From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulrich Drepper Subject: Re: NFSv4/pNFS possible POSIX I/O API standards Date: Fri, 15 Dec 2006 14:37:00 -0800 Message-ID: <4583238C.1020100@redhat.com> References: <4574C48A.8030007@mcs.anl.gov> <1165298200.5776.26.camel@lade.trondhjem.org> <20061205100748.GC5871@infradead.org> <4575E9B0.3060908@mcs.anl.gov> <20061205220538.GA1988@infradead.org> <45760702.6040805@redhat.com> <20061206100614.GX5937@schatzie.adilger.int> <4576FBB0.2070704@redhat.com> <4576FD78.4040603@mcs.anl.gov> <4577011F.6040107@redhat.com> <20061207055716.GM5937@schatzie.adilger.int> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mx1.redhat.com ([66.187.233.31]:50698 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752130AbWLOWhg (ORCPT ); Fri, 15 Dec 2006 17:37:36 -0500 To: Ulrich Drepper , Rob Ross , Christoph Hellwig , Trond Myklebust , Sage Weil , Brad Boyer , Anton Altaparmakov , Gary Grider , linux-fsdevel@vger.kernel.org In-Reply-To: <20061207055716.GM5937@schatzie.adilger.int> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Andreas Dilger wrote: > IMHO, once part of the information is optional, why bother making ANY > of it required? Consider "ls -s" on a distributed filesystem that ha= s > UID+GID mapping. It doesn't actually NEED to return the UID+GID to l= s > for each file, since it won't be shown, but if that is part of the=20 > "required" fields then the filesystem would have to remap each UID+GI= D > on each file in the directory. Similar arguments can be made for "fi= nd" > with various options (-atime, -mtime, etc) where any one of the "requ= ired" > parameters isn't needed. The kernel at least has to clear the fields in the stat structure in an= y=20 case. So, if information is easily available, why add another 'if' in=20 the case if the real information can be filled in just as easily? I don't know the kernel code but I would sincerely look at this case.=20 The extra 'if's might be more expensive than just doing it. > I used to think this also, but even though Lustre supplies d_type inf= o > GNU ls will still do stat operations because "ls --color" depends on > st_mode in order to color executable files differently. Right, and only executables. You can easily leave out the :ex=3D*** part of LS_COLORS. I don't think it's useful to introduce a new system call just to have=20 this support. --=20 =E2=9E=A7 Ulrich Drepper =E2=9E=A7 Red Hat, Inc. =E2=9E=A7 444 Castro S= t =E2=9E=A7 Mountain View, CA =E2=9D=96 - 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