Change in vdsm[master]: vm: update volume apparentsize after snapshot

[Federico Simoncelli]

Federico Simoncelli has uploaded a new change for review.

Change subject: vm: update volume apparentsize after snapshot
......................................................................

vm: update volume apparentsize after snapshot

After a live snapshot succeeded we need to force the update of the
volume apparentsize to avoid races in the extension requests.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=923964
Change-Id: I472c2931551643914e6a09b54d3d96f371f34864
Signed-off-by: Federico Simoncelli 
---
M vdsm/libvirtvm.py
1 file changed, 41 insertions(+), 25 deletions(-)

git pull ssh://gerrit.ovirt.org:29418/vdsm refs/changes/46/13346/1

diff --git a/vdsm/libvirtvm.py b/vdsm/libvirtvm.py
index cb792b5..8e4f5ce 100644
--- a/vdsm/libvirtvm.py
+++ b/vdsm/libvirtvm.py
@@ -146,16 +146,7 @@
             return

for vmDrive in self._vm._devices[vm.DISK_DEVICES]:
-            if vmDrive.device == 'disk' and vmDrive.isVdsmImage():
-                volSize = self._vm.cif.irs.getVolumeSize(
-                    vmDrive.domainID, vmDrive.poolID, vmDrive.imageID,
-                    vmDrive.volumeID)
-
-                if volSize['status']['code'] != 0:
-                    continue
-
-                vmDrive.truesize = int(volSize['truesize'])
-                vmDrive.apparentsize = int(volSize['apparentsize'])
+            self._vm.updateDriveVolume(vmDrive)

def _sampleCpu(self):
         cpuStats = self._vm._dom.getCPUStats(True, 0)
@@ -1929,28 +1920,47 @@

raise LookupError("No such drive: '%s'" % drive)

-    def _updateDrive(self, drive):
+    def updateDriveVolume(self, vmDrive):
+        if not vmDrive.device == 'disk' or not vmDrive.isVdsmImage():
+            return
+
+        volSize = self.cif.irs.getVolumeSize(
+            vmDrive.domainID, vmDrive.poolID, vmDrive.imageID,
+            vmDrive.volumeID)
+
+        if volSize['status']['code'] != 0:
+            self.log.error(
+                "Unable to update the volume %s (domain: %s image: %s) "
+                "for the drive %s" % (vmDrive.volumeID, vmDrive.domainID,
+                                      vmDrive.imageID, vmDrive.name))
+            return
+
+        vmDrive.truesize = int(volSize['truesize'])
+        vmDrive.apparentsize = int(volSize['apparentsize'])
+
+    def updateDriveParameters(self, driveParams):
         """Update the drive with the new volume information"""

-        # Updating the drive object
-        for device in self._devices[vm.DISK_DEVICES][:]:
-            if device.name == drive["name"]:
-                for k, v in drive.iteritems():
-                    setattr(device, k, v)
+        # Updating the vmDrive object
+        for vmDrive in self._devices[vm.DISK_DEVICES][:]:
+            if vmDrive.name == driveParams["name"]:
+                for k, v in driveParams.iteritems():
+                    setattr(vmDrive, k, v)
+                self.updateDriveVolume(vmDrive)
                 break
         else:
             self.log.error("Unable to update the drive object for: %s",
-                           drive["name"])
+                           driveParams["name"])

# Updating the VM configuration
-        for device in self.conf["devices"][:]:
-            if (device['type'] == vm.DISK_DEVICES and
-                    device.get("name") == drive["name"]):
-                device.update(drive)
+        for vmDriveConfig in self.conf["devices"][:]:
+            if (vmDriveConfig['type'] == vm.DISK_DEVICES and
+                    vmDriveConfig.get("name") == driveParams["name"]):
+                vmDriveConfig.update(driveParams)
                 break
         else:
             self.log.error("Unable to update the device configuration ",
-                           "for: %s", drive["name"])
+                           "for: %s", driveParams["name"])

self.saveState()

@@ -2055,6 +2065,12 @@
         snapxml = snap.toprettyxml()

self.log.debug(snapxml)
+
+        # We need to stop the collection of the stats for two reasons, one
+        # is to prevent spurious libvirt errors about missing drive paths
+        # (since we're changing them), and also to prevent to trigger a drive
+        # extension for the new volume with the apparent size of the old one
+        # (the apparentsize is updated as last step in updateDriveParameters)
         self.stopDisksStatsCollection()

snapFlags = (libvirt.VIR_DOMAIN_SNAPSHOT_CREATE_DISK_ONLY |
@@ -2089,7 +2105,7 @@
             else:
                 # Update the drive information
                 for drive in newDrives.values():
-                    self._updateDrive(drive)
+                    self.updateDriveParameters(drive)
             finally:
                 self.startDisksStatsCollection()

@@ -2315,7 +2331,7 @@

# Updating the destination disk device and name, the device is used by
         # prepareVolumePath (required to fill the new information as the path)
-        # and the name is used by _updateDrive.
+        # and the name is used by updateDriveParameters.
         dstDiskCopy.update({'device': srcDrive.device, 'name': srcDrive.name})
         dstDiskCopy['path'] = self.cif.prepareVolumePath(dstDiskCopy)

@@ -2356,7 +2372,7 @@
                 # There is nothing we can do at this point other than logging
                 self.log.error("Unable to teardown the previous chain: %s",
                                diskToTeardown, exc_info=True)
-            self._updateDrive(dstDiskCopy)  # Updating the drive structure
+            self.updateDriveParameters(dstDiskCopy)
         finally:
             self._delDiskReplica(srcDrive)
             self.startDisksStatsCollection()

--
To view, visit http://gerrit.ovirt.org/13346
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I472c2931551643914e6a09b54d3d96f371f34864
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Federico Simoncelli