From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: [PATCH 1/6] xstat: Add a pair of system calls to make extended file stats available Date: Tue, 01 May 2012 00:31:36 +0100 Message-ID: <1335828696.8274.22.camel@deadeye> References: <20120430162715.GS3932@decadent.org.uk> <29495.1335816956@redhat.com> <20120430203053.GB20420@fieldses.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-vI4MeB/aufFS92SKJoQw" Cc: David Howells , linux-fsdevel@vger.kernel.org To: "J. Bruce Fields" Return-path: Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:44994 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757408Ab2D3Xbs (ORCPT ); Mon, 30 Apr 2012 19:31:48 -0400 In-Reply-To: <20120430203053.GB20420@fieldses.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: --=-vI4MeB/aufFS92SKJoQw Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2012-04-30 at 16:30 -0400, J. Bruce Fields wrote: > On Mon, Apr 30, 2012 at 09:15:56PM +0100, David Howells wrote: > > Ben Hutchings wrote: > >=20 > > > Try 86,400 seconds - the actual granularity of atime on VFAT. > >=20 > > 24 hours? Really? I guess it makes the updating of atime on the media > > something you can be lazy about. > >=20 > > > (For mtime it's 2 seconds, and for ctime 0.01 seconds.) >=20 > Does it actually support ctime, or is there some confusion here between > unix ctime and file creation time? I think there is some confusion, yes. The Linux implementation stores ctime, but the documentation I can find refers to creation time. > > Sigh. Okay. Ugh. I guess I need separate granularities after all... = Not > > only that, but a 32-bit integer isn't sufficiently capacious to hold th= e full > > range I now know about (1nS up to 1 day). > >=20 > > I wonder if granularity should be left to a statfsxat() syscall? > >=20 > > And I know Linus didn't like it, but I wonder if I can pack it in to a = 32-bit > > word either by doing an x * 10^y thing. >=20 > Does it matter if we don't get vfat's atime granularity exactly right? > Is anyone ever going to use it for anything? I thought the point of this extension was to let callers know what information we *really* have. In which case, let's not cop out on this. Ben. --=20 Ben Hutchings Design a system any fool can use, and only a fool will want to use it. --=-vI4MeB/aufFS92SKJoQw Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIVAwUAT58g2Oe/yOyVhhEJAQr/Dw/+LQReq7syR/GS4EyuU62QD1po9wfx1ZEm jWgB1IUlxaQBYrxJixg5xJIeOKohyR77DDuWOIC5IGweyWBHkalM+scyfByAd7l9 cj98dL1JadG5xNrKU3F2Q+tnS3to1AJ8oGJzFwn6DnJMVzrlyDbEhoZKy+J5jjEL LKtCQL3cHMFRc1CDG//NkvlFh1jzA3hssm0rLLnuK7ZklFnrWwj1wLuQ4t5ectMv mbAMupNP3QmKkPehXvNkLErI7b/t/6+7nJ7HOmZuxzvK1scglarob1kmG3tJsRo7 rq5h1ugsfP/jZYg7c+8FrrspeUH9B9rhvZ4I7LwKcyWgCPnpkrMyXftR/QboJwW5 jMmk1rTgL0Gq9gZDSAP5ifRP7vt1gEXFEXhNWT/c0nNcbCRe9s/QsbuG6nlVP5I6 iRK0c/XoTLiXthde8SKY89NEEe33GwfqI13pyTUc6JrKc8wpf7DYCzgxs/x42KeU H4CXDeboSeFD4kYNS/zbIzeLrX697ns7+GFPKI75jVTE/swnzYHM04d2jMvvaJmJ 7szcGStPRNUdW4IZtTne946W/R0gu6C4oN0Fck0QP0GXWNbAUQVJDCzIchXmMatl 3tyJ/gbFtFrGucsFuei/0a84Aj+vXewXTGQVHkRs9pi2+BKqTBhylzd0n6g3a85Y Dbj6pnvmIZk= =StNG -----END PGP SIGNATURE----- --=-vI4MeB/aufFS92SKJoQw--