From: Eric Sandeen Subject: Re: Tool to view extent metadata Date: Mon, 13 Jul 2009 10:28:54 -0500 Message-ID: <4A5B52B6.1060003@redhat.com> References: <23904f640907091517w10608fa4y9b3b8b3a631217c@mail.gmail.com> <20090709225507.GH5073@webber.adilger.int> <23904f640907130803w20089c79md6f6ceef54ff8f8e@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Andreas Dilger , linux-ext4@vger.kernel.org To: Manuel Benitez Return-path: Received: from mx2.redhat.com ([66.187.237.31]:45628 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755856AbZGMP3B (ORCPT ); Mon, 13 Jul 2009 11:29:01 -0400 In-Reply-To: <23904f640907130803w20089c79md6f6ceef54ff8f8e@mail.gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Manuel Benitez wrote: > Andreas, > > Thank you for the reply. I wrote a program that uses FIEMAP to see > what I could get from it. It gives the same information that you can > extract from FIBMAP except that it is much more efficient (one ioctl > call per extent rather than one call per block). Unfortunately, it > does not give much insight into the structure of the metadata, so > there is no way to tell how efficiently the metadata represents the > file (depth of extent tree, number of internal and leaf nodes, etc.). adding something to debugfs should not be hard either; look at how it prints out the BLOCKS: when you stat a file, for extent-format files it'd be nice to have a better representation. If you wanted to write a patch for this it'd be great. :) -Eric