diff mbox

[WIP,V2] Buffer resubmittion test

Message ID 20170710133418.7083-1-cmaiolino@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Carlos Maiolino July 10, 2017, 1:34 p.m. UTC 
Hi folks,

this is the 2nd version of this test case. I still keep the number as
999 to avoid conflicts while it's still WIP, next version should be ok
to make it into a real patch with the right number.

Reason of this patch is still to check if AIL items are being properly
resubmitted after an error during writeback from buffers containing AIL
items.

This V2 includes:

	- Better indentation
	- More comments
	- Add copyright
	- use $SCRATCH_MNT instead of local created mount point
	- redirect outputs to $seqres.full instead of dev/null

- It doesn't change sleep by wait, because AFAIK, wait requires the process
being waited to return. Fsfreeze here is expected to hang until the
underlying device is extended.

Let me know your thoughts.

cheers.

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
---
 tests/xfs/999     | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 tests/xfs/999.out |   2 +
 tests/xfs/group   |   1 +
 3 files changed, 122 insertions(+)
 create mode 100755 tests/xfs/999
 create mode 100644 tests/xfs/999.out

Comments

Brian Foster July 10, 2017, 2:55 p.m. UTC | #1 
On Mon, Jul 10, 2017 at 03:34:18PM +0200, Carlos Maiolino wrote:
> Hi folks,
> 
> this is the 2nd version of this test case. I still keep the number as
> 999 to avoid conflicts while it's still WIP, next version should be ok
> to make it into a real patch with the right number.
> 
> Reason of this patch is still to check if AIL items are being properly
> resubmitted after an error during writeback from buffers containing AIL
> items.
> 
> This V2 includes:
> 
> 	- Better indentation
> 	- More comments
> 	- Add copyright
> 	- use $SCRATCH_MNT instead of local created mount point
> 	- redirect outputs to $seqres.full instead of dev/null
> 
> - It doesn't change sleep by wait, because AFAIK, wait requires the process
> being waited to return. Fsfreeze here is expected to hang until the
> underlying device is extended.
> 

Thinking more about this, we could keep the sleep and also add the wait
right before the unfreeze, right?

> Let me know your thoughts.
> 
> cheers.
> 
> Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> ---

Mostly looks good to me. A few minor notes...

>  tests/xfs/999     | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/xfs/999.out |   2 +
>  tests/xfs/group   |   1 +

The test is still under xfs (rather than generic).

>  3 files changed, 122 insertions(+)
>  create mode 100755 tests/xfs/999
>  create mode 100644 tests/xfs/999.out
> 
> diff --git a/tests/xfs/999 b/tests/xfs/999
> new file mode 100755
> index 0000000..b46f1cc
> --- /dev/null
> +++ b/tests/xfs/999
> @@ -0,0 +1,119 @@
> +#! /bin/bash
> +# FS QA Test 999
> +#
> +# Test buffer resubmission after a failed writeback with to a full overcommited
> +# dm-thin device.
> +#
> +# When a dm-thin device reaches its full capacity, but the virtual device still
> +# shows available space, XFS loops indefinitely in xfsaild due items still in
> +# AIL. The buffers containing such items couldn't be resubmitted because the
> +# items were flush locked. Test the kernel fix and ensure the buffers are
> +# properly resubmitted.
> +#
> +# This test will hang the filesystem when ran on an unpatched kernel
> +#
> +#-----------------------------------------------------------------------
> +# Copyright (c) 2017 Red Hat, Inc. All Rights Reserved.
> +#
> +# This program is free software; you can redistribute it and/or
> +# modify it under the terms of the GNU General Public License as
> +# published by the Free Software Foundation.
> +#
> +# This program is distributed in the hope that it would be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program; if not, write the Free Software Foundation,
> +# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> +#-----------------------------------------------------------------------
> +#
> +
> +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.*
> +	$UMOUNT_PROG $SCRATCH_MNT >>$seqres.full 2>&1
> +	$LVM_PROG vgremove -ff $vgname >>$seqres.full 2>&1
> +	$LVM_PROG pvremove -ff $SCRATCH_DEV >>$seqres.full 2>&1
> +}
> +
> +# get standard environment, filters and checks
> +. ./common/rc
> +. ./common/filter

Is filter used anywhere?

> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs xfs
> +_supported_os Linux
> +_require_scratch_nocheck
> +_require_dm_target thin-pool
> +_require_command $LVM_PROG lvm
> +
> +# remove previous $seqres.full before test
> +rm -f $seqres.full
> +
> +vgname=vg_$seq
> +lvname=lv_$seq
> +poolname=pool_$seq
> +snapname=snap_$seq
> +origpsize=100
> +virtsize=200
> +newpsize=200
> +
> +# Ensure we have enough disk space
> +_scratch_mkfs_sized $((250 * 1024 * 1024)) >>$seqres.full 2>&1
> +
> +# Create a 100MB dm-thin POOL
> +$LVM_PROG pvcreate -f $SCRATCH_DEV >>$seqres.full 2>&1
> +$LVM_PROG vgcreate -f $vgname $SCRATCH_DEV >>$seqres.full 2>&1
> +
> +$LVM_PROG lvcreate  --thinpool $poolname  --errorwhenfull y \
> +		    --zero n -L $origpsize \
> +		    --poolmetadatasize 4M $vgname >>$seqres.full 2>&1
> +
> +# Create a overprovisioned 200MB dm-thin virt. device
> +$LVM_PROG lvcreate  --virtualsize $virtsize \
> +		    -T $vgname/$poolname \
> +		    -n $lvname >>$seqres.full 2>&1
> +
> +_mkfs_dev /dev/mapper/$vgname-$lvname >>$seqres.full 2>&1
> +
> +
> +$LVM_PROG lvcreate  -k n -s $vgname/$lvname \
> +		    -n $snapname >>$seqres.full 2>&1

What's the reason for using a snapshot? Is the original thin vol not
sufficient?

