[PATCH v4 2/6] btrfs: quota mode helpers

[Boris Burkov <boris@bur.io>]

To facilitate skipping tests depending on the qgroup mode after mkfs,
add support for figuring out the mode. This cannot just rely on the new
sysfs file, since it might not be present on older kernels.

Signed-off-by: Boris Burkov <boris@bur.io>
---
 common/btrfs | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/common/btrfs b/common/btrfs
index c9903a413..8d51bd522 100644
--- a/common/btrfs
+++ b/common/btrfs
@@ -689,3 +689,41 @@ _require_btrfs_scratch_logical_resolve_v2()
 	fi
 	_scratch_unmount
 }
+
+_qgroup_mode()
+{
+	local dev=$1
+
+	if [ ! -b "$dev" ]; then
+		_fail "Usage: _qgroup_mode <mounted_device>"
+	fi
+
+	if _has_fs_sysfs_attr $dev /qgroups/mode; then
+		_get_fs_sysfs_attr $dev qgroups/mode
+	else
+		echo "disabled"
+	fi
+}
+
+_check_regular_qgroup()
+{
+	_qgroup_mode "$@" | grep -q 'qgroup'
+}
+
+_require_scratch_qgroup()
+{
+	_scratch_mkfs >>$seqres.full 2>&1
+	_scratch_mount
+	_run_btrfs_util_prog quota enable $SCRATCH_MNT
+	_check_regular_qgroup $SCRATCH_DEV || _notrun "not running normal qgroups"
+	_scratch_unmount
+}
+
+_require_scratch_enable_simple_quota()
+{
+	_scratch_mkfs >>$seqres.full 2>&1
+	_scratch_mount
+	_qgroup_mode $SCRATCH_DEV | grep 'squota' && _notrun "cannot enable simple quota; on by default"
+	$BTRFS_UTIL_PROG quota enable --simple $SCRATCH_MNT || _notrun "simple quotas not available"
+	_scratch_unmount
+}
-- 
2.42.0