ovl: encode lower file handles

For indexed or lower non-dir, encode a non-connectable lower file handle
from origin inode. For indexed or lower dir, when ofs->numlower == 1,
encode a lower file handle from lower dir.
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>

fs/overlayfs/export.c

@@ -90,7 +90,6 @@ static int ovl_encode_maybe_copy_up(struct dentry *dentry)
 
 static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen)
 {
-	struct dentry *upper;
 	struct dentry *origin = ovl_dentry_lower(dentry);
 	struct ovl_fh *fh = NULL;
 	int err;
@@ -107,13 +106,8 @@ static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen)
 		origin = NULL;
 	}
 
-	upper = ovl_dentry_upper(dentry);
-	err = -EACCES;
-	if (!upper || origin)
-		goto fail;
-
-	/* TODO: encode non pure-upper by origin */
-	fh = ovl_encode_fh(upper, true);
+	/* Encode an upper or origin file handle */
+	fh = ovl_encode_fh(origin ?: ovl_dentry_upper(dentry), !origin);
 
 	err = -EOVERFLOW;
 	if (fh->len > buflen)