diff --git a/common/fail_make_request b/common/fail_make_request
new file mode 100644
index 00000000..581d176a
--- /dev/null
+++ b/common/fail_make_request
@@ -0,0 +1,47 @@
+##/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# common functions for setting up and tearing down block device error injection
+
+_require_fail_make_request()
+{
+    [ -f "$DEBUGFS_MNT/fail_make_request/probability" ] \
+	|| _notrun "$DEBUGFS_MNT/fail_make_request \
+ not found. Seems that CONFIG_FAULT_INJECTION_DEBUG_FS kernel config option not enabled"
+}
+
+_allow_fail_make_request()
+{
+    local prob="${1:-100}"
+    local times="${2:-9999999}"
+    local verbose="${3:-0}"
+
+    echo "Allow global fail_make_request feature"
+    echo "$prob" > $DEBUGFS_MNT/fail_make_request/probability
+    echo "$times" > $DEBUGFS_MNT/fail_make_request/times
+    echo "$verbose" > $DEBUGFS_MNT/fail_make_request/verbose
+}
+
+_disallow_fail_make_request()
+{
+    echo "Disallow global fail_make_request feature"
+    echo 0 > $DEBUGFS_MNT/fail_make_request/probability
+    echo 0 > $DEBUGFS_MNT/fail_make_request/times
+    echo 0 > $DEBUGFS_MNT/fail_make_request/verbose
+}
+
+_start_fail_scratch_dev()
+{
+    local SYSFS_BDEV=`_sysfs_dev $SCRATCH_DEV`
+    echo "Force SCRATCH_DEV device failure"
+    echo " echo 1 > $SYSFS_BDEV/make-it-fail" >> $seqres.full
+    echo 1 > $SYSFS_BDEV/make-it-fail
+}
+
+_stop_fail_scratch_dev()
+{
+    local SYSFS_BDEV=`_sysfs_dev $SCRATCH_DEV`
+    echo "Make SCRATCH_DEV device operable again"
+    echo " echo 0 > $SYSFS_BDEV/make-it-fail" >> $seqres.full
+    echo 0 > $SYSFS_BDEV/make-it-fail
+}
diff --git a/common/rc b/common/rc
index 197c9415..09c81be6 100644
--- a/common/rc
+++ b/common/rc
@@ -2887,13 +2887,6 @@ _require_debugfs()
     [ -d "$DEBUGFS_MNT/boot_params" ] || _notrun "Debugfs not mounted"
 }
 
-_require_fail_make_request()
-{
-    [ -f "$DEBUGFS_MNT/fail_make_request/probability" ] \
-	|| _notrun "$DEBUGFS_MNT/fail_make_request \
- not found. Seems that CONFIG_FAULT_INJECTION_DEBUG_FS kernel config option not enabled"
-}
-
 # Disable extent zeroing for ext4 on the given device
 _ext4_disable_extent_zeroout()
 {
diff --git a/tests/btrfs/088 b/tests/btrfs/088
index d9c5528b..59972ae7 100755
--- a/tests/btrfs/088
+++ b/tests/btrfs/088
@@ -18,27 +18,23 @@ _begin_fstest auto quick metadata
 
 # Import common functions.
 . ./common/filter
+. ./common/fail_make_request
 
 # real QA test starts here
 _supported_fs btrfs
 _require_scratch
 _require_fail_make_request
 
-SYSFS_BDEV=`_sysfs_dev $SCRATCH_DEV`
-
 enable_io_failure()
 {
-	echo 100 > $DEBUGFS_MNT/fail_make_request/probability
-	echo 1000 > $DEBUGFS_MNT/fail_make_request/times
-	echo 0 > $DEBUGFS_MNT/fail_make_request/verbose
-	echo 1 > $SYSFS_BDEV/make-it-fail
+	_allow_fail_make_request 100 1000 > /dev/null
+	_start_fail_scratch_dev > /dev/null
 }
 
 disable_io_failure()
 {
-	echo 0 > $SYSFS_BDEV/make-it-fail
-	echo 0 > $DEBUGFS_MNT/fail_make_request/probability
-	echo 0 > $DEBUGFS_MNT/fail_make_request/times
+	_stop_fail_scratch_dev > /dev/null
+	_disallow_fail_make_request > /dev/null
 }
 
 # We will abort a btrfs transaction later, which always produces a warning in
diff --git a/tests/btrfs/150 b/tests/btrfs/150
index c5e9c709..a7d7d9cc 100755
--- a/tests/btrfs/150
+++ b/tests/btrfs/150
@@ -15,6 +15,7 @@ _begin_fstest auto quick dangerous read_repair
 
