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Date:   Tue, 23 May 2023 11:34:02 +0200
From:   Miquel Raynal <miquel.raynal@bootlin.com>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Jens Axboe <axboe@kernel.dk>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Mike Snitzer <snitzer@kernel.org>,
        Joern Engel <joern@lazybastard.org>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Pavel Machek <pavel@ucw.cz>, dm-devel@redhat.com,
        linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
        linux-mtd@lists.infradead.org, linux-pm@vger.kernel.org
Subject: Re: [PATCH 23/24] mtd: block2mtd: don't call early_lookup_bdev
 after the system is running
Message-ID: <20230523113402.32fa86ba@xps-13>
In-Reply-To: <20230523074535.249802-24-hch@lst.de>
References: <20230523074535.249802-1-hch@lst.de>
        <20230523074535.249802-24-hch@lst.de>
Organization: Bootlin
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Hi Christoph,

hch@lst.de wrote on Tue, 23 May 2023 09:45:34 +0200:

> early_lookup_bdev is supposed to only be called from the early boot
> code, but mdtblock_early_get_bdev is called as a general fallback when
> lookup_bdev fails, which is problematic because early_lookup_bdev
> bypasses all normal path based permission checking, and might cause
> problems with certain container environments renaming devices.
>=20
> Switch to only call early_lookup_bdev when dm is built-in and the system
> state in not running yet.
>=20
> Note that this strictly speaking changes the kernel ABI as the PARTUUID=3D
> and PARTLABEL=3D style syntax is now not available during a running
> systems.  They never were intended for that, but this breaks things
> we'll have to figure out a way to make them available again.  But if
> avoidable in any way I'd rather avoid that.

Sounds reasonable to me. Richard?

Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

Thanks,
Miqu=C3=A8l