From: Theodore Ts'o Subject: Re: Fwd: Fwd: strange e2fsck magic number behaviour Date: Fri, 13 Sep 2013 15:46:15 -0400 Message-ID: <20130913194615.GD15366@thunk.org> References: <5231EF7D.20501@redhat.com> <52320EFB.6080100@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eric Sandeen , linux-ext4@vger.kernel.org To: Alexander Harrowell Return-path: Received: from imap.thunk.org ([74.207.234.97]:59831 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754684Ab3IMTqT (ORCPT ); Fri, 13 Sep 2013 15:46:19 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-ext4-owner@vger.kernel.org List-ID: On Fri, Sep 13, 2013 at 01:33:12PM +0000, Alexander Harrowell wrote: > Hmm, coming back to this, block 16777215 with identical content is > recurring at intervals of 8 inodes. So you might want to check and see if there are overlapping metadata blocks --- that is, a bitmap allocation block that is also part of the inode table block, or multiple block groups that point at the same place for their inode table block. The other thing is before you do more experimentation, I hope you have made an image backup of your disk. The more you play games by running clri and then re-running e2fsck, the more likely that you might accidentally do damage that might cause less data to be recovered. In general, especially when the file system is this small such that it's relatively easy to do an image level backup, the moment that you think something might have gone off the rails, the wisest thing to do is to make an image-level backup of the partition before you try to repair things. The other thing that has to be asked here is how much do you care about this 64GB worth of data? How much is OS data that can be easily reproduced via an install, and how much are things like your home directory? And how recent was your last backup? It may be that it's not worth doing a whole lot more work trying to figure out what was going on. The other thing is that if this file system is this small, would you be willing to use e2image to send me a copy of the metadata blocks, so I can take a look at it myself. No guarantees that I will find anything useful, but I'll probably get more information that way. Regards, - Ted