From: Calvin Walton <calvin.walton@gmail.com>
To: Michael Niederle <mniederle@gmx.at>
Cc: "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>
Subject: Re: mount snapshot by object-id
Date: Thu, 09 Dec 2010 09:31:44 -0500 [thread overview]
Message-ID: <1291905104.15070.6.camel@ayu> (raw)
In-Reply-To: <20101209145114.07f55914@simplux>
On Thu, 2010-12-09 at 14:51 +0100, Michael Niederle wrote:
> Hi!
>
> I'm currently writing a btrfs-rescue tool and therefor began to study the
> btrfs-on-disk structures in detail.
>
> The root tree contains a ROOT_ITEM entry for *every* subvolume in the whole
> file system, but only DIR_ITEM entries for subvolumes that were created in the
> root directory of the filesystem.
>
> If we have a destroyed root directory, there is no way to access subvolumes
> stored deeper in the fs-tree by name. It might be nice to have the ability to
> mount a subvolume by object-id. A simple tool could list all available
> subvolumes with their object-ids, generation numbers, and so on.
Unless I misunderstand something, this is actually already possible;
just poorly documented. You can use the 'subvolid=' mount option to
mount by object id; the object id can be found using the tool
btrfs subvolume list <filesystem>
The subvolid= mount option was missing from the wiki, so I've just added
it:
https://btrfs.wiki.kernel.org/index.php/Getting_started#Mount_Options
--
Calvin Walton <calvin.walton@gmail.com>
next prev parent reply other threads:[~2010-12-09 14:31 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-12-09 13:51 mount snapshot by object-id Michael Niederle
2010-12-09 14:31 ` Calvin Walton [this message]
2010-12-09 14:53 ` Dipl.-Ing. Michael Niederle
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