Re: [PATCH] fstests: btrfs: new test case for leaking BTRFS_FS_STATE_REMOUNTING flag

[Anand Suveer Jain <asj@kernel.org>]

On 4/7/26 16:52, Qu Wenruo wrote:
> This is a regression test for the patch "btrfs: fix leaking
> BTRFS_FS_STATE_REMOUNTING flag", where conflicting mount options can
> cause btrfs leave BTRFS_FS_STATE_REMOUNTING set.
> 
> Such set BTRFS_FS_STATE_REMOUNTING will interrupt several features, and
> the test case will use "btrfs qgroup rescan" to catch the
> BTRFS_FS_STATE_REMOUNTING flag.
> 
> Signed-off-by: Qu Wenruo <wqu@suse.com>
> ---
>  tests/btrfs/352     | 53 +++++++++++++++++++++++++++++++++++++++++++++
>  tests/btrfs/352.out |  2 ++
>  2 files changed, 55 insertions(+)
>  create mode 100755 tests/btrfs/352
>  create mode 100644 tests/btrfs/352.out
> 
> diff --git a/tests/btrfs/352 b/tests/btrfs/352
> new file mode 100755
> index 00000000..2ccf7fab
> --- /dev/null
> +++ b/tests/btrfs/352
> @@ -0,0 +1,53 @@
> +#! /bin/bash
> +# SPDX-License-Identifier: GPL-2.0
> +# Copyright (c) 2026 SUSE S.A.  All Rights Reserved.
> +#
> +# FS QA Test 352
> +#
> +# A regression test to make sure failed remount won't leave
> +# BTRFS_FS_STATE_REMOUNTING flag set, which can interrupt several features,
> +# one of them is btrfs qgroup rescan.
> +#
> +. ./common/preamble
> +_begin_fstest auto quick remount
> +
> +_fixed_by_kernel_commit XXXXXXXXXXXX \
> +	"btrfs: fix leaking BTRFS_FS_STATE_REMOUNTING flag"
> +



We can replace this section with the existing helpers or,
even better, with a new one as shown below. I am not too
particular about creating a new helper, that is up to you.
However, the use of existing helpers such as
_require_btrfs_fs_sysfs and _require_btrfs_fs_feature
will be better. Thanks


> +rescue_opts="/sys/fs/btrfs/features/supported_rescue_options"
> +if [ ! -f "$rescue_opts" ]; then
> +	_notrun "No supported_rescue_options sysfs interface"
> +fi
> +
> +if ! grep -q "ignorebadroots" "$rescue_opts"; then
> +	_notrun "\"rescue=ignorebadroots\" mount option not supported"
> +fi
> +


diff --git a/common/btrfs b/common/btrfs
index 30288f07b61a..57453fb39893 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -100,6 +100,29 @@ _require_btrfs_mkfs_uuid_option()
 	fi
 }

+# Check for the availability of a specific option within a btrfs
feature set
+# Arguments:
+#   $1 - Feature attribute of /sys/fs/btrfs/features/
+#   $2 - Option string to verify inside that file
+_require_btrfs_fs_feature_option()
+{
+	local feat=$1
+	local feat_type=$2
+
+	if [ -z "$feat" ] || [ -z "$feat_type" ]; then
+		echo "Missing argument(s) for _require_btrfs_fs_feature_type"
+		_exit 1
+	fi
+
+	modprobe btrfs > /dev/null 2>&1
+
+	_require_btrfs_fs_feature "$feat"
+
+	if ! grep -qw "$feat_type" "/sys/fs/btrfs/features/$feat"; then
+		_notrun "Feature type '$feat_type' not supported by the available
btrfs version"
+	fi
+}
+
 _require_btrfs_fs_feature()
 {
 	if [ -z $1 ]; then
diff --git a/tests/btrfs/352 b/tests/btrfs/352
index 2ccf7fabdb71..14e357dbaa37 100755
--- a/tests/btrfs/352
+++ b/tests/btrfs/352
@@ -14,15 +14,8 @@ _begin_fstest auto quick remount
 _fixed_by_kernel_commit XXXXXXXXXXXX \
 	"btrfs: fix leaking BTRFS_FS_STATE_REMOUNTING flag"

-rescue_opts="/sys/fs/btrfs/features/supported_rescue_options"
-if [ ! -f "$rescue_opts" ]; then
-	_notrun "No supported_rescue_options sysfs interface"
-fi
-
-if ! grep -q "ignorebadroots" "$rescue_opts"; then
-	_notrun "\"rescue=ignorebadroots\" mount option not supported"
-fi
-
+_require_btrfs_fs_sysfs
+_require_btrfs_fs_feature_option "supported_rescue_options"
"ignorebadroots"
 _require_btrfs_command quota rescan -w
 _require_scratch
 _scratch_mkfs >> $seqres.full