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 "${module} load failed"
51 # Check that the module for FSTYP can be loaded.
52 _require_loadable_fs_module()
56 modinfo "${module}" > /dev/null 2>&1 || _notrun "${module}: must be a module."
58 # Unload test fs, try to reload module, remount
60 local had_scratchfs=""
61 _check_mounted_on TEST_DEV $TEST_DEV TEST_DIR $TEST_DIR && had_testfs="true"
62 _check_mounted_on SCRATCH_DEV $SCRATCH_DEV SCRATCH_MNT $SCRATCH_MNT && had_scratchfs="true"
63 test -n "${had_testfs}" && _test_unmount
64 test -n "${had_scratchfs}" && _scratch_unmount
67 _patient_rmmod "${module}" || unload_ok=0
68 modprobe "${module}" || load_ok=0
69 test -n "${had_scratchfs}" && _scratch_mount 2> /dev/null
70 test -n "${had_testfs}" && _test_mount 2> /dev/null
71 test -z "${unload_ok}" || _notrun "Require module ${module} to be unloadable"
72 test -z "${load_ok}" || _notrun "${module} load failed"
75 # Print the value of a filesystem module parameter
76 # at /sys/module/$FSTYP/parameters/$PARAM
78 # Usage example (FSTYP=overlay):
79 # _get_fs_module_param index
80 _get_fs_module_param()
82 cat /sys/module/${FSTYP}/parameters/${1} 2>/dev/null
85 # checks the refcount and returns 0 if we can safely remove the module. rmmod
86 # does this check for us, but we can use this to also iterate checking for this
87 # refcount before we even try to remove the module. This is useful when using
88 # debug test modules which take a while to quiesce.
89 _patient_rmmod_check_refcnt()
94 if [[ -f /sys/module/$module/refcnt ]]; then
95 refcnt=$(cat /sys/module/$module/refcnt 2>/dev/null)
96 if [[ $? -ne 0 || $refcnt -eq 0 ]]; then
104 # Patiently tries to wait to remove a module by ensuring first
105 # the refcnt is 0 and then trying to persistently remove the module within
106 # the time allowed. The timeout is configurable per test, just set
107 # MODPROBE_PATIENT_RM_TIMEOUT_SECONDS prior to including this file.
108 # If you want this to try forever just set MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
109 # to the special value of "forever". This applies to both cases where kmod
110 # supports the patient module remover (modrobe -p) and where it does not.
112 # If your version of kmod supports modprobe -p, we instead use that
113 # instead. Otherwise we have to implement a patient module remover
118 local max_tries_max=$MODPROBE_PATIENT_RM_TIMEOUT_SECONDS
121 local refcnt_is_zero=0
123 if [[ ! -z $MODPROBE_REMOVE_PATIENT ]]; then
124 $MODPROBE_REMOVE_PATIENT $module
126 if [[ $mod_ret -ne 0 ]]; then
127 echo "kmod patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max returned $mod_ret"
132 max_tries=$max_tries_max
134 # We must use a string check as otherwise if max_tries is set to
135 # "forever" and we don't use a string check we can end up skipping
136 # entering this loop.
137 while [[ "$max_tries" != "0" ]]; do
138 _patient_rmmod_check_refcnt $module
139 if [[ $? -eq 0 ]]; then
144 if [[ "$max_tries" == "forever" ]]; then
147 let max_tries=$max_tries-1
150 if [[ $refcnt_is_zero -ne 1 ]]; then
151 echo "custom patient module removal for $module timed out waiting for refcnt to become 0 using timeout of $max_tries_max"
155 # If we ran out of time but our refcnt check confirms we had
156 # a refcnt of 0, just try to remove the module once.
157 if [[ "$max_tries" == "0" ]]; then
162 # If we have extra time left. Use the time left to now try to
163 # persistently remove the module. We do this because although through
164 # the above we found refcnt to be 0, removal can still fail since
165 # userspace can always race to bump the refcnt. An example is any
166 # blkdev_open() calls against a block device. These issues have been
167 # tracked and documented in the following bug reports, which justifies
168 # our need to do this in userspace:
169 # https://bugzilla.kernel.org/show_bug.cgi?id=212337
170 # https://bugzilla.kernel.org/show_bug.cgi?id=214015
171 while [[ $max_tries != 0 ]]; do
172 if [[ -d /sys/module/$module ]]; then
173 modprobe -r $module 2> /dev/null
175 if [[ $mod_ret == 0 ]]; then
179 if [[ "$max_tries" == "forever" ]]; then
182 let max_tries=$max_tries-1
186 if [[ $mod_ret -ne 0 ]]; then
187 echo "custom patient module removal for $module timed out trying to remove $module using timeout of $max_tries_max last try returned $mod_ret"