Re: [PATCH v2 2/2] dax: add regression test for stale mmap reads

On Tue, Apr 25, 2017 at 02:51:06PM -0600, Ross Zwisler wrote:

> diff --git a/tests/generic/427 b/tests/generic/427 > new file mode 100755 > index 0000000..6e265a1 > --- /dev/null > +++ b/tests/generic/427 > @@ -0,0 +1,67 @@ > +#! /bin/bash > +# FS QA Test 427 > +# > +# This is a regression test for kernel patch: > +# dax: fix data corruption due to stale mmap reads > +# created by Ross Zwisler <ross.zwisler(a)linux.intel.com&gt; > +# > +#----------------------------------------------------------------------- > +# Copyright (c) 2017 Intel Corporation. All Rights Reserved. > +# > +# This program is free software; you can redistribute it and/or > +# modify it under the terms of the GNU General Public License as > +# published by the Free Software Foundation. > +# > +# This program is distributed in the hope that it would be useful, > +# but WITHOUT ANY WARRANTY; without even the implied warranty of > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > +# GNU General Public License for more details. > +# > +# You should have received a copy of the GNU General Public License > +# along with this program; if not, write the Free Software Foundation, > +# Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA > +#----------------------------------------------------------------------- > +# > + > +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 > + > +# Modify as appropriate. > +_supported_fs generic > +_supported_os Linux > +_require_test_program "t_dax_stale_pmd" > +_require_xfs_io_command "falloc" I'm wondering if falloc is really needed? If not, this test could be run with ext2/3 too. See below. > +_require_user This is not needed anymore.

> + > +# real QA test starts here > + > +# ensure we have no pre-existing block allocations, so we get a hole > +rm -f $TEST_DIR/testfile > +$XFS_IO_PROG -f -c "falloc 0 4M" $TEST_DIR/testfile >> $seqres.full 2>&1 I found that 'xfs_io -fc "truncate 4M" $TEST_DIR/testfile' works too, from the comments in test and kernel patch, if I understand correctly, we only need to mmap un-allocated blocks, right? If truncate(2) works too, I think we can move truncate operation to the t_dax_stale_pmd program too, because the whole truncate && mmap && read sequence are logically together, this also avoids the confusion on why testfile is in 4M size.