Kernel 4.9.0-8 package released versions, and getting previous version

[Michael Firth <MFirth@nevion.com>]

Hi,

It seems that the minor version number of the kernel for Debian Stretch has stopped incrementing, so a lot of different kernels have been released as package version 4.9.0-8.

If I am understanding the way the installation of this package is working correctly, that means that on a kernel update the kernel you were previously running is removed, and is no longer available as an option to boot from.

Two key questions from this are:
 * Is there a list somewhere of which versions of 4.9.0-8 have been released onto the public Debian mirrors?
    My impression is that from the end of October until mid February, the release was 4.9.130-2, and it has now changed to 4.9.144-3.1 - is that correct?
 * Is there a way of getting back previous versions of the 4.9.0-8 kernel?

I'm asking as my system was running reliably with a BTRFS filesystem on 4.9.130-2 from November until last week, when I updated to the new kernel. Today, the filesystem failed (without giving any error messages to the system long) and started reporting "No space left on device", despite having almost 100GB free. Rebooting the server cleared the error.

There are over 1000 lines in the changelog between the 4.9.130-2 and 4.9.144-3.1, of which 35 explicitly mention BTRFS, so there is a chance that one of these changes have caused the issue, but I have no real way of knowing.

If I get another failure I would like to be able to roll back to the 4.9.130-2 kernel quickly, but I'm not even sure how I would go about doing that - would installing the .dpkg file for it work, if I can find it somewhere?

The best option would be to be able to have both versions installed and select between them from Grub, but I don't think that will be possible as they are both identified as the same 4.9.0-8 high level kernel version, despite being very different.

Thanks

Michael