Re: [PATCH v6] test unaligned punch hole at ENOSPC

[Filipe Manana <fdmanana@gmail.com>]

On Sun, Sep 30, 2018 at 2:40 AM Anand Jain <anand.jain@oracle.com> wrote:
>
> Try to punch hole with unaligned size and offset when the FS is
> full. Mainly holes are punched at locations which are unaligned
> with the file extent boundaries when the FS is full by data.
> As the punching holes at unaligned location will involve
> truncating blocks instead of just dropping the extents, it shall
> involve reserving data and metadata space for delalloc and so data
> alloc fails as the FS is full.
>
> btrfs_punch_hole()
>  btrfs_truncate_block()
>    btrfs_check_data_free_space() <-- ENOSPC
>
> We don't fail punch hole if the holes are aligned with the file
> extent boundaries as it shall involve just dropping the related
> extents, without truncating data extent blocks.
>
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>

Looks good, thanks!

> ---
> v5->v6:
>  fix comments at two places in the test case
>  drop -f when using xfs_io to punch hole
>  sync after dd is dropped
>  change log is slightly updated
> v4->v5:
>  Update the change log
>  Drop the directio option for xfs_io
> v3->v4:
>  Add to the group punch
> v2->v3:
>  Add _require_xfs_io_command "fpunch"
>  Add more logs to $seqfull.full
>    mount options and
>    group profile info
>  Add sync after dd upto ENOSPC
>  Drop fallocate -p and use xfs_io punch to create holes
>  Use a testfile instead of filler file so that easy to trace
> v1->v2: Use at least 256MB to test.
> This test case fails on btrfs as of now.
>  tests/btrfs/172     | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/172.out |  2 ++
>  tests/btrfs/group   |  1 +
>  3 files changed, 76 insertions(+)
>  create mode 100755 tests/btrfs/172
>  create mode 100644 tests/btrfs/172.out
>
> diff --git a/tests/btrfs/172 b/tests/btrfs/172
> new file mode 100755
> index 000000000000..0dffb2dff40b
> --- /dev/null
> +++ b/tests/btrfs/172
> @@ -0,0 +1,73 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2018 Oracle. All Rights Reserved.
> +#
> +# FS QA Test 172
> +#
> +# Test if the unaligned (by size and offset) punch hole is successful when FS
> +# is at ENOSPC.
> +#
> +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
> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs btrfs
> +_supported_os Linux
> +_require_scratch
> +_require_xfs_io_command "fpunch"
> +
> +_scratch_mkfs_sized $((256 * 1024 *1024)) >> $seqres.full
> +
> +# max_inline ensures data is not inlined within metadata extents
> +_scratch_mount "-o max_inline=0,nodatacow"
> +
> +cat /proc/self/mounts | grep $SCRATCH_DEV >> $seqres.full
> +$BTRFS_UTIL_PROG filesystem df $SCRATCH_MNT >> $seqres.full
> +
> +extent_size=$(_scratch_btrfs_sectorsize)
> +unalign_by=512
> +echo extent_size=$extent_size unalign_by=$unalign_by >> $seqres.full
> +
> +$XFS_IO_PROG -f -c "pwrite -S 0xab 0 $((extent_size * 10))" \
> +                                       $SCRATCH_MNT/testfile >> $seqres.full
> +
> +echo "Fill all space available for data and all unallocated space." >> $seqres.full
> +dd status=none if=/dev/zero of=$SCRATCH_MNT/filler bs=512 >> $seqres.full 2>&1
> +
> +hole_offset=0
> +hole_len=$unalign_by
> +$XFS_IO_PROG -c "fpunch $hole_offset $hole_len" $SCRATCH_MNT/testfile
> +
> +hole_offset=$(($extent_size + $unalign_by))
> +hole_len=$(($extent_size - $unalign_by))
> +$XFS_IO_PROG -c "fpunch $hole_offset $hole_len" $SCRATCH_MNT/testfile
> +
> +hole_offset=$(($extent_size * 2 + $unalign_by))
> +hole_len=$(($extent_size * 5))
> +$XFS_IO_PROG -c "fpunch $hole_offset $hole_len" $SCRATCH_MNT/testfile
> +
> +# success, all done
> +echo "Silence is golden"
> +status=0
> +exit
> diff --git a/tests/btrfs/172.out b/tests/btrfs/172.out
> new file mode 100644
> index 000000000000..ce2de3f0d107
> --- /dev/null
> +++ b/tests/btrfs/172.out
> @@ -0,0 +1,2 @@
> +QA output created by 172
> +Silence is golden
> diff --git a/tests/btrfs/group b/tests/btrfs/group
> index feffc45b6564..45782565c3b7 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -174,3 +174,4 @@
>  169 auto quick send
>  170 auto quick snapshot
>  171 auto quick qgroup
> +172 auto quick punch
> --
> 1.8.3.1
>


-- 
Filipe David Manana,

“Whether you think you can, or you think you can't — you're right.”