Docker containers may be (and default to, and in the shared host case,
must be) deprivileged; thus, they cannot mount devices, much less tell
the kernel (via iscsi userspace tools, etc) to make devices.
Therefore, we must setup any storage backing devices (temp LVs, iscsi
attachments) outside the container. This commit makes that possible for
rc.storage and linux liblocstorage. Basically, rc.storage now supports
(for the Linux liblocstorage and Docker) the -j vnodeid calling
convention; and if it's being called on behalf of a vnodeid, it uses
per-vnodeid fstab for any mounts, storage.conf for its state; etc.
I modified libvnode_docker to *not* create virtual networks for
remote blockstore links, because those are pinned to /30s, and thus I
have no client blockstore link address to place on a device in the root
context. However, I (ab)used the existing Docker network setup for the
blockstore links, and that all happens the same as it used to; we just
no longer create the Docker virtual network nor attach the container to
Finally, I modified tmcd dostorageconfig slightly to return
HOSTIP/HOSTMASK for remote blockstores; and now
libsetup::getstorageconfig will use HOSTIP in preference to its own
HOSTID->HOSTIP translation. I had to do this so that libvnode_docker in
the root context would not have to go through the mess of translating
HOSTID on behalf of a vnode.