On Fri, Jul 5, 2019 at 8:43 AM Eryu Guan <guaneryu@xxxxxxxxx> wrote:
>
> On Fri, Jun 28, 2019 at 11:08:36PM +0100, fdmanana@xxxxxxxxxx wrote:
> > From: Filipe Manana <fdmanana@xxxxxxxx>
> >
> > Test that if we clone a file with some large extents into a file that has
> > many small extents, when the fs is nearly full, the clone operation does
> > not fail and produces the correct result.
> >
> > This is motivated by a bug found in btrfs wich is fixed by the following
> > patches for the linux kernel:
> >
> > [PATCH 1/2] Btrfs: factor out extent dropping code from hole punch handler
> > [PATCH 2/2] Btrfs: fix ENOSPC errors, leading to transaction aborts, when
> > cloning extents
> >
> > The test currently passes on xfs.
> >
> > Signed-off-by: Filipe Manana <fdmanana@xxxxxxxx>
> > ---
> >
> > V2: Use _scratch_cycle_mount instead of _scratch_remount, as we want to see
> > if the operation was durably persisted (otherwise we are seeing content
> > from the page cache).
> > Use _reflink instead of calling xfs_io with the reflink command.
> > Make the comment before filling the filesystem more clear about why it
> > is done the way it is instead of using _fill_fs.
> >
> > tests/generic/558 | 80 +++++++++++++++++++++++++++++++++++++++++++++++++++
> > tests/generic/558.out | 5 ++++
> > tests/generic/group | 1 +
> > 3 files changed, 86 insertions(+)
> > create mode 100755 tests/generic/558
> > create mode 100644 tests/generic/558.out
> >
> > diff --git a/tests/generic/558 b/tests/generic/558
> > new file mode 100755
> > index 00000000..f982930d
> > --- /dev/null
> > +++ b/tests/generic/558
> > @@ -0,0 +1,80 @@
> > +#! /bin/bash
> > +# SPDX-License-Identifier: GPL-2.0
> > +# Copyright (C) 2019 SUSE Linux Products GmbH. All Rights Reserved.
> > +#
> > +# FSQA Test No. 558
> > +#
> > +# Test that if we clone a file with some large extents into a file that has
> > +# many small extents, when the fs is nearly full, the clone operation does
> > +# not fail and produces the correct result.
> > +#
> > +seq=`basename $0`
> > +seqres=$RESULT_DIR/$seq
> > +echo "QA output created by $seq"
> > +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
> > +. ./common/reflink
> > +
> > +# real QA test starts here
> > +_supported_fs generic
> > +_supported_os Linux
> > +_require_scratch_reflink
> > +
> > +rm -f $seqres.full
> > +
> > +_scratch_mkfs_sized $((512 * 1024 * 1024)) >>$seqres.full 2>&1
> > +_scratch_mount
> > +
> > +file_size=$(( 128 * 1024 * 1024 )) # 128Mb
> > +extent_size=4096
> > +num_extents=$(( $file_size / $extent_size ))
> > +
> > +# Create a file with many small extents.
> > +for ((i = 0; i < $num_extents; i++)); do
> > + offset=$(( $i * $extent_size ))
> > + $XFS_IO_PROG -f -s -c "pwrite -S 0xe5 $offset $extent_size" \
> > + $SCRATCH_MNT/foo >>/dev/null
> > +done
>
> This is taking too long time (1000+s) to finish when testing on XFS.
Hum, for on 5.2-rc, debug kernel (lockdep, plenty of other debug stuff
enabled that slows things down), it takes about 350 seconds for me.
> I'm
> wondering if we could take use of src/punch-alternating to punch out
> every other block to create a file with many small extents.
That's fine, I didn't remember about that.
>
> i.e. with the following diffs, test runs & passes with XFS within 90s
> while still reproduces the btrfs bug (note that I have to increase the
> file_size to 200M to reproduce the btrfs bug, while 256M seems bring
> test time back to 1000+s). Would you please check if this works for you?
It does, thanks!
And, because of the holes, it uncovered a bug in my fix (second patch).
Now it takes ~15 seconds on btrfs instead of ~300s and ~100s on xfs for me.