> +
> +_mount /dev/mapper/$vgname-$snapname $SCRATCH_MNT
> +
> +# Consume all space available in the volume and freeze to ensure everything
> +# required to make the fs consistent is flushed to disk.
> +xfs_io -f -d -c 'pwrite -b 1m 0 120m' $SCRATCH_MNT/f1 >>$seqres.full 2>&1

$XFS_IO_PROG

> +
> +# This freeze will never complete until the dm-thin POOL device is extended.
> +# This is expected, it is only used so xfsaild is triggered to flush AIL items.
> +fsfreeze -f $SCRATCH_MNT &
> +
> +# Wait enough so xfsaild can run
> +sleep 10
> +
> +# Make some extra space available so the freeze above can proceed
> +lvextend -L $newpsize $vgname/$poolname >>$seqres.full 2>&1

$LVM_PROG lvmextend ?

Brian

> +
> +# Try to thaw the filesystem, and complete test if if succeed.
> +# NOTE: This will hang on affected XFS filesystems.
> +fsfreeze -u $SCRATCH_MNT
> +echo "Test OK"
> +
> +status=0
> +exit
> diff --git a/tests/xfs/999.out b/tests/xfs/999.out
> new file mode 100644
> index 0000000..8c3c938
> --- /dev/null
> +++ b/tests/xfs/999.out
> @@ -0,0 +1,2 @@
> +QA output created by 999
> +Test OK
> diff --git a/tests/xfs/group b/tests/xfs/group
> index 792161a..2bde916 100644
> --- a/tests/xfs/group
> +++ b/tests/xfs/group
> @@ -416,3 +416,4 @@
>  416 dangerous_fuzzers dangerous_scrub dangerous_repair
>  417 dangerous_fuzzers dangerous_scrub dangerous_online_repair
>  418 dangerous_fuzzers dangerous_scrub dangerous_repair
> +999 dangerous
> -- 
> 2.9.4
> 
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Carlos Maiolino July 10, 2017, 3:06 p.m. UTC | #2 
> 
> Thinking more about this, we could keep the sleep and also add the wait
> right before the unfreeze, right?

Well, depends, we still need to sleep there, an lvextend right after the freeze
won't give xfsaild enough time to run, so the problem won't be triggered, and
adding a wait right before unfreeze, seems pointless to me.
> 
> > Let me know your thoughts.
> > 
> > cheers.
> > 
> > Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> > ---
> 
> Mostly looks good to me. A few minor notes...
> 
> >  tests/xfs/999     | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> >  tests/xfs/999.out |   2 +
> >  tests/xfs/group   |   1 +
> 
> The test is still under xfs (rather than generic).
> 

yup, didn't move it to generic yet. I have a question about it. How do we
specify which filesystem to run the test on without needing to mkfs the device
for the filesystem in question?


> >  3 files changed, 122 insertions(+)
> >  create mode 100755 tests/xfs/999
> >  create mode 100644 tests/xfs/999.out
> > 
> > diff --git a/tests/xfs/999 b/tests/xfs/999
> > new file mode 100755
> > index 0000000..b46f1cc
> > --- /dev/null
> > +++ b/tests/xfs/999
> > @@ -0,0 +1,119 @@
> > +#! /bin/bash
> > +# FS QA Test 999
> > +#
> > +# Test buffer resubmission after a failed writeback with to a full overcommited
> > +# dm-thin device.
> > +#
> > +# When a dm-thin device reaches its full capacity, but the virtual device still
> > +# shows available space, XFS loops indefinitely in xfsaild due items still in
> > +# AIL. The buffers containing such items couldn't be resubmitted because the
> > +# items were flush locked. Test the kernel fix and ensure the buffers are
> > +# properly resubmitted.
> > +#
> > +# This test will hang the filesystem when ran on an unpatched kernel
> > +#
> > +#-----------------------------------------------------------------------
> > +# Copyright (c) 2017 Red Hat, Inc. All Rights Reserved.
> > +#
> > +# This program is free software; you can redistribute it and/or
> > +# modify it under the terms of the GNU General Public License as
> > +# published by the Free Software Foundation.
> > +#
> > +# This program is distributed in the hope that it would be useful,
> > +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > +# GNU General Public License for more details.
> > +#
> > +# You should have received a copy of the GNU General Public License
> > +# along with this program; if not, write the Free Software Foundation,
> > +# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> > +#-----------------------------------------------------------------------
> > +#
> > +
> > +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.*
> > +	$UMOUNT_PROG $SCRATCH_MNT >>$seqres.full 2>&1
> > +	$LVM_PROG vgremove -ff $vgname >>$seqres.full 2>&1
> > +	$LVM_PROG pvremove -ff $SCRATCH_DEV >>$seqres.full 2>&1
> > +}
> > +
> > +# get standard environment, filters and checks
> > +. ./common/rc
> > +. ./common/filter
> 
> Is filter used anywhere?

Nope, the first thing I was doing was filtering dmesg for the IO errors before
extending the dm-thin device, and I forgot to remove the filter from here, I'll
remove it.

