GFS2: smbd proccess hangs with flock() call.

GFS2 currently does not support mandatory flocks. An flock() call with
LOCK_MAND triggers unexpected behavior because gfs2 is not checking for
this lock type. This patch corrects that.
Signed-off-by: NAbhi Das <adas@redhat.com>
Signed-off-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/file.c

@@ -698,8 +698,8 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
 
 	if (!(fl->fl_flags & FL_FLOCK))
 		return -ENOLCK;
-	if (__mandatory_lock(&ip->i_inode))
-		return -ENOLCK;
+	if (fl->fl_type & LOCK_MAND)
+		return -EOPNOTSUPP;
 
 	if (fl->fl_type == F_UNLCK) {
 		do_unflock(file, fl);