tp-qemu: update unplug disk test steps

Signed-off-by: NXu Tian <xutian@redhat.com>

qemu/tests/cfg/multi_disk_random_hotplug.cfg

@@ -15,11 +15,14 @@
     Linux:
         # We have multiple disks so just ignor first one of each type
         no_stress_cmds = 100
-        stress_cmd = "touch /tmp/disk_stress ; "
-        stress_cmd += "while [ -f /tmp/disk_stress ] ; do "
-        stress_cmd += "READ=`ls /dev/[shv]d[a-z]* | egrep -v '^/dev/[vhs]da[0-9]*$' | sort -R | tail -n 1` ;"
-        stress_cmd += "WRITE=`ls /dev/[shv]d[a-z]* | egrep -v '^/dev/[vhs]da[0-9]*$' | sort -R | tail -n 1` ;"
-        stress_cmd += "dd if=$READ of=$WRITE bs=1k count=10 iflag=direct oflag=direct conv=nocreat; done &>/dev/null &"
+        stress_cmd = 'sh -c " touch /tmp/disk_stress ; '
+        stress_cmd += 'while [ -f /tmp/disk_stress ] ; do '
+        stress_cmd += 'READ=`ls /dev/[shv]d[a-z]* | egrep -v '^/dev/[vhs]da[0-9]*$' | sort -R | tail -n 1` ;'
+        stress_cmd += 'WRITE=`ls /dev/[shv]d[a-z]* | egrep -v '^/dev/[vhs]da[0-9]*$' | sort -R | tail -n 1` ;'
+        stress_cmd += 'dd if=$READ of=$WRITE bs=1k count=10 iflag=direct oflag=direct conv=nocreat; done >/dev/null" &'
+        stress_cmd += 'echo $! > /tmp/disk_stress'
+        stress_stop_cmd = kill -19 `cat /tmp/disk_stress`
+        stress_cont_cmd = kill -18 `cat /tmp/disk_stress`
         stress_kill_cmd = "rm -f /tmp/disk_stress"
     variants:
         - all_types:

qemu/tests/multi_disk_random_hotplug.py

@@ -77,10 +77,11 @@ def run(test, params, env):
     1) prepares multiple disks to be hotplugged
     2) hotplugs them
     3) verifies that they are in qtree/guest system/...
-    4) unplugs them
-    5) verifies they are not in qtree/guest system/...
-    6) repeats $repeat_times
-    *) During the whole test stress_cmd might be executed
+    4) stop I/O stress_cmd
+    5) unplugs them
+    6) continue I/O stress_cmd
+    7) verifies they are not in qtree/guest system/...
+    8) repeats $repeat_times
 
     :param test: QEMU test object
     :param params: Dictionary with the test parameters
@@ -448,7 +449,11 @@ def run(test, params, env):
             utils_test.run_virt_sub_test(test, params, env, sub_type)
 
         error.context("Unplug and remove the devices", logging.debug)
+        if stress_cmd:
+            session.cmd(params["stress_stop_cmd"])
         unplug(new_devices, qdev, monitor)
+        if stress_cmd:
+            session.cmd(params["stress_cont_cmd"])
         _postprocess_images()
 
         error.context("Verify disks after unplug", logging.debug)