Re: [PATCH] fstests: btrfs: Verify falloc on multiple holes won't cause qgroup reserved data space leak

[Eryu Guan <guaneryu@gmail.com>]

On Fri, Sep 13, 2019 at 09:51:51AM +0800, Qu Wenruo wrote:
> Add a test case where falloc is called on multiple holes with qgroup
> enabled.
> 
> This can cause qgroup reserved data space leak and false EDQUOT error
> even we're not reaching the limit.
> 
> The fix is titled:
> "btrfs: qgroup: Fix the wrong target io_tree when freeing
>  reserved data space"
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  tests/btrfs/192     | 72 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/192.out | 18 ++++++++++++
>  tests/btrfs/group   |  1 +
>  3 files changed, 91 insertions(+)
>  create mode 100755 tests/btrfs/192
>  create mode 100644 tests/btrfs/192.out
> 
> diff --git a/tests/btrfs/192 b/tests/btrfs/192
> new file mode 100755
> index 00000000..361b6d92
> --- /dev/null
> +++ b/tests/btrfs/192
> @@ -0,0 +1,72 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (C) 2019 SUSE Linux Products GmbH. All Rights Reserved.
> +#
> +# FS QA Test 192
> +#
> +# Test if btrfs is going to leak qgroup reserved data space when
> +# falloc on multiple holes fails.
> +# The fix is titled:
> +# "btrfs: qgroup: Fix the wrong target io_tree when freeing reserved data space"
> +#
> +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 $seqres.full
> +
> +# real QA test starts here
> +
> +# Modify as appropriate.
> +_supported_fs btrfs
> +_supported_os Linux
> +_require_scratch
> +_require_xfs_io_command falloc
> +
> +_scratch_mkfs > /dev/null
> +_scratch_mount
> +
> +$BTRFS_UTIL_PROG quota enable "$SCRATCH_MNT" > /dev/null
> +$BTRFS_UTIL_PROG quota rescan -w "$SCRATCH_MNT" > /dev/null
> +$BTRFS_UTIL_PROG qgroup limit -e 256M "$SCRATCH_MNT"
> +
> +for i in $(seq 3); do

Why do we need to loop 3 times? Some comments would be good, or we could
just remove the loop?

Other than that the test looks fine to me.

Thanks,
Eryu

> +	# Create a file with the following layout:
> +	# 0         128M      256M      384M
> +	# |  Hole   |4K| Hole |4K| Hole |
> +	# The total hole size will be 384M - 8k
> +	truncate -s 384m "$SCRATCH_MNT/file"
> +	$XFS_IO_PROG -c "pwrite 128m 4k" -c "pwrite 256m 4k" \
> +		"$SCRATCH_MNT/file" | _filter_xfs_io
> +
> +	# Falloc 0~384M range, it's going to fail due to the qgroup limit
> +	$XFS_IO_PROG -c "falloc 0 384m" "$SCRATCH_MNT/file" |\
> +		_filter_xfs_io_error
> +	rm "$SCRATCH_MNT/file"
> +
> +	# Ensure above delete reaches disk and free some space
> +	sync
> +done
> +
> +# We should be able to write at least 3/4 of the limit
> +$XFS_IO_PROG -f -c "pwrite 0 192m" "$SCRATCH_MNT/file" | _filter_xfs_io
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/btrfs/192.out b/tests/btrfs/192.out
> new file mode 100644
> index 00000000..13bc6036
> --- /dev/null
> +++ b/tests/btrfs/192.out
> @@ -0,0 +1,18 @@
> +QA output created by 192
> +wrote 4096/4096 bytes at offset 134217728
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +wrote 4096/4096 bytes at offset 268435456
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +fallocate: Disk quota exceeded
> +wrote 4096/4096 bytes at offset 134217728
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +wrote 4096/4096 bytes at offset 268435456
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +fallocate: Disk quota exceeded
> +wrote 4096/4096 bytes at offset 134217728
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +wrote 4096/4096 bytes at offset 268435456
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> +fallocate: Disk quota exceeded
> +wrote 201326592/201326592 bytes at offset 0
> +XXX Bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
> diff --git a/tests/btrfs/group b/tests/btrfs/group
> index 2474d43e..160fe927 100644
> --- a/tests/btrfs/group
> +++ b/tests/btrfs/group
> @@ -194,3 +194,4 @@
>  189 auto quick send clone
>  190 auto quick replay balance qgroup
>  191 auto quick send dedupe
> +192 auto qgroup fast enospc limit
> -- 
> 2.22.0
>