Re: [PATCH v6 7/7] generic: Verify the inheritance behavior of FS_XFLAG_DAX flag in various combinations

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Wed, Jul 15, 2020 at 05:44:53PM +0800, Xiao Yang wrote:
> On 2020/7/15 13:39, Xiao Yang wrote:
> > On 2020/7/15 10:48, Ira Weiny wrote:
> > > On Tue, Jul 14, 2020 at 05:40:09PM +0800, Xiao Yang wrote:
> > > > Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
> > > > ---
> > > >   tests/generic/605     | 199
> > > > ++++++++++++++++++++++++++++++++++++++++++
> > > >   tests/generic/605.out |   2 +
> > > >   tests/generic/group   |   1 +
> > > >   3 files changed, 202 insertions(+)
> > > >   create mode 100644 tests/generic/605
> > > >   create mode 100644 tests/generic/605.out
> > > > 
> > > > diff --git a/tests/generic/605 b/tests/generic/605
> > > > new file mode 100644
> > > > index 00000000..6924223a
> > > > --- /dev/null
> > > > +++ b/tests/generic/605
> > > > @@ -0,0 +1,199 @@
> > > > +#! /bin/bash
> > > > +# SPDX-License-Identifier: GPL-2.0
> > > > +# Copyright (c) 2020 Fujitsu.  All Rights Reserved.
> > > > +#
> > > > +# FS QA Test 605
> > > > +#
> > > > +# Verify the inheritance behavior of FS_XFLAG_DAX flag in
> > > > various combinations.
> > > > +# 1) New files and directories automatically inherit
> > > > FS_XFLAG_DAX from their parent directory.
> > > > +# 2) cp operation make files and directories inherit the
> > > > FS_XFLAG_DAX from new parent directory.
> > > > +# 3) mv operation make files and directories preserve the
> > > > FS_XFLAG_DAX from old parent directory.
> > > > +# In addition, setting/clearing FS_XFLAG_DAX flag is not
> > > > impacted by dax mount options.
> > > > +
> > > > +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
> > > > +
> > > > +# remove previous $seqres.full before test
> > > > +rm -f $seqres.full
> > > > +
> > > > +_supported_fs generic
> > > > +_supported_os Linux
> > > > +_require_scratch
> > > > +_require_dax_iflag
> > > > +_require_xfs_io_command "lsattr" "-v"
> > > > +
> > > > +check_xflag()
> > > > +{
> > > > +    local target=$1
> > > > +    local exp_xflag=$2
> > > > +
> > > > +    if [ $exp_xflag -eq 0 ]; then
> > > > +        _test_inode_flag dax $target&&  echo "$target has
> > > > unexpected FS_XFLAG_DAX flag"
> > > > +    else
> > > > +        _test_inode_flag dax $target || echo "$target doen't
> > > > have expected FS_XFLAG_DAX flag"
> > > > +    fi
> > > > +}
> > > > +
> > > > +test_xflag_inheritance1()
> > > > +{
> > > > +    mkdir -p a
> > > > +    $XFS_IO_PROG -c "chattr +x" a
> > > > +    mkdir -p a/b/c
> > > > +    touch a/b/c/d
> > > > +
> > > > +    check_xflag a 1
> > > > +    check_xflag a/b 1
> > > > +    check_xflag a/b/c 1
> > > > +    check_xflag a/b/c/d 1
> > > > +
> > > > +    rm -rf a
> > > > +}
> > > > +
> > > > +test_xflag_inheritance2()
> > > > +{
> > > > +    mkdir -p a/b
> > > > +    $XFS_IO_PROG -c "chattr +x" a
> > > > +    mkdir -p a/b/c a/d
> > > > +    touch a/b/c/e a/d/f
> > > > +
> > > > +    check_xflag a 1
> > > > +    check_xflag a/b 0
> > > > +    check_xflag a/b/c 0
> > > > +    check_xflag a/b/c/e 0
> > > > +    check_xflag a/d 1
> > > > +    check_xflag a/d/f 1
> > > > +
> > > > +    rm -rf a
> > > > +}
> > > > +
> > > > +test_xflag_inheritance3()
> > > > +{
> > > > +    mkdir -p a/b
> > > > +    $XFS_IO_PROG -c "chattr +x" a/b
> > > > +    mkdir -p a/b/c a/d
> > > > +    touch a/b/c/e a/d/f
> > > > +
> > > > +    check_xflag a 0
> > > > +    check_xflag a/b 1
> > > > +    check_xflag a/b/c 1
> > > > +    check_xflag a/b/c/e 1
> > > > +    check_xflag a/d 0
> > > > +    check_xflag a/d/f 0
> > > > +
> > > > +    rm -rf a
> > > > +}
> > > It really seems like 2 and 3 test the same thing?
> > Hi Ira,
> > 
> > 2 constructs the following steps:
> > 1) a is the parent directory of b
> > 2) a doesn't have xflag and b has xflag
> > 3) touch many directories/files in a and b
> > 
> > 3 constructs the following steps:
> > 1) a is the parent directory of b and b is the parent directory of c
> > 2) a and c have xflag, and b doesn't have xflag
> > 3) touch many directories/files in b and c
> Hi Ira,
> 
> Sorry for misreading your comment, above is the difference between 3 and 4.
> The correct one is:
> 2 constructs the following steps:
> 1) a is the parent directory of b
> 2) a has xflag and b doesn't have xflag
> 3) touch many directories/files in a and b
> 
> 3 constructs the following steps:
> 1) a is the parent directory of b
> 2) a doesn't have xflag and b has xflag
> 3) touch many directories/files in a and b
> 
> Do you think they are same? I can remove one if you think so.

