From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 461F1C3B187 for ; Wed, 12 Feb 2020 19:51:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2897321569 for ; Wed, 12 Feb 2020 19:51:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728226AbgBLTva (ORCPT ); Wed, 12 Feb 2020 14:51:30 -0500 Received: from zeniv.linux.org.uk ([195.92.253.2]:42906 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727361AbgBLTva (ORCPT ); Wed, 12 Feb 2020 14:51:30 -0500 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1j1y2Y-00BZG4-EI; Wed, 12 Feb 2020 19:51:18 +0000 Date: Wed, 12 Feb 2020 19:51:18 +0000 From: Al Viro To: Florian Weimer Cc: "Darrick J. Wong" , Christoph Hellwig , linux-xfs@vger.kernel.org, libc-alpha@sourceware.org, linux-fsdevel@vger.kernel.org, Rich Felker Subject: Re: XFS reports lchmod failure, but changes file system contents Message-ID: <20200212195118.GN23230@ZenIV.linux.org.uk> References: <874kvwowke.fsf@mid.deneb.enyo.de> <20200212161604.GP6870@magnolia> <20200212181128.GA31394@infradead.org> <20200212183718.GQ6870@magnolia> <87d0ajmxc3.fsf@mid.deneb.enyo.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87d0ajmxc3.fsf@mid.deneb.enyo.de> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Wed, Feb 12, 2020 at 08:15:08PM +0100, Florian Weimer wrote: > | Further, I've found some inconsistent behavior with ext4: chmod on the > | magic symlink fails with EOPNOTSUPP as in Florian's test, but fchmod > | on the O_PATH fd succeeds and changes the symlink mode. This is with > | 5.4. Cany anyone else confirm this? Is it a problem? > > It looks broken to me because fchmod (as an inode-changing operation) > is not supposed to work on O_PATH descriptors. Why? O_PATH does have an associated inode just fine; where does that "not supposed to" come from?