From: Lennart Poettering <mzxreary@0pointer.de>
To: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Rajeev Mishra <rajeevm@hpe.com>
Subject: [REGRESSION] loopback block device on top of block devices don't work anymore
Date: Wed, 27 Aug 2025 21:30:46 +0200 [thread overview]
Message-ID: <aK9c5jJepHEWIONM@gardel-login> (raw)
Heya!
Recent kernels fail if it is attempted to create a loopback block
device on top of a block device (rather than a regular file), which is a
feature long supported on Linux kernels, and that systemd relies on
(specifically, systemd-repart does).
For example, this used to work:
losetup --find --show --offset=4096 --sizelimit=409600 /dev/nvme0n1
But now it doesn't anymore...
This is on 6.17rc3. My educated guess is that this is caused by
Rajeev's 8aa5a3b68ad144da49a3d17f165e6561255e3529, which tightened the
screws on validating the backing file's size, which now fails if the
backing file isn't actually a file, but a block device.
(But I didn't spend more time tracking this down.)
Lennart
next reply other threads:[~2025-08-27 19:36 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-27 19:30 Lennart Poettering [this message]
2025-08-27 19:55 ` Jens Axboe
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