CRED: Pass credentials through dentry_open()

Pass credentials through dentry_open() so that the COW creds patch can have
SELinux's flush_unauthorized_files() pass the appropriate creds back to itself
when it opens its null chardev.

The security_dentry_open() call also now takes a creds pointer, as does the
dentry_open hook in struct security_operations.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index 625abf5..ec16255 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -307,7 +307,8 @@
 			goto out;
 		}
 
-		filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY);
+		filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
+				   current_cred());
 		if (IS_ERR(filp)) {
 			err = PTR_ERR(filp);
 			goto out;