From patchwork Mon Feb 23 03:25:40 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Theodore Ts'o X-Patchwork-Id: 23549 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by ozlabs.org (Postfix) with ESMTP id 2E1FFDDDFF for ; Mon, 23 Feb 2009 14:25:48 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751146AbZBWDZr (ORCPT ); Sun, 22 Feb 2009 22:25:47 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751234AbZBWDZq (ORCPT ); Sun, 22 Feb 2009 22:25:46 -0500 Received: from thunk.org ([69.25.196.29]:37052 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751146AbZBWDZq (ORCPT ); Sun, 22 Feb 2009 22:25:46 -0500 Received: from root (helo=closure.thunk.org) by thunker.thunk.org with local-esmtp (Exim 4.50 #1 (Debian)) id 1LbRRw-0003W8-4v; Sun, 22 Feb 2009 22:25:44 -0500 Received: from tytso by closure.thunk.org with local (Exim 4.69) (envelope-from ) id 1LbRRs-0005Tu-GF; Sun, 22 Feb 2009 22:25:40 -0500 Date: Sun, 22 Feb 2009 22:25:40 -0500 From: Theodore Tso To: Zhang Xiliang Cc: Ext4 Developers List Subject: Re: [PATCH -v2]ext4: add the spec for ext4 subdirectory limit(was: Problems with the max value for create directory) Message-ID: <20090223032540.GB19739@mit.edu> References: <499B9CD3.8060608@cn.fujitsu.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <499B9CD3.8060608@cn.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@mit.edu X-SA-Exim-Scanned: No (on thunker.thunk.org); SAEximRunCond expanded to false Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org I really don't think this tweak to Documentation/filesystems/ext4.txt is necessary, but if we going to do this, I want to tighten up the explanation. - Ted ext4: Add fine print for the 32000 subdirectory limit Some poeple are reading the ext4 feature list too literally and create dubious test cases involving very long filenames and 1k blocksize and then complain when they run into an htree-imposed limit. So add fine print to the "fix 32000 subdirectory limit" ext4 feature. Signed-off-by: "Theodore Ts'o" --- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index cec829b..5c484ae 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -85,7 +85,7 @@ Note: More extensive information for getting started with ext4 can be * extent format more robust in face of on-disk corruption due to magics, * internal redundancy in tree * improved file allocation (multi-block alloc) -* fix 32000 subdirectory limit +* lift 32000 subdirectory limit imposed by i_links_count[1] * nsec timestamps for mtime, atime, ctime, create time * inode version field on disk (NFSv4, Lustre) * reduced e2fsck time via uninit_bg feature @@ -100,6 +100,9 @@ Note: More extensive information for getting started with ext4 can be * efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force the ordering) +[1] Filesystems with a block size of 1k may see a limit imposed by the +directory hash tree having a maximum depth of two. + 2.2 Candidate features for future inclusion * Online defrag (patches available but not well tested)