Test for handling discard request on huge CAS device

Signed-off-by: Slawomir Jankowski <slawomir.jankowski@intel.com>

test/functional/tests/volumes/test_discard_on_huge_core.py

@@ -0,0 +1,68 @@
+#
+# Copyright(c) 2020 Intel Corporation
+# SPDX-License-Identifier: BSD-3-Clause-Clear
+#
+
+import pytest
+
+from api.cas import casadm
+from storage_devices.disk import DiskType, DiskTypeSet
+from core.test_run import TestRun
+from test_utils.size import Size, Unit
+
+scsi_dev_size_gb = str(40 * 1024)
+
+
+@pytest.mark.os_dependent
+@pytest.mark.require_plugin("scsi_debug", virtual_gb=scsi_dev_size_gb, opts="1")
+@pytest.mark.require_disk("cache", DiskTypeSet([DiskType.optane, DiskType.nand]))
+def test_discard_on_huge_core():
+    """
+        title: Test for handling discard request on huge CAS device.
+        description: |
+          Test if OpenCAS could handle discard requests on large CAS devices
+          and if there is no RCU-sched stall in dmesg log.
+        pass_criteria:
+          - No system crash.
+          - Discard request is handled without errors.
+          - There is no RCU-sched type stall in dmesg log.
+    """
+    with TestRun.step("Clear dmesg log."):
+        TestRun.executor.run_expect_success(f"dmesg -c")
+
+    with TestRun.step("Prepare devices for cache and core."):
+        cache_dev = TestRun.disks['cache']
+        cache_dev.create_partitions([Size(10, Unit.GibiByte)])
+        cache_part = cache_dev.partitions[0]
+        core_dev = TestRun.scsi_debug_devices[0]
+
+    with TestRun.step("Start cache and add SCSI device as core."):
+        cache = casadm.start_cache(cache_part, force=True)
+        core = cache.add_core(core_dev)
+
+    with TestRun.step("Execute blkdiscard on core few times."):
+        # RCU-sched type stall sometimes appears in dmesg log after more
+        # than one execution of blkdiscard.
+        for _ in range(8):
+            TestRun.executor.run_expect_success(f"blkdiscard {core.system_path}")
+
+    with TestRun.step("Check dmesg for RCU-sched stall."):
+        check_for_rcu_sched_type_stall()
+
+
+def check_for_rcu_sched_type_stall():
+    output = TestRun.executor.run_expect_success(f"dmesg")
+    rcu_sched_found = False
+    dmesg_log_id = ""
+
+    results = output.stdout.splitlines()
+    for line in results:
+        if "rcu_sched" in line:
+            rcu_sched_found = True
+            dmesg_log_id = line[:line.index(".")]
+
+        if rcu_sched_found and line.startswith(dmesg_log_id):
+            TestRun.LOGGER.error(line)
+
+    if not rcu_sched_found:
+        TestRun.LOGGER.info("There is no rcu_sched type stall.")