[NEW PATCH] BZ#716833 - Fix race in metadata offset computation during simultaneously volume creation in block storage domain (via gerrit-bot)

[Igor Lvovsky]

New patch submitted by Igor Lvovsky (ilvovsky(a)redhat.com)

You can review this change at: http://gerrit.usersys.redhat.com/626

commit a015a5919308b374add65495b1e577ee7de42677
Author: Igor Lvovsky <ilvovsky(a)redhat.com&gt;
Date:   Mon Jun 27 21:51:26 2011 +0300

    BZ#716833 - Fix race in metadata offset computation during simultaneously volume
creation in block storage domain
    
    Change-Id: I94af85026809f3a776f664c88197bdcbe1a1e3bd

diff --git a/vdsm/storage/blockSD.py b/vdsm/storage/blockSD.py
index 6f68d49..214e8a4 100644
--- a/vdsm/storage/blockSD.py
+++ b/vdsm/storage/blockSD.py
@@ -506,7 +506,7 @@ class BlockStorageDomain(sd.StorageDomain):
                     break
 
             if offset is None:
-                self.log.warn("Could not find mapping for lv %s", lv.name)
+                self.log.warn("Could not find mapping for lv %s/%s",
self.sdUUID, lv.name)
                 continue
 
             if size is None:
@@ -533,6 +533,7 @@ class BlockStorageDomain(sd.StorageDomain):
 
             freeSlot = offset + size
 
+        self.log.debug("Found freeSlot %s in VG %s", freeSlot, self.sdUUID)
         return freeSlot
 
     def getVolumeMetadataOffsetFromPvMapping(self, vol_name):
diff --git a/vdsm/storage/blockVolume.py b/vdsm/storage/blockVolume.py
index d2d6044..7398a61 100644
--- a/vdsm/storage/blockVolume.py
+++ b/vdsm/storage/blockVolume.py
@@ -10,6 +10,7 @@
 
 import os.path
 import uuid
+import threading
 
 from config import config
 import storage_exception as se
@@ -42,6 +43,8 @@ rmanager = rm.ResourceManager.getInstance()
 class BlockVolume(volume.Volume):
     """ Actually represents a single volume (i.e. part of virtual disk).
     """
+    _tagCreateLock = threading.Lock()
+
     def __init__(self, repoPath, sdUUID, imgUUID, volUUID):
         self.metaoff = None
         volume.Volume.__init__(self, repoPath, sdUUID, imgUUID, volUUID)
@@ -201,12 +204,17 @@ class BlockVolume(volume.Volume):
             raise
 
         try:
-            offs = mysd.mapMetaOffset(volUUID)
+            try:
+                cls._tagCreateLock.acquire()
+                offs = mysd.mapMetaOffset(volUUID)
+                lvm.addLVTags(sdUUID, volUUID, ("%s%s" % (TAG_PREFIX_MD,
offs),
+                                                "%s%s" % (TAG_PREFIX_PARENT,
srcVolUUID,),
+                                                "%s%s" % (TAG_PREFIX_IMAGE,
imgUUID,)))
+            finally:
+                cls._tagCreateLock.release()
+            lvm.deactivateLVs(sdUUID, volUUID)
             vars.task.pushRecovery(task.Recovery("create block volume metadata
rollback", "blockVolume", "BlockVolume",
"createVolumeMetadataRollback",
                                                  [sdUUID, str(offs)]))
-            lvm.addLVTags(sdUUID, volUUID, ("%s%s" % (TAG_PREFIX_MD, offs),
-                            "%s%s" % (TAG_PREFIX_PARENT, srcVolUUID,),
"%s%s" % (TAG_PREFIX_IMAGE, imgUUID,)))
-            lvm.deactivateLVs(sdUUID, volUUID)
             # Set metadata and mark volume as legal.
             # FIXME: In next version we should remove imgUUID and srcVolUUID, as they are
saved on lvm tags
             cls.newMetadata([sdUUID, offs], sdUUID, imgUUID, srcVolUUID,

[MERGED PATCH] BZ#716833 - Fix race in metadata offset computation during simultaneously volume creation in block storage domain (via gerrit-bot)

[Igor Lvovsky]

Patch merged into repository

You can review this change at: http://gerrit.usersys.redhat.com/626