Re: [PATCH] generic: add test for fsync after shrinking truncate and rename

[Filipe Manana <fdmanana@kernel.org>]

On Mon, Mar 4, 2019 at 3:04 PM Amir Goldstein <amir73il@gmail.com> wrote:
>
> On Mon, Mar 4, 2019 at 4:44 PM <fdmanana@kernel.org> wrote:
> >
> > From: Filipe Manana <fdmanana@suse.com>
> >
> > Test that if we truncate a file to reduce its size, rename it and then
> > fsync it, after a power failure the file has a correct size and name.
> >
>
> I am not sure that ext4/xfs semantics guaranty anything about
> persisting file name after fsync of file?...
>
> > This test is motivated by a bug found in btrfs, which is fixed by a
> > patch for the linux kernel titled:
> >
> >   "Btrfs: fix incorrect file size after shrinking truncate and fsync"
>
> At least the title of this patch says nothing about persisting the
> name.

Because the bug in btrfs is not about persisting the name, it's about
persisting the correct inode size.

>
> >
> > This test currently passes on ext4, xfs, f2fs and patched btrfs.
> >
> > Signed-off-by: Filipe Manana <fdmanana@suse.com>
> > ---
> >  tests/generic/532     | 66 +++++++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/generic/532.out |  8 +++++++
> >  tests/generic/group   |  1 +
> >  3 files changed, 75 insertions(+)
> >  create mode 100755 tests/generic/532
> >  create mode 100644 tests/generic/532.out
> >
> > diff --git a/tests/generic/532 b/tests/generic/532
> > new file mode 100755
> > index 00000000..64992d85
> > --- /dev/null
> > +++ b/tests/generic/532
> > @@ -0,0 +1,66 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (C) 2019 SUSE Linux Products GmbH. All Rights Reserved.
> > +#
> > +# FS QA Test No. 532
> > +#
> > +# Test that if we truncate a file to reduce its size, rename it and then fsync
> > +# it, after a power failure the file has a correct size and name.
> > +#
> > +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 $SCRATCH_DEV
> > +_init_flakey
> > +_mount_flakey
> > +
> > +# Create our test file with an initial size of 8000 bytes, then fsync it,
> > +# followed by a truncate that reduces its size down to 3000 bytes.
> > +$XFS_IO_PROG -f -c "pwrite -S 0xab 0 8000" \
> > +            -c "fsync" \
> > +            -c "truncate 3000" \
> > +            $SCRATCH_MNT/foo | _filter_xfs_io
> > +
> > +# Now rename the file and fsync it again.
> > +mv $SCRATCH_MNT/foo $SCRATCH_MNT/bar
> > +$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/bar
> > +
> > +# Simulate a power failure and mount the filesystem to check that the file was
> > +# persisted with the new name and has a size of 3000 bytes.
> > +_flakey_drop_and_remount
> > +
> > +[ -f $SCRATCH_MNT/bar ] || echo "file name 'bar' is missing"
> > +[ -f $SCRATCH_MNT/foo ] && echo "file name 'foo' still exists"
> > +
> > +echo "File content after power failure:"
> > +od -A d -t x1 $SCRATCH_MNT/bar
> > +
> > +_unmount_flakey
> > +
> > +status=0
> > +exit
> > diff --git a/tests/generic/532.out b/tests/generic/532.out
> > new file mode 100644
> > index 00000000..554fbe2a
> > --- /dev/null
> > +++ b/tests/generic/532.out
> > @@ -0,0 +1,8 @@
> > +QA output created by 532
> > +wrote 8000/8000 bytes at offset 0
> > +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> > +File content after power failure:
> > +0000000 ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab ab
> > +*
> > +0002992 ab ab ab ab ab ab ab ab
> > +0003000
> > diff --git a/tests/generic/group b/tests/generic/group
> > index 31011ac8..7d63f303 100644
> > --- a/tests/generic/group
> > +++ b/tests/generic/group
> > @@ -534,3 +534,4 @@
> >  529 auto quick attr
> >  530 auto quick unlink
> >  531 auto quick unlink
> > +532 auto quick log
> > --
> > 2.11.0
> >