From: Heiko Carstens Subject: Re: Interface for the new fallocate() system call Date: Fri, 30 Mar 2007 10:39:18 +0200 Message-ID: <20070330083918.GD8365@osiris.boeblingen.de.ibm.com> References: <20070117094658.GA17390@amitarora.in.ibm.com> <20070225022326.137b4875.akpm@linux-foundation.org> <20070301183445.GA7911@amitarora.in.ibm.com> <20070316143101.GA10152@amitarora.in.ibm.com> <20070316161704.GE8525@osiris.boeblingen.de.ibm.com> <20070317111036.GC29931@parisc-linux.org> <20070321120425.GA27273@amitarora.in.ibm.com> <20070329115126.GB7374@amitarora.in.ibm.com> <20070329101010.7a2b8783.akpm@linux-foundation.org> <20070330071417.GI355@devserv.devel.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andrew Morton , "Amit K. Arora" , torvalds@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org, xfs@oss.sgi.com, suparna@in.ibm.com, cmm@us.ibm.com To: Jakub Jelinek Return-path: Received: from mtagate3.de.ibm.com ([195.212.29.152]:6190 "EHLO mtagate3.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1945948AbXC3IjV (ORCPT ); Fri, 30 Mar 2007 04:39:21 -0400 Content-Disposition: inline In-Reply-To: <20070330071417.GI355@devserv.devel.redhat.com> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Fri, Mar 30, 2007 at 02:14:17AM -0500, Jakub Jelinek wrote: > On Thu, Mar 29, 2007 at 10:10:10AM -0700, Andrew Morton wrote: > > > Platform: s390 > > > -------------- > > > s390 prefers following layout: > > > > > > int fallocate(int fd, loff_t offset, loff_t len, int mode) > > > > > > For details on why and how "int, int, loff_t, loff_t" is a problem on > > > s390, please see Heiko's mail on 16th March. Here is the link: > > > http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg133595.html > > > > > > Platform: ppc, arm > > > ------------------ > > > ppc (32 bit) has a problem with "int, loff_t, loff_t, int" layout, > > > since this will result in a pad between fd and offset, making seven > > > arguments total - which is not supported by ppc32. It supports only > > > 6 arguments. Thus the desired layout by ppc32 is: > > > > > > int fallocate(int fd, int mode, loff_t offset, loff_t len) > > > > > > Even ARM prefers above kind of layout. For details please see the > > > definition of sys_arm_sync_file_range(). > > > > This is a clean-looking option. Can s390 be changed to support seven-arg > > syscalls? > > Wouldn't > int fallocate(loff_t offset, loff_t len, int fd, int mode) > work on both s390 and ppc/arm? glibc will certainly wrap it and > reorder the arguments as needed, so there is no need to keep fd first. That would be fine for s390.