diff -r c1f20ce4abcf -r 3e88ff8f41d5 userlibandfileserver/fileserver/sfile/sf_plugin_ops.cpp
--- a/userlibandfileserver/fileserver/sfile/sf_plugin_ops.cpp	Tue Aug 31 16:34:26 2010 +0300
+++ b/userlibandfileserver/fileserver/sfile/sf_plugin_ops.cpp	Wed Sep 01 12:34:56 2010 +0100
@@ -153,7 +153,7 @@
 	if(pF->IsDriveSupported(drive) == EFalse)
 		return KErrNotSupported;
 
-	FsPluginManager::ReadLockChain();
+	FsPluginManager::LockChain();
 	err = FsPluginManager::IsInChain(pF->UniquePosition(),aRequest->Message().Int2(),aRequest->Message().Int1(), pF);
 
 	// plugin might have been mounted in different pos and drive. Find the right one
@@ -209,7 +209,7 @@
 
 	TInt drive = aRequest->Message().Int1();
 
-	FsPluginManager::WriteLockChain();
+	FsPluginManager::LockChain();
 
 	TInt err = FsPluginManager::IsInChain(pF->UniquePosition(),aRequest->Message().Int2(),drive, pF);
 	if(err >= 0)
@@ -219,8 +219,11 @@
 		err = FsPluginManager::Plugin(plugin, pos);
 		if(err == KErrNone)
 			{
-			FsPluginManager::DismountPlugin(*pF,pos);
-			aRequest->SetScratchValue(0);
+			if(aRequest->iCurrentPlugin == plugin)
+				{
+				FsPluginManager::DismountPlugin(*pF,pos);
+				aRequest->SetScratchValue(0);
+				}
 			}
 		}
 	FsPluginManager::UnlockChain();
@@ -247,7 +250,7 @@
 TInt TFsPluginName::DoRequestL(CFsRequest* aRequest)
 	{
 	CFsPlugin* plugin=NULL;
-	FsPluginManager::ReadLockChain();
+	FsPluginManager::LockChain();
 	TInt err = FsPluginManager::Plugin(plugin, aRequest->Message().Int2());
 	if(err != KErrNone) //should be ok but just in case
 	    {