Storage Daemon in Initramfs
Hi,
I'm trying to troubleshoot an issue I'm experiencing in a scenario where a storage daemon that starts up in initramfs is required for rootfs. Specifically, zfs-fuse - I'm running rootfs on zfs-fuse.
I have already read the following, and modified zfs-fuse so that it marks itself (argv[0][0]='@') to avoid switchr-root killing spree:
http://www.freedesktop.org/wiki/Software/systemd/RootStorageDaemons/
I can successfully boot up the rootfs, that part works.
I also mount --bind {/dev,/proc,/sys} to the rootfs before switch-root kicks off, along with the direcory where zfs-fuse keeps it's unix domain socket.
At that point almost everything works. Almost.
@sbin/zfs-fuse is running, and the other userspace tools can talk to it (zfs, zpool, etc.) I can list file systems and create them. But - I cannot mount them, and I cannot import new pools. All of this works in the initramfs before switchr-root (tested at point of rd.break=mount).
But after zfs-fuse daemon is below the rootfs "plane", it no longer works. Mount returns either error 2 (canonicalization error) if I tell it to mount to /sysroot/mount/point (/sysroot being where dracut mounts the real root), or error 5 if I tell it to mount anywhere else, as if it cannot find the mount point.
So what I am trying to figure out is how can I get the storage daemon that is running below the rootfs plane of existance to still be able to mount stuff into the rootfs it is responsible for after switch-root.
It seemed to work when I use a simple chroot, but switch-root seems to be a harder barrier to cross.
I would expect this kind of thing impacts other things and not just zfs-fuse, so I presume there is either a reasonly standard way of dealing with it, or at least a documented set of functionality that a storage daemon has to implement to deal with it.
Since this is a systemctl switch-root issue, I think it only affects systemd, and not other init systems.
What to do? Other than rebuild my entire distro without systemd (tempted as I am on a daily basis).
TIA
Gordan