Re: [PATCH v2] btrfs: test block group size class loading logic

[Anand Jain <anand.jain@oracle.com>]

On 26/01/2023 06:43, Boris Burkov wrote:
> Add a new test which checks that size classes in freshly loaded block
> groups after a cycle mount match size classes before going down
> 
> Depends on the kernel patch:
> btrfs: add size class stats to sysfs
> 
> Signed-off-by: Boris Burkov <boris@bur.io>
> ---
> v2: drop the fixed_by_kernel_commit since the fix is not out past the
> btrfs development tree, so the fix is getting rolled in to the original
> broken commit. Modified the commit message to note the dependency on the
> new sysfs counters.

You can add it as below, it will be helpful to some extent.
Depending on the status of the kernel patch at a later point,
we can update the fixed_by_kernel_commit.

fixed_by_kernel_commit xxxxxxxx "btrfs: add size class stats to sysfs".


> 
>   tests/btrfs/283     | 49 +++++++++++++++++++++++++++++++++++++++++++++
>   tests/btrfs/283.out |  2 ++
>   2 files changed, 51 insertions(+)
>   create mode 100755 tests/btrfs/283
>   create mode 100644 tests/btrfs/283.out
> 
> diff --git a/tests/btrfs/283 b/tests/btrfs/283
> new file mode 100755
> index 00000000..b3614786
> --- /dev/null
> +++ b/tests/btrfs/283
> @@ -0,0 +1,49 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2023 Meta Platforms, Inc.  All Rights Reserved.
> +#
> +# FS QA Test 283
> +#
> +# Test that mounting a btrfs filesystem properly loads block group size classes.
> +#
> +. ./common/preamble
> +_begin_fstest auto quick mount
> +
> +sysfs_size_classes() {
> +	local uuid="$(findmnt -n -o UUID "$SCRATCH_MNT")"
> +	cat "/sys/fs/btrfs/$uuid/allocation/data/size_classes"

The kernels without the sysfs patch must fail with not_run.
  _require_fs_sysfs() will help here.

Thx.