> 
> > +
> > +# real QA test starts here
> > +
> > +# Modify as appropriate.
> > +_supported_fs xfs
> > +_supported_os Linux
> > +_require_scratch_nocheck
> > +_require_dm_target thin-pool
> > +_require_command $LVM_PROG lvm
> > +
> > +# remove previous $seqres.full before test
> > +rm -f $seqres.full
> > +
> > +vgname=vg_$seq
> > +lvname=lv_$seq
> > +poolname=pool_$seq
> > +snapname=snap_$seq
> > +origpsize=100
> > +virtsize=200
> > +newpsize=200
> > +
> > +# Ensure we have enough disk space
> > +_scratch_mkfs_sized $((250 * 1024 * 1024)) >>$seqres.full 2>&1
> > +
> > +# Create a 100MB dm-thin POOL
> > +$LVM_PROG pvcreate -f $SCRATCH_DEV >>$seqres.full 2>&1
> > +$LVM_PROG vgcreate -f $vgname $SCRATCH_DEV >>$seqres.full 2>&1
> > +
> > +$LVM_PROG lvcreate  --thinpool $poolname  --errorwhenfull y \
> > +		    --zero n -L $origpsize \
> > +		    --poolmetadatasize 4M $vgname >>$seqres.full 2>&1
> > +
> > +# Create a overprovisioned 200MB dm-thin virt. device
> > +$LVM_PROG lvcreate  --virtualsize $virtsize \
> > +		    -T $vgname/$poolname \
> > +		    -n $lvname >>$seqres.full 2>&1
> > +
> > +_mkfs_dev /dev/mapper/$vgname-$lvname >>$seqres.full 2>&1
> > +
> > +
> > +$LVM_PROG lvcreate  -k n -s $vgname/$lvname \
> > +		    -n $snapname >>$seqres.full 2>&1
> 
> What's the reason for using a snapshot? Is the original thin vol not
> sufficient?

No, it's not, honestly I don't remember now, exactly why not, I've been using
the snapshot in my internal test case since I started to work on this problem,
but without the snapshot I can't trigger the bug, at least not at a 100% rate.

> 
> > +
> > +_mount /dev/mapper/$vgname-$snapname $SCRATCH_MNT
> > +
> > +# Consume all space available in the volume and freeze to ensure everything
> > +# required to make the fs consistent is flushed to disk.
> > +xfs_io -f -d -c 'pwrite -b 1m 0 120m' $SCRATCH_MNT/f1 >>$seqres.full 2>&1
> 
> $XFS_IO_PROG

True, will change it

> 
> > +
> > +# This freeze will never complete until the dm-thin POOL device is extended.
> > +# This is expected, it is only used so xfsaild is triggered to flush AIL items.
> > +fsfreeze -f $SCRATCH_MNT &
> > +
> > +# Wait enough so xfsaild can run
> > +sleep 10
> > +
> > +# Make some extra space available so the freeze above can proceed
> > +lvextend -L $newpsize $vgname/$poolname >>$seqres.full 2>&1
> 
> $LVM_PROG lvmextend ?
> 
Indeed, missed it, will fix.

> Brian
> 
> > +
> > +# Try to thaw the filesystem, and complete test if if succeed.
> > +# NOTE: This will hang on affected XFS filesystems.
> > +fsfreeze -u $SCRATCH_MNT
> > +echo "Test OK"
> > +
> > +status=0
> > +exit
> > diff --git a/tests/xfs/999.out b/tests/xfs/999.out
> > new file mode 100644
> > index 0000000..8c3c938
> > --- /dev/null
> > +++ b/tests/xfs/999.out
> > @@ -0,0 +1,2 @@
> > +QA output created by 999
> > +Test OK
> > diff --git a/tests/xfs/group b/tests/xfs/group
> > index 792161a..2bde916 100644
> > --- a/tests/xfs/group
> > +++ b/tests/xfs/group
> > @@ -416,3 +416,4 @@
> >  416 dangerous_fuzzers dangerous_scrub dangerous_repair
> >  417 dangerous_fuzzers dangerous_scrub dangerous_online_repair
> >  418 dangerous_fuzzers dangerous_scrub dangerous_repair
> > +999 dangerous
> > -- 
> > 2.9.4
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe fstests" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> --
> To unsubscribe from this list: send the line "unsubscribe fstests" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Brian Foster July 10, 2017, 3:13 p.m. UTC | #3 
On Mon, Jul 10, 2017 at 05:06:12PM +0200, Carlos Maiolino wrote:
> > 
> > Thinking more about this, we could keep the sleep and also add the wait
> > right before the unfreeze, right?
> 
> Well, depends, we still need to sleep there, an lvextend right after the freeze
> won't give xfsaild enough time to run, so the problem won't be triggered, and
> adding a wait right before unfreeze, seems pointless to me.

Right, this wouldn't change the existing sleep at all. Basically it's
just a preference to have the test block in wait rather than freeze and
unfreeze because the latter seems a bit more confusing to me. Not a big
deal either way.

> > 
> > > Let me know your thoughts.
> > > 
> > > cheers.
> > > 
> > > Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> > > ---
> > 
> > Mostly looks good to me. A few minor notes...
> > 
> > >  tests/xfs/999     | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > >  tests/xfs/999.out |   2 +
> > >  tests/xfs/group   |   1 +
> > 
> > The test is still under xfs (rather than generic).
> > 
> 
> yup, didn't move it to generic yet. I have a question about it. How do we
> specify which filesystem to run the test on without needing to mkfs the device
> for the filesystem in question?
> 

$FSTYP should contain the target fs, if I understand the question..?

