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From: Matthew Warren <matthewwarren101010@gmail.com>
To: dsterba@suse.cz, Matthew Warren <matthewwarren101010@gmail.com>,
	linux-btrfs@vger.kernel.org
Subject: Re: Changing the checksum algorithm on an existing BTRFS filesystem
Date: Mon, 4 Oct 2021 11:01:51 -0500	[thread overview]
Message-ID: <CA+H1V9yopc2okgT=5XeCwvHF8oXPVhnojaf_rZOeuiThZEfqWQ@mail.gmail.com> (raw)
In-Reply-To: <20211004095146.GU9286@twin.jikos.cz>

I don't know how btrfs is layed out internally, but is checksum tree
separate from file (meta)data or is it part of the (meta)data? If it's
separate it should be possible to build a second csum tree and then
replace the old one once it's done, right?

Matthew Warren

On Mon, Oct 4, 2021 at 4:52 AM David Sterba <dsterba@suse.cz> wrote:
>
> On Mon, Oct 04, 2021 at 12:26:16AM -0500, Matthew Warren wrote:
> > Is there currently any way to change the checksum used by btrfs
> > without recreating the filesystem and copying data to the new fs?
>
> I have a WIP patch but it's buggy. It works on small filesystems but
> when I tried it on TB-sized images it blew up somewhere. Also the WIP is
> not too smart, it deletes the whole checksum tree and rebuilds if from
> the on-disk data, so it lacks the verification against the existing
> csums. I intend to debug it some day but it's a nice to have feature,
> I'm aware that people have been asking for it but at this point it would
> be to dangerous to provide even the prototype.

  reply	other threads:[~2021-10-04 16:02 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-04  5:26 Changing the checksum algorithm on an existing BTRFS filesystem Matthew Warren
2021-10-04  6:20 ` Nikolay Borisov
2021-10-04  9:51 ` David Sterba
2021-10-04 16:01   ` Matthew Warren [this message]
2021-10-04 20:37     ` Chris Murphy
2021-10-04 22:54     ` Qu Wenruo
2021-10-05  3:26       ` Zygo Blaxell
2021-10-05  6:00         ` Qu Wenruo

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