CONFIG_ZFS_FS rule for Linux

[bademux]

Support linux kernel build infrastructure.

[ryao]

Would you elaborate on how you envision this being done?

[behlendorf]

Please do, since we already rely heavily on the kernel build infrastructure. What do you mean?

[bademux]

Sorry for the late response.
it would be nice to add the ability of the configuration zfs module from kernel's global configuration (and may be with visual tools like menuconfig).
btw, thank you for the great peace of software.

[ryao]

Exactly how do you envision us doing this? Are you asking for a patch set for the Linux kernel sources or are you asking us to provide our own patched tarball?

So far, this sounds like something more appropriate to request downstream, although I would expect the downtream maintainer(s) to suggest using an initramfs generator like genkernel to attain similar results.

[bademux]

I think that an archive of a particular version of the kernel is the best solution, because there are many questions which kernel version is the most zfs-stable

[behlendorf]

I'd prefer to avoid creating patched kernel archives, it would become too much of a maintenance burden. If your just looking for the most stable version of ZFS for a production environment I would suggest using one of the Enterprise Linux Distributions, RHEL or SLES. These experience the least change on the kernel side while still getting critical security updates. At LLNL we target RHEL so that certainly gets a lot of testing and abuse.

If you need/want to run something more current then I'd stick with one of the downstream distro versions. They will be the best integrated with your distro and receive considerable testing. Currently, Gentoo and Ubuntu are the distributions I'd recommend if your not going to use an Enterprise distro.

[ryao]

For what it is worth, Gentoo is capable of booting with RHEL's kernel, although you would need to import one of the Funtoo packages if you want the package manager to install RHEL's kernel for you.

http://www.funtoo.org/wiki/Funtoo_Linux_Kernels

Gentoo maintains multiple packages for different kernel patch sets, such as sys-kernel/hardened-sources and sys-kernel/zen-sources. In the context of this, I can imagine Gentoo having sys-kernel/zfs-sources, which would provide what @bademux wants. With that said, I cannot imagine anyone volunteering to maintain this. It is a big commitment, my hands are already full with sys-fs/zfs and Gentoo's developer resources are already stretched thin.

[behlendorf]

A bit to my surprise this actually got done as issue #851. Etienne Dechamps did the heavy lifting and extended the build infrastructure so it can be easily used to patch zfs in to a kernel source tree. The changes has been merged in to master, see the following commits for details.

openzfs/spl@7440380
4ab8a72

For those interested in this change, please give it a try.

[bademux]

thanks

[ryao]

Here is a patch that you can apply to your kernel sources to add ZFS support:

http://dev.gentoo.org/~ryao/dist/linux-3.5.0-zfs.patch

If you want to build it into the kernel binary, you should also apply this patch:

http://dev.gentoo.org/~prometheanfire/dist/kernel-patches/linux-3.5.0-zfs-builtin.patch

Lastly, I recommend applying this patch regardless of whether ZFS is built into the kernel or not:

http://dev.gentoo.org/~prometheanfire/dist/kernel-patches/linux-3.5.0-gfp-vmalloc.patch

It will prevent deadlocks.