Brian

> 
> > >  3 files changed, 122 insertions(+)
> > >  create mode 100755 tests/xfs/999
> > >  create mode 100644 tests/xfs/999.out
> > > 
> > > diff --git a/tests/xfs/999 b/tests/xfs/999
> > > new file mode 100755
> > > index 0000000..b46f1cc
> > > --- /dev/null
> > > +++ b/tests/xfs/999
> > > @@ -0,0 +1,119 @@
> > > +#! /bin/bash
> > > +# FS QA Test 999
> > > +#
> > > +# Test buffer resubmission after a failed writeback with to a full overcommited
> > > +# dm-thin device.
> > > +#
> > > +# When a dm-thin device reaches its full capacity, but the virtual device still
> > > +# shows available space, XFS loops indefinitely in xfsaild due items still in
> > > +# AIL. The buffers containing such items couldn't be resubmitted because the
> > > +# items were flush locked. Test the kernel fix and ensure the buffers are
> > > +# properly resubmitted.
> > > +#
> > > +# This test will hang the filesystem when ran on an unpatched kernel
> > > +#
> > > +#-----------------------------------------------------------------------
> > > +# Copyright (c) 2017 Red Hat, Inc. All Rights Reserved.
> > > +#
> > > +# This program is free software; you can redistribute it and/or
> > > +# modify it under the terms of the GNU General Public License as
> > > +# published by the Free Software Foundation.
> > > +#
> > > +# This program is distributed in the hope that it would be useful,
> > > +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > +# GNU General Public License for more details.
> > > +#
> > > +# You should have received a copy of the GNU General Public License
> > > +# along with this program; if not, write the Free Software Foundation,
> > > +# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> > > +#-----------------------------------------------------------------------
> > > +#
> > > +
> > > +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.*
> > > +	$UMOUNT_PROG $SCRATCH_MNT >>$seqres.full 2>&1
> > > +	$LVM_PROG vgremove -ff $vgname >>$seqres.full 2>&1
> > > +	$LVM_PROG pvremove -ff $SCRATCH_DEV >>$seqres.full 2>&1
> > > +}
> > > +
> > > +# get standard environment, filters and checks
> > > +. ./common/rc
> > > +. ./common/filter
> > 
> > Is filter used anywhere?
> 
> Nope, the first thing I was doing was filtering dmesg for the IO errors before
> extending the dm-thin device, and I forgot to remove the filter from here, I'll
> remove it.
> 
> > 
> > > +
> > > +# real QA test starts here
> > > +
> > > +# Modify as appropriate.
> > > +_supported_fs xfs
> > > +_supported_os Linux
> > > +_require_scratch_nocheck
> > > +_require_dm_target thin-pool
> > > +_require_command $LVM_PROG lvm
> > > +
> > > +# remove previous $seqres.full before test
> > > +rm -f $seqres.full
> > > +
> > > +vgname=vg_$seq
> > > +lvname=lv_$seq
> > > +poolname=pool_$seq
> > > +snapname=snap_$seq
> > > +origpsize=100
> > > +virtsize=200
> > > +newpsize=200
> > > +
> > > +# Ensure we have enough disk space
> > > +_scratch_mkfs_sized $((250 * 1024 * 1024)) >>$seqres.full 2>&1
> > > +
> > > +# Create a 100MB dm-thin POOL
> > > +$LVM_PROG pvcreate -f $SCRATCH_DEV >>$seqres.full 2>&1
> > > +$LVM_PROG vgcreate -f $vgname $SCRATCH_DEV >>$seqres.full 2>&1
> > > +
> > > +$LVM_PROG lvcreate  --thinpool $poolname  --errorwhenfull y \
> > > +		    --zero n -L $origpsize \
> > > +		    --poolmetadatasize 4M $vgname >>$seqres.full 2>&1
> > > +
> > > +# Create a overprovisioned 200MB dm-thin virt. device
> > > +$LVM_PROG lvcreate  --virtualsize $virtsize \
> > > +		    -T $vgname/$poolname \
> > > +		    -n $lvname >>$seqres.full 2>&1
> > > +
> > > +_mkfs_dev /dev/mapper/$vgname-$lvname >>$seqres.full 2>&1
> > > +
> > > +
> > > +$LVM_PROG lvcreate  -k n -s $vgname/$lvname \
> > > +		    -n $snapname >>$seqres.full 2>&1
> > 
> > What's the reason for using a snapshot? Is the original thin vol not
> > sufficient?
> 
