From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 26 Aug 2002 07:49:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 26 Aug 2002 07:49:51 -0400 Received: from carisma.slowglass.com ([195.224.96.167]:21006 "EHLO phoenix.infradead.org") by vger.kernel.org with ESMTP id ; Mon, 26 Aug 2002 07:49:51 -0400 Date: Mon, 26 Aug 2002 12:54:06 +0100 From: Christoph Hellwig To: Alan Cox Cc: linux-kernel@vger.kernel.org Subject: Re: Linux 2.4.20-pre4-ac2 Message-ID: <20020826125406.A25513@infradead.org> Mail-Followup-To: Christoph Hellwig , Alan Cox , linux-kernel@vger.kernel.org References: <200208261035.g7QAZ4G19985@devserv.devel.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <200208261035.g7QAZ4G19985@devserv.devel.redhat.com>; from alan@redhat.com on Mon, Aug 26, 2002 at 06:35:04AM -0400 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 26, 2002 at 06:35:04AM -0400, Alan Cox wrote: > o Khttpd race fixes (Dan Kegel) This includes some wrong documentation updates: + kHTTPd is *not* currently compatible with tmpfs. Trying to serve + files stored on a tmpfs partition is known to cause kernel oopses + as of 2.4.18. This is due to the same problem that prevents sendfile() + from being usable with tmpfs. A tmpfs patch is floating around that seems + to fix this, but has not been released as of 27 May 2002. + kHTTPD does work fine with ramfs, though. This is _not_ a problem with tmpfs, but with khttpd. The same problem is also present with nay filesystem that uses the pagecache but not generic_file_read or a non-trivial wrapper around generic_file_read, such as smbfs, ncpff, nfs, (open-)gfs, or xfs. This might not always mean those filesystems don't work at all with khttpd, but at least it opens race conditions. khttpd uses do_generic_file_read directly instead of using a file operation, and the problem is that do_generic_file_read should never have been exported to allow such a layering violation. sendfile() and the loop driver have the same issue. In 2.5 of those only the loop issue is still existant, and I plan to fix that one and make do_generic_file_read static. + There is debate about whether to remove kHTTPd from the main + kernel sources. This will probably happen in the 2.5 kernel series, + after which khttpd will still be available as a patch. khttpd is gone in 2.5