[dm-crypt] btrfs and "requested offset is beyond real size of device"

Jay Sullivan jaythomassullivan at gmail.com
Sun Feb 15 23:43:22 CET 2015


I don't know if this belongs on the btrfs, GRUB, or LUKS mailing list, but
it is a cryptsetup error, so I figure maybe someone here can help me
understand what this error means.

*What I'm doing*

I'm trying to set up a system with a btrfs /boot partition, and a few
encrypted btrfs-over-LUKS partitions. Nothing special, except that I'm
using btrfs for all of my partitions.

*The Problem*

I did get the setup "working", I'm able to successfully boot into it.
Here's the weird part: it only successfully boots about half of the time.

The other half of the time,  I see this error just after I successfully
enter my password:

    requested offset is beyond real size of device

When this happens, it continues to fail when it prompts me again for my
password, until I reboot.  It seems to fall into this issue about 50% of
the boots.

The culprit seems to be when the /boot partition is btrfs. If I use ext4 as
/boot, everything works fine and dandy.

This should be reproducible on any machine, I've tried several times on
different machines to rule out hardware. I can give complete instructions
to reproduce if someone wants it, but before I go through the effort, has
anyone heard of this behavior before? Does anyone have any insight on why
this may be happening, especially why it only happens sometimes.

I'm using Ubuntu 14.10's LiveCD to install the operating system, where
cryptsetup's version says 1.6.1, and btrfs's version is 3.14.1.

Jay Sullivan
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