> No, it's not, honestly I don't remember now, exactly why not, I've been using
> the snapshot in my internal test case since I started to work on this problem,
> but without the snapshot I can't trigger the bug, at least not at a 100% rate.
> 
> > 
> > > +
> > > +_mount /dev/mapper/$vgname-$snapname $SCRATCH_MNT
> > > +
> > > +# Consume all space available in the volume and freeze to ensure everything
> > > +# required to make the fs consistent is flushed to disk.
> > > +xfs_io -f -d -c 'pwrite -b 1m 0 120m' $SCRATCH_MNT/f1 >>$seqres.full 2>&1
> > 
> > $XFS_IO_PROG
> 
> True, will change it
> 
> > 
> > > +
> > > +# This freeze will never complete until the dm-thin POOL device is extended.
> > > +# This is expected, it is only used so xfsaild is triggered to flush AIL items.
> > > +fsfreeze -f $SCRATCH_MNT &
> > > +
> > > +# Wait enough so xfsaild can run
> > > +sleep 10
> > > +
> > > +# Make some extra space available so the freeze above can proceed
> > > +lvextend -L $newpsize $vgname/$poolname >>$seqres.full 2>&1
> > 
> > $LVM_PROG lvmextend ?
> > 
> Indeed, missed it, will fix.
> 
> > Brian
> > 
> > > +
> > > +# Try to thaw the filesystem, and complete test if if succeed.
> > > +# NOTE: This will hang on affected XFS filesystems.
> > > +fsfreeze -u $SCRATCH_MNT
> > > +echo "Test OK"
> > > +
> > > +status=0
> > > +exit
> > > diff --git a/tests/xfs/999.out b/tests/xfs/999.out
> > > new file mode 100644
> > > index 0000000..8c3c938
> > > --- /dev/null
> > > +++ b/tests/xfs/999.out
> > > @@ -0,0 +1,2 @@
> > > +QA output created by 999
> > > +Test OK
> > > diff --git a/tests/xfs/group b/tests/xfs/group
> > > index 792161a..2bde916 100644
> > > --- a/tests/xfs/group
> > > +++ b/tests/xfs/group
> > > @@ -416,3 +416,4 @@
> > >  416 dangerous_fuzzers dangerous_scrub dangerous_repair
> > >  417 dangerous_fuzzers dangerous_scrub dangerous_online_repair
> > >  418 dangerous_fuzzers dangerous_scrub dangerous_repair
> > > +999 dangerous
> > > -- 
> > > 2.9.4
> > > 
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe fstests" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > --
> > To unsubscribe from this list: send the line "unsubscribe fstests" in
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> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> -- 
> Carlos
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Carlos Maiolino July 10, 2017, 3:52 p.m. UTC | #4 
On Mon, Jul 10, 2017 at 11:13:44AM -0400, Brian Foster wrote:
> On Mon, Jul 10, 2017 at 05:06:12PM +0200, Carlos Maiolino wrote:
> > > 
> > > Thinking more about this, we could keep the sleep and also add the wait
> > > right before the unfreeze, right?
> > 
> > Well, depends, we still need to sleep there, an lvextend right after the freeze
> > won't give xfsaild enough time to run, so the problem won't be triggered, and
> > adding a wait right before unfreeze, seems pointless to me.
> 
> Right, this wouldn't change the existing sleep at all. Basically it's
> just a preference to have the test block in wait rather than freeze and
> unfreeze because the latter seems a bit more confusing to me. Not a big
> deal either way.
> 
> > > 
> > > > Let me know your thoughts.
> > > > 
> > > > cheers.
> > > > 
> > > > Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
> > > > ---
> > > 
> > > Mostly looks good to me. A few minor notes...
> > > 
> > > >  tests/xfs/999     | 119 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> > > >  tests/xfs/999.out |   2 +
> > > >  tests/xfs/group   |   1 +
> > > 
> > > The test is still under xfs (rather than generic).
> > > 
> > 
> > yup, didn't move it to generic yet. I have a question about it. How do we
> > specify which filesystem to run the test on without needing to mkfs the device
> > for the filesystem in question?
> > 
> 
> $FSTYP should contain the target fs, if I understand the question..?

