From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam03on0076.outbound.protection.outlook.com ([104.47.42.76]:39230 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753228AbeGBIqw (ORCPT ); Mon, 2 Jul 2018 04:46:52 -0400 Date: Mon, 2 Jul 2018 11:46:22 +0300 From: Yury Norov To: Florian Weimer Cc: libc-alpha@sourceware.org, Alexander Viro , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org Subject: Re: [PATCH] Add renameat2 function [BZ #17662] Message-ID: <20180702084622.GA15274@yury-thinkpad> References: <20180630121447.E4C8643994575@oldenburg.str.redhat.com> <20180701214901.GA32498@yury-thinkpad> <60505ccf-a399-6320-74f5-e2e17965d25c@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <60505ccf-a399-6320-74f5-e2e17965d25c@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: + Alexander Viro , kernel maillists. On Mon, Jul 02, 2018 at 08:48:36AM +0200, Florian Weimer wrote: > On 07/01/2018 11:49 PM, Yury Norov wrote: > > > > +#ifdef __USE_GNU > > > +/* Flags for renameat. */ > > > > Flags for renameat2, right? > > Thanks, fixed. > > > > +# define RENAME_NOREPLACE (1 << 0) > > > +# define RENAME_EXCHANGE (1 << 1) > > > +# define RENAME_WHITEOUT (1 << 2) > > > > I really don't understand how it works. Could you / somebody explain me? > > > > include/uapi/linux/fs.h in kernel sources already defines this flags, > > and this file is usually available in Linux distribution. So I don't > > understand what for it is duplicated here. If you keep in mind > > old linux headers or non-linux systems, I think it should be protected > > with #ifndef guards. > > undefines and defines macros not mentioned in the standards > (and it even contains a few unrelated structs), so we cannot include it > without _GNU_SOURCE. > > It might be possible to include it only for _GNU_SOURCE, but there are a > lot of things in , so that does not seem to be particularly > advisable. > > We still support building glibc with 3.2 kernel headers, and if the > definitions you quoted above are not available, building the test case > would fail. Is my understanding correct that glibc community finds inappropriate for their use, and prefer to re-introduce (duplicate) its functionality locally? I think it's wrong. The right way to go is to make kernel headers comfortable for users instead of ignoring it. Are you OK to switch to kernel RENAME_* definitions if they will be located in separated small file? Like in the patch below. Signed-off-by: Yury Norov --- include/uapi/linux/fs.h | 4 +--- include/uapi/linux/rename.h | 12 ++++++++++++ 2 files changed, 13 insertions(+), 3 deletions(-) create mode 100644 include/uapi/linux/rename.h diff --git a/include/uapi/linux/fs.h b/include/uapi/linux/fs.h index c27576d471c2..46c03ea31a76 100644 --- a/include/uapi/linux/fs.h +++ b/include/uapi/linux/fs.h @@ -44,9 +44,7 @@ #define SEEK_HOLE 4 /* seek to the next hole */ #define SEEK_MAX SEEK_HOLE -#define RENAME_NOREPLACE (1 << 0) /* Don't overwrite target */ -#define RENAME_EXCHANGE (1 << 1) /* Exchange source and dest */ -#define RENAME_WHITEOUT (1 << 2) /* Whiteout source */ +#include struct file_clone_range { __s64 src_fd; diff --git a/include/uapi/linux/rename.h b/include/uapi/linux/rename.h new file mode 100644 index 000000000000..7178f0565657 --- /dev/null +++ b/include/uapi/linux/rename.h @@ -0,0 +1,12 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _UAPI_LINUX_RENAME_H +#define _UAPI_LINUX_RENAME_H + +/* + * Definitions for rename syscall family. + */ +#define RENAME_NOREPLACE (1 << 0) /* Don't overwrite target */ +#define RENAME_EXCHANGE (1 << 1) /* Exchange source and dest */ +#define RENAME_WHITEOUT (1 << 2) /* Whiteout source */ + +#endif /* _UAPI_LINUX_RENAME_H */ -- 2.17.1