From: Christoph Hellwig <hch@lst.de>
To: Sven <dm-devel@schwermer.no>
Cc: Christoph Hellwig <hch@lst.de>, dm-devel@lists.linux.dev
Subject: Re: dm-init/dm-verity: Data device lookup failed
Date: Wed, 17 Apr 2024 17:03:13 +0200 [thread overview]
Message-ID: <20240417150313.GA1914@lst.de> (raw)
In-Reply-To: <847a0907-b174-4ba2-90b0-3be96db2e2da@schwermer.no>
On Mon, Apr 15, 2024 at 03:02:25PM +0200, Sven wrote:
>> Yea, the early lookup behavior is weird. But it also dates back
>> a long time, so I'm not sure this changed, except for maybe timings?
>
> This might just be a timing change. I don't know. As mentioned in the
> initial email, this change looks relevant:
> https://lore.kernel.org/all/20230531125535.676098-19-hch@lst.de/
Well, only in terms of timing. But as asked before, any chance
you could try to bisect the issue?
>> If you go down the device open route it should us the kernel open
>> routins and not just the not open ones.
>
> OK. Would you mind elaborating why?
Because the no open ones are competely internal.
>> That being said the right
>> fix is to not use this code at all, which was only shoe horned together
>> and doesn't have a chance to work solidly and just wait for the
>> device in userspace because we do have reliably udev events there.
>
> I cannot wait for user space because my root device is dm-verity-backed
> which is why I am using dm-init in the first place. And I am not using an
> initramfs.
But that's exactly the use case the initramfs is made for.
> Isn't the point of dm-init to be able to use e.g. dm-verity for
> the root device or did I misunderstand the docs?
It's sort of the point, but dm-init is a really broken concept and
should never have been merged as the whole early bdev lookup is a
hack and only works outside the core init code by accident.
prev parent reply other threads:[~2024-04-17 15:03 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-09 11:33 dm-init/dm-verity: Data device lookup failed Sven
2024-04-09 14:23 ` Christoph Hellwig
2024-04-09 16:33 ` Sven
2024-04-12 9:13 ` Sven
2024-04-15 7:38 ` Christoph Hellwig
2024-04-15 13:02 ` Sven
2024-04-17 15:03 ` Christoph Hellwig [this message]
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