From: "Ricardo M. Correia" Subject: Re: Mentor for a GSoC application wanted (Online ext2/3 filesystem checker) Date: Mon, 21 Apr 2008 18:29:34 +0100 Message-ID: <1208798974.14123.28.camel@localhost> References: <20080419012952.GE25797@mit.edu> <20080419185603.GA30449@mit.edu> <480A42F6.2030005@redhat.com> <20080419220432.GB30449@mit.edu> <87iqyc85q7.fsf@basil.nowhere.org> <20080420234241.GB23292@shareable.org> <20080421080111.GD14446@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Theodore Tso , Eric Sandeen , Alexey Zaytsev , linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org, Rik van Riel To: Andi Kleen Return-path: In-reply-to: <20080421080111.GD14446@one.firstfloor.org> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org (sorry if this is a duplicate, my previous email was rejected) Hi Andi, On Seg, 2008-04-21 at 10:01 +0200, Andi Kleen wrote:=20 > > (I continue to be surprised at the un-safety of Linux fsync) >=20 > Note barrier less does not necessarily always mean unsafe fsync, > it just often means that. Am I correct that the Linux fsync(), when used =EF=BB=BF(from userspace= ) directly on file descriptors associated with block devices doesn't actually flush the disk write cache and wait for the data to reach the disk before returning? Is there a reason why this isn't being done other than performance? I would imagine that the only reason a process is using fsync() is because it is worried about data loss, and therefore is perfectly willing to lose some performance if necessary.. Regards, Ricardo -- Ricardo Manuel Correia Lustre Engineering Sun Microsystems, Inc. Portugal Phone +351.214134023 / x58723 Mobile +351.912590825 Email Ricardo.M.Correia@Sun.COM -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html