Robustify LINSTOR _get_diskful_hosts test regarding coalesce

It's possible that the test fails due to an incorrect verification
on the resource linked to a VDI. Indeed, if a coalesce occurs just
after fetching the diskless resource to be monitored, it may be
deleted which causes the test to fail. The fix is therefore to
refetch the resource associated with a VDI rather than caching it.

Signed-off-by: Ronan Abhamon <ronan.abhamon@vates.tech>

Author: Wescoeur

tests/storage/linstor/test_linstor_sr.py

@@ -137,14 +137,21 @@ def test_linstor_missing(self, linstor_sr, host):
 
 # --- Test diskless resources --------------------------------------------------
 
-def _get_diskful_hosts(host, controller_option, volume_name):
+def _get_diskful_hosts(host, controller_option, sr_group_name, vdi_uuid):
     # TODO: If any resource is in a temporary creation state or unknown, then need to wait intelligently.
     attempt = 0
     retries = 3
     sleep_sec = 5
 
     while attempt < retries:
         try:
+            # Get volume name from VDI UUID
+            # "xcp/volume/{vdi_uuid}/volume-name": "{volume_name}"
+            volume_name = host.ssh([
+                "linstor-kv-tool", "--dump-volumes", "-g", sr_group_name,
+                "|", "grep", "volume-name", "|", "grep", f"/{vdi_uuid}/"
+            ]).split(': ')[1].split('"')[1]
+
             # Find host where volume is UpToDate
             # | {volume_name} | {host} | 7017 | Unused | Ok    |   UpToDate | 2023-10-24 18:52:05 |
             lines = host.ssh([
@@ -163,8 +170,8 @@ def _get_diskful_hosts(host, controller_option, volume_name):
                 raise
             time.sleep(sleep_sec)
 
-def _ensure_resource_remain_diskless(host, controller_option, volume_name, diskless):
-    diskfuls = _get_diskful_hosts(host, controller_option, volume_name)
+def _ensure_resource_remain_diskless(host, controller_option, sr_group_name, vdi_uuid, diskless):
+    diskfuls = _get_diskful_hosts(host, controller_option, sr_group_name, vdi_uuid)
     for diskless_host in diskless:
         assert diskless_host.param_get("name-label").lower() not in diskfuls
 
@@ -181,16 +188,7 @@ def test_diskless_kept(self, host, linstor_sr, vm_on_linstor_sr, storage_pool_na
             controller_option += f"{member.hostname_or_ip},"
 
         sr_group_name = "xcp-sr-" + storage_pool_name.replace("/", "_")
-
-        # Get volume name from VDI uuid
-        # "xcp/volume/{vdi_uuid}/volume-name": "{volume_name}"
-        output = host.ssh([
-            "linstor-kv-tool", "--dump-volumes", "-g", sr_group_name,
-            "|", "grep", "volume-name", "|", "grep", f"/{vdi_uuid}/"
-        ])
-        volume_name = output.split(': ')[1].split('"')[1]
-
-        diskfuls = _get_diskful_hosts(host, controller_option, volume_name)
+        diskfuls = _get_diskful_hosts(host, controller_option, sr_group_name, vdi_uuid)
         diskless = []
         for member in host.pool.hosts:
             if member.param_get("name-label").lower() not in diskfuls:
@@ -200,7 +198,7 @@ def test_diskless_kept(self, host, linstor_sr, vm_on_linstor_sr, storage_pool_na
         # Start VM on host with diskless resource
         vm.start(on=diskless[0].uuid)
         vm.wait_for_os_booted()
-        _ensure_resource_remain_diskless(host, controller_option, volume_name, diskless)
+        _ensure_resource_remain_diskless(host, controller_option, sr_group_name, vdi_uuid, diskless)
 
         vm.shutdown(verify=True)
-        _ensure_resource_remain_diskless(host, controller_option, volume_name, diskless)
+        _ensure_resource_remain_diskless(host, controller_option, sr_group_name, vdi_uuid, diskless)