Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758882Ab0GVMZw (ORCPT ); Thu, 22 Jul 2010 08:25:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:25658 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757979Ab0GVMZr (ORCPT ); Thu, 22 Jul 2010 08:25:47 -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 In-Reply-To: References: <20100715021709.5544.64506.stgit@warthog.procyon.org.uk> <20100715021712.5544.44845.stgit@warthog.procyon.org.uk> <20100718084824.GA27794@infradead.org> To: Jan Engelhardt Cc: dhowells@redhat.com, Christoph Hellwig , viro@ZenIV.linux.org.uk, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-kernel@vger.kernel.org, samba-technical@lists.samba.org, linux-ext4@vger.kernel.org, drepper@redhat.com, torvalds@linux-foundation.org Subject: Re: [PATCH 02/18] xstat: Add a pair of system calls to make extended file stats available [ver #6] Date: Thu, 22 Jul 2010 13:25:31 +0100 Message-ID: <30638.1279801531@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1130 Lines: 30 Jan Engelhardt wrote: > >> (8) Allow the filesystem to indicate what it can/cannot provide: A > >> filesystem can now say it doesn't support a standard stat feature if > >> that isn't available. > > > >What for? > > Given xstat.otime=0, how would you determine whether the file is really > tagged with a date of 1970, or whether it's just the fs which didnot > store this kind of information. I was thinking more of stuff that's already in the Linux stat struct, some of which is fabricated because the underlying fs doesn't support it. Take RomFS for example: it fabricates all of st_mtime, st_atime, st_ctime, st_nlinks, st_blocks, st_uid and st_gid because none of them are stored in the medium Similarly, UbiFS fabricates st_blocks and complains in a comment that it makes no sense for that type of filesystem. There are other examples. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/