For an earlier version of this series I thought about recommending that
each of these functions describe what they aim to test.  Then I realized
that such descriptions would probably be nearly as long as the function
body, and said nothing.

But now that Ira's confused, I think that's a stronger argument for each
of the test functions having a short description.

	# If a/ is +x and b/ is -x, check that b's new children don't
	# inherit +x from a/.
	test_xflag_inheritance2() {...}

Put another way, this adds enough redundancy between the comment and the
code that someone else can feel confident that the code still captures
the intent of the author.

FWIW I think 2 and 3 test opposite variations of the same thing (a's
state doesn't somehow override b's), so they're fine.  The xfs
implementation uses the same inheritance control code for FS_XFLAG_DAX,
but doesn't mean everyone else will necessarily do that.

--D

> Best Regards,
> Xiao Yang
> > 
> > Do you think they are same? I can remove one if you think so.
> > 
> > > > +
> > > > +test_xflag_inheritance4()
> > > > +{
> > > > +    mkdir -p a
> > > > +    $XFS_IO_PROG -c "chattr +x" a
> > > > +    mkdir -p a/b/c
> > > > +    $XFS_IO_PROG -c "chattr -x" a/b
> > > > +    mkdir -p a/b/c/d a/b/e
> > > > +    touch a/b/c/d/f a/b/e/g
> > > > +
> > > > +    check_xflag a 1
> > > > +    check_xflag a/b 0
> > > > +    check_xflag a/b/c 1
> > > > +    check_xflag a/b/c/d 1
> > > > +    check_xflag a/b/c/d/f 1
> > > > +    check_xflag a/b/e 0
> > > > +    check_xflag a/b/e/g 0
> > > > +
> > > > +    rm -rf a
> > > > +}
> > > > +
> > > > +test_xflag_inheritance5()
> > > > +{
> > > > +    mkdir -p a b
> > > > +    $XFS_IO_PROG -c "chattr +x" a
> > > > +    mkdir -p a/c a/d b/e b/f
> > > > +    touch a/g b/h
> > > > +
> > > > +    cp -r a/c b/
> > > > +    cp -r b/e a/
> > > > +    cp -r a/g b/
> > > > +    mv a/d b/
> > > > +    mv b/f a/
> > > > +    mv b/h a/
> > > > +
> > > > +    check_xflag b/c 0
> > > > +    check_xflag b/d 1
> > > > +    check_xflag a/e 1
> > > > +    check_xflag a/f 0
> > > > +    check_xflag b/g 0
> > > > +    check_xflag a/h 0
> > > > +
> > > > +    rm -rf a b
> > > > +}
> > > > +
> > > > +do_xflag_tests()
> > > > +{
> > > > +    local option=$1
> > > > +
> > > > +    _scratch_mount "$option"
> > > > +    cd $SCRATCH_MNT
> > > > +
> > > > +    for i in $(seq 1 5); do
> > > > +        test_xflag_inheritance${i}
> > > > +    done
> > > > +
> > > > +    cd ->  /dev/null
> > > > +    _scratch_unmount
> > > > +}
> > > > +
> > > > +check_dax_mountopt()
> > > > +{
> > > > +    local option=$1
> > > > +    local ret=0
> > > > +
> > > > +    _try_scratch_mount "-o $option">>  $seqres.full 2>&1 || return 1
> > > > +
