From: Martin Steigerwald <Martin@lichtvoll.de>
To: xfs@oss.sgi.com
Subject: Re: accidentally deleted very large file (3.5TB) but still available through loop device
Date: Thu, 26 Mar 2009 17:36:52 +0100 [thread overview]
Message-ID: <200903261736.53093.Martin@lichtvoll.de> (raw)
In-Reply-To: <49CBA221.2090701@cjx.com>
Am Donnerstag 26 März 2009 schrieb Chris Allen:
> Hi,
Hi Chris,
> In a nutshell, I did the following:
>
> 1. dd if=some_filesystem_dump of=some_file (where some_file resides on
> an XFS filesystem and is 3.5TB large)
>
> 2. losetup /dev/loop0 some_file
>
> 3. mount /dev/loop0 /recovered
>
> [.... i can now access my recovered filesystem through /recovered ...]
>
> 4. rm some_file (remotely via an nfs export) (oops!)
>
> So, I just removed my 3.5TB file even though it is attached to the loop
> device and mounted (XFS did this almost instantly).
>
>
> Now it *appears* that the filesystem as attached to /dev/loop0 and
> mounted on /recovered is still OK. I
> can cd around it and copy files off.
>
> So I have these questions:
>
>
> 1. Is there any way I can get back the 1 file that I accidentally
> deleted (nothing else has been written to that partition since)
dd if=/dev/loop0 of=somefile-restore
should work IMHO.
> 2. Am I safe in accessing my filesystem through /dev/loop0 and
> /recovered even though the underlying file has been zapped? If so
> I can quickly copy everything off onto another partition.
Yes. XFS as other linux filesystems perform the real delete - i.e. freeing
the blocks the file occupies - only after the last user of it has closed
it. Before just the directory entry of the file is removed.
> 3. Will this command: dd if=/dev/loop0 of=saved_file get my file back?
I think it will. Just try it.
Ciao,
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
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next prev parent reply other threads:[~2009-03-26 16:36 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-26 15:41 accidentally deleted very large file (3.5TB) but still available through loop device Chris Allen
2009-03-26 16:06 ` Eric Sandeen
2009-03-26 16:43 ` Chris Allen
2009-03-26 16:36 ` Martin Steigerwald [this message]
2009-03-26 20:24 ` Matthias Schniedermeyer
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