Windows: Hold PagingResource across ExtendingWrite

When the file allocation size changes the PagingResource must
be held exclusively to prevent races.

Change-Id: I6ff3a2061563dbb858bb284b463913f6d3b33e7a
Reviewed-on: http://gerrit.openafs.org/7223
Reviewed-by: Peter Scott <pscott@kerneldrivers.com>
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Jeffrey Altman <jaltman@secure-endpoints.com>
Tested-by: Jeffrey Altman <jaltman@secure-endpoints.com>

diff --git a/src/WINNT/afsrdr/kernel/lib/AFSWrite.cpp b/src/WINNT/afsrdr/kernel/lib/AFSWrite.cpp
index 5a94875f8acdb0368292aa033121a121aa8ca790..a9b5225fd12df2fcc2bdfc76c07db6215606d4d5 100644 (file)
--- a/src/WINNT/afsrdr/kernel/lib/AFSWrite.cpp
+++ b/src/WINNT/afsrdr/kernel/lib/AFSWrite.cpp
@@ -1657,6 +1657,15 @@ AFSExtendingWrite( IN AFSFcb *Fcb,
     NTSTATUS      ntStatus = STATUS_SUCCESS;
     AFSCcb       *pCcb = (AFSCcb *)FileObject->FsContext2;
 
+    AFSDbgLogMsg( AFS_SUBSYSTEM_LOCK_PROCESSING,
+                  AFS_TRACE_LEVEL_VERBOSE,
+                  "AFSExtendingWrite Acquiring Fcb PagingIo lock %08lX EXCL %08lX\n",
+                  &Fcb->NPFcb->PagingResource,
+                  PsGetCurrentThread());
+
+    AFSAcquireExcl( &Fcb->NPFcb->PagingResource,
+                    TRUE);
+
     if( NewLength > Fcb->Header.AllocationSize.QuadPart)
     {
 
@@ -1681,12 +1690,6 @@ AFSExtendingWrite( IN AFSFcb *Fcb,
                                          Fcb->ObjectInformation,
                                          &pCcb->AuthGroup);
 
-    AFSDbgLogMsg( AFS_SUBSYSTEM_LOCK_PROCESSING,
-                  AFS_TRACE_LEVEL_VERBOSE,
-                  "AFSExtendingWrite Acquiring Fcb lock %08lX EXCL %08lX\n",
-                  &Fcb->NPFcb->Resource,
-                  PsGetCurrentThread());
-
     if (NT_SUCCESS(ntStatus))
     {
 
@@ -1710,6 +1713,8 @@ AFSExtendingWrite( IN AFSFcb *Fcb,
         Fcb->Header.AllocationSize = liSaveAllocation;
     }
 
+    AFSReleaseResource( &Fcb->NPFcb->PagingResource);
+
     //
     // DownConvert file resource to shared
     //