[issue1407] disklabel64 boot problem

[Simon 'corecode' Schubert]

Matthew Dillon wrote:
:Booting DragonFly from disklabel64 slice has problems:
: - using HAMMER it almost works: one module can't be read
:Reading /modules/acpi.ko fails; after booting (host can run without ACPI)
:(i.e. by kernel) acpi.ko can be read and contents is correct.
:(files on test HAMMER system are just cpdup'ed from a working system;
:cmp verified acpi.ko is readable and has same contents)
    It sounds like the hammer fs read code in the boot loader isn't
    handling all the cases properly.
Yes, we should try and fix that.  Thomas, can you compile hammerread.c 
and try to find out why it is having a problem?

    I'm going to be blunt on the HAMMER boot thing... I don't actually
    like the idea, because the boot code can't run the UNDO's after a
    crash and so might not be able to find the kernel and other boot
    related files.  I would rather just boot from a small UFS /boot
    partition and then have the kernel mount HAMMER as the root.
    I guess I'll have to deal with changing the installer to create a
    BOOT+HAMMER setup instead of a straight HAMMER setup.
However so far nobody had problems since we fixed the last bugs.  I 
absolutely agree that we should have the boot code reading the UNDO, and 
also multi-volume HAMMER file systems will not work with the boot loader 
(will never).  However I think for a simple setup, having just one 
HAMMER file system should be supported and perfectly fine.

But then, maybe I'm too much an HAMMER enthusiast, and we should go the 
Linux route and always install a (UFS) /boot.  Then it is also easier to 
run more complex setups, like vinum, ccd, etc.

cheers
  simon