From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Nieder Subject: [PATCH 9/9] racy-git.txt: explain nsec problem in more detail Date: Fri, 9 Oct 2009 05:25:54 -0500 Message-ID: <20091009102554.GI16558@progeny.tock> References: <20091009101400.GA16549@progeny.tock> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Junio C Hamano To: git@vger.kernel.org X-From: git-owner@vger.kernel.org Fri Oct 09 12:23:31 2009 Return-path: Envelope-to: gcvg-git-2@lo.gmane.org Received: from vger.kernel.org ([209.132.176.167]) by lo.gmane.org with esmtp (Exim 4.50) id 1MwCcR-0007cM-4l for gcvg-git-2@lo.gmane.org; Fri, 09 Oct 2009 12:22:39 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760651AbZJIKSU convert rfc822-to-quoted-printable (ORCPT ); Fri, 9 Oct 2009 06:18:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760648AbZJIKSU (ORCPT ); Fri, 9 Oct 2009 06:18:20 -0400 Received: from mail-yw0-f176.google.com ([209.85.211.176]:34432 "EHLO mail-yw0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760646AbZJIKST (ORCPT ); Fri, 9 Oct 2009 06:18:19 -0400 Received: by ywh6 with SMTP id 6so6102824ywh.4 for ; Fri, 09 Oct 2009 03:17:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:date:from:to:cc:subject :message-id:references:mime-version:content-type:content-disposition :content-transfer-encoding:in-reply-to:user-agent; bh=hHnXZeAMwgA1LpEo5d9lLjGbkZ6+l1bCIGaFM026Wfs=; b=ikCBFRuKY4SGTOr6EoMwUW+wRNCToYr1+Iv+ZXkE28dQ8OYqc+v6fgmO8VCCBu39Xx gUO34ZEqK3x4qL6OblERRxGnNE2k8H7grfIgg8ljj7o0ugYev5UJ22RslNAcMvEIM4yA HgqaSbS9OFkx7H8RHhbWr8NWP86ehY7bPv2Cc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:content-transfer-encoding :in-reply-to:user-agent; b=YLMjz6VNy1bFV1V9z6FkAGwfFOj/9wmHjAWMip7cacLgfuM0tPLx9kO3YLecWwbP5l o+fZPCcnRuY+gbSXt3AGvE2VE2CAvoYvmWPwATdwwJxjm7JisH7FQzTPTvZEO/lPOpg2 ZAn/Dal2a20zSQJaOs4Rn1ri2wRiTO6Q4yL6c= Received: by 10.151.92.3 with SMTP id u3mr4439594ybl.145.1255083463041; Fri, 09 Oct 2009 03:17:43 -0700 (PDT) Received: from progeny.tock (c-98-212-3-231.hsd1.il.comcast.net [98.212.3.231]) by mx.google.com with ESMTPS id 16sm450617gxk.7.2009.10.09.03.17.41 (version=SSLv3 cipher=RC4-MD5); Fri, 09 Oct 2009 03:17:41 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20091009101400.GA16549@progeny.tock> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Idealists may want USE_NSEC to be the default on Linux some day. Point to a patch to better explain the requirements on filesystem code for that to happen. Signed-off-by: Jonathan Nieder --- Am I understanding the problem here correctly? It seems to me that ext2/3/4, tmpfs, ntfs, and so on shouldn=E2=80=99t have problems with USE_NSEC, and all that is left is the monster that is networked filesystems. Documentation/technical/racy-git.txt | 10 ++++++---- 1 files changed, 6 insertions(+), 4 deletions(-) diff --git a/Documentation/technical/racy-git.txt b/Documentation/techn= ical/racy-git.txt index 48bb97f..53aa0c8 100644 --- a/Documentation/technical/racy-git.txt +++ b/Documentation/technical/racy-git.txt @@ -42,10 +42,12 @@ compared, but this is not enabled by default becaus= e this member is not stable on network filesystems. With `USE_NSEC` compile-time option, `st_mtim.tv_nsec` and `st_ctim.tv_nsec` members are also compared, but this is not enabled by default -because the value of this member becomes meaningless once the -inode is evicted from the inode cache on filesystems that do not -store it on disk. - +because in-core timestamps can have finer granularity than +on-disk timestamps, resulting in meaningless changes when an +inode is evicted from the inode cache. See commit 8ce13b0 +of git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git +([PATCH] Sync in core time granuality with filesystems, +2005-01-04). =20 Racy git -------- --=20 1.6.5.rc1.199.g596ec