linux-kernel - [PATCH 4.4 046/138] ovl: disallow overlayfs as upperdir

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Date:	Thu, 18 Aug 2016 15:57:36 +0200
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Andrei Vagin <avagin@...il.com>,
	Miklos Szeredi <mszeredi@...hat.com>
Subject: [PATCH 4.4 046/138] ovl: disallow overlayfs as upperdir

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Miklos Szeredi <mszeredi@...hat.com>

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@...il.com>
Signed-off-by: Miklos Szeredi <mszeredi@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/overlayfs/super.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -376,7 +376,8 @@ static struct ovl_entry *ovl_alloc_entry
 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)