Do not loop in cifsd demultiplex thread when someone sigkills it.

On unmount of second user on same tcp session, make sure that we
do not kill cifsd prematurely.

Signed-off-by: Steve French (sfrench@us.ibm.com)

fs/cifs/CHANGES

@@ -6,7 +6,8 @@ is the usual maximum active multiplex SMB/CIFS requests per server).
 Do not kill cifsd (and thus hurt the other SMB session) when more than one
 session to the same server (but with different userids) exists and one
 of the two user's smb sessions is being removed while leaving the other.
-
+Do not loop reconnecting in cifsd demultiplex thread when admin
+kills the thread without going through unmount.
 
 Version 1.18
 ------------

fs/cifs/cifssmb.c

@@ -315,8 +315,6 @@ CIFSSMBTDis(const int xid, struct cifsTconInfo *tcon)
 		return 0;  
 	}
 
-/* BB remove (from server) list of shares - but with smp safety  BB */
-/* BB is ses active - do we need to check here - but how? BB */
 	if((tcon->ses == 0) || (tcon->ses->server == 0)) {    
 		up(&tcon->tconSem);
 		return -EIO;

fs/cifs/connect.c

@@ -253,13 +253,12 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 				/* some servers kill tcp session rather than returning
 					smb negprot error in which case reconnecting here is
 					not going to help - return error to mount */
-				spin_lock(&GlobalMid_Lock);
-				server->tcpStatus = CifsExiting;
-				spin_unlock(&GlobalMid_Lock);
-				wake_up(&server->response_q);
 				break;
 			}
-
+			if(length == -EINTR) { 
+				cFYI(1,("cifsd thread killed"));
+				break;
+			}
 			cFYI(1,("Reconnecting after unexpected peek error %d",length));
 			cifs_reconnect(server);
 			csocket = server->ssocket;
@@ -292,11 +291,6 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 					/* if nack on negprot (rather than 
 					ret of smb negprot error) reconnecting
 					not going to help, ret error to mount */
-					spin_lock(&GlobalMid_Lock);
-					server->tcpStatus = CifsExiting;
-					spin_unlock(&GlobalMid_Lock);
-					/* wake up thread doing negprot */
-					wake_up(&server->response_q);
 					break;
 				} else {
 					/* give server a second to
@@ -407,15 +401,19 @@ cifs_demultiplex_thread(struct TCP_Server_Info *server)
 	}
 	spin_lock(&GlobalMid_Lock);
 	server->tcpStatus = CifsExiting;
-	spin_unlock(&GlobalMid_Lock);
+	server->tsk = NULL;
 	atomic_set(&server->inFlight, 0);
+	spin_unlock(&GlobalMid_Lock);
 	/* Although there should not be any requests blocked on 
 	this queue it can not hurt to be paranoid and try to wake up requests
 	that may haven been blocked when more than 50 at time were on the wire 
 	to the same server - they now will see the session is in exit state
 	and get out of SendReceive.  */
-	wake_up_all(&server->request_q);   
-	server->tsk = NULL;
+	wake_up_all(&server->request_q);
+	/* give those requests time to exit */
+	set_current_state(TASK_INTERRUPTIBLE);
+	schedule_timeout(HZ/8);
+
 	if(server->ssocket) {
 		sock_release(csocket);
 		server->ssocket = NULL;
@@ -1358,31 +1356,37 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
 			}
 		}
 	}
-	if (pSesInfo->capabilities & CAP_LARGE_FILES) {
-		cFYI(0, ("Large files supported "));
-		sb->s_maxbytes = (u64) 1 << 63;
-	} else
-		sb->s_maxbytes = (u64) 1 << 31;	/* 2 GB */
+	if(pSesInfo) {
+		if (pSesInfo->capabilities & CAP_LARGE_FILES) {
+			sb->s_maxbytes = (u64) 1 << 63;
+		} else
+			sb->s_maxbytes = (u64) 1 << 31;	/* 2 GB */
+	}
 
 /* on error free sesinfo and tcon struct if needed */
 	if (rc) {
+		/* if session setup failed, use count is zero but
+		we still need to free cifsd thread */
 		if(atomic_read(&srvTcp->socketUseCount) == 0) {
 			spin_lock(&GlobalMid_Lock);
 			srvTcp->tcpStatus = CifsExiting;
 			spin_unlock(&GlobalMid_Lock);
+			if(srvTcp->tsk)
+				send_sig(SIGKILL,srvTcp->tsk,1);
 		}
 		 /* If find_unc succeeded then rc == 0 so we can not end */
-		if (tcon)  /* up here accidently freeing someone elses tcon struct */
+		if (tcon)  /* up accidently freeing someone elses tcon struct */
 			tconInfoFree(tcon);
 		if (existingCifsSes == 0) {
 			if (pSesInfo) {
-				if (pSesInfo->server) {
-					if (pSesInfo->Suid)
-						CIFSSMBLogoff(xid, pSesInfo);
-					if(pSesInfo->server->tsk)
+				if ((pSesInfo->server) && 
+				    (pSesInfo->status == CifsGood)) {
+					int temp_rc;
+					temp_rc = CIFSSMBLogoff(xid, pSesInfo);
+					/* if the socketUseCount is now zero */
+					if((temp_rc == -ESHUTDOWN) &&
+					   (pSesInfo->server->tsk))
 						send_sig(SIGKILL,pSesInfo->server->tsk,1);
-					set_current_state(TASK_INTERRUPTIBLE);
-					schedule_timeout(HZ / 4);	/* give captive thread time to exit */
 				} else
 					cFYI(1, ("No session or bad tcon"));
 				sesInfoFree(pSesInfo);
@@ -2791,12 +2795,6 @@ cifs_umount(struct super_block *sb, struct cifs_sb_info *cifs_sb)
 				FreeXid(xid);
 				return 0;
 			} else if (rc == -ESHUTDOWN) {
-			/* should we add wake_up_all(&server->request_q); 
-			   and add a check in  the check inFlight loop
-			   for the session ending */
-				set_current_state(TASK_INTERRUPTIBLE);
-			/* give captive thread time to exit */
-				schedule_timeout(HZ / 4);
 				cFYI(1,("Waking up socket by sending it signal"));
 				send_sig(SIGKILL,cifsd_task,1);
 				rc = 0;

fs/cifs/file.c

@@ -627,7 +627,6 @@ cifs_write(struct file * file, const char *write_data,
 			while we blocked so return what we managed to write */
 				return total_written;
 			} 
-                        open_file = (struct cifsFileInfo *) file->private_data;
 			if(open_file->closePend) {
 				FreeXid(xid);
 				if(total_written)

fs/cifs/transport.c

@@ -215,8 +215,14 @@ SendReceive(const unsigned int xid, struct cifsSesInfo *ses,
 					 < CIFS_MAX_REQ);
 				spin_lock(&GlobalMid_Lock);
 			} else {
+				if(ses->server->tcpStatus == CifsExiting) {
+					spin_unlock(&GlobalMid_Lock);
+					return -ENOENT;
+				}
+
 			/* can not count locking commands against total since
 			   they are allowed to block on server */
+					
 				if(long_op < 3) {
 				/* update # of requests on the wire to server */
 					atomic_inc(&ses->server->inFlight);