Pretty much,

I'll update the patch and send it properly formatted with an updated test
number.

thanks for the review

> 
> Brian
> 
> > 
> > > >  3 files changed, 122 insertions(+)
> > > >  create mode 100755 tests/xfs/999
> > > >  create mode 100644 tests/xfs/999.out
> > > > 
> > > > diff --git a/tests/xfs/999 b/tests/xfs/999
> > > > new file mode 100755
> > > > index 0000000..b46f1cc
> > > > --- /dev/null
> > > > +++ b/tests/xfs/999
> > > > @@ -0,0 +1,119 @@
> > > > +#! /bin/bash
> > > > +# FS QA Test 999
> > > > +#
> > > > +# Test buffer resubmission after a failed writeback with to a full overcommited
> > > > +# dm-thin device.
> > > > +#
> > > > +# When a dm-thin device reaches its full capacity, but the virtual device still
> > > > +# shows available space, XFS loops indefinitely in xfsaild due items still in
> > > > +# AIL. The buffers containing such items couldn't be resubmitted because the
> > > > +# items were flush locked. Test the kernel fix and ensure the buffers are
> > > > +# properly resubmitted.
> > > > +#
> > > > +# This test will hang the filesystem when ran on an unpatched kernel
> > > > +#
> > > > +#-----------------------------------------------------------------------
> > > > +# Copyright (c) 2017 Red Hat, Inc. All Rights Reserved.
> > > > +#
> > > > +# This program is free software; you can redistribute it and/or
> > > > +# modify it under the terms of the GNU General Public License as
> > > > +# published by the Free Software Foundation.
> > > > +#
> > > > +# This program is distributed in the hope that it would be useful,
> > > > +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > > +# GNU General Public License for more details.
> > > > +#
> > > > +# You should have received a copy of the GNU General Public License
> > > > +# along with this program; if not, write the Free Software Foundation,
> > > > +# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> > > > +#-----------------------------------------------------------------------
> > > > +#
> > > > +
> > > > +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.*
> > > > +	$UMOUNT_PROG $SCRATCH_MNT >>$seqres.full 2>&1
> > > > +	$LVM_PROG vgremove -ff $vgname >>$seqres.full 2>&1
> > > > +	$LVM_PROG pvremove -ff $SCRATCH_DEV >>$seqres.full 2>&1
> > > > +}
> > > > +
> > > > +# get standard environment, filters and checks
> > > > +. ./common/rc
> > > > +. ./common/filter
> > > 
> > > Is filter used anywhere?
> > 
> > Nope, the first thing I was doing was filtering dmesg for the IO errors before
> > extending the dm-thin device, and I forgot to remove the filter from here, I'll
> > remove it.
> > 
> > > 
> > > > +
> > > > +# real QA test starts here
> > > > +
> > > > +# Modify as appropriate.
> > > > +_supported_fs xfs
> > > > +_supported_os Linux
> > > > +_require_scratch_nocheck
> > > > +_require_dm_target thin-pool
> > > > +_require_command $LVM_PROG lvm
> > > > +
> > > > +# remove previous $seqres.full before test
> > > > +rm -f $seqres.full
> > > > +
> > > > +vgname=vg_$seq
> > > > +lvname=lv_$seq
> > > > +poolname=pool_$seq
> > > > +snapname=snap_$seq
> > > > +origpsize=100
> > > > +virtsize=200
> > > > +newpsize=200
> > > > +
> > > > +# Ensure we have enough disk space
> > > > +_scratch_mkfs_sized $((250 * 1024 * 1024)) >>$seqres.full 2>&1
> > > > +
> > > > +# Create a 100MB dm-thin POOL
> > > > +$LVM_PROG pvcreate -f $SCRATCH_DEV >>$seqres.full 2>&1
> > > > +$LVM_PROG vgcreate -f $vgname $SCRATCH_DEV >>$seqres.full 2>&1
> > > > +
> > > > +$LVM_PROG lvcreate  --thinpool $poolname  --errorwhenfull y \
> > > > +		    --zero n -L $origpsize \
> > > > +		    --poolmetadatasize 4M $vgname >>$seqres.full 2>&1
> > > > +
> > > > +# Create a overprovisioned 200MB dm-thin virt. device
> > > > +$LVM_PROG lvcreate  --virtualsize $virtsize \
> > > > +		    -T $vgname/$poolname \
> > > > +		    -n $lvname >>$seqres.full 2>&1
> > > > +
> > > > +_mkfs_dev /dev/mapper/$vgname-$lvname >>$seqres.full 2>&1
> > > > +
> > > > +
> > > > +$LVM_PROG lvcreate  -k n -s $vgname/$lvname \
> > > > +		    -n $snapname >>$seqres.full 2>&1
> > > 
> > > What's the reason for using a snapshot? Is the original thin vol not
> > > sufficient?
> > 
> > No, it's not, honestly I don't remember now, exactly why not, I've been using
> > the snapshot in my internal test case since I started to work on this problem,
> > but without the snapshot I can't trigger the bug, at least not at a 100% rate.
> > 
> > > 
> > > > +
> > > > +_mount /dev/mapper/$vgname-$snapname $SCRATCH_MNT
> > > > +
> > > > +# Consume all space available in the volume and freeze to ensure everything
> > > > +# required to make the fs consistent is flushed to disk.
> > > > +xfs_io -f -d -c 'pwrite -b 1m 0 120m' $SCRATCH_MNT/f1 >>$seqres.full 2>&1
> > > 
> > > $XFS_IO_PROG
> > 
> > True, will change it
> > 
> > > 
> > > > +
> > > > +# This freeze will never complete until the dm-thin POOL device is extended.
> > > > +# This is expected, it is only used so xfsaild is triggered to flush AIL items.
> > > > +fsfreeze -f $SCRATCH_MNT &
> > > > +
> > > > +# Wait enough so xfsaild can run
> > > > +sleep 10
> > > > +
> > > > +# Make some extra space available so the freeze above can proceed
> > > > +lvextend -L $newpsize $vgname/$poolname >>$seqres.full 2>&1
> > > 
> > > $LVM_PROG lvmextend ?
> > > 
> > Indeed, missed it, will fix.
> > 
> > > Brian
> > > 
> > > > +
> > > > +# Try to thaw the filesystem, and complete test if if succeed.
> > > > +# NOTE: This will hang on affected XFS filesystems.
> > > > +fsfreeze -u $SCRATCH_MNT
> > > > +echo "Test OK"
> > > > +
> > > > +status=0
> > > > +exit
> > > > diff --git a/tests/xfs/999.out b/tests/xfs/999.out
> > > > new file mode 100644
> > > > index 0000000..8c3c938
> > > > --- /dev/null
> > > > +++ b/tests/xfs/999.out
> > > > @@ -0,0 +1,2 @@
> > > > +QA output created by 999
> > > > +Test OK
> > > > diff --git a/tests/xfs/group b/tests/xfs/group
> > > > index 792161a..2bde916 100644
> > > > --- a/tests/xfs/group
> > > > +++ b/tests/xfs/group
> > > > @@ -416,3 +416,4 @@
> > > >  416 dangerous_fuzzers dangerous_scrub dangerous_repair
> > > >  417 dangerous_fuzzers dangerous_scrub dangerous_online_repair
> > > >  418 dangerous_fuzzers dangerous_scrub dangerous_repair
> > > > +999 dangerous
> > > > -- 
> > > > 2.9.4
> > > > 
> > > > --
> > > > To unsubscribe from this list: send the line "unsubscribe fstests" in
> > > > the body of a message to majordomo@vger.kernel.org
> > > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > > --
> > > To unsubscribe from this list: send the line "unsubscribe fstests" in
> > > the body of a message to majordomo@vger.kernel.org
> > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > 
> > -- 
> > Carlos
> --
> To unsubscribe from this list: send the line "unsubscribe fstests" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Carlos Maiolino July 11, 2017, 8:39 a.m. UTC | #5 
Hi Brian,

