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Date: Wed, 7 Jan 2026 10:08:44 +0100
From: Christoph Hellwig <hch@lst.de>
To: "Darrick J. Wong" <djwong@kernel.org>
Cc: cem@kernel.org, linux-xfs@vger.kernel.org, hch@lst.de,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 01/11] docs: discuss autonomous self healing in the xfs
 online repair design doc
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References: <176766637179.774337.3663793412524347917.stgit@frogsfrogsfrogs> <176766637268.774337.4525804382445415752.stgit@frogsfrogsfrogs>
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On Mon, Jan 05, 2026 at 11:10:52PM -0800, Darrick J. Wong wrote:
> +The filesystem must therefore create event objects in response to stimuli
> +(metadata corruption, file I/O errors, etc.) and dispatch these events to
> +downstream consumers.
> +Downstream consumers that are in the kernel itself are easy to implement with
> +the ``xfs_hooks`` infrastructure created for other parts of online repair; these
> +are basically indirect function calls.

These hooks mostly went away, didn't they?

> +Being private gives the kernel and ``xfs_healer`` the flexibility to change
> +or update the event format in the future without worrying about backwards
> +compatibility.

I think that ship has sailed once the ABI is out in the wild.

This whole why not use XYZ discussion seems vaguely interesting for a
commit log, but does it belong into the main documentation?

> +*Answer*: Yes.
> +fanotify is much more careful about filtering out events to processes that
> +aren't running with privileges.
> +These processes should have a means to receive simple notifications about
> +file errors.
> +However, this will require coordination between fanotify, ext4, and XFS, and
> +is (for now) outside the scope of this project.

Didn't this already get merged by Christian, and thus this information
is stale already?

> +When a filesystem mounts, the Linux kernel initiates a uevent describing the
> +mount and the path to the data device.

This also isn't true anymore, is it?