Re: [PATCH v2] generic/391: check inode metadata on f{data}sync after power-cut

[Eryu Guan <eguan@redhat.com>]

On Thu, Nov 17, 2016 at 11:20:51AM -0800, Jaegeuk Kim wrote:
> This patch adds tests/generic/391 to test fsync and fdatasync with power-cuts.
> 
> The rule to check is:
> 1) fsync should guarantee all the inode metadata after power-cut,
> 2) fdatasync should guarantee i_size and i_blocks at least after power-cut.
> 
> Suggested-by: Chao Yu <yuchao0@huawei.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  tests/generic/391     | 136 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/391.out |  11 ++++
>  tests/generic/group   |   1 +
>  3 files changed, 148 insertions(+)
>  create mode 100644 tests/generic/391
>  create mode 100644 tests/generic/391.out
> 
> diff --git a/tests/generic/391 b/tests/generic/391
> new file mode 100644
> index 0000000..2b95151
> --- /dev/null
> +++ b/tests/generic/391
> @@ -0,0 +1,136 @@
> +#! /bin/bash
> +# FS QA Test 391
> +#
> +# Test inode's metadata after fsync or fdatasync calls.
> +# In the case of fsync, filesystem should recover all the inode metadata, while
> +# recovering i_blocks and i_size at least for fdatasync.
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2016 Jaegeuk Kim.  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
> +. ./common/punch
> +
> +# real QA test starts here
> +_supported_fs generic
> +_supported_os Linux
> +
> +rm -f $seqres.full
> +_require_scratch
> +_require_scratch_shutdown
> +_require_xfs_io_command "fpunch"
> +
> +_scratch_mkfs >/dev/null 2>&1
> +_scratch_mount
> +
> +testfile=$SCRATCH_MNT/testfile
> +
> +# check inode metadata after shutdown
> +check_inode_metadata()
> +{
> +	$XFS_IO_PROG -r -c "stat -v" $1 >$tmp.before
> +	src/godown $SCRATCH_MNT >> $seqres.full
> +	_scratch_cycle_mount
> +	$XFS_IO_PROG -r -c "stat -v" $1 >$tmp.after
> +
> +	if [ $FSTYP = xfs ]; then
> +		sed -i '/stat.blocks/d' $tmp.before
> +		sed -i '/stat.blocks/d' $tmp.after
> +	fi

Blacklist some fs "randomly" seems not easy to maintain, at least we
need some comments to explain why we do this.

I prefer the other way Brian suggested, i.e. truncate the file to
correct size before the real fsync/fdatasync to remove any preallocated
blocks past eof. I made the following update and test passed on XFS
without problems, what do you think?

--- a/tests/generic/391
+++ b/tests/generic/391
@@ -65,10 +65,6 @@ check_inode_metadata()
        _scratch_cycle_mount
        $XFS_IO_PROG -r -c "stat -v" $1 >$tmp.after
 
-       if [ $FSTYP = xfs ]; then
-               sed -i '/stat.blocks/d' $tmp.before
-               sed -i '/stat.blocks/d' $tmp.after
-       fi
        diff $tmp.before $tmp.after >$tmp.diff
 
        if [ "$2" = "fdatasync" ]; then
@@ -82,13 +78,19 @@ check_inode_metadata()
 }
 
 # append XX KB with f{data}sync, followed by power-cut
+# truncate file to the current size to avoid post-eof preallocated
+# blocks on XFS
 test_i_size()
 {
+       local len=$2
+       local base_len=$((4 * 1024 * 1024))
+       local new_len=$((base_len + len))
        echo "==== i_size $2 test with $1 ====" | tee -a $seqres.full
-       $XFS_IO_PROG -f -c "pwrite 0 4M"        \
-                       -c "fsync"              \
-                       -c "pwrite 4M $2"       \
-                       -c "$1"                 \
+       $XFS_IO_PROG -f -c "pwrite 0 $base_len"         \
+                       -c "fsync"                      \
+                       -c "pwrite $base_len $len"      \
+                       -c "truncate $new_len"          \
+                       -c "$1"                         \
                        $testfile >/dev/null
        check_inode_metadata $testfile $1
 }
@@ -108,12 +110,15 @@ test_i_time()
 }
 
 # punch XX KB with f{data}sync, followed by power-cut
+# truncate file to the current size to avoid post-eof preallocated
+# blocks on XFS
 test_punch()
 {
        echo "==== fpunch $2 test with $1 ====" | tee -a $seqres.full
        $XFS_IO_PROG -f -c "pwrite 0 4202496"   \
                        -c "fsync"              \
-                       -c "fpunch 4194304 $2"\
+                       -c "fpunch 4194304 $2"  \
+                       -c "truncate 4202496"   \
                        -c "$1"                 \
                        $testfile >/dev/null
 
Thanks,
Eryu