From: Miklos Szeredi <miklos@szeredi.hu>
Date: Mon, 12 Oct 2015 13:56:20 +0000 (+0200)
Subject: ovl: fix open in stacked overlay
X-Git-Tag: v4.1.12-108.0.20170806_1300~49
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=be7d810e0217b7af18dd3513fcbfb209ac4bee60;p=users%2Fjedix%2Flinux-maple.git

ovl: fix open in stacked overlay

If two overlayfs filesystems are stacked on top of each other, then we need
recursion in ovl_d_select_inode().

I guess d_backing_inode() is supposed to do that.  But currently it doesn't
and that functionality is open coded in vfs_open().  This is now copied
into ovl_d_select_inode() to fix this regression.

Reported-by: Alban Crequy <alban.crequy@gmail.com>
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay...")
Cc: David Howells <dhowells@redhat.com>
Cc: <stable@vger.kernel.org> # v4.2+

Orabug: 26401569

(backport upstream commit 1c8a47df36d72ace8cf78eb6c228aa0f8027d3c2)

Signed-off-by: Shan Hai <shan.hai@oracle.com>
Reviewed-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@oracle.com>
---

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 9934bd993e786..9d41fc376bc9d 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -404,6 +404,9 @@ struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags)
 		ovl_path_upper(dentry, &realpath);
 	}
 
+	if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE)
+		return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags);
+
 	return d_backing_inode(realpath.dentry);
 }