Re: [PATCH] generic: Verify how to change the S_DAX flag on an existing file

[Ira Weiny <ira.weiny@intel.com>]

On Fri, Aug 07, 2020 at 09:41:19AM +0800, Xiao Yang wrote:
> On 2020/8/7 3:28, Ira Weiny wrote:
> > On Thu, Aug 06, 2020 at 09:09:22AM -0700, 'Ira Weiny' wrote:
> > > On Wed, Aug 05, 2020 at 08:57:37AM +0800, Xiao Yang wrote:
> > > > On 2020/8/4 23:38, Darrick J. Wong wrote:
> > > > > On Tue, Aug 04, 2020 at 09:11:40AM +0800, Xiao Yang wrote:
> > > > > > Change FS_XFLAG_DAX on an existing file and check if S_DAX on the
> > > > > > file can take effect immediately by the following steps:
> > > > > > 1) Stop all applications which are using the file.
> > > > > > 2) Do drop_caches or umount&   mount cycle.
> > > > > Slightly related question: is there a test to check that if a filesystem
> > > > > recognizes dax=always, it will also accept dax=inode and dax=none?  This
> > > > > test checks that dax=always and dax=inode work, but I don't think I saw
> > > > > one that tests dax=always ensuring that dax=none works too.
> > > > Hi Darrick,
> > > > 
> > > > Good question.  dax=inode and dax=none have the same behavior so do you want
> > > > to
> > > > add another combination(-o dax=none)  for all tests which include dax=inode?
> > > > Right?
> > > FWIW, it is '-o dax=never'
> > > 
> > > I had a test for dax=never as well.  Basically FS_XFLAG_DAX=n should result in
> > > S_DAX=y in that case.
> > Sorry I have this backwards...
> > ... FS_XFLAG_DAX=y   ====>   S_DAX=n ...
> > 
> > <sigh>
> > Ira
> Hi Ira,
> 
> 1) I think '-o dax=never' combination you mentioned has been included by
> generic/606 from my patch set. :-)

Awesome!  Yes thanks!

> 2) This test is designed to verify that modify FS_XFLAG_DAX on an existing
> file and then S_DAX become valid/invalid immediately by drop_caches or
> umount & mount.
>      FS_XFLAG_DAX  will be ignored and modifying it cannot change S_DAX if
> '-o dax=always' or '-o dax=never' is mounted.
>      In this case, drop_caches or umount & mount  doesn't make sense.
> 

yep!

