Re: [RFC PATCH] generic: regression test for a FALLOC_FL_UNSHARE bug in XFS

["Darrick J. Wong" <djwong@kernel.org>]

On Tue, Aug 24, 2021 at 05:33:28PM +0800, Zorro Lang wrote:
> On Mon, Aug 23, 2021 at 05:38:35PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> > 
> > This is a regression test for "xfs: only set IOMAP_F_SHARED when
> > providing a srcmap to a write".
> > 
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > ---
> >  tests/generic/729     |   73 +++++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/generic/729.out |    2 +
> >  2 files changed, 75 insertions(+)
> >  create mode 100755 tests/generic/729
> >  create mode 100644 tests/generic/729.out
> > 
> > diff --git a/tests/generic/729 b/tests/generic/729
> > new file mode 100755
> > index 00000000..269aed65
> > --- /dev/null
> > +++ b/tests/generic/729
> > @@ -0,0 +1,73 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (c) 2021 Oracle.  All Rights Reserved.
> > +#
> > +# FS QA Test 729
> > +#
> > +# This is a regression test for "xfs: only set IOMAP_F_SHARED when providing a
> > +# srcmap to a write".  If a user creates a sparse shared region in a file,
> > +# convinces XFS to create a copy-on-write delayed allocation reservation
> > +# spanning both the shared blocks and the holes, and then calls the fallocate
> > +# unshare command to unshare the entire sparse region, XFS incorrectly tells
> > +# iomap that the delalloc blocks for the holes are shared, which causes it to
> > +# error out while trying to unshare a hole.
> > +#
> > +. ./common/preamble
> > +_begin_fstest auto clone unshare
> > +
> > +# Override the default cleanup function.
> > +_cleanup()
> > +{
> > +	cd /
> > +	rm -r -f $tmp.* $TEST_DIR/$seq
> > +}
> > +
> > +# Import common functions.
> > +. ./common/reflink
> > +. ./common/filter
> > +
> > +# real QA test starts here
> > +
> > +# Modify as appropriate.
> > +_supported_fs generic
> > +_require_cp_reflink
> > +_require_test_reflink
> > +_require_test_program "punch-alternating"
> > +_require_xfs_io_command "fpunch"
> 
> I didn't find "fpunch" in this case,

It covers the punch activities in punch-alternating.  I'll add a comment
pointing out that subtlety.

> but find "cowextsize". Did I miss something?

Oops.  Yes, I'll add that too.

> Others looks good to me.
> Reviewed-by: Zorro Lang <zlang@redhat.com>
> 
> cc fstests@vger.kernel.org, due to it's a patch to xfstests.

<nod> Thanks for reviewing.

--D

> Thanks,
> Zorro
> 
> > +_require_xfs_io_command "funshare"
> > +
> > +mkdir $TEST_DIR/$seq
> > +file1=$TEST_DIR/$seq/a
> > +file2=$TEST_DIR/$seq/b
> > +
> > +$XFS_IO_PROG -f -c "pwrite -S 0x58 -b 10m 0 10m" $file1 >> $seqres.full
> > +
> > +f1sum0="$(md5sum $file1 | _filter_test_dir)"
> > +
> > +_cp_reflink $file1 $file2
> > +$here/src/punch-alternating -o 1 $file2
> > +
> > +f2sum0="$(md5sum $file2 | _filter_test_dir)"
> > +
> > +# set cowextsize to the defaults (128k) to force delalloc cow preallocations
> > +test "$FSTYP" = "xfs" && $XFS_IO_PROG -c 'cowextsize 0' $file2
> > +$XFS_IO_PROG -c "funshare 0 10m" $file2
> > +
> > +f1sum1="$(md5sum $file1 | _filter_test_dir)"
> > +f2sum1="$(md5sum $file2 | _filter_test_dir)"
> > +
> > +test "${f1sum0}" = "${f1sum1}" || echo "file1 should not have changed"
> > +test "${f2sum0}" = "${f2sum1}" || echo "file2 should not have changed"
> > +
> > +_test_cycle_mount
> > +
> > +f1sum2="$(md5sum $file1 | _filter_test_dir)"
> > +f2sum2="$(md5sum $file2 | _filter_test_dir)"
> > +
> > +test "${f1sum2}" = "${f1sum1}" || echo "file1 should not have changed ondisk"
> > +test "${f2sum2}" = "${f2sum1}" || echo "file2 should not have changed ondisk"
> > +
> > +# success, all done
> > +echo Silence is golden
> > +status=0
> > +exit
> > diff --git a/tests/generic/729.out b/tests/generic/729.out
> > new file mode 100644
> > index 00000000..0f175ae2
> > --- /dev/null
> > +++ b/tests/generic/729.out
> > @@ -0,0 +1,2 @@
> > +QA output created by 729
> > +Silence is golden
> > 
>