> > > > 
> > > > The test is still under xfs (rather than generic).
> > > > 

I'm still not really convinced this test should be added to generic, this tests
a very specific behavior of XFS journal, the journal behavior on XFS and ext4
for example, are very different,

either ext4 or btrfs for example, will remount the filesystem as RO during the
xfs_io process to fill the filesystem, so, even though the filesystem can keep
consistency, the test shows it as a failure.

What do you think? I honestly believe it would be better to keep this test as a
XFS test, the behavior here is XFS specific.

cheers

> > > 
> > > yup, didn't move it to generic yet. I have a question about it. How do we
> > > specify which filesystem to run the test on without needing to mkfs the device
> > > for the filesystem in question?
> > > 
> > 
> > $FSTYP should contain the target fs, if I understand the question..?
> 
> Pretty much,
> 
> I'll update the patch and send it properly formatted with an updated test
> number.
> 
> thanks for the review
> 
> > 
> > Brian
> > 
> > > 
> > > > >  3 files changed, 122 insertions(+)
> > > > >  create mode 100755 tests/xfs/999
> > > > >  create mode 100644 tests/xfs/999.out
> > > > > 
> > > > > diff --git a/tests/xfs/999 b/tests/xfs/999
> > > > > new file mode 100755
> > > > > index 0000000..b46f1cc
> > > > > --- /dev/null
> > > > > +++ b/tests/xfs/999
> > > > > @@ -0,0 +1,119 @@
> > > > > +#! /bin/bash
> > > > > +# FS QA Test 999
> > > > > +#
> > > > > +# Test buffer resubmission after a failed writeback with to a full overcommited
> > > > > +# dm-thin device.
> > > > > +#
> > > > > +# When a dm-thin device reaches its full capacity, but the virtual device still
> > > > > +# shows available space, XFS loops indefinitely in xfsaild due items still in
> > > > > +# AIL. The buffers containing such items couldn't be resubmitted because the
> > > > > +# items were flush locked. Test the kernel fix and ensure the buffers are
> > > > > +# properly resubmitted.
> > > > > +#
> > > > > +# This test will hang the filesystem when ran on an unpatched kernel
> > > > > +#
> > > > > +#-----------------------------------------------------------------------
> > > > > +# Copyright (c) 2017 Red Hat, Inc. All Rights Reserved.
> > > > > +#
> > > > > +# This program is free software; you can redistribute it and/or
> > > > > +# modify it under the terms of the GNU General Public License as
> > > > > +# published by the Free Software Foundation.
> > > > > +#
> > > > > +# This program is distributed in the hope that it would be useful,
> > > > > +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > > > +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > > > +# GNU General Public License for more details.
> > > > > +#
> > > > > +# You should have received a copy of the GNU General Public License
> > > > > +# along with this program; if not, write the Free Software Foundation,
> > > > > +# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
> > > > > +#-----------------------------------------------------------------------
> > > > > +#
> > > > > +
> > > > > +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.*
> > > > > +	$UMOUNT_PROG $SCRATCH_MNT >>$seqres.full 2>&1
> > > > > +	$LVM_PROG vgremove -ff $vgname >>$seqres.full 2>&1
> > > > > +	$LVM_PROG pvremove -ff $SCRATCH_DEV >>$seqres.full 2>&1
> > > > > +}
> > > > > +
> > > > > +# get standard environment, filters and checks
> > > > > +. ./common/rc
> > > > > +. ./common/filter
> > > > 
> > > > Is filter used anywhere?
> > > 
> > > Nope, the first thing I was doing was filtering dmesg for the IO errors before
> > > extending the dm-thin device, and I forgot to remove the filter from here, I'll
> > > remove it.
> > > 
> > > > 
> > > > > +
> > > > > +# real QA test starts here
> > > > > +
> > > > > +# Modify as appropriate.
> > > > > +_supported_fs xfs
> > > > > +_supported_os Linux
> > > > > +_require_scratch_nocheck
> > > > > +_require_dm_target thin-pool
> > > > > +_require_command $LVM_PROG lvm
> > > > > +
> > > > > +# remove previous $seqres.full before test
> > > > > +rm -f $seqres.full
> > > > > +
> > > > > +vgname=vg_$seq
> > > > > +lvname=lv_$seq
> > > > > +poolname=pool_$seq
> > > > > +snapname=snap_$seq
> > > > > +origpsize=100
> > > > > +virtsize=200
> > > > > +newpsize=200
> > > > > +
> > > > > +# Ensure we have enough disk space
> > > > > +_scratch_mkfs_sized $((250 * 1024 * 1024)) >>$seqres.full 2>&1
> > > > > +
> > > > > +# Create a 100MB dm-thin POOL
> > > > > +$LVM_PROG pvcreate -f $SCRATCH_DEV >>$seqres.full 2>&1
> > > > > +$LVM_PROG vgcreate -f $vgname $SCRATCH_DEV >>$seqres.full 2>&1
> > > > > +
> > > > > +$LVM_PROG lvcreate  --thinpool $poolname  --errorwhenfull y \
> > > > > +		    --zero n -L $origpsize \
> > > > > +		    --poolmetadatasize 4M $vgname >>$seqres.full 2>&1
> > > > > +
> > > > > +# Create a overprovisioned 200MB dm-thin virt. device
> > > > > +$LVM_PROG lvcreate  --virtualsize $virtsize \
> > > > > +		    -T $vgname/$poolname \
> > > > > +		    -n $lvname >>$seqres.full 2>&1
> > > > > +
> > > > > +_mkfs_dev /dev/mapper/$vgname-$lvname >>$seqres.full 2>&1
> > > > > +
> > > > > +
> > > > > +$LVM_PROG lvcreate  -k n -s $vgname/$lvname \
> > > > > +		    -n $snapname >>$seqres.full 2>&1
> > > > 
> > > > What's the reason for using a snapshot? Is the original thin vol not
> > > > sufficient?
> > > 
> > > No, it's not, honestly I don't remember now, exactly why not, I've been using
> > > the snapshot in my internal test case since I started to work on this problem,
> > > but without the snapshot I can't trigger the bug, at least not at a 100% rate.
> > > 
> > > > 
> > > > > +
> > > > > +_mount /dev/mapper/$vgname-$snapname $SCRATCH_MNT
> > > > > +
> > > > > +# Consume all space available in the volume and freeze to ensure everything
> > > > > +# required to make the fs consistent is flushed to disk.
> > > > > +xfs_io -f -d -c 'pwrite -b 1m 0 120m' $SCRATCH_MNT/f1 >>$seqres.full 2>&1
> > > > 
> > > > $XFS_IO_PROG
> > > 
> > > True, will change it
> > > 
> > > > 
> > > > > +
