fix oops in send_sig on unmount of cifs vfs due to sending signal to...

fix oops in send_sig on unmount of cifs vfs due to sending signal to demultiplex thread after it has exited.  
Do not treat invalid handle warning in response to oplock break (of file that is now closed) as an error.

fs/cifs/CHANGES

-Verison 0.95
+Version 0.96
+------------
+Fix oops (in send_sig) caused by CIFS unmount code trying to
+wake up the demultiplex thread after it had exited. Do not log
+error on harmless oplock release of closed handle.
+
+Version 0.95
 ------------
 Fix unsafe global variable usage and password hash failure on gcc 3.3.1
 Fix problem reconnecting secondary mounts to same server after session 

fs/cifs/connect.c

@@ -317,9 +317,10 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 		}
 	}
 	/* BB add code to lock SMB sessions while releasing */
+        server->tsk = NULL;
 	if(server->ssocket) {
 		sock_release(csocket);
-	    server->ssocket = NULL;
+		server->ssocket = NULL;
 	}
 	set_fs(temp_fs);
 	if (smb_buffer) /* buffer usually freed in free_mid - need to free it on error or exit */
@@ -1064,8 +1065,6 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 						CIFSSMBLogoff(xid, pSesInfo);
 					if(pSesInfo->server->tsk)
 						send_sig(SIGKILL,pSesInfo->server->tsk,1);
-					else
-						cFYI(1,("Can not wake captive thread on cleanup of failed mount"));
 					set_current_state(TASK_INTERRUPTIBLE);
 					schedule_timeout(HZ / 4);	/* give captive thread time to exit */
 				} else

fs/cifs/misc.c

@@ -25,6 +25,8 @@
 #include "cifsglob.h"
 #include "cifsproto.h"
 #include "cifs_debug.h"
+#include "smberr.h"
+#include "nterr.h"
 
 extern kmem_cache_t *cifs_req_cachep;
 extern struct task_struct * oplockThread;
@@ -369,8 +371,22 @@ is_valid_oplock_break(struct smb_hdr *buf)
 	cFYI(1,("Checking for oplock break"));    
 	if(pSMB->hdr.Command != SMB_COM_LOCKING_ANDX)
 		return FALSE;
-	if(pSMB->hdr.Flags & SMBFLG_RESPONSE)
-		return FALSE; /* server sends us "request" here */
+	if(pSMB->hdr.Flags & SMBFLG_RESPONSE) {
+		/* no sense logging error on invalid handle on oplock
+		   break - harmless race between close request and oplock
+		   break response is expected from time to time writing out
+		   large dirty files cached on the client */
+		if ((NT_STATUS_INVALID_HANDLE) == 
+		   le32_to_cpu(pSMB->hdr.Status.CifsError)) { 
+			cFYI(1,("invalid handle on oplock break"));
+			return TRUE;
+		} else if (ERRbadfid == 
+		   le16_to_cpu(pSMB->hdr.Status.DosError.Error)) {
+			return TRUE;	  
+		} else {
+			return FALSE; /* on valid oplock brk we get "request" */
+		}
+	}
 	if(pSMB->hdr.WordCount != 8)
 		return FALSE;