From mboxrd@z Thu Jan 1 00:00:00 1970 From: Max Subject: Re: files of size larger than fs size Date: Wed, 16 Mar 2005 20:52:13 -0800 Message-ID: <42390CFD.3040004@unn.ac.ru> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, Phillip Lougher Received: from pimout2-ext.prodigy.net ([207.115.63.101]:26758 "EHLO pimout2-ext.prodigy.net") by vger.kernel.org with ESMTP id S261833AbVCQExB (ORCPT ); Wed, 16 Mar 2005 23:53:01 -0500 To: Bryan Henderson In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Bryan, I'm not experienced in filesystems. But I've derived the testcase program from some buggy application that occasionally created huge files on my fs. That was not so easy to reproduce since not every sequence of seeks/reads/writes results in a huge file. But finally I got it 100% reproducible. So I would appriciate if somebody make any good from that testcase code. Different filesizes look strange to me. What I have so far: JFS: 281474976706576 = 2**48 - 4080 XFS: 72057594037923856 = 2**56 - 4080 EXT3: 1099511627784 = 2**40 + 8 Thanks, Max P.S. direct link to the testcase program: http://bugzilla.kernel.org/attachment.cgi?id=4729 Bryan Henderson wrote: >>But anyway it's interesting why the resulting sparse >>files have different size on different fs? > > > That looks like a bug. Assuming you didn't see any seeks or writes fail, > the file size on all filesystems should be 2^56 + 4. I suspect this is > beyond the maximum file size allowed by the filesystem in some cases, so > the write isn't happening, which means you should get a failure return > code. > > In the results you showed, the filesize ends up being a little less than > 2^48, which is not a place that you wrote ever. > > -- > Bryan Henderson IBM Almaden Research Center > San Jose CA Filesystems > >