Re: [fstests PATCH] generic: add test for executables on read-only DAX mounts

[Eryu Guan <eguan@redhat.com>]

On Tue, Aug 29, 2017 at 04:37:15PM -0600, Ross Zwisler wrote:
> This adds a regression test for the following kernel patch:
> 
> commit 42d4a99b09cb ("ext4: fix fault handling when mounted with -o dax,ro")
> 
> The above patch fixes an issue with ext4 where executables cannot be run on
> read-only filesystems mounted with the DAX option.
> 
> This issue does not appear to be present in ext2 or XFS, as they both pass
> the test.  I've also confirmed outside of the test that they are both
> indeed able to execute binaries on read-only DAX mounts.
> 
> Thanks to Randy Dodgen for the bug report and reproduction steps.
> 
> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> Cc: Randy Dodgen <rdodgen@gmail.com>
> Cc: Christoph Hellwig <hch@infradead.org>
> Cc: Theodore Ts'o <tytso@mit.edu>
> 
> ---
> 
> Sorry if we collided, Randy, but I was 90% done with the test by the time I
> saw your mail. :)
> ---
>  tests/generic/452     | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/452.out |  2 ++
>  tests/generic/group   |  1 +
>  3 files changed, 90 insertions(+)
>  create mode 100755 tests/generic/452
>  create mode 100644 tests/generic/452.out
> 
> diff --git a/tests/generic/452 b/tests/generic/452
> new file mode 100755
> index 0000000..54dda8c
> --- /dev/null
> +++ b/tests/generic/452
> @@ -0,0 +1,87 @@
> +#! /bin/bash
> +# FS QA Test 452
> +#
> +# This is a regression test for kernel patch:
> +#   commit 42d4a99b09cb ("ext4: fix fault handling when mounted with -o dax,ro")
> +# created by Ross Zwisler <ross.zwisler@linux.intel.com>
> +#
> +#-----------------------------------------------------------------------
> +# 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_scratch
> +
> +# real QA test starts here
> +# format and mount
> +_scratch_mkfs > $seqres.full 2>&1
> +_scratch_mount >> $seqres.full 2>&1

Need to _notrun if scratch device was mounted with "noexec" option.

_exclude_scratch_mount_option "noexec"

> +
> +LS=$(which ls --skip-alias --skip-functions) 2>/dev/null
> +if [ $? -ne 0 ]; then
> +	status=$?
> +	echo "Couldn't find 'ls'!?"
> +	exit
> +fi
> +
> +cp $LS $SCRATCH_MNT
> +SCRATCH_LS=$SCRATCH_MNT/ls
> +
> +$SCRATCH_LS >/dev/null 2>&1
> +if [ $? -ne 0 ]; then
> +	status=$?
> +	echo "$SCRATCH_LS not working before remount"
> +	exit
> +fi
> +
> +_scratch_remount ro
> +
> +$SCRATCH_LS >/dev/null 2>&1
> +if [ $? -ne 0 ]; then
> +	status=$?
> +	echo "$SCRATCH_LS not working after remount"
> +	exit
> +fi

Hmm, I don't think all these checks on return value are needed, just
print out the error messages on failure and that will break the golden
image, as this is not a destructive test, continuing with errors only
fail the test :)

I think this can be simplified to something like:

LS=$(which ls ....)
SCRATCH_LS=$SCRATCH_MNT/ls_on_scratch
cp $LS $SCRATCH_LS

$SCRATCH_LS $SCRATCH_LS | _filter_scratch

_scratch_remount ro

$SCRATCH_LS $SCRATCH_LS | _filter_scratch

And update .out file accordingly.

Thanks,
Eryu

> +
> +# success, all done
> +echo "Silence is golden"
> +status=0
> +exit
> diff --git a/tests/generic/452.out b/tests/generic/452.out
> new file mode 100644
> index 0000000..db92441
> --- /dev/null
> +++ b/tests/generic/452.out
> @@ -0,0 +1,2 @@
> +QA output created by 452
> +Silence is golden
> diff --git a/tests/generic/group b/tests/generic/group
> index 044ec3f..45f5789 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -453,3 +453,4 @@
>  449 auto quick acl enospc
>  450 auto quick rw
>  451 auto quick rw aio
> +452 auto quick
> -- 
> 2.9.5
> 
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