[libvirt] [PATCH 04/11] nodedev: Add the ability to create vHBA by parent wwnn/wwpn or fabric_wwn

[Ján Tomko]

On Fri, Nov 18, 2016 at 09:26:30AM -0500, John Ferlan wrote:
>https://bugzilla.redhat.com/show_bug.cgi?id=1349696
>
>When creating a vHBA, the process is to feed XML to nodeDeviceCreateXML
>that lists the <parent> scsi_hostX to use to create the vHBA. However,
>between reboots, it's possible that the <parent> changes its scsi_hostX
>to scsi_hostY and saved XML to perform the creation will either fail or
>create a vHBA using the wrong parent.
>
>So add the ability to provide <parent_wwnn> and <parent_wwpn> or
><parent_fabric_wwn> in order to use those values as more consistent

These are all flattening the XML and duplicating the "parent" in their
name.

Can we no longer put subelements in <parent> after we've used its
contents as text?

>search parameters. For some providing the wwnn/wwpn pair will provide
>the most specific search option, while for others providing a fabric_wwn
>will at least ensure usage of the same SAN.
>
>This patch will add the new fields to the nodedev.rng for input purposes
>only since the input XML is essentially thrown away, no need to Format
>the values since they'd already be printed as part of the scsi_host
>data block.
>
>New API virNodeDeviceGetParentHostByWWNs will take the parent_wwnn and
>parent_wwpn in order to search the list of devices for matching capability
>data fields wwnn and wwpn.
>
>New API virNodeDeviceGetParentHostByFabricWWN will take the parent_fabric_wwn
>in order to search the list of devices for matching capability data field
>fabric_wwn.
>
>Signed-off-by: John Ferlan <jferlan at redhat.com>
>---
> docs/schemas/nodedev.rng             |  15 +++++
> src/conf/node_device_conf.c          | 120 +++++++++++++++++++++++++++++++++++
> src/conf/node_device_conf.h          |  14 ++++
> src/libvirt_private.syms             |   2 +
> src/node_device/node_device_driver.c |  13 ++++
> 5 files changed, 164 insertions(+)
>
>diff --git a/docs/schemas/nodedev.rng b/docs/schemas/nodedev.rng
>index 93a88d8..6fe49a3 100644
>--- a/docs/schemas/nodedev.rng
>+++ b/docs/schemas/nodedev.rng
>@@ -18,6 +18,21 @@
>       <optional>
>         <element name="parent"><text/></element>
>       </optional>

>+      <optional>
>+        <element name="parent_wwnn">
>+          <ref name='wwn'/>
>+        </element>
>+      </optional>
>+      <optional>
>+        <element name="parent_wwpn">
>+          <ref name='wwn'/>
>+        </element>
>+      </optional>

This allows either of {nn,pn} to be present, but the code expects both.
Please put them in a single <optional> block if omitting either does not
make sense.

>+      <optional>
>+        <element name="parent_fabric_wwn">
>+          <ref name='wwn'/>
>+        </element>
>+      </optional>
>
>       <optional>
>         <element name="driver">

>@@ -1652,6 +1719,10 @@ virNodeDeviceDefParseXML(xmlXPathContextPtr ctxt,
>
>     /* Extract device parent, if any */
>     def->parent = virXPathString("string(./parent[1])", ctxt);
>+    def->parent_wwnn = virXPathString("string(./parent_wwnn[1])", ctxt);
>+    def->parent_wwpn = virXPathString("string(./parent_wwpn[1])", ctxt);

Should we error out if only one was provided?

>+    def->parent_fabric_wwn = virXPathString("string(./parent_fabric_wwn[1])",
>+                                            ctxt);
>
>     /* Parse device capabilities */
>     nodes = NULL;

Weak ACK, I'd rather see the XML nested (if possible).

Jan
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