common/module

##/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
}