Choose aufs or overlay on the kernel commandline

The 'init' script in the initrd reads "qfix=option1,option2,option3" from the kernel commandline, where those options are a comma-separated list of bootup choices. In the old Puppy Linux days, it was called "pfix".

However, most of these options can be chosen in the menu in the initrd, posted about with photos yesterday:

"Dropout to shell in initrd'
https://bkhome.org/news/202509/dropout-to-shell-in-initrd.html

Anyway, here are some blog posts about the commandline options:

"Shutdown menu now has reboot with filesystem check"
https://bkhome.org/news/202007/shutdown-menu-now-has-reboot-with-filesystem-check.html

"User override of top-level zram"
https://bkhome.org/news/202206/user-override-of-top-level-zram.html

"Shutdown menu has lockdown and debug items"
https://bkhome.org/news/202008/shutdown-menu-has-lockdown-and-debug-items.html

"Keep some settings when erase session"
https://bkhome.org/news/202008/keep-some-settings-when-erase-session.html

"EasyOS version 2.3.8 released"
https://bkhome.org/news/202008/easyos-version-238-released.html

"Dropping out to shell in initrd"
https://bkhome.org/news/202008/dropping-out-to-shell-in-initrd.html

I have now added an override to choose aufs or overlay. Currently I have set overlay as the default for the next release of Easy, likely 7.0.7+

It does of course depend on the kernel having support. As overlay filesystem is builtin to the kernel source, it is going to be available. Aufs on the otherhand, is an external project, and I will keep it for the 6.12.x kernel. It very much depends how much we like overlay going forward.

The commandline override is provided by "qfix=aufs", or, if the the default is aufs, can change it with "qfix=overlay"

Potentially, there is trouble with changing an existing installation, due to the different system of whiteout files and overlay use of xattrs. I will study, that, see if need some fixing code in the initrd. In the case of overlay, made the policy decision that no whiteouts or xattrs will get saved to permanent storage, so flipping to aufs should be OK. The other way, though, might need some fixing.  

Tags: easy