[libvirt] [PATCHv2 28/62] qemu: Add field to store QDEV path of a disk in private data

[Peter Krempa]

When using -blockdev you need to use the qdev path to refer to the disk
fronends. Add means for storing the path and getting it after restart.

Signed-off-by: Peter Krempa <pkrempa at redhat.com>
---
 src/qemu/qemu_domain.c                    | 27 +++++++++++++++++++++++++++
 src/qemu/qemu_domain.h                    |  2 ++
 tests/qemustatusxml2xmldata/modern-in.xml |  3 +++
 3 files changed, 32 insertions(+)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index 032ad80baa..3058ceca79 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -1065,6 +1065,7 @@ qemuDomainDiskPrivateDispose(void *obj)

     VIR_FREE(priv->blockJobError);
     virStorageSourceFree(priv->migrSource);
+    VIR_FREE(priv->backendQomName);
 }

 static virClassPtr qemuDomainStorageSourcePrivateClass;
@@ -2123,6 +2124,30 @@ qemuStorageSourcePrivateDataFormat(virStorageSourcePtr src,
 }


+static int
+qemuDomainDiskPrivateParse(xmlXPathContextPtr ctxt,
+                           virDomainDiskDefPtr disk)
+{
+    qemuDomainDiskPrivatePtr priv = QEMU_DOMAIN_DISK_PRIVATE(disk);
+
+    priv->backendQomName = virXPathString("string(./qom/@backend)", ctxt);
+
+    return 0;
+}
+
+
+static int
+qemuDomainDiskPrivateFormat(virDomainDiskDefPtr disk,
+                            virBufferPtr buf)
+{
+    qemuDomainDiskPrivatePtr priv = QEMU_DOMAIN_DISK_PRIVATE(disk);
+
+    virBufferEscapeString(buf, "<qom backend='%s'/>\n", priv->backendQomName);
+
+    return 0;
+}
+
+
 static void
 qemuDomainObjPrivateXMLFormatVcpus(virBufferPtr buf,
                                    virDomainDefPtr def)
@@ -2973,6 +2998,8 @@ virDomainXMLPrivateDataCallbacks virQEMUDriverPrivateDataCallbacks = {
     .alloc = qemuDomainObjPrivateAlloc,
     .free = qemuDomainObjPrivateFree,
     .diskNew = qemuDomainDiskPrivateNew,
+    .diskParse = qemuDomainDiskPrivateParse,
+    .diskFormat = qemuDomainDiskPrivateFormat,
     .vcpuNew = qemuDomainVcpuPrivateNew,
     .chrSourceNew = qemuDomainChrSourcePrivateNew,
     .vsockNew = qemuDomainVsockPrivateNew,
diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
index 5dcbdfbbe1..7d0b304727 100644
--- a/src/qemu/qemu_domain.h
+++ b/src/qemu/qemu_domain.h
@@ -396,6 +396,8 @@ struct _qemuDomainDiskPrivate {
     /* information about the device */
     bool tray; /* device has tray */
     bool removable; /* device media can be removed/changed */
+
+    char *backendQomName; /* QOM path to the eligible block backend */
 };

 # define QEMU_DOMAIN_STORAGE_SOURCE_PRIVATE(src) \
diff --git a/tests/qemustatusxml2xmldata/modern-in.xml b/tests/qemustatusxml2xmldata/modern-in.xml
index 4fb5f326c2..21d4faca66 100644
--- a/tests/qemustatusxml2xmldata/modern-in.xml
+++ b/tests/qemustatusxml2xmldata/modern-in.xml
@@ -331,6 +331,9 @@
         <target dev='vdb' bus='virtio'/>
         <alias name='virtio-disk1'/>
         <address type='pci' domain='0x0000' bus='0x00' slot='0x0b' function='0x0'/>
+        <privateData>
+          <qom backend='virtio-disk1/virtio-backend'/>
+        </privateData>
       </disk>
       <disk type='file' device='cdrom'>
         <driver name='qemu' type='raw'/>
-- 
2.16.2