2 # SPDX-License-Identifier: GPL-2.0+
3 # Copyright (c) 2017 Oracle. All Rights Reserved.
5 # Routines for messing around with loadable kernel modules
7 # Return the module name for this fs.
13 # Reload a particular module. This module MUST NOT be the module that
14 # underlies the filesystem.
19 _patient_rmmod "${module}" || _fail "${module} unload failed"
20 modprobe "${module}" || _fail "${module} load failed"
23 # Reload the filesystem module.
28 # Unload test fs, try to reload module, remount
30 local had_scratchfs=""
31 _check_mounted_on TEST_DEV $TEST_DEV TEST_DIR $TEST_DIR && had_testfs="true"
32 _check_mounted_on SCRATCH_DEV $SCRATCH_DEV SCRATCH_MNT $SCRATCH_MNT && had_scratchfs="true"
33 test -n "${had_testfs}" && _test_unmount
34 test -n "${had_scratchfs}" && _scratch_unmount
35 _reload_module "${module}"
36 test -n "${had_scratchfs}" && _scratch_mount 2> /dev/null
37 test -n "${had_testfs}" && _test_mount 2> /dev/null
40 # Check that we have a module that can be loaded. This module MUST NOT
41 # be the module that underlies the filesystem.
42 _require_loadable_module()
46 modinfo "${module}" > /dev/null 2>&1 || _notrun "${module}: must be a module."
47 _patient_rmmod "${module}" || _notrun "Require ${module} to be unloadable"
48 modprobe "${module}" || _notrun "${module} load failed"
51 # Test if the module for FSTYP can be unloaded and reloaded.
53 # If not, returns 1 if $FSTYP is not a loadable module; 2 if the module could
54 # not be unloaded; or 3 if loading the module fails.
55 _test_loadable_fs_module()
59 modinfo "${module}" > /dev/null 2>&1 || return 1
61 # Unload test fs, try to reload module, remount
63 local had_scratchfs=""
64 _check_mounted_on TEST_DEV $TEST_DEV TEST_DIR $TEST_DIR && had_testfs="true"
65 _check_mounted_on SCRATCH_DEV $SCRATCH_DEV SCRATCH_MNT $SCRATCH_MNT && had_scratchfs="true"
66 test -n "${had_testfs}" && _test_unmount
67 test -n "${had_scratchfs}" && _scratch_unmount
70 _patient_rmmod "${module}" || unload_ok=0
71 modprobe "${module}" || load_ok=0
72 test -n "${had_scratchfs}" && _scratch_mount 2> /dev/null
73 test -n "${had_testfs}" && _test_mount 2> /dev/null
74 test -z "${unload_ok}" || return 2
75 test -z "${load_ok}" || return 3
79 _require_loadable_fs_module()
83 _test_loadable_fs_module "${module}"
87 _notrun "${module}: must be a module."
90 _notrun "${module}: module could not be unloaded"
93 _notrun "${module}: module reload failed"
98 # Print the value of a filesystem module parameter
99 # at /sys/module/$FSTYP/parameters/$PARAM
101 # Usage example (FSTYP=overlay):
102 # _get_fs_module_param index
103 _get_fs_module_param()
105 cat /sys/module/${FSTYP}/parameters/${1} 2>/dev/null
108 # checks the refcount and returns 0 if we can safely remove the module. rmmod
109 # does this check for us, but we can use this to also iterate checking for this
110 # refcount before we even try to remove the module. This is useful when using
111 # debug test modules which take a while to quiesce.
112 _patient_rmmod_check_refcnt()
117 if [[ -f /sys/module/$module/refcnt ]]; then
118 refcnt=$(cat /sys/module/$module/refcnt 2>/dev/null)
119 if [[ $? -ne 0 || $refcnt -eq 0 ]]; then
127 # Patiently tries to wait to remove a module by ensuring first
128 # the refcnt is 0 and then trying to persistently remove the module within
129 # the time allowed. The timeout is configurable per test, just set
130 # MODPROBE_PATIENT_RM_TIMEOUT_SECONDS prior to including this file.
131 # If you want this to try forever just set MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
132 # to the special value of "forever". This applies to both cases where kmod
133 # supports the patient module remover (modrobe -p) and where it does not.
135 # If your version of kmod supports modprobe -p, we instead use that
136 # instead. Otherwise we have to implement a patient module remover
141 local max_tries_max=$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
144 local refcnt_is_zero=0
146 if [[ ! -z $MODPROBE_REMOVE_PATIENT ]]; then
147 $MODPROBE_REMOVE_PATIENT $module
149 if [[ $mod_ret -ne 0 ]]; then
150 echo "kmod patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max returned $mod_ret"
155 max_tries=$max_tries_max
157 # We must use a string check as otherwise if max_tries is set to
158 # "forever" and we don't use a string check we can end up skipping
159 # entering this loop.
160 while [[ "$max_tries" != "0" ]]; do
161 _patient_rmmod_check_refcnt $module
162 if [[ $? -eq 0 ]]; then
167 if [[ "$max_tries" == "forever" ]]; then
170 let max_tries=$max_tries-1
173 if [[ $refcnt_is_zero -ne 1 ]]; then
174 echo "custom patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max"
178 # If we ran out of time but our refcnt check confirms we had
179 # a refcnt of 0, just try to remove the module once.
180 if [[ "$max_tries" == "0" ]]; then
185 # If we have extra time left. Use the time left to now try to
186 # persistently remove the module. We do this because although through
187 # the above we found refcnt to be 0, removal can still fail since
188 # userspace can always race to bump the refcnt. An example is any
189 # blkdev_open() calls against a block device. These issues have been
190 # tracked and documented in the following bug reports, which justifies
191 # our need to do this in userspace:
192 # https://bugzilla.kernel.org/show_bug.cgi?id=212337
193 # https://bugzilla.kernel.org/show_bug.cgi?id=214015
194 while [[ $max_tries != 0 ]]; do
195 if [[ -d /sys/module/$module ]]; then
196 modprobe -r $module 2> /dev/null
198 if [[ $mod_ret == 0 ]]; then
202 if [[ "$max_tries" == "forever" ]]; then
205 let max_tries=$max_tries-1
211 if [[ $mod_ret -ne 0 ]]; then
212 echo "custom patient module removal for $module timed out trying to remove $module using timeout of $max_tries_max last try returned $mod_ret"