> > > > > +# This freeze will never complete until the dm-thin POOL device is extended.
> > > > > +# This is expected, it is only used so xfsaild is triggered to flush AIL items.
> > > > > +fsfreeze -f $SCRATCH_MNT &
> > > > > +
> > > > > +# Wait enough so xfsaild can run
> > > > > +sleep 10
> > > > > +
> > > > > +# Make some extra space available so the freeze above can proceed
> > > > > +lvextend -L $newpsize $vgname/$poolname >>$seqres.full 2>&1
> > > > 
> > > > $LVM_PROG lvmextend ?
> > > > 
> > > Indeed, missed it, will fix.
> > > 
> > > > Brian
> > > > 
> > > > > +
> > > > > +# Try to thaw the filesystem, and complete test if if succeed.
> > > > > +# NOTE: This will hang on affected XFS filesystems.
> > > > > +fsfreeze -u $SCRATCH_MNT
> > > > > +echo "Test OK"
> > > > > +
> > > > > +status=0
> > > > > +exit
> > > > > diff --git a/tests/xfs/999.out b/tests/xfs/999.out
> > > > > new file mode 100644
> > > > > index 0000000..8c3c938
> > > > > --- /dev/null
> > > > > +++ b/tests/xfs/999.out
> > > > > @@ -0,0 +1,2 @@
> > > > > +QA output created by 999
> > > > > +Test OK
> > > > > diff --git a/tests/xfs/group b/tests/xfs/group
> > > > > index 792161a..2bde916 100644
> > > > > --- a/tests/xfs/group
> > > > > +++ b/tests/xfs/group
> > > > > @@ -416,3 +416,4 @@
> > > > >  416 dangerous_fuzzers dangerous_scrub dangerous_repair
> > > > >  417 dangerous_fuzzers dangerous_scrub dangerous_online_repair
> > > > >  418 dangerous_fuzzers dangerous_scrub dangerous_repair
> > > > > +999 dangerous
> > > > > -- 
> > > > > 2.9.4
> > > > > 
> > > > > --
> > > > > To unsubscribe from this list: send the line "unsubscribe fstests" in
> > > > > the body of a message to majordomo@vger.kernel.org
> > > > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > > > --
> > > > To unsubscribe from this list: send the line "unsubscribe fstests" in
> > > > the body of a message to majordomo@vger.kernel.org
> > > > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > > 
> > > -- 
> > > Carlos
> > --
> > To unsubscribe from this list: send the line "unsubscribe fstests" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> -- 
> Carlos
> --
> To unsubscribe from this list: send the line "unsubscribe fstests" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/tests/xfs/999 b/tests/xfs/999
new file mode 100755
index 0000000..b46f1cc
--- /dev/null
+++ b/tests/xfs/999
@@ -0,0 +1,119 @@ 
+#! /bin/bash
+# FS QA Test 999
+#
+# Test buffer resubmission after a failed writeback with to a full overcommited
+# dm-thin device.
+#
+# When a dm-thin device reaches its full capacity, but the virtual device still
+# shows available space, XFS loops indefinitely in xfsaild due items still in
+# AIL. The buffers containing such items couldn't be resubmitted because the
+# items were flush locked. Test the kernel fix and ensure the buffers are
+# properly resubmitted.
+#
+# This test will hang the filesystem when ran on an unpatched kernel
+#
+#-----------------------------------------------------------------------
+# Copyright (c) 2017 Red Hat, Inc. All Rights Reserved.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it would be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write the Free Software Foundation,
+# Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+#-----------------------------------------------------------------------
+#
+
+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.*
+	$UMOUNT_PROG $SCRATCH_MNT >>$seqres.full 2>&1
+	$LVM_PROG vgremove -ff $vgname >>$seqres.full 2>&1
+	$LVM_PROG pvremove -ff $SCRATCH_DEV >>$seqres.full 2>&1
+}
+
+# get standard environment, filters and checks
+. ./common/rc
+. ./common/filter
+
+# real QA test starts here
+
+# Modify as appropriate.
+_supported_fs xfs
+_supported_os Linux
+_require_scratch_nocheck
+_require_dm_target thin-pool
+_require_command $LVM_PROG lvm
+
+# remove previous $seqres.full before test
+rm -f $seqres.full
+
+vgname=vg_$seq
+lvname=lv_$seq
+poolname=pool_$seq
+snapname=snap_$seq
+origpsize=100
+virtsize=200
+newpsize=200
+
+# Ensure we have enough disk space
+_scratch_mkfs_sized $((250 * 1024 * 1024)) >>$seqres.full 2>&1
+
+# Create a 100MB dm-thin POOL
+$LVM_PROG pvcreate -f $SCRATCH_DEV >>$seqres.full 2>&1
+$LVM_PROG vgcreate -f $vgname $SCRATCH_DEV >>$seqres.full 2>&1
+
+$LVM_PROG lvcreate  --thinpool $poolname  --errorwhenfull y \
+		    --zero n -L $origpsize \
+		    --poolmetadatasize 4M $vgname >>$seqres.full 2>&1
+
+# Create a overprovisioned 200MB dm-thin virt. device
+$LVM_PROG lvcreate  --virtualsize $virtsize \
+		    -T $vgname/$poolname \
+		    -n $lvname >>$seqres.full 2>&1
+
+_mkfs_dev /dev/mapper/$vgname-$lvname >>$seqres.full 2>&1
+
+
+$LVM_PROG lvcreate  -k n -s $vgname/$lvname \
+		    -n $snapname >>$seqres.full 2>&1
+
+_mount /dev/mapper/$vgname-$snapname $SCRATCH_MNT
+
+# Consume all space available in the volume and freeze to ensure everything
+# required to make the fs consistent is flushed to disk.
+xfs_io -f -d -c 'pwrite -b 1m 0 120m' $SCRATCH_MNT/f1 >>$seqres.full 2>&1
+
+# This freeze will never complete until the dm-thin POOL device is extended.
+# This is expected, it is only used so xfsaild is triggered to flush AIL items.
+fsfreeze -f $SCRATCH_MNT &
+
+# Wait enough so xfsaild can run
+sleep 10
+
+# Make some extra space available so the freeze above can proceed
+lvextend -L $newpsize $vgname/$poolname >>$seqres.full 2>&1
+
+# Try to thaw the filesystem, and complete test if if succeed.
+# NOTE: This will hang on affected XFS filesystems.
+fsfreeze -u $SCRATCH_MNT
+echo "Test OK"
+
+status=0
+exit
diff --git a/tests/xfs/999.out b/tests/xfs/999.out
new file mode 100644
index 0000000..8c3c938
--- /dev/null
+++ b/tests/xfs/999.out
@@ -0,0 +1,2 @@ 
+QA output created by 999
+Test OK
diff --git a/tests/xfs/group b/tests/xfs/group
index 792161a..2bde916 100644
--- a/tests/xfs/group
+++ b/tests/xfs/group
@@ -416,3 +416,4 @@ 
 416 dangerous_fuzzers dangerous_scrub dangerous_repair
 417 dangerous_fuzzers dangerous_scrub dangerous_online_repair
 418 dangerous_fuzzers dangerous_scrub dangerous_repair
+999 dangerous