From: Miklos Szeredi <mszeredi@redhat.com>
Date: Fri, 29 Jul 2016 10:05:24 +0000 (+0200)
Subject: ovl: disallow overlayfs as upperdir
X-Git-Tag: v4.7.2~116
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=015734c9f4e0da11330a686b7948e5d2e7885352;p=thirdparty%2Fkernel%2Fstable.git

ovl: disallow overlayfs as upperdir

commit 76bc8e2843b66f8205026365966b49ec6da39ae7 upstream.

This does not work and does not make sense.  So instead of fixing it
(probably not hard) just disallow.

Reported-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index 9a7693d5f8fff..6db75cbb668f9 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -404,7 +404,8 @@ static struct ovl_entry *ovl_alloc_entry(unsigned int numlower)
 static bool ovl_dentry_remote(struct dentry *dentry)
 {
 	return dentry->d_flags &
-		(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE);
+		(DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE |
+		 DCACHE_OP_REAL);
 }
 
 static bool ovl_dentry_weird(struct dentry *dentry)