From patchwork Mon Jun 1 13:52:16 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Howells X-Patchwork-Id: 6522271 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 04A9CC0020 for ; Mon, 1 Jun 2015 13:52:27 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 4D983205B7 for ; Mon, 1 Jun 2015 13:52:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E5062058A for ; Mon, 1 Jun 2015 13:52:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753154AbbFANwW (ORCPT ); Mon, 1 Jun 2015 09:52:22 -0400 Received: from mx1.redhat.com ([209.132.183.28]:59563 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751643AbbFANwV convert rfc822-to-8bit (ORCPT ); Mon, 1 Jun 2015 09:52:21 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 3CC83DAF; Mon, 1 Jun 2015 13:52:21 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-112-71.phx2.redhat.com [10.3.112.71]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t51DqHcg026375; Mon, 1 Jun 2015 09:52:18 -0400 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells To: Miklos Szeredi , viro@zeniv.linux.org.uk Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-unionfs@vger.kernel.org, dhowells@redhat.com Subject: Can ovl_drop_write() be called earlier in ovl_dentry_open() MIME-Version: 1.0 Content-ID: <21901.1433166736.1@warthog.procyon.org.uk> Date: Mon, 01 Jun 2015 14:52:16 +0100 Message-ID: <21902.1433166736@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP In ovl_dentry_open(), ovl_drop_write() is called after vfs_open() - but is this actually necessary? Can't we just drop it post-copyup? After all, that's all we wanted the write lock for, right? David --- -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -356,16 +356,14 @@ static int ovl_dentry_open(struct dentry *dentry, struct inode *inode, err = ovl_copy_up_last(dentry, NULL, true); else err = ovl_copy_up(dentry); + ovl_drop_write(dentry); if (err) - goto out_drop_write; + goto out; ovl_path_upper(dentry, &realpath); } err = vfs_open(&realpath, d_backing_inode(realpath.dentry), file, cred); -out_drop_write: - if (want_write) - ovl_drop_write(dentry); out: return err; }