[gentoo-genkernel] genkernel 3.4.49 released

[Richard Yao]

Dear Everyone,

I am pleased to announce the release of 3.4.49. This fixes a minor ZFS
support regression in 3.4.48 that affected a small number of people. I
had said that 3.4.48 would be subject to fast track stabilization, but
that regression formed a stabilization blocker. Consequently, I am doing
3.4.49 early while pushing back some of the things originally planned
for it to 3.4.50.

A highlight of this release is improved boot speed, which merits some
explanation. In short, genkernel loads modules using busybox insmod.
busybox's insmod did an unnecessary copy by reading modules from tmpfs
into userland and then told the kernel read modules from userland into
the kernel. It now makes clever use of mmap() to tell the kernel to read
from the tmpfs. This noticeably improves the speed of the boot process.

Another highlight are the changes to ZFS support, which require some
mention:

1. genkernel will now automatically enable --zfs on systems that have a
zfs root filesystem, even when it is not specified, unless explicitly
overwritten in genkernel.conf.
2. genkernel will now store the system's hostid inside the initramfs
archive. This eliminates a rare scenario in which dozfs=force was needed
to force import a root pool. Force imports should no longer be required.
3. dozfs is now depreciated because of #2. All use cases for it should
be handled automatically by genkernel. The message suggesting that
people use dozfs will be removed in the next release, but support for
dozfs itself will not be removed. The code required to support it is
only a few lines and I fully intend to leave it in place indefinitely.
Expect it to stay in place at least until ZFS support for booting
without an initramfs is ready and likely for some time afterward.

In addition, genkernel now has a workaround in place for a possible
Linux kernel bug that affects busybox modprobe. I plan to send my
workaround to upstream busybox and a patch to fix it at upstream Linux
after I understand what is wrong inside the kernel and correct it. That
could delay the next release, so expect it in 4 to 6 weeks.

Improvements planned for the next release include:

* Add a CONTRIBUTING file to the repository documenting how to send
patches to me for new releases. We have plenty of bugs that need
attention and insufficient developer time, so I want to make it as easy
as possible for others to help out.
* btrfs support improvements from Martin Drummer. He sent an early
version to me, but it had a few issues that caused me to send it back to
him for revision.
* /dev/disk/by-* support. This will be implemented by importing Funtoo's
mdev.conf into the main tree's mdev and then copying configuration files
into genkernel. That will require some collaboration with the Gentoo
busybox maintainers, but I foresee no difficulties in doing this by 3.4.50.
* Initial work toward re-unification with Sabayon's genkernel-next fork.
* Spend some time on bugs in the Gentoo tracker.
* Look into integrating multidisk LUKS code that I believe that a member
of the ZFSOnLinux community started developing.

Yours truly,
Richard Yao

P.S. The shortlog follows:

Martin Dummer (3):
      Advertise zfs support in genkernel.conf
      fix broken function prompt_user()
      Fix endless loop in gen_funcs.sh when LOGLEVEL is empty

Richard Yao (8):
      Record hostid into initramfs
      Create rootfs_type_is() helper function
      Include ZFS support when / is ZFS
      Try mmap() when loading modules
      Load modules by absolute path in busybox modprobe
      Revert "Workaround busybox modprobe's inability to load ZFS modules"
      call_func_timeout() should return 1 upon failure
      Bump version to 3.4.49