Re: [PATCH 1/2] fstests: generic, test fsync after succession of file renames

[Filipe Manana <fdmanana@kernel.org>]

On Tue, Feb 19, 2019 at 1:29 AM Chao Yu <yuchao0@huawei.com> wrote:
>
> On 2019/2/13 2:08, fdmanana@kernel.org wrote:
> > From: Filipe Manana <fdmanana@suse.com>
> >
> > Test that after a combination of file renames, linking and creating a new
> > file with the old name of a renamed file, if we fsync the new file, after
> > a power failure we are able to mount the filesystem and all file names
> > correspond to the correct inodes.
> >
> > This test is motivated by a bug found in btrfs which is fixed by a patch
> > for the linux kernel titled:
> >
> >   "Btrfs: fix fsync after succession of renames of different files"
> >
> > The test passes on ext4, xfs and patched btrfs, however at least in a
> > 5.0-rc5 linux kernel, it fails on f2fs.
>
> We have introduced one additional mount option to handle that case:
>
> fsync_mode=%s
>
> Control the policy of fsync. Currently supports "posix",
> "strict", and "nobarrier". In "posix" mode, which is
> default, fsync will follow POSIX semantics and does a
> light operation to improve the filesystem performance.
> In "strict" mode, fsync will be heavy and behaves in line
> with xfs, ext4 and btrfs, where xfstest generic/342 will
> pass, but the performance will regress. "nobarrier" is
> based on "posix", but doesn't issue flush command for
> non-atomic files likewise "nobarrier" mount option.
>
> I've tested for confirmation, it passed both tests 526/527 on f2fs once I
> changed mount option from default to fsync_mode=strict.
>
> Filipe, could you please check that?

Thanks. I wasn't aware of that mount option.
Btw, it seems complicated for a user to know which option to use for
that mount option,
even if it's very well documented, as it's unlikely the user is aware
of what all applications
in the system do and expect (or make the strict mode the default).

Thanks.

>
> Thanks,
>
> >
> > Signed-off-by: Filipe Manana <fdmanana@suse.com>
> > ---
> >  tests/generic/526     | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/generic/526.out |  5 ++++
> >  tests/generic/group   |  1 +
> >  3 files changed, 78 insertions(+)
> >  create mode 100755 tests/generic/526
> >  create mode 100644 tests/generic/526.out
> >
> > diff --git a/tests/generic/526 b/tests/generic/526
> > new file mode 100755
> > index 00000000..d0b51f87
> > --- /dev/null
> > +++ b/tests/generic/526
> > @@ -0,0 +1,72 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (C) 2018 SUSE Linux Products GmbH. All Rights Reserved.
> > +#
> > +# FS QA Test No. 526
> > +#
> > +# Test that after a combination of file renames, linking and creating a new file
> > +# with the old name of a renamed file, if we fsync the new file, after a power
> > +# failure we are able to mount the filesystem and all file names correspond to
> > +# the correct inodes.
> > +#
> > +seq=`basename $0`
> > +seqres=$RESULT_DIR/$seq
> > +echo "QA output created by $seq"
> > +tmp=/tmp/$$
> > +status=1     # failure is the default!
> > +trap "_cleanup; exit \$status" 0 1 2 3 15
> > +
> > +_cleanup()
> > +{
> > +     _cleanup_flakey
> > +     cd /
> > +     rm -f $tmp.*
> > +}
> > +
> > +# get standard environment, filters and checks
> > +. ./common/rc
> > +. ./common/filter
> > +. ./common/dmflakey
> > +
> > +# real QA test starts here
> > +_supported_fs generic
> > +_supported_os Linux
> > +_require_scratch
> > +_require_dm_target flakey
> > +
> > +rm -f $seqres.full
> > +
> > +_scratch_mkfs >>$seqres.full 2>&1
> > +_require_metadata_journaling $SCRATCH_DEV
> > +_init_flakey
> > +_mount_flakey
> > +
> > +mkdir $SCRATCH_MNT/testdir
> > +echo -n "foo" > $SCRATCH_MNT/testdir/fname1
> > +echo -n "hello" > $SCRATCH_MNT/testdir/fname2
> > +
> > +# Make sure everything done so far is durably persisted.
> > +sync
> > +
> > +# Rename and link files such that one new name corresponds to the name of
> > +# another renamed file and one new file has the old name of one of the renamed
> > +# files. Then fsync only the new file.
> > +mv $SCRATCH_MNT/testdir/fname1 $SCRATCH_MNT/testdir/fname3
> > +mv $SCRATCH_MNT/testdir/fname2 $SCRATCH_MNT/testdir/fname4
> > +ln $SCRATCH_MNT/testdir/fname3 $SCRATCH_MNT/testdir/fname2
> > +echo -n "bar" > $SCRATCH_MNT/testdir/fname1
> > +$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/testdir/fname1
> > +
> > +# Simulate a power failure and mount the filesystem to check that all file names
> > +# exist and correspond to the correct inodes.
> > +_flakey_drop_and_remount
> > +
> > +echo "File fname1 data after power failure: $(cat $SCRATCH_MNT/testdir/fname1)"
> > +echo "File fname2 data after power failure: $(cat $SCRATCH_MNT/testdir/fname2)"
> > +echo "File fname3 data after power failure: $(cat $SCRATCH_MNT/testdir/fname3)"
> > +echo "File fname4 data after power failure: $(cat $SCRATCH_MNT/testdir/fname4)"
> > +
> > +_unmount_flakey
> > +
> > +status=0
> > +exit
> > diff --git a/tests/generic/526.out b/tests/generic/526.out
> > new file mode 100644
> > index 00000000..83979d28
> > --- /dev/null
> > +++ b/tests/generic/526.out
> > @@ -0,0 +1,5 @@
> > +QA output created by 526
> > +File fname1 data after power failure: bar
> > +File fname2 data after power failure: foo
> > +File fname3 data after power failure: foo
> > +File fname4 data after power failure: hello
> > diff --git a/tests/generic/group b/tests/generic/group
> > index cfd003d3..492a5875 100644
> > --- a/tests/generic/group
> > +++ b/tests/generic/group
> > @@ -528,3 +528,4 @@
> >  523 auto quick attr
> >  524 auto quick
> >  525 auto quick rw
> > +526 auto quick log
> >
>