Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932951Ab1ESPBn (ORCPT ); Thu, 19 May 2011 11:01:43 -0400 Received: from mail-px0-f173.google.com ([209.85.212.173]:37991 "EHLO mail-px0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932548Ab1ESPBm (ORCPT ); Thu, 19 May 2011 11:01:42 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=ttEBC9q7VylZ6J+zGT6wTrbBRYH5OguVUbdGknEuGoPd78BjXSosX0axTwCbxA0Q4q K0xXp2t+J1sjfM12nDifGq0Vq9L7lbwbvft0j0bZj9278sXGHNJH0AQyGSpDvJ2bpVVe eOOIoYpM/7CchP6q84B7uWXQpQix4lYBKTBGs= MIME-Version: 1.0 In-Reply-To: <20110519153928.40521b93@lxorguk.ukuu.org.uk> References: <20110519144312.38177704@lxorguk.ukuu.org.uk> <20110519153928.40521b93@lxorguk.ukuu.org.uk> From: "D. Jansen" Date: Thu, 19 May 2011 17:01:02 +0200 Message-ID: Subject: Re: [rfc] Ignore Fsync Calls in Laptop_Mode To: Alan Cox Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, tytso@mit.edu Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1515 Lines: 37 On Thu, May 19, 2011 at 4:39 PM, Alan Cox wrote: >> > That at least cuts down most failures (but not all - eg commits with a network >> > component such as email receives) >> >> I don't understand your email example. > > Think about sendmail and SMTP > > Mail arrives > Commit to disk > fsync > [X] > Confirm receipt to other system > Other system removes it from the queue it holds > > So if it crashes at X even though you've kept ordering and you've > got an internally consistent view (as if it crashed earlier), that > has been observed and acted upon by another system - so your email > just went into the cosmic trashcan. > > Ok, I think I understand your example. But isn't that the user's risk and more a problem of the general idea of laptop mode? If I enable laptop_mode and set MAX_LOST_WORK_SECONDS, I risk to lose data. I would say that includes email and whatever else may happen. (And if I don't switch it on, I risk running out of battery and being unable to create data...). btw. I don't think it would be a good idea for people to use sendmail or other crucial data storage applications with laptop_mode active. I would see this as a switch for e.g. notebooks at conferences, in class, lectures, etc. (sorry, lost the CCs) -- 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/