fstests: add module reloading helpers

Add some helper functions to require that we can reload a given
module, and add a helper to actually do that.  Refactor the existing
users to use the generics.

We need to hoist completely the behaviors of the old btrfs module
helper because we need to confirm before starting the test that we
actually can remove the module.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Eryu Guan <eguan@redhat.com>

1 files changed, 99 insertions, 0 deletions

diff --git a/common/module b/common/module
new file mode 100644
index 00000000..ebaf2906
--- /dev/null
+++ b/common/module
@@ -0,0 +1,99 @@
+##/bin/bash
+
+# Routines for messing around with loadable kernel modules
+#
+#-----------------------------------------------------------------------
+#  Copyright (c) 2017 Oracle.  All Rights Reserved.
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 2 of the License, or
+#  (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License
+#  along with this program; if not, write to the Free Software
+#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
+#  USA
+#-----------------------------------------------------------------------
+
+# Return the module name for this fs.
+_module_for_fs()
+{
+	echo "${FSTYP}"
+}
+
+# Reload a particular module.  This module MUST NOT be the module that
+# underlies the filesystem.
+_reload_module()
+{
+	local module="$1"
+
+	modprobe -r "${module}" || _fail "${module} unload failed"
+	modprobe "${module}" || _fail "${module} load failed"
+}
+
+# Reload the filesystem module.
+_reload_fs_module()
+{
+	local module="$1"
+
+	# Unload test fs, try to reload module, remount
+	local had_testfs=""
+	local had_scratchfs=""
+	_check_mounted_on TEST_DEV $TEST_DEV TEST_DIR $TEST_DIR && had_testfs="true"
+	_check_mounted_on SCRATCH_DEV $SCRATCH_DEV SCRATCH_MNT $SCRATCH_MNT && had_scratchfs="true"
+	test -n "${had_testfs}" && _test_unmount
+	test -n "${had_scratchfs}" && _scratch_unmount
+	_reload_module "${module}"
+	test -n "${had_scratchfs}" && _scratch_mount 2> /dev/null
+	test -n "${had_testfs}" && _test_mount 2> /dev/null
+}
+
+# Check that we have a module that can be loaded.  This module MUST NOT
+# be the module that underlies the filesystem.
+_require_loadable_module()
+{
+	local module="$1"
+
+	modinfo "${module}" > /dev/null 2>&1 || _notrun "${module}: must be a module."
+	modprobe -r "${module}" || _notrun "Require ${module} to be unloadable"
+	modprobe "${module}" || _notrun "${module} load failed"
+}
+
+# Check that the module for FSTYP can be loaded.
+_require_loadable_fs_module()
+{
+	local module="$1"
+
+	modinfo "${module}" > /dev/null 2>&1 || _notrun "${module}: must be a module."
+
+	# Unload test fs, try to reload module, remount
+	local had_testfs=""
+	local had_scratchfs=""
+	_check_mounted_on TEST_DEV $TEST_DEV TEST_DIR $TEST_DIR && had_testfs="true"
+	_check_mounted_on SCRATCH_DEV $SCRATCH_DEV SCRATCH_MNT $SCRATCH_MNT && had_scratchfs="true"
+	test -n "${had_testfs}" && _test_unmount
+	test -n "${had_scratchfs}" && _scratch_unmount
+	local unload_ok=""
+	local load_ok=""
+	modprobe -r "${module}" || unload_ok=0
+	modprobe "${module}" || load_ok=0
+	test -n "${had_scratchfs}" && _scratch_mount 2> /dev/null
+	test -n "${had_testfs}" && _test_mount 2> /dev/null
+	test -z "${unload_ok}" || _notrun "Require module ${module} to be unloadable"
+	test -z "${load_ok}" || _notrun "${module} load failed"
+}
+
+# Print the value of a filesystem module parameter
+# at /sys/module/$FSTYP/parameters/$PARAM
+#
+# Usage example (FSTYP=overlay):
+#   _get_fs_module_param index
+_get_fs_module_param()
+{
+	cat /sys/module/${FSTYP}/parameters/${1} 2>/dev/null
+}