Re: [PATCH] xfs: test mkfs.xfs sizing of internal logs that

["Darrick J. Wong" <djwong@kernel.org>]

On Wed, May 25, 2022 at 09:44:26AM +1000, Dave Chinner wrote:
> On Tue, May 24, 2022 at 12:52:57PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> > 
> > This is a regression test that exercises the mkfs.xfs code that creates
> > log sizes that are very close to the AG size when stripe units are in
> > play and/or when the log is forced to be in AG 0.
> > 
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > ---
> >  tests/xfs/843     |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/xfs/843.out |    2 ++
> >  2 files changed, 58 insertions(+)
> >  create mode 100755 tests/xfs/843
> >  create mode 100644 tests/xfs/843.out
> > 
> > diff --git a/tests/xfs/843 b/tests/xfs/843
> > new file mode 100755
> > index 00000000..3384b1aa
> > --- /dev/null
> > +++ b/tests/xfs/843
> > @@ -0,0 +1,56 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (c) 2022 Oracle.  All Rights Reserved.
> > +#
> > +# FS QA Test 843
> > +#
> > +# Now that we've increased the default log size calculation, test mkfs with
> > +# various stripe units and filesystem sizes to see if we can provoke mkfs into
> > +# breaking.
> > +#
> > +. ./common/preamble
> > +_begin_fstest auto mkfs
> > +
> > +_cleanup()
> > +{
> > +	cd /
> > +	rm -r -f $tmp.* $testfile
> > +}
> 
> I'd omit this completely.
> 
> > +# real QA test starts here
> > +
> > +# Modify as appropriate.
> > +_supported_fs xfs
> > +_require_test
> > +
> > +testfile=$TEST_DIR/a
> > +rm -f $testfile
> > +
> > +test_format() {
> > +	local tag="$1"
> > +	shift
> > +
> > +	echo "$tag" >> $seqres.full
> > +	$MKFS_XFS_PROG $@ -d file,name=$testfile &>> $seqres.full
> > +	local res=$?
> > +	test $res -eq 0 || echo "$tag FAIL $res" | tee -a $seqres.full
> 
> What breakage are you trying to provoke? Just the log size
> calculation? If so, why do we need to actually write the filesystem
> to disk? Won't "-N" still calculate everything and fail if it's
> broken or quit with success without needing to write anything to
> disk?

It will, but...

> > +}
> > +
> > +# First we try various small filesystems and stripe sizes.
> > +for M in `seq 298 302` `seq 490 520`; do
> > +	for S in `seq 32 4 64`; do
> > +		test_format "M=$M S=$S" -dsu=${S}k,sw=1,size=${M}m
> > +	done
> > +done
> > +
> > +# log so large it pushes the root dir into AG 1
> > +test_format "log pushes rootdir into AG 1" -d agcount=3200,size=6366g -lagnum=0

...this particular check in mkfs only happens after we allocate the root
directory, which an -N invocation doesn't do.

> > +
> > +# log end rounded beyond EOAG due to stripe unit
> > +test_format "log end beyond eoag" -d agcount=3200,size=6366g -d su=256k,sw=4
> > +
> > +echo Silence is golden
> 
> Put this at the top where the test is being set up (i.e. where you
> define testfile). That tells the reader straight away that no output
> is expected on a successful run before they start reading the test
> code....

Hmm, we probably ought to update the ./new template too.

--D

> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com