>
> Thanks,
> Eryu
>
>
> diff --git a/tests/generic/558 b/tests/generic/558
> index f982930d65a2..40f8a7a98d3f 100755
> --- a/tests/generic/558
> +++ b/tests/generic/558
> @@ -30,22 +30,22 @@ _cleanup()
> _supported_fs generic
> _supported_os Linux
> _require_scratch_reflink
> +_require_test_program "punch-alternating"
> +_require_xfs_io_command "fpunch"
>
> rm -f $seqres.full
>
> _scratch_mkfs_sized $((512 * 1024 * 1024)) >>$seqres.full 2>&1
> _scratch_mount
>
> -file_size=$(( 128 * 1024 * 1024 )) # 128Mb
> +file_size=$(( 200 * 1024 * 1024 )) # 200MB
> extent_size=4096
> num_extents=$(( $file_size / $extent_size ))
These two variables, extent_size and num_extents, are no longer needed.
Do you want me to send another version of the patch or can you apply
this patch on top of it?
Thanks.
>
> # Create a file with many small extents.
> -for ((i = 0; i < $num_extents; i++)); do
> - offset=$(( $i * $extent_size ))
> - $XFS_IO_PROG -f -s -c "pwrite -S 0xe5 $offset $extent_size" \
> - $SCRATCH_MNT/foo >>/dev/null
> -done
> +$XFS_IO_PROG -f -c "pwrite -S 0xe5 -b $file_size 0 $file_size" \
> + $SCRATCH_MNT/foo >>/dev/null
> +$here/src/punch-alternating $SCRATCH_MNT/foo >> $seqres.full
>
> # Create file bar with the same size that file foo has but with large extents.
> $XFS_IO_PROG -f -c "pwrite -S 0xc7 -b $file_size 0 $file_size" \
> diff --git a/tests/generic/558.out b/tests/generic/558.out
> index d1e8e70f5b79..00cb5a9744aa 100644
> --- a/tests/generic/558.out
> +++ b/tests/generic/558.out
> @@ -2,4 +2,4 @@ QA output created by 558
> File foo data after cloning and remount:
> 0000000 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7
> *
> -134217728
> +209715200
>
> > +
> > +# Create file bar with the same size that file foo has but with large extents.
> > +$XFS_IO_PROG -f -c "pwrite -S 0xc7 -b $file_size 0 $file_size" \
> > + $SCRATCH_MNT/bar >>/dev/null
> > +
> > +# Fill the fs (For btrfs we are interested in filling all unallocated space
> > +# and most of the existing metadata block group(s), so that after this there
> > +# will be no unallocated space and metadata space will be mostly full but with
> > +# more than enough free space for the clone operation below to succeed, we
> > +# create files with 2Kb because that results in extents inlined in the metadata
> > +# (btree leafs) and it's the fastest way to fill metadata space on btrfs, by
> > +# default btrfs inlines up to 2Kb of data).
> > +i=1
> > +while true; do
> > + $XFS_IO_PROG -f -c "pwrite 0 2K" $SCRATCH_MNT/filler_$i &> /dev/null
> > + [ $? -ne 0 ] && break
> > + i=$(( i + 1 ))
> > +done
> > +
> > +# Now clone file bar into file foo. This is supposed to succeed and not fail
> > +# with ENOSPC for example.
> > +_reflink $SCRATCH_MNT/bar $SCRATCH_MNT/foo >>$seqres.full
> > +
> > +# Unmount and mount the filesystem again to verify the operation was durably
> > +# persisted.
> > +_scratch_cycle_mount
> > +
> > +echo "File foo data after cloning and remount:"
> > +od -A d -t x1 $SCRATCH_MNT/foo
> > +
> > +status=0
> > +exit
> > diff --git a/tests/generic/558.out b/tests/generic/558.out
> > new file mode 100644
> > index 00000000..d1e8e70f
> > --- /dev/null
> > +++ b/tests/generic/558.out
> > @@ -0,0 +1,5 @@
> > +QA output created by 558
> > +File foo data after cloning and remount:
> > +0000000 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7 c7
> > +*
> > +134217728
> > diff --git a/tests/generic/group b/tests/generic/group
> > index 543c0627..c06c1cd1 100644
> > --- a/tests/generic/group
> > +++ b/tests/generic/group
> > @@ -560,3 +560,4 @@
> > 555 auto quick cap
> > 556 auto quick casefold
> > 557 auto quick log
> > +558 auto clone
> > --
> > 2.11.0
> >
