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Date:   Mon, 4 Oct 2021 11:51:46 +0200
From:   David Sterba <dsterba@suse.cz>
To:     Matthew Warren <matthewwarren101010@gmail.com>
Cc:     linux-btrfs@vger.kernel.org
Subject: Re: Changing the checksum algorithm on an existing BTRFS filesystem
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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.