From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Subject: Re: Tool to view extent metadata
Date: Fri, 10 Jul 2009 10:49:29 +0530
Message-ID: <20090710051929.GA17701@skywalker>
References: <23904f640907091517w10608fa4y9b3b8b3a631217c@mail.gmail.com>
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Cc: linux-ext4@vger.kernel.org
To: Manuel Benitez <rickyb@google.com>
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On Thu, Jul 09, 2009 at 03:17:00PM -0700, Manuel Benitez wrote:
> I'm currently evaluating the ext4 allocator and one thing I've come
> across is the lack of a tool that displays the exact structure of the
> extents making up a file. I've found plenty of tools that will tell me
> how many contiguous segments a file contains, but nothing so far to
> let me see the actual makeup of the extents that map the inode to the
> blocks that comprise the file. Have I just missed something obvious,
> or would this be something worth me spending some time doing?
> 
> If so, one option would be to either modify the stat command or add a
> similar command in debugfs to show the extents from the roots through
> the root down to the leafs. Anyone have preferences or opinions?
> 


tst_exents in lib/ext2fs/ provide a debugfs similar interface. There are
commands for inode, root etc

-aneesh