From: Andreas Dilger Subject: Re: [EXT4 set 7][PATCH 1/1]Remove 32000 subdirs limit. Date: Wed, 11 Jul 2007 06:45:34 -0600 Message-ID: <20070711124534.GA6417@schatzie.adilger.int> References: <1183275498.4010.135.camel@localhost.localdomain> <20070710224011.e60b9864.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: cmm@us.ibm.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org To: Andrew Morton Return-path: Received: from 74-0-229-162.T1.lbdsl.net ([74.0.229.162]:36509 "EHLO mail.clusterfs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761426AbXGKMpg (ORCPT ); Wed, 11 Jul 2007 08:45:36 -0400 Content-Disposition: inline In-Reply-To: <20070710224011.e60b9864.akpm@linux-foundation.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Jul 10, 2007 22:40 -0700, Andrew Morton wrote: > On Sun, 01 Jul 2007 03:38:18 -0400 Mingming Cao wrote: > > A EXT4_FEATURE_RO_COMPAT_DIR_NLINK flag has been added and it is set if > > the subdir count for any directory crosses 65000. > > Would I be correct in assuming that a later fsck will clear > EXT4_FEATURE_RO_COMPAT_DIR_NLINK if there are no longer any >65000 subdir > directories? Correct. > If so, that is worth a mention in the changelog, perhaps? > > Please remind us what is the behaviour of an RO_COMPAT flag? It means that > old ext4, ext3 and ext2 can only mount this fs read-only, yes? Also correct. The COMPAT flag behaviour is described in detail in Documentation/filesystems/ext[234].txt > > +static inline void ext4_inc_count(handle_t *handle, struct inode *inode) > > +{ > > + inc_nlink(inode); > > + if (is_dx(inode) && inode->i_nlink > 1) { > > + /* limit is 16-bit i_links_count */ > > + if (inode->i_nlink >= EXT4_LINK_MAX || inode->i_nlink == 2) { > > + inode->i_nlink = 1; > > + EXT4_SET_RO_COMPAT_FEATURE(inode->i_sb, > > + EXT4_FEATURE_RO_COMPAT_DIR_NLINK); > > + } > > + } > > +} > > Why do we set EXT4_FEATURE_RO_COMPAT_DIR_NLINK if i_nlink==2? Because that means it was previously 1 (inc_nlink() was already called). Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc.