From: Eric Sandeen Subject: Re: [PATCH 5 2/4] Return 32/64-bit dir name hash according to usage type Date: Wed, 25 Apr 2012 10:36:36 -0500 Message-ID: <4F981A04.1090802@redhat.com> References: <20120109132137.2616029.76288.stgit@localhost.localdomain> <20120109132148.2616029.68798.stgit@localhost.localdomain> <4F91C15B.6070200@redhat.com> <4F93FED6.6090505@itwm.fraunhofer.de> <4F95BD72.6090200@redhat.com> <4F95C109.1030401@itwm.fraunhofer.de> <4F95D65A.8070608@redhat.com> <4F96D08B.2020606@itwm.fraunhofer.de> <4F96FD45.9080902@redhat.com> <4F971602.7090005@itwm.fraunhofer.de> <4F9812C7.3020300@redhat.com> <4F981458.1010708@itwm.fraunhofer.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Andreas Dilger , linux-ext4@vger.kernel.org, Fan Yong , bfields@redhat.com To: Bernd Schubert Return-path: Received: from mx1.redhat.com ([209.132.183.28]:17779 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755187Ab2DYPgl (ORCPT ); Wed, 25 Apr 2012 11:36:41 -0400 In-Reply-To: <4F981458.1010708@itwm.fraunhofer.de> Sender: linux-ext4-owner@vger.kernel.org List-ID: On 4/25/12 10:12 AM, Bernd Schubert wrote: > On 04/25/2012 05:05 PM, Eric Sandeen wrote: >> On 4/24/12 5:24 PM, Andreas Dilger wrote: >>> On 2012-04-24, at 4:07 PM, Bernd Schubert wrote: >>>>> 1) For SEEK_END, we now return -EINVAL for a positive offset >>>>> (i.e. past EOF) >>>> >>>> I definitely introduces that one, as I cannot see how an >>>> application might ever run into it. Especially as ext4 >>>> directories cannot shrink. So if an application tries to exceed >>>> the directory size limit, it looks to me as some of attempt to >>>> break something or as an error in the application. However, if >>>> there should be the slightest chance to break existing >>>> applications relying on that, we need to remove that. >>> >>> I think the other reason to avoid SEEK_END + n is that since >>> SEEK_END for a hash offset is (signed) MAX_LONG, so if one seeks >>> beyond that it will wrap to a negative offset. >> >> Makes sense. >> >> Wishing this had been done as a separate patch, though, since it's >> really addressing a separate issue from the $SUBJECT, and could >> have used specific documentation of the change. Nitpicky I know, >> but it helps. > > Sorry, my fault. No worries, I should have reviewed sooner too :) > Maybe we should simply document it in the code? And > how do we proceed in general. Shall I write a patch to use > generic_file_llseek() and update that function to take more > arguments? I don't think that would go into 3.4. Unless there is obviously _wrong_ behavior to be fixed I don't think it's needed for 3.4. We could maybe do one patch to make it lockless again, if there's good confidence in that, since it's sort of a "regression." Trying to munge things into the upstream seek function would be post-3.4, I'm sure, if it turns out it can be done at all. Thanks, -Eric > Thanks, Bernd