From: Theodore Tso Subject: Re: [PATCH][BUG] ext4: dx_map_entry cannot support over 64KB block size Date: Sun, 21 Jun 2009 22:47:57 -0400 Message-ID: <20090622024757.GB26079@mit.edu> References: <20090605165049.e8bd9c74.toshi.okajima@jp.fujitsu.com> <20090605212000.GV9002@webber.adilger.int> <20090608163055.0eab9737.toshi.okajima@jp.fujitsu.com> <20090621035731.GA6719@mit.edu> <4A3EE269.3020704@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andreas Dilger , linux-ext4@vger.kernel.org To: Toshiyuki Okajima Return-path: Received: from THUNK.ORG ([69.25.196.29]:38480 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751403AbZFVCsA (ORCPT ); Sun, 21 Jun 2009 22:48:00 -0400 Content-Disposition: inline In-Reply-To: <4A3EE269.3020704@jp.fujitsu.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, Jun 22, 2009 at 10:46:17AM +0900, Toshiyuki Okajima wrote: > I have been reviewing the logic around dir_index(fs/ext4/dir.c > fs/ext4/namei.c) for the sake of performance and quality > improvement. Then I found this bug. Sorry, therefore it is not a > result of the real test. I've started doing some testing on the e2fsprogs side, and fixed some problems in for the upcoming e2fsprogs 1.41.7, but both the kernel and e2fsprogs currently don't officially support a blocksize larger than 64k. At least e2fsprogs in the git tree will mke2fs that passes e2fsck for a 128k block filesystem; this is *not* yet true for 256k block filesystems (but it requires some commits in the 64k block numbers patches which I don't want to merge into the maint branch). Are you aware of any patches that enable an IA64 system to support a page size greater than 64kB? (And whether any customer would actually want to use them, given the downsides of very large page size?) The issue is that Linux doesn't support filesystem block sizes > than the page size. In any case, I don't mind adding patches that attempt to make it better to support large block sizes; I don't really want to claim that we support it until we can actually fully test for that feature, though. Is it your intent to actually try to provide support for this at some point? I'll help you if you are, but you'll have to do the testing, since I don't have access to an IA64 platform that might be able to support these sorts of large pages. Thanks, - Ted