[libvirt] [PATCHv6 6/7] qemu: Add support for networked disks for block commit

[Peter Krempa]

Now that we are able to select images from the backing chain via indexed
access we should also convert possible network sources to
qemu-compatible strings before passing them to qemu.
---
 src/qemu/qemu_driver.c | 39 ++++++++++++++++++++++++++++++++++-----
 1 file changed, 34 insertions(+), 5 deletions(-)

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index ba1bfe2..c142646 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -15499,11 +15499,14 @@ qemuDomainBlockCommit(virDomainPtr dom,
     const char *top_parent = NULL;
     bool clean_access = false;
     virStorageSourcePtr mirror = NULL;
-
+    char *topPath = NULL;
+    char *basePath = NULL;
+    char *backingPath = NULL;

     /* XXX Add support for COMMIT_DELETE */
     virCheckFlags(VIR_DOMAIN_BLOCK_COMMIT_SHALLOW |
-                  VIR_DOMAIN_BLOCK_COMMIT_ACTIVE, -1);
+                  VIR_DOMAIN_BLOCK_COMMIT_ACTIVE |
+                  VIR_DOMAIN_BLOCK_COMMIT_RELATIVE, -1);

     if (!(vm = qemuDomObjFromDomain(dom)))
         goto cleanup;
@@ -15633,6 +15636,31 @@ qemuDomainBlockCommit(virDomainPtr dom,
         mirror->format = baseSource->format;
     }

+    if (qemuGetDriveSourceString(topSource, NULL, &topPath) < 0)
+        goto endjob;
+
+    if (qemuGetDriveSourceString(baseSource, NULL, &basePath) < 0)
+        goto endjob;
+
+    if (flags & VIR_DOMAIN_BLOCK_COMMIT_RELATIVE &&
+        topSource != disk->src) {
+        if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_CHANGE_BACKING_FILE)) {
+            virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
+                           _("this qemu doesn't support relative blockpull"));
+            goto endjob;
+        }
+
+        if (virStorageFileGetRelativeBackingPath(topSource, baseSource,
+                                                 &backingPath) < 0)
+            goto endjob;
+
+        if (!backingPath) {
+            virReportError(VIR_ERR_OPERATION_INVALID, "%s",
+                           _("can't keep relative backing relationship"));
+            goto endjob;
+        }
+    }
+
     /* Start the commit operation.  Pass the user's original spelling,
      * if any, through to qemu, since qemu may behave differently
      * depending on whether the input was specified as relative or
@@ -15640,9 +15668,7 @@ qemuDomainBlockCommit(virDomainPtr dom,
      * thing if the user specified a relative name). */
     qemuDomainObjEnterMonitor(driver, vm);
     ret = qemuMonitorBlockCommit(priv->mon, device,
-                                 top && !topIndex ? top : topSource->path,
-                                 base && !baseIndex ? base : baseSource->path,
-                                 NULL,
+                                 topPath, basePath, backingPath,
                                  bandwidth);
     qemuDomainObjExitMonitor(driver, vm);

@@ -15667,6 +15693,9 @@ qemuDomainBlockCommit(virDomainPtr dom,
         vm = NULL;

  cleanup:
+    VIR_FREE(topPath);
+    VIR_FREE(basePath);
+    VIR_FREE(backingPath);
     VIR_FREE(device);
     if (vm)
         virObjectUnlock(vm);
-- 
1.9.3