From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Kleikamp Subject: Re: files of size larger than fs size Date: Thu, 17 Mar 2005 09:22:35 -0600 Message-ID: <1111072955.8159.15.camel@localhost> References: <42390CFD.3040004@unn.ac.ru> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Bryan Henderson , fsdevel , Phillip Lougher Received: from e31.co.us.ibm.com ([32.97.110.129]:2737 "EHLO e31.co.us.ibm.com") by vger.kernel.org with ESMTP id S263083AbVCQPWi (ORCPT ); Thu, 17 Mar 2005 10:22:38 -0500 Received: from westrelay03.boulder.ibm.com (westrelay03.boulder.ibm.com [9.17.195.12]) by e31.co.us.ibm.com (8.12.10/8.12.9) with ESMTP id j2HFMbua279216 for ; Thu, 17 Mar 2005 10:22:37 -0500 Received: from d03av01.boulder.ibm.com (d03av01.boulder.ibm.com [9.17.195.167]) by westrelay03.boulder.ibm.com (8.12.10/NCO/VER6.6) with ESMTP id j2HFMbql154598 for ; Thu, 17 Mar 2005 08:22:37 -0700 Received: from d03av01.boulder.ibm.com (loopback [127.0.0.1]) by d03av01.boulder.ibm.com (8.12.11/8.12.11) with ESMTP id j2HFMaj8026303 for ; Thu, 17 Mar 2005 08:22:37 -0700 To: Max In-Reply-To: <42390CFD.3040004@unn.ac.ru> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Wed, 2005-03-16 at 20:52 -0800, Max wrote: > 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. man lseek tells you to test the return code against (off_t)-1. I found that for larger values, your test program is returning -1, but unsigned it appears as 18446744073709551615. > > 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 I can speak for jfs, and it supports file sizes up to 2**52. It uses 40 bits to address the logical block offset within a file with a 4K (2**12) size block. The individual file systems set sb->s_maxbytes to the appropriate value. > Thanks, > Max > > P.S. direct link to the testcase program: http://bugzilla.kernel.org/attachment.cgi?id=4729 -- David Kleikamp IBM Linux Technology Center