rbd: Create snapshot for cloning operations only when it is required

wido · wido · commit a7004db7c850 · 2014-05-02T11:55:34.000+02:00
We used to create the snapshot after the copy from Secondary Storage,
but it could be that we never use the snapshot.

Now we check if the snapshot exists prior to performing the cloning operation
diff --git a/plugins/hypervisors/kvm/src/com/cloud/hypervisor/kvm/storage/LibvirtStorageAdaptor.java b/plugins/hypervisors/kvm/src/com/cloud/hypervisor/kvm/storage/LibvirtStorageAdaptor.java
@@ -1036,6 +1036,30 @@ private KVMPhysicalDisk createDiskFromTemplateOnRBD(KVMPhysicalDisk template,
                                 + " is RBD format 2. We will perform a RBD clone using snapshot "
                                 + this.rbdTemplateSnapName);
                                 /* The source image is format 2, we can do a RBD snapshot+clone (layering) */
+
+
+                        s_logger.debug("Checking if RBD snapshot " + srcPool.getSourceDir() + "/" + template.getName()
+                                       + "@" + rbdTemplateSnapName + " exists prior to attempting a clone operation.");
+
+                        List<RbdSnapInfo> snaps = srcImage.snapList();
+                        s_logger.debug("Found " + snaps.size() +  " snapshots on RBD image " + srcPool.getSourceDir() + "/" + template.getName());
+                        boolean snapFound = false;
+                        for (RbdSnapInfo snap : snaps) {
+                            if (rbdTemplateSnapName.equals(snap.name)) {
+                                s_logger.debug("RBD snapshot " + srcPool.getSourceDir() + "/" + template.getName()
+                                               + "@" + rbdTemplateSnapName + " already exists.");
+                                snapFound = true;
+                                break;
+                            }
+                        }
+
+                        if (!snapFound) {
+                            s_logger.debug("Creating RBD snapshot " + rbdTemplateSnapName + " on image " + name);
+                            srcImage.snapCreate(rbdTemplateSnapName);
+                            s_logger.debug("Protecting RBD snapshot " + rbdTemplateSnapName + " on image " + name);
+                            srcImage.snapProtect(rbdTemplateSnapName);
+                        }
+
                         rbd.clone(template.getName(), this.rbdTemplateSnapName, io, disk.getName(), this.rbdFeatures, this.rbdOrder);
                         s_logger.debug("Succesfully cloned " + template.getName() + "@" + this.rbdTemplateSnapName + " to " + disk.getName());
                     }
@@ -1234,12 +1258,6 @@ public KVMPhysicalDisk copyPhysicalDisk(KVMPhysicalDisk disk, String name, KVMSt
 
                 RbdImage image = rbd.open(name);
 
-                /* Snapshot the image and protect that snapshot so we can clone (layer) from it */
-                s_logger.debug("Creating RBD snapshot " + rbdTemplateSnapName + " on image " + name);
-                image.snapCreate(rbdTemplateSnapName);
-                s_logger.debug("Protecting RBD snapshot " + rbdTemplateSnapName + " on image " + name);
-                image.snapProtect(rbdTemplateSnapName);
-
                 rbd.close(image);
                 r.ioCtxDestroy(io);
             } catch (QemuImgException e) {
