ovl: use ovl_path_getxattr() wrapper

Add a helper that allows to retrieve ovl xattrs from either lower or
upper layers. To stop passing mnt and dentry separately everywhere use
struct path which more accurately reflects the tight coupling between
mount and dentry in this helper. Swich over all places to pass a path
argument that can operate on either upper or lower layers. This is
needed to support idmapped base layers with overlayfs.

Some helpers are always called with an upper dentry, which is now utilized
by these helpers to create the path.  Make this usage explicit by renaming
the argument to "upperdentry" and by renaming the function as well in some
cases.  Also add a check in ovl_do_getxattr() to catch misuse of these
functions.

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>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 927abe7e7ab2..3d58fa721fcc 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -398,7 +398,7 @@ static struct dentry *ovl_clear_empty(struct dentry *dentry,
 	if (IS_ERR(opaquedir))
 		goto out_unlock;
 
-	err = ovl_copy_xattr(dentry->d_sb, upper, opaquedir);
+	err = ovl_copy_xattr(dentry->d_sb, &upperpath, opaquedir);
 	if (err)
 		goto out_cleanup;