From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: with ECARTIS (v1.0.0; list xfs); Mon, 07 May 2007 11:46:21 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com [66.187.233.31]) by oss.sgi.com (8.12.10/8.12.10/SuSE Linux 0.7) with ESMTP id l47IkAfB010835 for ; Mon, 7 May 2007 11:46:12 -0700 Message-ID: <463F7368.8090101@sandeen.net> Date: Mon, 07 May 2007 13:43:52 -0500 From: Eric Sandeen MIME-Version: 1.0 Subject: Re: RESVSP problems References: <200705072004.22848.lucke@o2.pl> In-Reply-To: <200705072004.22848.lucke@o2.pl> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: xfs-bounce@oss.sgi.com Errors-to: xfs-bounce@oss.sgi.com List-Id: xfs To: lucke@o2.pl Cc: xfs@oss.sgi.com Łukasz Fibinger wrote: > Hello, guys, > > I've been trying to implement RESVSP-based allocation in rtorrent. From the > very beginning it has, alas, misbehaved, thus (also considering my very basic > programming skills and experience and unfamiliarity with rtorrent's code) > after hours of trying to determine what's wrong, I finally observed that > blocks of files allocated with RESVSP (previously ftruncated to a proper > size) and being downloaded in rtorrent don't have their unwritten flags > removed (as confirmed by xfs_bmap -vp). You've probably hit: http://oss.sgi.com/bugzilla/show_bug.cgi?id=418 unwritten extents remain unwritten after mmap() modifies them Bug dchinner about it... ;-) > In the effect downloaded file > promptly corrupts (read: changes its md5sum). What is interesting, files > RESVSP-allocated in ktorrent and then imported to rtorrent seem to download > properly. > > Everything works properly with ALLOCSP (although I've noticed that while > RESVSP worked with l_start = 0 and l_length = size, ALLOCSP worked with > l_start = size and l_length = 0; is that intended?). yeah... ISTR that the arguments are funky. I can't remember if it's a bug or not. :) FWIW, allocsp just writes zeros to the file, so you could do it just as well from userspace w/ no fancy ioctls... ALLOCSP is a bit pointless if you ask me... though maybe someone knows why it's there :) -Eric > I'm not quite sure what's at fault here. Perhaps rtorrent, as it prides itself > on "directly between file pages mapped to memory by the mmap() function and > the network stack". I haven't been yet able to determine how it actually > writes chunks to files (aforementioned lacks of skills, experience and > familiarity). Perhaps it's somehow XFS's fault, hence my posting to this ML. > Any help/suggestions would be appreciated. > > Cheers, > > Luke > >