Date: Thu, 20 Sep 2007 16:22:08 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Avantika Mathur <mathur@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org,
       Andreas Dilger <adilger@clusterfs.com>, cmm@us.ibm.com
Subject: Re: [PATCH] Ext4: Uninitialized Block Groups
Message-Id: <20070920162208.17f96f78.akpm@linux-foundation.org>
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On Tue, 18 Sep 2007 17:25:31 -0700
Avantika Mathur <mathur@linux.vnet.ibm.com> wrote:

> In pass1 of e2fsck, every inode table in the fileystem is scanned and checked, 
> regardless of whether it is in use.  This is this the most time consuming part 
> of the filesystem check.  The unintialized block group feature can greatly 
> reduce e2fsck time by eliminating checking of uninitialized inodes.  
> 
> With this feature, there is a a high water mark of used inodes for each block 
> group.  Block and inode bitmaps can be uninitialized on disk via a flag in the
> group descriptor to avoid reading or scanning them at e2fsck time.  A checksum
> of each group descriptor is used to ensure that corruption in the group
> descriptor's bit flags does not cause incorrect operation.

This needed a few fixups due to conflicts with
ext2-ext3-ext4-add-block-bitmap-validation.patch but they were pretty
straightforward.  Please check that the result is OK.


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