From: Steven Whitehouse <swhiteho@redhat.com>
To: Pavel Machek <pavel@ucw.cz>
Cc: yangsheng <sickamd@gmail.com>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org
Subject: Re: [PATCH] Update atime from future.
Date: Thu, 13 Jan 2011 14:18:57 +0000 [thread overview]
Message-ID: <1294928337.2401.28.camel@dolmen> (raw)
In-Reply-To: <20110111133314.GA10705@atrey.karlin.mff.cuni.cz>
Hi,
On Tue, 2011-01-11 at 14:33 +0100, Pavel Machek wrote:
> return 1;
> > > + /*
> > > + * Is the previous atime value old than a day? If yes,
> > > * update atime:
> > > */
> > > if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
> >
> > I don't think this is a good plan for cluster filesystems, since if the
> > times on the nodes are not exactly synchronised (we do highly recommend
> > people run ntp or similar) then this might lead to excessive atime
> > updating. The current behaviour is to ignore atimes which are in the
> > future for exactly this reason,
>
> Well, would these "update storms" really be a problem?
>
> AFAICT they should be fairly non-frequent, and worst thing that can
> happen is that you'll do as many updates as different time settings,
> settling for the lowest value...?
> Pavel
Sorry for the delay in replying. It has been a problem in the past,
certainly. I think it is best to be cautious in this case, since that
way we can be sure it won't be a problem. The chosen solution looks ok
to me,
Steve.
next prev parent reply other threads:[~2011-01-13 14:18 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-29 13:58 [PATCH] Update atime from future yangsheng
2011-01-03 10:17 ` Andrew Morton
2011-01-03 12:54 ` YangSheng
2011-01-04 14:56 ` Rogier Wolff
2011-01-03 10:27 ` Steven Whitehouse
2011-01-03 16:27 ` Andreas Dilger
2011-01-03 16:41 ` Steven Whitehouse
2011-01-03 16:44 ` YangSheng
2011-01-11 13:33 ` Pavel Machek
2011-01-13 14:18 ` Steven Whitehouse [this message]
-- strict thread matches above, loose matches on Subject: below --
2011-01-04 9:08 yangsheng
2012-12-03 17:56 yangsheng
2012-12-03 18:08 ` Greg KH
2012-12-04 19:41 ` Zach Brown
2012-12-04 20:24 ` Dave Chinner
2012-12-05 0:22 ` Andreas Dilger
2012-12-07 0:49 ` Dave Chinner
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