Re: [PATCH v4] generic: add a test for umount racing mount

[Zorro Lang <zlang@redhat.com>]

On Mon, Jul 20, 2020 at 12:05:56PM -0700, Boris Burkov wrote:
> Test if dirtying many inodes (which can delay umount) then
> unmounting and quickly mounting again causes the mount to fail.
> 
> A race, which breaks the test in btrfs, is fixed by the patch:
> "btrfs: fix mount failure caused by race with umount"
> 
> Signed-off-by: Boris Burkov <boris@bur.io>
> ---

This version looks good to me,
Reviewed-by: Zorro Lang <zlang@redhat.com>

> - dd to XFS_IO_PROG
> - 1M writes to 4k writes
> 
>  tests/generic/603     | 53 +++++++++++++++++++++++++++++++++++++++++++
>  tests/generic/603.out |  2 ++
>  tests/generic/group   |  1 +
>  3 files changed, 56 insertions(+)
>  create mode 100755 tests/generic/603
>  create mode 100644 tests/generic/603.out
> 
> diff --git a/tests/generic/603 b/tests/generic/603
> new file mode 100755
> index 00000000..90f0d1d3
> --- /dev/null
> +++ b/tests/generic/603
> @@ -0,0 +1,53 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2020 Facebook  All Rights Reserved.
> +#
> +# FS QA Test 603
> +#
> +# Evicting dirty inodes can take a long time during umount.
> +# Check that a new mount racing with such a delayed umount succeeds.
> +#
> +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 generic
> +_supported_os Linux
> +_require_scratch
> +
> +_scratch_mkfs > /dev/null 2>&1
> +_scratch_mount
> +for i in $(seq 0 500)
> +do
> +	$XFS_IO_PROG -c "pwrite 0 4K" $SCRATCH_MNT/$i >/dev/null 2>&1
> +done
> +_scratch_unmount &
> +_scratch_mount
> +wait
> +
> +echo "Silence is golden"
> +
> +# success, all done
> +status=0
> +exit
> diff --git a/tests/generic/603.out b/tests/generic/603.out
> new file mode 100644
> index 00000000..6810da89
> --- /dev/null
> +++ b/tests/generic/603.out
> @@ -0,0 +1,2 @@
> +QA output created by 603
> +Silence is golden
> diff --git a/tests/generic/group b/tests/generic/group
> index d9ab9a31..c0ace35b 100644
> --- a/tests/generic/group
> +++ b/tests/generic/group
> @@ -605,3 +605,4 @@
>  600 auto quick quota
>  601 auto quick quota
>  602 auto quick encrypt
> +603 auto quick
> -- 
> 2.24.1
>