCRATCH_MNT
> > +
> > +rg=`xfs_bmap -v $SCRATCH_MNT/sh | _filter_bmap_gno`
> > +rg="${rg// /}"
> > +
> > +_scratch_unmount
> > +
> > +$XFS_DB_PROG -x $SCRATCH_DEV \
> > +	-c "path -m /rtgroups/$rg.csum" \
> > +	-c 'dblock 0' \
> > +	-c 'write csums[0] 4266'
> > +
> > +_scratch_mount
> > +$XFS_SCRUB_PROG -x -a 1 $SCRATCH_MNT >> $seqres.full 2>&1
> > +if [ $? -eq 0 ]; then
> > +	_fail "scrub did not find corruption"
> > +fi
> > +
> > +# Test buffered I/O
> > +$XFS_IO_PROG -c 'pread 0 64k' $SCRATCH_MNT/sh
> > +
> > +# Test direct  I/O
> > +$XFS_IO_PROG -d -c 'pread 0 64k' $SCRATCH_MNT/sh
> 
> Should this also run xfs_repair to make sure that it also notices the
> checksum validation errors?

xfs_repair does not validate checksums.  That would mean make it run
forever and is generally not helpful if people have corrupted file systems..