Ira

> Thanks,
> Xiao Yang
> > > I think this patch is good for what it does though.
> > > 
> > > Reviewed-by: Ira Weiny<ira.weiny@intel.com>
> > > 
> > > Ira
> > > 
> > > > Thanks,
> > > > Xiao Yang
> > > > > > Signed-off-by: Xiao Yang<yangx.jy@cn.fujitsu.com>
> > > > > Seems decent otherwise,
> > > > > Reviewed-by: Darrick J. Wong<darrick.wong@oracle.com>
> > > > > 
> > > > > --D
> > > > > 
> > > > > > ---
> > > > > > 
> > > > > > Note: It is based on the following patch set:
> > > > > > https://www.spinics.net/lists/fstests/msg14457.html
> > > > > > 
> > > > > >    tests/generic/608     | 110 ++++++++++++++++++++++++++++++++++++++++++
> > > > > >    tests/generic/608.out |   2 +
> > > > > >    tests/generic/group   |   1 +
> > > > > >    3 files changed, 113 insertions(+)
> > > > > >    create mode 100644 tests/generic/608
> > > > > >    create mode 100644 tests/generic/608.out
> > > > > > 
> > > > > > diff --git a/tests/generic/608 b/tests/generic/608
> > > > > > new file mode 100644
> > > > > > index 00000000..33c5235d
> > > > > > --- /dev/null
> > > > > > +++ b/tests/generic/608
> > > > > > @@ -0,0 +1,110 @@
> > > > > > +#! /bin/bash
> > > > > > +# SPDX-License-Identifier: GPL-2.0
> > > > > > +# Copyright (c) 2020 Fujitsu.  All Rights Reserved.
> > > > > > +#
> > > > > > +# FS QA Test 608
> > > > > > +# Change FS_XFLAG_DAX on an existing file and check if S_DAX on
> > > > > > +# the file can take effect immediately by the following steps:
> > > > > > +# 1) Stop all applications which are using the file.
> > > > > > +# 2) Do drop_caches or umount&   mount cycle.
> > > > > > +
> > > > > > +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 $seqres.full
> > > > > > +
> > > > > > +_supported_fs generic
> > > > > > +_supported_os Linux
> > > > > > +_require_scratch_dax_mountopt "dax=always"
> > > > > > +_require_dax_iflag
> > > > > > +_require_xfs_io_command "lsattr" "-v"
> > > > > > +_require_xfs_io_command "statx" "-r"
> > > > > > +
> > > > > > +test_drop_caches()
> > > > > > +{
> > > > > > +	local t_file=$SCRATCH_MNT/testfile
> > > > > > +
> > > > > > +	rm -f $t_file
> > > > > > +	touch $t_file
> > > > > > +	_check_xflag $t_file 0
> > > > > > +	_check_s_dax $t_file 0
> > > > > > +
> > > > > > +	exec 3<   $t_file
> > > > > > +
> > > > > > +	$XFS_IO_PROG -c 'chattr +x' $t_file
> > > > > > +	_check_xflag $t_file 1
> > > > > > +	_check_s_dax $t_file 0
> > > > > > +
> > > > > > +	# One application is using test file and check if S_DAX on
> > > > > > +	# the file doesn't take effect immediately by drop_caches
> > > > > > +	echo 2>   /proc/sys/vm/drop_caches
> > > > > > +	_check_s_dax $t_file 0
> > > > > > +
> > > > > > +	exec 3<&-
> > > > > > +
> > > > > > +	# No application is using test file and check if S_DAX on
> > > > > > +	# the file takes effect immediately by drop_caches
> > > > > > +	echo 2>   /proc/sys/vm/drop_caches
> > > > > > +	_check_s_dax $t_file 1
> > > > > > +}
> > > > > > +
> > > > > > +test_cycle_mount()
> > > > > > +{
> > > > > > +	local t_dir=$SCRATCH_MNT/testdir
> > > > > > +	local t_file=$t_dir/testfile
> > > > > > +
> > > > > > +	mkdir -p $t_dir
> > > > > > +	$XFS_IO_PROG -c 'chattr +x' $t_dir
> > > > > > +	rm -f $t_file
> > > > > > +	touch $t_file
> > > > > > +	_check_xflag $t_file 1
> > > > > > +	_check_s_dax $t_file 1
> > > > > > +
> > > > > > +	exec 3<   $t_file
> > > > > > +
> > > > > > +	$XFS_IO_PROG -c 'chattr -x' $t_file
> > > > > > +	_check_xflag $t_file 0
> > > > > > +	_check_s_dax $t_file 1
> > > > > > +
> > > > > > +	exec 3<&-
> > > > > > +
> > > > > > +	# No application is using test file and check if S_DAX on
> > > > > > +	# the file takes effect immediately by umount&   mount
> > > > > > +	_scratch_cycle_mount "dax=inode"
> > > > > > +	_check_s_dax $t_file 0
> > > > > > +}
> > > > > > +
> > > > > > +do_tests()
> > > > > > +{
> > > > > > +	test_drop_caches
> > > > > > +
> > > > > > +	test_cycle_mount
> > > > > > +}
> > > > > > +
> > > > > > +_scratch_mkfs>>   $seqres.full 2>&1
> > > > > > +
> > > > > > +_scratch_mount "-o dax=inode"
> > > > > > +
> > > > > > +do_tests
> > > > > > +
> > > > > > +# success, all done
> > > > > > +echo "Silence is golden"
> > > > > > +status=0
> > > > > > +exit
> > > > > > diff --git a/tests/generic/608.out b/tests/generic/608.out
> > > > > > new file mode 100644
> > > > > > index 00000000..1e534458
> > > > > > --- /dev/null
> > > > > > +++ b/tests/generic/608.out
> > > > > > @@ -0,0 +1,2 @@
> > > > > > +QA output created by 608
> > > > > > +Silence is golden
> > > > > > diff --git a/tests/generic/group b/tests/generic/group
> > > > > > index 5bd289c3..aa969bcb 100644
> > > > > > --- a/tests/generic/group
> > > > > > +++ b/tests/generic/group
> > > > > > @@ -610,3 +610,4 @@
> > > > > >    605 auto attr quick dax
> > > > > >    606 auto attr quick dax
> > > > > >    607 auto attr quick dax
> > > > > > +608 auto attr quick dax
> > > > > > -- 
> > > > > > 2.21.0
> > > > > > 
> > > > > > 
> > > > > > 
> > > > > .
> > > > > 
> > > > 
> > > > 
> > 
> > .
> > 
> 
> 
>