[libvirt] [PATCH v3 4/4] storage: Disallow usage of the HBA for a fc_host backing

[John Ferlan]

Disallow providing the wwnn/wwpn of the HBA in the adapter XML:

  <adapter type='fc_host' [parent='scsi_hostN'] wwnn='HBA_wwnn'
    wwpn='HBA_wwpn'/>

This should be considered a configuration error since a vHBA
would not be created. In order to use the HBA as the backing the
following XML should be used:

  <adapter type='scsi_host' name='scsi_hostN'/>

This also alters the caller such that the @parent_name param
into checkParent can be NULL so as to confirm that at least
the provided wwnn/wwpn found a vHBA instead of an HBA.

Signed-off-by: John Ferlan <jferlan at redhat.com>
---
 docs/formatstorage.html.in         | 27 +++++++++++++----------
 src/storage/storage_backend_scsi.c | 45 ++++++++++++++++++++++++++++----------
 2 files changed, 49 insertions(+), 23 deletions(-)

diff --git a/docs/formatstorage.html.in b/docs/formatstorage.html.in
index 4946ddf..27578e8 100644
--- a/docs/formatstorage.html.in
+++ b/docs/formatstorage.html.in
@@ -207,18 +207,21 @@
         </dl>
         <dl>
           <dt><code>wwnn</code> and <code>wwpn</code></dt>
-          <dd>The "World Wide Node Name" (<code>wwnn</code>) and "World Wide
-            Port Name" (<code>wwpn</code>) are used by the "fc_host" adapter
-            to uniquely identify the device in the Fibre Channel storage fabric
-            (the device can be either a HBA or vHBA). Both wwnn and wwpn should
-            be specified. Use the command 'virsh nodedev-dumpxml' to determine
-            how to set the values for the wwnn/wwpn of a (v)HBA. The wwnn and
-            wwpn have very specific numerical format requirements based on the
-            hypervisor being used, thus care should be taken if you decide to
-            generate your own to follow the standards; otherwise, the pool
-            will fail to start with an opaque error message indicating failure
-            to write to the vport_create file during vport create/delete due
-            to "No such file or directory".
+          <dd>The required "World Wide Node Name" (<code>wwnn</code>) and
+            "World Wide Port Name" (<code>wwpn</code>) are used by the
+            "fc_host" adapter to uniquely identify the vHBA device in the
+            Fibre Channel storage fabric. If the vHBA device already exists
+            as a Node Device, then libvirt will use it; otherwise, the vHBA
+            will be created using the provided values. It is considered a
+            configuration error use the values from the HBA as those would
+            be for a "scsi_host" <code>type</code> pool instead. The
+            <code>wwnn</code> and <code>wwpn</code> have very specific
+            format requirements based on the hypervisor being used, thus
+            care should be taken if you decide to generate your own to
+            follow the standards; otherwise, the pool will fail to start
+            with an opaque error message indicating failure to write to
+            the vport_create file during vport create/delete due to
+            "No such file or directory".
             <span class="since">Since 1.0.4</span>
           </dd>
         </dl>
diff --git a/src/storage/storage_backend_scsi.c b/src/storage/storage_backend_scsi.c
index af12889..c802738 100644
--- a/src/storage/storage_backend_scsi.c
+++ b/src/storage/storage_backend_scsi.c
@@ -231,22 +231,47 @@ checkParent(virConnectPtr conn,
     if (!conn)
         return true;
 
-    if (virSCSIHostGetNumber(parent_name, &host_num) < 0) {
-        virReportError(VIR_ERR_XML_ERROR,
-                       _("parent '%s' is not properly formatted"),
-                       parent_name);
+    /* If there's a parent_name, then make sure it's valid */
+    if (parent_name) {
+        if (virSCSIHostGetNumber(parent_name, &host_num) < 0) {
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("parent '%s' is not properly formatted"),
+                           parent_name);
+            goto cleanup;
+        }
+
+        if (!virVHBAPathExists(NULL, host_num)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
+                           _("parent '%s' is not an fc_host for the wwnn/wwpn"),
+                           parent_name);
+            goto cleanup;
+        }
+    }
+
+    if (virAsprintf(&scsi_host_name, "scsi_%s", name) < 0)
+        goto cleanup;
+
+    if (virSCSIHostGetNumber(scsi_host_name, &host_num) < 0) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("host name '%s' is not properly formatted"),
+                       name);
         goto cleanup;
     }
 
-    if (!virVHBAPathExists(NULL, host_num)) {
+    /* If scsi_host_name is vport capable, then it's an HBA. This is
+     * a configuration error as the wwnn/wwpn should only be for a vHBA */
+    if (virVHBAIsVportCapable(NULL, host_num)) {
         virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
-                       _("parent '%s' is not an fc_host for the wwnn/wwpn"),
-                       parent_name);
+                       _("the wwnn/wwpn for '%s' are assigned to an HBA"),
+                       scsi_host_name);
         goto cleanup;
     }
 
-    if (virAsprintf(&scsi_host_name, "scsi_%s", name) < 0)
+    /* No parent name, then no need to get/compare against vhba_parent */
+    if (!parent_name) {
+        retval = true;
         goto cleanup;
+    }
 
     if (!(vhba_parent = virNodeDeviceGetParentName(conn, scsi_host_name)))
         goto cleanup;
@@ -288,9 +313,7 @@ createVport(virConnectPtr conn,
      * this pool and we don't have to create the vHBA
      */
     if ((name = virVHBAGetHostByWWN(NULL, fchost->wwnn, fchost->wwpn))) {
-        /* If a parent was provided, let's make sure the 'name' we've
-         * retrieved has the same parent. If not this will cause failure. */
-        if (!fchost->parent || checkParent(conn, name, fchost->parent))
+        if (checkParent(conn, name, fchost->parent))
             ret = 0;
 
         goto cleanup;
-- 
2.9.4