Re: [PATCH v2] xfs: test XFS torn log write detection

[Dave Chinner <david@fromorbit.com>]

On Mon, Jan 04, 2016 at 11:03:41AM -0500, Brian Foster wrote:
> XFS torn log write detection includes a mechanism to inject CRC errors
> into log records at runtime and shutdown the fs accordingly. This
> ensures that the CRC verification pass on the subsequent mount discovers
> an invalid record near the head of the log and considers it a torn
> write.
> 
> This test runs a workload with error injection enabled and verifies that
> the subsequent mount is successful. The test repeats for several
> iterations using a random frequency factor for the error event each
> time.
> 
> Signed-off-by: Brian Foster <bfoster@redhat.com>
> ---
> 
> Here's a v2 of the XFS log crc verification test case now that the
> associated kernel code has been merged. The only change is the bugfix
> noted in the changelog below.
> 
> Brian
> 
> v2:
> - Update random failure frequency calculation to ensure factor is never
>   0.
> v1: http://article.gmane.org/gmane.comp.file-systems.fstests/1406
> 
>  tests/xfs/350     | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/xfs/350.out |  2 ++
>  tests/xfs/group   |  1 +
>  3 files changed, 88 insertions(+)
>  create mode 100755 tests/xfs/350
>  create mode 100644 tests/xfs/350.out
> 
> diff --git a/tests/xfs/350 b/tests/xfs/350
> new file mode 100755
> index 0000000..1a1de6f
> --- /dev/null
> +++ b/tests/xfs/350
> @@ -0,0 +1,85 @@
> +#! /bin/bash
> +# FS QA Test No. 350
> +#
> +# Use the XFS log record CRC error injection mechanism to test torn writes to
> +# the log. The error injection mechanism writes an invalid CRC and shuts down
> +# the filesystem. The test verifies that a subsequent remount recovers the log
> +# and that the filesystem is consistent.
> +#
> +# Note that this test requires a DEBUG mode kernel.
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2015 Red Hat, Inc. 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.*
> +	killall -9 fsstress > /dev/null 2>&1
> +	wait > /dev/null 2>&1
> +}
> +
> +rm -f $seqres.full
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs xfs
> +_supported_os Linux
> +_require_xfs_sysfs $(_short_dev $SCRATCH_DEV)/log/log_badcrc_factor

Scratch is not mounted at this point, so I don't think you can test
the scratch device sysfs attrs here. I changed it to look at the
test device instead and it works fine.

Cheers,

Dave.

-- 
Dave Chinner
david@fromorbit.com