> > > > +    # Match option name exactly
> > > > +    _fs_options $SCRATCH_DEV | egrep -q "$option(,|$)" || ret=1
> > > > +
> > > > +    _scratch_unmount
> > > > +
> > > > +    return $ret
> > > > +}
> > > Should this be a common function?
> > 
> > I am not sure if it should be a common function, because it may not be
> > used by other tests in future.
> > I also consider to merge the function into
> > _require_scratch_dax_mountopt().
> > 
> > > > +
> > > > +do_tests()
> > > > +{
> > > > +    # Mount without dax option
> > > > +    do_xflag_tests
> > > > +
> > > > +    # Mount with old dax option if fs only supports it.
> > > > +    check_dax_mountopt "dax"&&  do_xflag_tests "-o dax"
> > > I don't understand the order here.  If we are on an older kernel and
> > > the FS
> > > only supports '-o dax' the do_xflag_tests will fail won't it?
> > 
> > With both old dax and new dax, the inheritance behavior of FS_XFLAG_DAX
> > works well.
> > 
> > > So shouldn't we do this first and bail/'not run' this test if that
> > > is the case?
> > > 
> > > I really don't think there is any point in testing the old XFS
> > > behavior because
> > > the FS_XFLAG_DAX had no effect.  So even if it is broken it does not
> > > matter.
> > > Or perhaps I am missing something here?
> > 
> > This test is designed to verify the inheritance behavior of
> > FS_XFLAG_DAX(not related to S_DAX)
> > so I think it is fine for both old dax and new dax to run the test.
> > 
> > Best Regards,
> > Xiao Yang
> > > Ira
> > > 
> > > > +
> > > > +    # Mount with new dax options if fs supports them.
> > > > +    if check_dax_mountopt "dax=always"; then
> > > > +        for dax_option in "dax=always" "dax=inode" "dax=never"; do
> > > > +            do_xflag_tests "-o $dax_option"
> > > > +        done
> > > > +    fi
> > > > +}
> > > > +
> > > > +_scratch_mkfs>>  $seqres.full 2>&1
> > > > +
> > > > +do_tests
> > > > +
> > > > +# success, all done
> > > > +echo "Silence is golden"
> > > > +status=0
> > > > +exit
> > > > diff --git a/tests/generic/605.out b/tests/generic/605.out
> > > > new file mode 100644
> > > > index 00000000..1ae20049
> > > > --- /dev/null
> > > > +++ b/tests/generic/605.out
> > > > @@ -0,0 +1,2 @@
> > > > +QA output created by 605
> > > > +Silence is golden
> > > > diff --git a/tests/generic/group b/tests/generic/group
> > > > index 676e0d2e..a8451862 100644
> > > > --- a/tests/generic/group
> > > > +++ b/tests/generic/group
> > > > @@ -607,3 +607,4 @@
> > > >   602 auto quick encrypt
> > > >   603 auto attr quick dax
> > > >   604 auto attr quick dax
> > > > +605 auto attr quick dax
> > > > -- 
> > > > 2.21.0
> > > > 
> > > > 
> > > > 
> > > 
> > > .
> > > 
> > 
> > 
> > 
> > .
> > 
> 
> 
>