From: Andreas Dilger Subject: Re: ext4 compat flag assignments Date: Wed, 4 Oct 2006 18:19:06 -0600 Message-ID: <20061005001906.GN22010@schatzie.adilger.int> References: <20060922091520.GC6335@schatzie.adilger.int> <20060928085515.GC27104@openx1.frec.bull.fr> <20061004200440.GB1656@thunk.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Alexandre Ratchov , linux-ext4@vger.kernel.org Return-path: Received: from mail.clusterfs.com ([206.168.112.78]:24273 "EHLO mail.clusterfs.com") by vger.kernel.org with ESMTP id S1751243AbWJEATK (ORCPT ); Wed, 4 Oct 2006 20:19:10 -0400 To: Theodore Tso Content-Disposition: inline In-Reply-To: <20061004200440.GB1656@thunk.org> Sender: linux-ext4-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org On Oct 04, 2006 16:04 -0400, Theodore Tso wrote: > On Thu, Sep 28, 2006 at 10:55:15AM +0200, Alexandre Ratchov wrote: > > struct ext4_super_block > > { > > /* at offset 0xfe */ > > __le32 s_desc_size; /* Group descriptor size */ > > /* at offset 0x150 */ > > __le32 s_blocks_count_hi; /* Blocks count */ > > __le32 s_r_blocks_count_hi; /* Reserved blocks count */ > > __le32 s_free_blocks_count_hi; /* Free blocks count */ > > __le32 s_jnl_blocks_hi[17]; /* Backup of the journal inode */ > > }; > > Why do we need to have the high blocks # of the journal inode. > s_jnl_blocks was just a backup of the i_blocks[] array. But if we are > assuming that we will only support 64-bits using extents, we shouldn't > need s_jnl_blocks_hi[]. How specifically is this array being used in > the patches? Good question, I don't know that it is. Even if the journal was extent mapped (possible, but would need support in e2fsprogs for this) the data would be stored in the same sized i_blocks array. Cheers, Andreas -- Andreas Dilger Principal Software Engineer Cluster File Systems, Inc.