Re: [PATCH] xfs: stress test cycling parent pointers with online repair

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

On Thu, Mar 16, 2023 at 02:02:06AM +0800, Zorro Lang wrote:
> On Tue, Mar 14, 2023 at 05:58:17PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <djwong@kernel.org>
> > 
> > Add a couple of new tests to exercise directory and parent pointer
> > repair against rename() calls moving child subdirectories from one
> > parent to another.  This is a useful test because it turns out that the
> > VFS doesn't lock the child subdirectory (it does lock the parents), so
> > repair must be more careful.
> > 
> > Signed-off-by: Darrick J. Wong <djwong@kernel.org>
> > ---
> 
> This patchset looks good to me.
> 
> Two questions before acking this patch:
> 1) The 2nd case fails [1] on mainline linux and xfsprogs, but test passed on
> your djwong linux and xfsprogs repo. Is this expected? Is it a known issue
> you've fixed in your repo?

Yes.  These two new 854/855 tests are a result of Jan Kara pointing out
that if you do this:

mkdir -p /tmp/a
mv /tmp/a /mnt/

The VFS won't lock /tmp/a while it does the rename.  The upstream parent
pointer checking code (which is really a dotdot checker) assumes that
holding *only* i_rwsem is sufficient to prevent directory updates, which
isn't true, and so the parent pointer checker emits false corruption
reports.

All of that is fixed in djwong-dev.

> 2) I remember there was a patchset [1] (from your team too) about parent pointer
> test half years ago. I've reviewed its 3rd version, but no more response anymore.
> Just curious, do you drop that patchset ? Or you hope to send it again after
> xfsprogs and kernel support that feature? If dropped, I'll remove it from my
> pending list :)

It'll be back (soonish, I hope) once we finish nailing down the ondisk
format and fixing up all the minor problems.

https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfstests-dev.git/log/?h=pptrs-ioctl-flexarray

--D

> Thanks,
> Zorro
> 
> [1]
> xfs/855 33s ... _check_xfs_filesystem: filesystem on /dev/sda3 failed health check
> (see /root/git/xfstests/results//simpledev/xfs/855.full for details)
> - output mismatch (see /root/git/xfstests/results//simpledev/xfs/855.out.bad)
>     --- tests/xfs/855.out       2023-03-16 00:47:28.256187590 +0800
>     +++ /root/git/xfstests/results//simpledev/xfs/855.out.bad   2023-03-16 01:42:25.764902276 +0800
>     @@ -1,2 +1,37 @@
>      QA output created by 855
>     +xfs_scrub reports uncorrected errors:
>     +Corruption: inode 100663424 (12/128) parent pointer: Repairs are required. (scrub.c line 190)
>     +Corruption: inode 125829312 (15/192) parent pointer: Repairs are required. (scrub.c line 190)
>     +xfs_scrub reports uncorrected errors:
>     +Corruption: inode 117440647 (14/135) parent pointer: Repairs are required. (scrub.c line 190)
>     +xfs_scrub reports uncorrected errors:
>     ...
>     (Run 'diff -u /root/git/xfstests/tests/xfs/855.out /root/git/xfstests/results//simpledev/xfs/855.out.bad'  to see the entire diff)
> Ran: xfs/854 xfs/855
> Failures: xfs/855
> Failed 1 of 2 tests
> 
> [2]
> [PATCH v3 0/4] xfstests: add parent pointer tests
> https://lore.kernel.org/fstests/20221028215605.17973-1-catherine.hoang@oracle.com/
> 
> 
> 
> >  common/fuzzy      |   15 +++++++++++++++
> >  tests/xfs/854     |   38 ++++++++++++++++++++++++++++++++++++++
> >  tests/xfs/854.out |    2 ++
> >  tests/xfs/855     |   38 ++++++++++++++++++++++++++++++++++++++
> >  tests/xfs/855.out |    2 ++
> >  5 files changed, 95 insertions(+)
> >  create mode 100755 tests/xfs/854
> >  create mode 100644 tests/xfs/854.out
> >  create mode 100755 tests/xfs/855
> >  create mode 100644 tests/xfs/855.out
> > 
> > diff --git a/common/fuzzy b/common/fuzzy
> > index 4609df4434..744d9ed65d 100644
> > --- a/common/fuzzy
> > +++ b/common/fuzzy
> > @@ -995,6 +995,20 @@ __stress_scrub_fsstress_loop() {
> >  	local focus=()
> >  
> >  	case "$stress_tgt" in
> > +	"parent")
> > +		focus+=('-z')
> > +
> > +		# Create a directory tree very gradually
> > +		for op in creat link mkdir; do
> > +			focus+=('-f' "${op}=2")
> > +		done
> > +		focus+=('-f' 'unlink=1' '-f' 'rmdir=1')
> > +
> > +		# But do a lot of renames to cycle parent pointers
> > +		for op in rename rnoreplace rexchange; do
> > +			focus+=('-f' "${op}=40")
> > +		done
> > +		;;
> >  	"dir")
> >  		focus+=('-z')
> >  
> > @@ -1285,6 +1299,7 @@ __stress_scrub_check_commands() {
> >  #       'writeonly': Only perform fs updates, no reads.
> >  #       'symlink': Only create symbolic links.
> >  #       'mknod': Only create special files.
> > +#       'parent': Focus on updating parent pointers
> >  #
> >  #       The default is 'default' unless XFS_SCRUB_STRESS_TARGET is set.
> >  # -X	Run this program to exercise the filesystem.  Currently supported
> > diff --git a/tests/xfs/854 b/tests/xfs/854
> > new file mode 100755
> > index 0000000000..0aa2c2ee4f
> > --- /dev/null
> > +++ b/tests/xfs/854
> > @@ -0,0 +1,38 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (c) 2023 Oracle, Inc.  All Rights Reserved.
> > +#
> > +# FS QA Test No. 854
> > +#
> > +# Race fsstress doing mostly renames and xfs_scrub in force-repair mode for a
> > +# while to see if we crash or livelock.
> > +#
> > +. ./common/preamble
> > +_begin_fstest online_repair dangerous_fsstress_repair
> > +
> > +_cleanup() {
> > +	cd /
> > +	_scratch_xfs_stress_scrub_cleanup &> /dev/null
> > +	rm -r -f $tmp.*
> > +}
> > +_register_cleanup "_cleanup" BUS
> > +
> > +# Import common functions.
> > +. ./common/filter
> > +. ./common/fuzzy
> > +. ./common/inject
> > +. ./common/xfs
> > +
> > +# real QA test starts here
> > +_supported_fs xfs
> > +_require_scratch
> > +_require_xfs_stress_online_repair
> > +
> > +_scratch_mkfs > "$seqres.full" 2>&1
> > +_scratch_mount
> > +_scratch_xfs_stress_online_repair -S '-k' -x 'parent'
> > +
> > +# success, all done
> > +echo Silence is golden
> > +status=0
> > +exit
> > diff --git a/tests/xfs/854.out b/tests/xfs/854.out
> > new file mode 100644
> > index 0000000000..f8d9e27958
> > --- /dev/null
> > +++ b/tests/xfs/854.out
> > @@ -0,0 +1,2 @@
> > +QA output created by 854
> > +Silence is golden
> > diff --git a/tests/xfs/855 b/tests/xfs/855
> > new file mode 100755
> > index 0000000000..6daff05995
> > --- /dev/null
> > +++ b/tests/xfs/855
> > @@ -0,0 +1,38 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (c) 2023 Oracle, Inc.  All Rights Reserved.
> > +#
> > +# FS QA Test No. 855
> > +#
> > +# Race fsstress doing mostly renames and xfs_scrub in read-only mode for a
> > +# while to see if we crash or livelock.
> > +#
> > +. ./common/preamble
> > +_begin_fstest scrub dangerous_fsstress_scrub
> > +
> > +_cleanup() {
> > +	cd /
> > +	_scratch_xfs_stress_scrub_cleanup &> /dev/null
> > +	rm -r -f $tmp.*
> > +}
> > +_register_cleanup "_cleanup" BUS
> > +
> > +# Import common functions.
> > +. ./common/filter
> > +. ./common/fuzzy
> > +. ./common/inject
> > +. ./common/xfs
> > +
> > +# real QA test starts here
> > +_supported_fs xfs
> > +_require_scratch
> > +_require_xfs_stress_scrub
> > +
> > +_scratch_mkfs > "$seqres.full" 2>&1
> > +_scratch_mount
> > +_scratch_xfs_stress_scrub -S '-n' -x 'parent'
> > +
> > +# success, all done
> > +echo Silence is golden
> > +status=0
> > +exit
> > diff --git a/tests/xfs/855.out b/tests/xfs/855.out
> > new file mode 100644
> > index 0000000000..fa60f65432
> > --- /dev/null
> > +++ b/tests/xfs/855.out
> > @@ -0,0 +1,2 @@
> > +QA output created by 855
> > +Silence is golden
> > 
>