 # Import common functions.
 . ./common/filter
+. ./common/fail_make_request
 
 # real QA test starts here
 
@@ -25,22 +26,18 @@ _require_fail_make_request
 _require_scratch_dev_pool 2
 _scratch_dev_pool_get 2
 
-SYSFS_BDEV=`_sysfs_dev $SCRATCH_DEV`
 enable_io_failure()
 {
-	echo 100 > $DEBUGFS_MNT/fail_make_request/probability
-	echo 1000 > $DEBUGFS_MNT/fail_make_request/times
-	echo 0 > $DEBUGFS_MNT/fail_make_request/verbose
+	_allow_fail_make_request 100 1000 > /dev/null
 	echo 1 > $DEBUGFS_MNT/fail_make_request/task-filter
-	echo 1 > $SYSFS_BDEV/make-it-fail
+	_start_fail_scratch_dev > /dev/null
 }
 
 disable_io_failure()
 {
-	echo 0 > $DEBUGFS_MNT/fail_make_request/probability
-	echo 0 > $DEBUGFS_MNT/fail_make_request/times
+	_disallow_fail_make_request > /dev/null
 	echo 0 > $DEBUGFS_MNT/fail_make_request/task-filter
-	echo 0 > $SYSFS_BDEV/make-it-fail
+	_stop_fail_scratch_dev > /dev/null
 }
 
 _check_minimal_fs_size $(( 1024 * 1024 * 1024 ))
diff --git a/tests/generic/019 b/tests/generic/019
index 45c91624..b68dd90c 100755
--- a/tests/generic/019
+++ b/tests/generic/019
@@ -14,47 +14,17 @@ fio_config=$tmp.fio
 
 # Import common functions.
 . ./common/filter
+. ./common/fail_make_request
 _supported_fs generic
 _require_scratch
 _require_block_device $SCRATCH_DEV
 _require_fail_make_request
 
-SYSFS_BDEV=`_sysfs_dev $SCRATCH_DEV`
-
-allow_fail_make_request()
-{
-    echo "Allow global fail_make_request feature"
-    echo 100 > $DEBUGFS_MNT/fail_make_request/probability
-    echo 9999999 > $DEBUGFS_MNT/fail_make_request/times
-    echo 0 >  /sys/kernel/debug/fail_make_request/verbose
-}
-
-disallow_fail_make_request()
-{
-    echo "Disallow global fail_make_request feature"
-    echo 0 > $DEBUGFS_MNT/fail_make_request/probability
-    echo 0 > $DEBUGFS_MNT/fail_make_request/times
-}
-
-start_fail_scratch_dev()
-{
-    echo "Force SCRATCH_DEV device failure"
-    echo " echo 1 > $SYSFS_BDEV/make-it-fail" >> $seqres.full
-    echo 1 > $SYSFS_BDEV/make-it-fail
-}
-
-stop_fail_scratch_dev()
-{
-    echo "Make SCRATCH_DEV device operable again"
-    echo " echo 0 > $SYSFS_BDEV/make-it-fail" >> $seqres.full
-    echo 0 > $SYSFS_BDEV/make-it-fail
-}
-
 # Override the default cleanup function.
 _cleanup()
 {
 	kill $fs_pid $fio_pid &> /dev/null
-	disallow_fail_make_request
+	_disallow_fail_make_request
 	cd /
 	rm -r -f $tmp.*
 }
@@ -129,7 +99,7 @@ _workout()
 
 	# Let's it work for awhile, and force device failure
 	sleep $RUN_TIME
-	start_fail_scratch_dev
+	_start_fail_scratch_dev
 	# After device turns in to failed state filesystem may yet not know about
 	# that so buffered write(2) may succeed, but any integrity operations
 	# such as (sync, fsync, fdatasync, direct-io) should fail.
@@ -147,7 +117,7 @@ _workout()
 	run_check _scratch_unmount
 	# Once filesystem was umounted no one is able to write to block device
 	# It is now safe to bring device back to normal state
-	stop_fail_scratch_dev
+	_stop_fail_scratch_dev
 
 	# In order to check that filesystem is able to recover journal on mount(2)
 	# perform mount/umount, after that all errors should be fixed
@@ -159,7 +129,7 @@ _workout()
 
 _scratch_mkfs >> $seqres.full 2>&1 || _fail "mkfs failed"
 _scratch_mount
-allow_fail_make_request
+_allow_fail_make_request
 _workout
 status=$?
 exit
