LSM: Pass original mount flags to security_sb_mount().

This patch allows LSM modules to determine based on original mount flags
passed to mount(). A LSM module can get masked mount flags (if needed) by

	flags &= ~(MS_NOSUID | MS_NOEXEC | MS_NODEV | MS_ACTIVE |
		   MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
		   MS_STRICTATIME);

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>

fs/namespace.c

@@ -1921,6 +1921,16 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
 	if (data_page)
 		((char *)data_page)[PAGE_SIZE - 1] = 0;
 
+	/* ... and get the mountpoint */
+	retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);
+	if (retval)
+		return retval;
+
+	retval = security_sb_mount(dev_name, &path,
+				   type_page, flags, data_page);
+	if (retval)
+		goto dput_out;
+
 	/* Default to relatime unless overriden */
 	if (!(flags & MS_NOATIME))
 		mnt_flags |= MNT_RELATIME;
@@ -1945,16 +1955,6 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
 		   MS_NOATIME | MS_NODIRATIME | MS_RELATIME| MS_KERNMOUNT |
 		   MS_STRICTATIME);
 
-	/* ... and get the mountpoint */
-	retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);
-	if (retval)
-		return retval;
-
-	retval = security_sb_mount(dev_name, &path,
-				   type_page, flags, data_page);
-	if (retval)
-		goto dput_out;
-
 	if (flags & MS_REMOUNT)
 		retval = do_remount(&path, flags & ~MS_REMOUNT, mnt_flags,
 				    data_page);