From 22f289ce1f8b10556617157819a48cf13370f06f Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner@kernel.org>
Date: Mon, 4 Apr 2022 12:51:49 +0200
Subject: ovl: use ovl_lookup_upper() wrapper

Introduce ovl_lookup_upper() as a simple wrapper around lookup_one().
Make it clear in the helper's name that this only operates on the upper
layer. The wrapper will take upper layer's idmapping into account when
checking permission in lookup_one().

Cc: <linux-unionfs@vger.kernel.org>
Tested-by: Giuseppe Scrivano <gscrivan@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
---
 fs/overlayfs/overlayfs.h | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'fs/overlayfs/overlayfs.h')

diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index bc81f279b170..e91f0df914f9 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -7,6 +7,7 @@
 #include <linux/kernel.h>
 #include <linux/uuid.h>
 #include <linux/fs.h>
+#include <linux/namei.h>
 #include "ovl_entry.h"
 
 #undef pr_fmt
@@ -310,6 +311,13 @@ static inline struct dentry *ovl_do_tmpfile(struct ovl_fs *ofs,
 	return ret;
 }
 
+static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
+					      const char *name,
+					      struct dentry *base, int len)
+{
+	return lookup_one(ovl_upper_mnt_userns(ofs), name, base, len);
+}
+
 static inline bool ovl_open_flags_need_copy_up(int flags)
 {
 	if (!flags)
-- 
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